A Scoping Study on Impact and Adaptation Strategies for Climate Change in Victoria
A Working Paper produced as part of a three-year research program on:
Assessment of climate change, impacts and possible adaptation strategies relevant to Victoria
Undertaken for the Greenhouse Unit of the Victorian Department of Sustainability and Environment by the Climate Impact Group, CSIRO Atmospheric Research
Authors: R.N. Jones and K.L. McInnes
April 2004 Address for correspondence
Dr Roger Jones CSIRO Atmospheric Research PMB No 1, Aspendale, Victoria 3195 Telephone (03) 9239 4555 FAX: (03) 9239 4444 E-mail: roger.jones@csiro.au
ACKNOWLEDGMENTS
The Victorian Department of Sustainability and Environment Greenhouse Unit organised the workshops. All the people who gave their time and attended are gratefully thanked. Those who presented and assisted at the workshops are Paul Holper, Janice Bathols, Bob Cechet, Kevin Hennessy, Mark Howden, Ian Mansergh, Cher Page, Ramasamy Suppiah, Kevin Walsh and Penny Whetton.
This work was produced by CAR under contract to the Victorian Department of Sustainability and Environment. This work also contributes to CSIRO’s Climate Change Research Program.
2 Executive Summary
This document is a working paper compiled by CSIRO to outline the first steps in developing an impact and adaptation assessment program for the Government of Victoria. Its role is twofold: 1. To describe methods being developed by CSIRO and international collaborators to carry out risk assessments of vulnerability to climate change and develop strategies for adaptation to climate change in Victoria, and 2. To describe the results of a series of workshops on catchments and water, agriculture, biodiversity and coasts held in May–June 2001.
Key climatic variables
Key climate variables were identified to distinguish the main drivers of change and climate hazards. This exercise demonstrated the importance of moisture, particularly rainfall and secondary variables derived from rainfall such as runoff and floods. Rainfall and its variability drive a large number of processes. For example, while extreme rainfall is likely to increase the magnitude of changes to annual mean rainfall are highly uncertain. Seasonal changes in rainfall indicate possible increases in summer– autumn and probable decreases in winter–spring, which could lead to an uneven seasonal distribution of increasing daily extreme rainfall. Temperature changes are less important but the magnitude of warming expected over the coming century poses significant risks. These findings from the four workshops will be used to guide the development of coping ranges that will be used to assess risk under a changing climate.
Sectoral findings
Water and catchments The recent CSIRO (2001a) climate projections and summary of impacts (CSIRO, 2001b) indicate that reductions in water supply are likely for Victoria. The adaptive capacity of water management to interannual climate variability (e.g. the El Niño – Southern Oscillation) is high, but the risks of longer- term, sustained reductions of water supply remain unknown. Climate change needs to be factored into ongoing water reform processes including market development, planning for water quality, river health and environmental flows. Possible interactions between climate change and salinity, including how they may influence salinity management options, is a key long term issue for catchment management.
Agriculture The agricultural sector is generally well adapted to climate variability. The relationships between climate and performance criteria, such as crop yield and quality, are known for most agricultural activities. Increases in atmospheric carbon dioxide will increase plant productivity, which is likely to counterbalance the impacts of lowered available moisture, as long as temperature effects remain tolerable. Further work on how climate change may affect production systems will be needed to maximise agricultural performance under such conditions, particularly at higher temperatures. Adaptation will be required for longer-lived crops near the boundaries of their current climatic limits. The impact of agriculture on land systems at the catchment scale, the risks of long-term water supply to irrigated agriculture and the long-term threats of dryland salinity under climate change require further research.
Biodiversity The relationships between biota and climate change are poorly known at the species level and largely unknown at the community level. The resilience of ecosystems to natural climate change is high if they are allowed time and space to respond. However, in a landscape where many systems are fragmented and subject to weed and pest invasion, ecosystems will be much more vulnerable. The
3 impacts of increased CO2 on ecosystem functions of natural communities and on species distribution is largely unknown. In order to develop options for planned adaptation, research needs include a better understanding of the dynamics between climate and biodiversity and processes of autonomous adaptation within the modern landscape. Fragmentation issues, and pests and weeds will need to be actively managed because the latter’s invasive potential will be enhanced by higher CO2, nutrient changes and increased ecosystem turnover.
Coasts New IPCC (2001a) projections of sea-level rise are slightly lower than previous estimates, being 9–88 cm by 2100. The regional rate of risk remains unknown. Sea-level rise is also expected to rise for centuries after stabilisation of greenhouse gases, so emissions over the next century will contribute to long-term risks. The impacts of sea level rise will be felt through storms and related surge events, with mean sea level rise adding to their severity. Storm patterns may not change greatly, but may become slightly less frequent but slightly more intense. The most vulnerable coasts are those that are low-lying with very little setback to allow for adaptation. Estuarine processes under climate change are poorly understood. Natural estuarine systems are biologically very important, so setback strategies will be needed rather than hard barriers such as sea walls, but will be limited where prior development has occurred. Some areas of coast may be subsiding due to tectonic or other processes; low-lying sections of these coasts will be the most vulnerable.
Integration needs
The workshop results consistently showed that criteria that demonstrate the success or failure of an activity are driven by both climate and socio-economic influences. Risk is a combination of the degree of harm measured by given criteria, and how often it may occur. The decision as to which criteria can be used in an assessment are ideally jointly made by stakeholders and researchers and may be couched in both monetary and non-monetary terms. It is the researchers’ task to take this information and quantify relationships within an analytic framework. The assessment of risk is a joint exercise made by stakeholders guided by expert advice.
The integration of biophysical and socio-economic drivers of change within the risk assessment framework shows that climate assessments cannot be considered in isolation but that they should be considered with the other major drivers of change. This is consistent with the idea of “sustainability science” where different drivers of change are integrated to develop a holistic approach to risk management. This suggests that adaptations to climate change will need to be part of a larger scale effort to implement sustainable development.
The integration with other sectors was raised in each of the workshops. Links from agriculture and biodiversity to catchment management, of water to agriculture, of agriculture to biodiversity and of catchments to coasts emphasises the importance of cross-sectoral interactions. Due to the large uncertainties and complexities involved, it is not possible to simulate these interactions in a predictive way but also lacking are the tools to explore these interactions. DSE needs to develop capacity in this area, perhaps building wider relationships between the relevant research institutes but also in collaboration with other organisations such as CSIRO, CRCs and universities.
Ongoing work
Several projects are ongoing, including:
Agriculture Development of an expert-based Geographical Information System for assessing change in agricultural activities. A scoping study for South Gippsland has been completed and a larger multi- year study is planned for 2003 onwards.
4 Hydrology Initial modelling has been undertaken for Ryan’s Creek in north central Victoria (Chapter 2) and a larger scoping study is being planned. Funds have been sought for a major collaborative study in the Goulburn-Broken catchment. The current drought has been the catalyst for discussion on longer term changes.
Biodiversity A collaborative study between the Arthur Rylah Institute and CSIRO is ongoing, investigating the bioclimatic envelope of twenty plant species representing important vegetation communities. A workshop was held at Arthur Rylah Institute in June 2002.
Coasts A coastal workshop for stakeholders was held by the Victorian Coastal Council in November 2002. Gippsland Coastal Board has a project planned to study sea-level change and coastal subsidence and their implications for the Gippsland coast.
Alpine Environments Studies currently completing work on projected snow cover for the ski industry. Further work is looking at the impacts of reduced snow cover on alpine biota. This is co-funded by the Australian Greenhouse Office.
Of the other sectors, such as human health and the built environment, there has been very little activity at a state level, save for some work on urban water systems.
Conclusions
This project marks a change in direction from the accepted model of impact and adaptation studies. That model applies climate scenarios to impact models, assesses the resultant biophysical and socio- economic impacts before suggesting adaptations. We are taking an approach that integrates the biophysical and socio-economic aspects of risk under current climate before assessing how climate and other drivers of change may alter future risks.
While this approach is a relatively new development for science, there are still a number of areas where traditional investigations are required. The workshops identified basic deficiencies in our understanding of the impacts of climate variability on biota and ecosystems, including estuaries. Long- term observations of natural systems are needed to observe change and to record system behaviour across a range of climate variability. For agriculture the largest challenges are at the landscape rather than the enterprise scale.
Integration between natural resource sectors are also very important in the long term. Agriculture is vulnerable to loss of water supply and salinity, biodiversity is vulnerable to land-use change and the impacts of altered nutrients and pest plant and animals, some areas of coast may be vulnerable but have not been well identified and so on. The largest challenges for integration with DSE and DPI are for the different institutes to collaborate and carry out work that is greater than the sum of its parts.
Further work also needs to be carried out to determine how to incorporate climate change into policy designed to increase the sustainability of these systems. This requires bringing climate change into mainstream management.
5 Introduction
This working paper is the first report on a program developing impact and adaptation strategies for climate change in Victoria. This development is being carried out within a risk assessment framework (see Chapter 1). The framework integrates a modification of conventional impact and adaptation analysis with the stakeholder-based characterisation of vulnerability and adaptation options (as risk management). The blending of socio-economic and bio-physical disciplines is a part of what is known as “sustainability science” which aims to limit the negative aspects of globalisation (climate change, weed and pest invasions, habitat degradation) and embrace the positive (connectivity, communication, diversity) at the local to regional scale. Although this project is centred on impacts of and adaptation to climate change, a long-term aim is to integrate with similar processes (e.g. greenhouse gas mitigation, salinity amelioration, water reform).
Developing a sustainable response to global change requires a new way of doing science. Mechanistic frameworks and traditional isolated frames of reference are rejected for more holistic frameworks that embrace uncertainty and complexity. This alters the science from being a “value free” exercise conducted in isolation to becoming an agent of change within a larger social framework. The assessment of vulnerability requires the exchange of values and information within a clear structure. Rather than objectivity, the framework is developed around transparency, where the communication of value judgements between the different players becomes the medium of exchange. More conventional “scientific” assessments are modified by, and fit within this framework.
These methods are in their early stages of development, so this project is finding its way by building links between the various players. Two parallel processes are being pursued. The first, involves the development of methods for risk assessment under climate change which is largely theoretical, and the second is applying these methods in a “learning by doing” environment where we are creating links between climate scientists, impact scientists and stakeholders. These links build on stakeholder- science relationships developed in similar processes such as those utilised in Landcare and salinity management. The four workshops on catchments and water, agriculture, biodiversity and coasts aimed to establish links between some of the major players, and to build a system of understanding and measuring vulnerability to climate and developing adaptation to reduce that vulnerability.
Chapter 1 illustrates how climate change risk can be characterised within a framework of risk under climate variability linking current and future vulnerability. The use of coping ranges is well established in the scientific literature. It is intuitively appealing to those engaged in activities affected by climate, where there is a zone of climate to which one is adapted and a zone of variability (extremes) where one is vulnerable. The zone between being adapted and being vulnerable may or may not be a continuum, but if a threshold of change can be established for management or assessment purposes then this threshold can be quantified and incorporated into a modelling framework. In a stationary climate, adaptation can increase the coping range reducing vulnerability (e.g. through increased productivity and/or medium term climate forecasting). This is the principle behind the existing application of drought exceptional circumstances.
Climate change adds two important layers of complexity, which need to be understood before adaptation options can be assessed and prioritised. The first is that climate change may take the range of variability for key climatic variables beyond the coping range. How far beyond the coping range an activity is taken depends on a large number of uncertainties. Some of these may be quantified (as detailed in Chapter 1), but how vulnerability and resilience are perceived by stakeholders will also influence their perception of risk. The second is that the coping range itself will change over time due to autonomous and planned adaptations. In human systems, technology and social capital are major drivers of such capacity. The planning horizon brings these elements together. However, all too often statements cite the need for sustainability while restricting their analysis to current conditions. We are trying to build tools to assist in policy development that address both short and long-term aims.
6 Conventional economics has tended to view natural resources as substitutable and all values as fungible, which assumes that for any ecosystem service removed by climatic or other damage (e.g. land degradation) technology can provide a substitute. Furthermore, perfect market competition will ensure that this substitute is priced appropriately. This view does not account for irreversibility – many of the criteria proposed to measure vulnerability during the workshops were considered vulnerable because they are not currently substitutable or reversible. This includes biological extinction, biodiversity, ecosystem service relationships and wetland loss. The development of non-monetary metrics for assessing value in terms of criteria and thresholds is one way of expanding value-based judgements. Another is to develop monetary values for ecosystem services and build these into the activities that use those services. The challenge for adaptation to climate change is to be seen as a legitimate part of economic reform that does not set environmental protection against economic growth. The current socio-political construct that sets the environment and the economy at the opposite ends of two poles allowing the choice of only one is unsustainable.
Report structure
Chapter 1 introduces methods for assessing climate risk developed by CSIRO. Chapters 2 to 5 describe output from each of four sectoral workshops. These workshops explored likely changes to climate as it effects each sector, the level of understanding of current climate risks, the policy development framework affecting each sector and socioeconomic process that participants felt likely to affect adaptations.
Each workshop was attended by DSE and stakeholder representatives and consisted of four parts: Part One – Briefing on climate change and major impacts for the sector. Part Two – Briefing on risk assessment methods and diagnosis of key climate variables linked to major impacts. Part Three – Investigation of vulnerability, resilience, thresholds, knowledge, management and policy on specific aspects of each sector by breakout groups. Part Four – Plenary discussion on how other drivers of change were affecting that sector.
7 Chapter 1 Assessing the risk of climate change
Greenhouse gas emissions are a major cause of recently observed historical global warming. This warming is expected to continue during the 21st century, along with changes in regional temperature, rainfall and a host of other climatic variables (IPCC, 2001a). Scientists cannot forecast these changes accurately. At best, they can produce estimated ranges of mean change bounded by upper and lower limits. These ranges combine researchers’ best assessments of change resulting from: (i) socio-economic factors with differing ranges of uncertainty including estimates of population growth, land-use change, technological change, and socio-economic change (Nakicenovic and Swart, 2000) and (ii) climate modelling uncertainties (IPCC, 2001a). Global warming will be reflected on a regional basis by increases in temperature and potential evaporation, and changes in rainfall totals, rainfall variability, sunshine, atmospheric moisture and other variables.
Even if greenhouse gas emissions can be reduced far beyond the targets contained in the Kyoto Protocol, significant impacts are likely (e.g. Wigley, 1998). These impacts will produce both winners and losers. What are the risks? What are the benefits? Can we adapt to these impacts and reduce the likelihood of harmful outcomes, particularly in circumstances where changes could lead to irreversible outcomes?
CSIRO Atmospheric Research has been closely involved in the development of methods for risk assessment under the Adaptation Policy Framework (Burton et al., in prep.), that can be used to address these questions. The general approach is summarised in this chapter. These methods incorporate the following considerations: • Changing the focus of assessment from a climate-based approach to a vulnerability-based approach. • Managing uncertainty by moving from a predictive (prescriptive) approach to a risk-based (diagnostic) approach. • Recognising the role of behaviour in adaptation by working with stakeholders to characterise and manage risk. • Using adaptations to current climate and other drivers of change as the springboard for future adaptations. • Managing adaptation over appropriate time horizons, taking account of both climate change and policy needs. Assessing current and future climate risks
The conventional approach to impact and adaptation assessment has been to construct scenarios of climate change, then apply them to impact models to determine how impacts may change. Adaptations are then designed to manage those changes. While this approach is broadly predictive in its structure, the outcomes are contingent upon the input scenarios and are limited by scenario uncertainty. The conventional approach has also often neglected the relationship between current climate risks, vulnerability to those risks and adaptations developed to manage those risks. How society has coped in the past will influence how it copes in the future, even if future adaptation strategies are very different to those of today. Therefore, adaptation will be more successful if it manages both current and future climate risks, requiring an understanding of how climate-related risks may change over time.
8 Risk
Risk is a combination of two factors: • The probability that an adverse event will occur, • The consequences of that adverse event (USPCC RARM, 1997). That combination can be expressed as:
Risk = probability × consequence
The probability of an adverse event can be expressed as the likelihood of a given climate hazard. The consequences of that adverse event are measured in social terms and can be characterised as vulnerability.
A hazard is an event with the potential to cause harm. Examples of climate hazards are tropical cyclones, droughts, floods, or conditions leading to an outbreak of disease-causing organisms (plant, animal or human). Vulnerability is the level of harm experienced, and is measured by indicators such as monetary cost, human mortality, production costs, ecosystem damage or any other metric that is considered important. Climate risk assessment involves identification of the relevant climatic hazards, how often they will occur and what the resulting consequences may be. Although the details of a risk assessment will be specific to a particular activity, there are two major pathways for assessing climate risk. One is the natural hazards-based approach that tests the effect of climate on society; the other is the vulnerability-based approach that begins with damages, then diagnoses the climatic conditions that contribute to particular levels of harm. These methods are complementary.
The coping range
Over time, societies have developed an understanding of climate variability in order to manage climate risk. People have learnt to modify their behaviour and their environment to reduce the harmful impacts of climate hazards and to take advantage of their local climatic conditions. They have observed biophysical and socio-economic systems responding automatically to climate, and have tried to understand and manage these responses. This social learning is the basis of planned adaptation. Planned adaptation is undertaken by all societies, but the degree of application and the methods used vary from place to place. Modern societies may rely most on science and government policy and traditional societies may rely on narrative traditions and local decision-making, but all these methods are based on a common structure.
This structure has a range of climate where the outcomes are beneficial, a range where the outcomes are negative but tolerable, and a range where the outcomes are harmful. Beneficial and tolerable outcomes form the coping range (Hewitt and Burton, 1971). Beyond that range, a society is said to be vulnerable. This structure is shown in Figure 1.1. The coping range is usually specific to an activity, group and/or sector, though society-wide coping ranges have been proposed by some researchers (Yohe and Tol, 2002).
The climatic stimuli and their responses for a particular locale, activity or social grouping can be used to construct a coping range if sufficient information is available. Figure 1.1, upper left, shows a time series of single variable under a stationary climate. If we imagine a cropping system represented by its response to a single variable e.g., temperature or rainfall, the greatest yields will be in the range to which that system is adapted. If conditions get too hot (wet) or cold (dry), then outcomes become negative. The response curve on the upper right shows a schematic relationship between climate and levels of profit and loss. Under normal circumstances, outcomes are positive but become negative in response to deviations from the norm caused by climate variability. Using that response relationship, we can select criteria or indicators, for the purposes of assessing risk.
9 Knowledge of how climate affects impacts within a system, will allow the construction of a response relationship and one or more criteria representing different levels of performance (Figure 1.1, lower left). For example a yield relationship can be divided into good, poor or disastrous segments. Other criteria may be decided on the ability to grow next season’s seed supply, grow next year’s food supply, break even economically, or produce sufficient surplus to pay for basic goods and services. While farmers try to maximise their production, from experience they also know the consequences of not meeting such criteria. One way of deciding how the coping range is separated from the area of vulnerability, is to determine the critical threshold, which is defined as the tolerable limit of harm. Knowledge of the level of performance within a system allows us to set criteria, such as critical thresholds, and therefore to assess risk (Figure 1.1, lower right).
Loss
Profit
Loss Loss Profit
Critical Threshold Vulnerable Probability
Coping Coping Range Range
Vulnerable Critical Threshold
Figure 1.1. Simple schematic of a coping range under a stationary climate representing rainfall or temperature and crop yield. Vulnerability is assumed not to change over time. The upper time series and chart shows a relationship between climate and profit and loss. The lower time series and chart shows the same time series divided into a coping range using critical thresholds to separate the coping range from a state of vulnerability. Assessing current climate risks
The most basic elements needed are a model of the system (a mental, or conceptual, model), and a basic knowledge of the hazards and vulnerabilities in order to prioritise risk. Both qualitative and quantitative methods can be used to assess risk depending on the quality of information needed by stakeholders and the data and knowledge available to provide that information.
Building conceptual models
The first step in an assessment is to establish an understanding of the important climate–society relationships within the system being investigated. Those relationships are dominated by the climate impacts within the system and the sensitivity of the system response. Climate sensitivity is defined as the degree to which a system is affected, either beneficially or adversely, by climate-related stimuli. The effect may be direct (e.g., a change in crop yield or response to a change in mean range or variability of temperature) or indirect (e.g., damages caused by an increase in the frequency of coastal flooding due to sea level rise; IPCC, 2001b). Vulnerability is the propensity of the system to experience damage in response to climate sensitivity.
Climate–society relationships can be identified through stakeholder workshops, or may be well known from previous work. The creation of lists, diagrams, tables, flow charts, pictograms and word pictures
10 will create a body of information that can be further analysed. Establishing conceptual models in the early stages of an assessment can help the different participants develop a common understanding of the main relationships and can also serve as the basis for scientific modelling. In this chapter, we utilise the coping range expensively because of its utility as a template for understanding and analysing climate risks but it is not the only such model that can be used.
Characterising climate extremes and hazards
Are the climate hazards (affecting the system) well understood? There are two steps to this: the identification of the relevant climate hazards and their analysis. If the hazards for a system need to be identified, or their sensitivity on the system investigated, the following questions can be addressed: • Which climate variables and criteria do stakeholders use in managing climate-affected activities? • Which climate variables most influence the ability to cope (i.e. are those linked to climate hazards)? • Which variables should be used in modelling and scenario construction?
These questions can be investigated by ways such as: 1. Moving through a comprehensive checklist of climate variables in stakeholder workshops 2. Literature search, expert assessment and information from past projects 3. Exploring climate sensitivity with stakeholders, through interview, survey or focus groups 4. Building conceptual models of a system in a group environment
Different aspects of climate variability will need to be examined. For example, rainfall can be separated into single events, daily variability and extremes, seasonal and annual totals and variability, and changes on longer (multi-annual and decadal) timescales. Daily extremes are important in urban systems for flash-flooding, interannual variability for disease vectors, and seasonal rains for dryland agriculture. Temperature can be divided into mean, maximum and minimum daily averages, variability and extremes. In each system, people will have a different set of variables that they use to manage that system. Even though this management may not be ‘scientific’, it may be very sophisticated. Each of these variables has a different level of skill in terms of climate modelling and has different degrees of predictability, information that is critical for building climate scenarios.
Relationships between climate variables and impacts can be analysed by a number of methods such as ranking in order of importance, identifying critical control points within relationships, and quantifying interactions through sensitivity modelling. Often, this knowledge exists in institutions (e.g., agricultural extension networks) where important relationships are well known. In such cases, stakeholder workshops will allow the information to be gathered relatively easily. In other situations, several stakeholder workshops may be needed; the first to introduce stakeholders to the issue of climate change and to establish areas of shared knowledge and gaps, before investigating the specifics of a particular activity.
Impact assessment
In assessing current risk, impact modelling may need to concentrate on assessing the impacts of extreme events and variability, perhaps undertaking modelling to extend the results based on relatively short records of historical data (e.g. through statistical analysis). Sensitivity modelling in testing changes to variability and investigating extreme-event probabilities can be of benefit later on when climate scenarios are being constructed. Given the difficulty in combining the various types of uncertainty, sensitivity modelling of impacts under climate variability will help identify which uncertainties need to be represented in scenarios.
Impacts can also be assessed from the socio-economic point of view by assessing vulnerability. The interactions between socio-economic factors and sensitivity as it effects vulnerability will also affect
11 the ability to cope, and identifying such interactions are likely to be important for identifying possible adaptatations.
Risk assessment criteria
Risk assessment criteria can be measured as a continuous function or in terms of limits or thresholds. For example, in farming, crop yields can be divided into good, moderate, poor and devastating yields depending on yield per hectare, per family or in terms of gross economic yield. This can allow a picture to be developed of the distribution of good and bad years and which combinations are sustainable. There is also a minimum level of yield below which hardship becomes intolerable. If this level is identified then it can become a criterion by which risk is measured, marking a reference point with known consequences to which probabilities can be attached.
Levels of criteria that attach outcomes to impacts and climate are known as impact thresholds. An impact threshold is any change in state associated with a given impact that can be linked with climate. They can be grouped into two main categories: biophysical thresholds mark a physical discontinuity on a spatial or temporal scale, and socio-economic thresholds trigger a change in behaviour, management or regulatory state. 1. Biophysical thresholds represent a distinct change in conditions, such as the drying of a wetland, floods, breeding events. Climatic thresholds include frost, snow and monsoon onset. Ecological thresholds include breeding events, species extinction or the removal of specific conditions for survival. 2. Socio-economic thresholds are set by benchmarking a level of performance. Exceeding a socio- economic threshold results in a change of legal, regulatory, economic or cultural behaviour. Examples of agricultural thresholds include the yield per unit area of a crop in weight, volume or gross income (Jones and Pittock, 1997).
Critical thresholds are defined as any degree of change that can link the onset of a given critical biophysical or socio-economic impact to a particular climatic state (Pittock and Jones, 2000). They can be assessed through vulnerability assessment and mark the limit of tolerable harm. Critical thresholds mark the limits of the coping range; the point where climate drives impacts beyond a level that is considered tolerable (Smit et al., 1999; Pittock and Jones, 2000). For any system, a critical threshold is the combination of biophysical and socio-economic factors that marks a transition into vulnerability.
Stakeholders and investigators jointly formulate criteria that become a common and agreed metric for an assessment (Jones, 2001). These may link a series of criteria ranked according to outcomes (e.g., low to high), or be in the form of thresholds. Critical thresholds can be defined simply, as in the amount of rainfall required to distinguish a severe drought, or can be complex, such as the accumulated deficit in irrigation allocations over a number of seasons (Jones and Page, 2001). Each assessment needs to develop its own criteria for the measurement of risk. For example, given a continuous function between climate and yield as in Figure 1.1, it is possible to assess the likelihood of any outcome within that relationship. It is also possible to calculate a particular threshold and calculate the probability of exceeding that threshold under a given set of conditions. There are no hard and fast rules for constructing thresholds – they are flexible tools that mark a change in state that is considered important. Table 1.1 lists criteria that have been used to estimate current and future climate risks.
12 Table 1.1 Examples of criteria for a number of different sectors that have been used in climate change impact assessments or are suitable for such assessments (Jones, 2001). Sector/Activity Criteria/threshold Source Ecology Species or community abundance Vulnerable Endangered Species Protection Act 1992 Endangered (Australia) Extinct Species distribution Climate profile shifts beyond current distribution Dexter et al. (1995), Chapman and Milne (1998) Quantified change in core climatic distribution Climatic thresholds affecting distribution Ecological processes Critical levels of mean browsing intensity Keinast et al. (1999) Flooding events affecting frequency of waterbird breeding events Johnson (1998) Climatic threshold between ecogeomorphic Lavee et al. (1998) systems Mass bleaching events on coral reefs Hoegh-Guldberg (1999) Phenology Winter chill – e.g. frequency of occurrence below Hennessy and Clayton-Greene (1995), Kenny et daily min. temp. threshold al. (2000) Cumulative degree days for various biological thresholds Spano et al. (1999) Daylength/temperature threshold for breeding Reading (1998) Temperature threshold for coral bleaching Huppert and Stone (1998) Alpine Tourism Days of snow cover delineating good, moderate Gyalistras, pers. comm (1998) and poor seasons Hydrology Water quality Regulated water quality standards for factors Widespread and locally specific. such as salinity, dO, nutrients, turbidity. Water supply Regulated and/or legislated annual supply volume Jones (1999, 2000b) at system, district or farm level Stress threshold for water storages Lane et al. (1999) Streamflow Maintenance or low flow event frequency and E.g. Australian Rainfall and Runoff (Pilgrim, duration 1987); Panagoulia and Dimou (1997) Controlled surcharge event (control flood) Uncontrolled surcharge event Catastrophic flow Flooding Expected Monetary Value Criteria 1 in 100 year flood Probable Maximum Flood Maximum historical flood Drought Palmer drought severity index Palmer (1965) Drought Exceptional Circumstances White and Karssies (1999) Hydroelectric power Current mean and minimum energy supply Mimikou and Baltas (1997)
Agriculture Animal Health Level of animal mortality (heat and cold stress) Heat and cold stress (level of production) Annual cost of disease prevention/production losses ratio or cost/benefit Animal production Carrying capacity (head of stock per ha) “Safe” carrying capacity of rangeland Hall et al. (1998) Crop production Accumulated degree days to fruit and/or harvest Kenny et al. (2000) Economic Net/Gross income per ha/farm/region/nation Human Health Vector Borne Diseases Aggregate epidemic potential Patz et al. (1998) Climatic envelope of disease vector McMichael (1996) Critical density of vector to maintain virus Jetten and Focks (1997) transmission Thermal stress Heat and cold temperature levels and duration McMichael (1996) Infrastructure Economic “write off” e.g. replacement less costly than repair Infrastructure condition falling below given standard Land degradation Threshold for overland flow erosion Tucker and Slingerland (1997)
Risk assessments
Current climate risks mainly deal with the recurrence of climate hazards within a stationary climate. The methods for risk assessment are well developed within some sectors (e.g. agriculture and water resources) and poorly developed within others (e.g. biodiversity).
13 Risk assessments ranging from those that are purely qualitative to those that apply numerical techniques can be conducted. As uncertainty decreases, the use of analytic and numerical methods increase and the capacity to understand the system over changing circumstances increases. The following list outlines this development: 1. Understanding the relationships contributing to risk 2. Being able to relate given states with a level of harm (e.g. low, medium and high risk) 3. Statistical analysis, regression relationships 4. Dynamic simulation 5. Integrated assessment (multiple models or methods)
These methods can be used to undertake the following investigations: • Understanding the relationship between climate and society at a given point in time • Establishing current climate and society relationships prior to investigating how climate change may affect these relationships (e.g. setting an adaptation baseline or reference) • Developing an understanding of how past adaptations have affected climate risks • Assessing how technology, social change and climate are influencing a system in order to be able to separate changes due to climate variability and changes due to ongoing adaptation • Assessing how known adaptation strategies can further reduce current climate risks
Assessing future climate risks
The assessment of future climate risks requires the incorporation of climate scenarios and planning horizons into the analytic framework. This requires the management of significant uncertainty, especially methods developed to construct and manage climate scenarios. How these are applied depends on the type of assessment, how much information is needed to manage risk and the tolls and resources available to carry out the assessment. Table 1.2 shows a number of climate risk assessments classified according to their major area of focus.
When carrying out a risk assessment the team needs to be aware of what type of information is needed to communicate the results. In some cases, qualitative information is all that is needed. For instance, an indication that current risks are likely to continue in future may be sufficient to warrant adaptation. In other cases, decisions about natural resource allocation based on climate change may be open to legal challenge, requiring the best possible science. However, uncertainty also limits choice. Sometimes, although stakeholders want accurate answers, uncertainty may only allow qualitative responses. In this case, a reasonable compromise is to rely less on analytic techniques and modelling, and rely more on techniques from the social sciences, such as eliciting information from different stakeholders on how they perceive climate risks.
Dealing with uncertainty
Risk assessment utilises a formalised set of techniques for managing uncertainty. Uncertainty under climate change is significant, and requires the use of specialised methods, such as the development and use of climate scenarios. The large uncertainty in predicting future climate is one reason why we recommend that assessments be anchored with an understanding of current climate risk. The understanding of uncertainty and its communication between all parties is very important. Moss and Schneider (2000) prepared a cross-cutting paper on uncertainty for the IPCC Third Assessment Report that provides valuable guidance on framing and communicating uncertainty. Further guidance on managing uncertainty within assessments is provided by Morgan and Henrion (1990).
The tool used to explore future climate is the climate scenario. A scenario is a coherent, internally consistent and plausible description of a possible future state of the world. They can range from simple to complex, and from narrative descriptions of a possible future to complex mathematical description combining mean climate changes with climate extremes. A scenario is not a prediction, and has no likelihood attached beyond being plausible. However, it is the basic building block of risk assessment
14 approaches under climate change that use scenarios, ranges of uncertainty and probability distribution functions.
Table 1.2. Types of climate risk assessments Type of assessment Basic method Examples Natural hazards based Investigate whether a specific Hurricanes (Lugo, 2000; Singh, 2002), Health climate hazard may change over (Hales et al., 2002) time Vulnerability based Investigate whether a particular Social vulnerability (Adger, 1999a); Methods social outcome assessed as a given (Dilley and Boudreau, 2001) level of damage or “natural disaster” is likely to change over time Policy-based Investigate existing or proposed Water (Stakhiv, 1998), Political Structure (Adger, policy to determine whether it may 1999b), Development Policy (Beg et al., 2002) need to be modified under climate change National/Regional Investigate a region to determine National Communications assessment (e.g., what the major future risks may be catchment, bioregion, and assess adaptation options international region) Sustainable development Investigate joint needs based on Uganda (Apuuli et al., 2000) climate risks and development needs and integrate adaptations into the development agenda Development proposal Investigate a specific development Water storage (Harrison and Whittington, 2002) proposal to determine whether anticipated adaptation is cost effective Maladaptive practice Determine whether a social trend is Desertification (Imeson and Lavee, 1998; increasing climate risk Sivakumar et al., 2000), catchment degradation (Chen et al., 2001) Sector-based Investigate changing risks to a Agriculture (Matthews et al., 1997; Lansigan et al., particular sector (e.g. health, 2000; Kumar and Parikh, 2001; Jones and agriculture, water) Thornton, 2002); Human Settlements (Magadza, 2000); Water resources (Tung, 2001; Mehrotra), Forestry (Fearnside, 1999)
Using coping ranges to measure future climate risks
The coping range can be used to assess how climate or the ability to cope, or both is changed over time. The next step is to see how the ability to cope is affected by a perturbed climate. Figure 1a (upper panel) shows how a coping range may be breached under climate change if the ability to cope is held constant. Represented in terms of temperature (or rainfall), the upper hot (or wet) baseline threshold is exceeded more frequently while the exceedance of the lower cold (or dry) baseline threshold reduces over time. Vulnerability will increase to extreme levels for the hot (wet) threshold over time. Figure 1.3 (lower panel) represents the expansion of the coping range through adaptation and the consequent reduction of vulnerability. The amount of adaptation depends on the planning horizon under assessment and the likelihood of exceeding given criteria over a given planning horizon.
The coping range can also be used to see how both climate and the ability to cope may change. For example, an agricultural assessment could account for projected growth in technology, yield and income that broadens the coping range. An assessment could then determine whether these changes are adequate to cope with projected changes in climate. These assessments should be carried out on an appropriate planning horizon.
15 Stationary Climate & Changing Climate Coping Range
Vulnerable
Coping Range
Vulnerable
Stationary Climate & Changing Climate Coping Range Vulnerable
Adaptation
Coping Range
Vulnerable Planning Horizon Figure 1.3. Coping range showing the relationship between (a) climate change and threshold exceedance, and (b) how adaptation can establish a new critical threshold, reducing vulnerability to climate change.
Planning and policy horizons
Planning horizons affect how far into the future a risk assessment may be projected. They relate to the lifetime of decision-making associated with a particular activity – how far into the future is it planned? Do current planning decisions assume the continuation of historical conditions? Is climate change likely to occur within this planning horizon? The same activity can be affected by several planning horizons used by different stakeholders (e.g. financial, urban planning and engineering horizons for infrastructure). For example, in a water resource or catchment-based assessment, the planning life of water storages may be 50+ years, but planning for supply may only be 5–15 years (Figure 3). A risk assessment may then want to create scenarios based on two time horizons such as 2020 and 2050 to accommodate both infrastructure and water policy horizons.
)
g
n i s t n e h r n g ) u s a i t l s e s c p p e o s h n r l t u o r o u y r n t d m i t t s y & r c s i e s t t o c i t a u s c a i f u o m r s l f w q e e f r r f e j t / o e e e c n e r l e s e o i e n c f l r r i v f p o ( a i l a i / s u r l g p h d m f s g n s s n a n s n o n w o l n o e n i k i i l g i ( i i r a r i t g e t o b i i c d a s t u s n e s a n a s y s e t p r r o e a a a o m m e c i t p u e n l e t / d b r e g a d t r l i l o r l a a n n l a r r t e a d b t r u t u r r n e e t o p i c - i t s c e o r t s o e g g i i g n e r r p n e t p o c w a g d r l r j n i e a e i r e g l e o a r u e a t l o r o a A n A P N B F P G N C T L E L M I 2040 2060 2100 2000 2020 2080 Figure 1.4. Planning horizons relevant to climate risk assessments.
16 The policy horizon is related to the period of time that a particular policy is being planned for. It is not always the same as a planning horizon. For instance, the infrastructure affecting an activity will have an engineering life of many decades, but the policy horizon that affects the operation of that infrastructure may only be a handful of years. Most natural resource policy is implemented over several years and may be reviewed or updated over time but is expected to manage resources over a much longer planning horizon. A risk assessment may extend over the longer planning horizon, but adaptations developed to manage those risks are likely to be applied over a much shorter policy horizon. Sometimes the planning horizon is the policy horizon; in such circumstances a risk assessment can be used to inform policymakers of the value of taking a longer-term view.
Likelihoods of climate change are constructed of frequency-based uncertainties of recurrent climate hazards and single event uncertainties associated with climate change; from a range of possible outcomes, only one can come true. Ranges such as temperature change, rainfall change and sea level rise are typical. Each range of uncertainty has three components: there is a full range of change that is unknown, a less extensive but quantifiable range that may or may not have a known probability distribution, and individual climate scenarios (Jones, 2000). A climate scenario can serve as an individual sample or a set of scenarios can be used to construct a range, which can then be resampled using bayesian techniques. If each scenario within an assessment is applied as a plausible sample with no attached likelihood, each outcome will have a different level of vulnerability (or potential benefit), suggesting different rates and magnitudes of adaptation. Without any means to prioritise these results, the fallback position is to suggest adaptations that will work across a wide range of possibilities.
Risk assessments
Risk assessment under climate change is a measure of how likely various activities are to be taken beyond their coping range. This is easiest if impacts can be expressed as a function of global warming and are likely to change in only one direction (e.g. increase or decrease). For example, for sea level rise we intuitively know that the lowest areas of coast will be inundated first and are the most likely to be inundated over the long term. Given the IPCC range of sea level rise of 9 to 88 cm at 2100, a section of coast with a critical threshold of 25 cm is much more likely to be inundated by 2100 than a section with a critical threshold of 75 cm. In terms of risk, hazard may be experienced as a storm surge, vulnerability can be measured through a given combination of surge and damage that exceeds tolerable levels (e.g., loss of important coastal ecosystems or infrastructure) and likelihood is the probability of threshold exceedance at a particular time.
This principle extends to all activities where it is possible to characterise critical thresholds or other risk-based criteria as a function of variables related to global warming. Coral reefs that repeatedly bleach at a warming threshold of 1°C face a far greater risk than those that will bleach at 2.5°C. Alpine ecosystems close to their marginal limits will be affected at much lower temperatures than at higher altitudes. Activities affected by rainfall change, though less directly linked than temperature, will also fit this general framework. Climate models indicate that once a direction of rainfall change is established, the magnitude increases with global warming. Therefore, drought and/or floods will intensify over time, requiring adaptation before damage can be alleviated or benefits realised. The regions where small changes in climate breach a critical threshold will be those that face the greatest risk.
Figure 1.5 shows how these thresholds can be related to global warming and sea level rise using the examples above. Risk is calculated as the probability of threshold exceedance and is highest at the minimum limit, nearest to the current coping range and lowest at the maximum limit away from the coping range. Figure 1.5 also shows how probability distribution functions based on two or more input uncertainties can be recast.
17 6 6 6
5 5 5
4 4 4
3 3 3 2.5°C Threshold
2 2 2
1°C Threshold
Temperature Increase (°C) Increase Temperature 1 1 1
0 0 0 1990 2010 2030 2050 2070 2090 050100 Ye ar Frequency (%) Frequency (%)
100 100 100
80 80 80 75cm Threshold
60 60 60
40 40 40
25cm Threshold Sea Level Rise (cm) Rise Level Sea 20 20 20
0 0 0 1990 2010 2030 2050 2070 2090 060 100 Year Probability (%) Probability (%)
Figure 1.5. Relating threshold exceedance to the likelihood of climate change. The left hand panels show ranges of temperature increase (upper charts) and sea level rise (lower charts) 1990–2100, showing a 1°C and 2.5°C warming threshold and a 25 cm and 75 cm sea level rise threshold, respectively. The centre panels illustrate the ‘most likely’ outcomes for temperature and sea level rise in 2100 based on prior assumptions of input uncertainties. These probability distributions each combine two ranges of uncertainty, randomly sampled and multiplied in a manner consistent with Schneider (2001). These are typical of those that will be constructed from two or more component ranges of uncertainty. The right hand panels show the same probability distributions recast as likelihood of threshold exceedance (cumulative probability). The dashed line represents a uniform probability distribution (all points are equally likely). These probabilities show that even though the likelihood of predicting a particular outcome in terms of climate is very low, the probability of calculating threshold exceedance is much less sensitive to the input assumptions.
Activities with critical thresholds that will be exceeded at low levels of warming will be the most at risk, requiring risk management in the form of adaptation, mitigation or “do nothing”. Those exceeded at moderate levels of global warming are less likely to occur and those close to the upper limit least likely to be exceeded. At increasing levels of warming the number of coping ranges being exceeded will increase, as will the damage to each activity already affected.
The role of vulnerability assessment is to identify the systems most sensitive to climate change, those with narrow coping ranges, those with low adaptation capacity and those exposed to current climate risks that are likely to be exacerbated under warming. Direct adaptation or increasing adaptive capacity (the ability to respond to an experienced or anticipated stress) can reduce net damages or even increase net benefits in many systems, but as global warming increases, the rate and magnitude of adaptation required will increase. Mitigation of greenhouse gases will reduce the risk of global
18 warming. If mitigation is sustained, it will act from the top down, reducing the highest potential temperatures first, then successively lower temperatures as mitigation continues.
The relationship between adaptation and mitigation and global warming in terms of risk assessment is shown in Figure 1.6. Adaptation will either reduce damages or provide net benefits for impacts affected by the warming that does occur, and mitigation will reduce the likelihood of even higher temperatures occurring. The two columns on the right side of Figure 1.6 provide guidance on how risk can be assessed. Likelihood goes from most likely to least likely with increasing global warming. Its probability distribution is unknown, but statistical techniques can be used to assess different realisations of that distribution based on prior assumptions.
Low probability, extreme outcomes
Least likely Considerable damage to most systems
Moderately Increased likely damage to many systems, fewer benefits
Highly likely
Damage to the Almost certain most sensitive, many benefits
Happening Vulnerable to now current climate Probability Consequence
Core benefits of adaptation and mitigation Probability – the likelihood of reaching or exceeding a given level of global warming Consequence – the effect of reaching or exceeding a given level of global warming Risk = Probability × Consequence Figure 1.6. Synthesis of risk assessment approach to global warming. The left part of the figure shows global warming based on the six SRES greenhouse gas emission marker scenarios9 with the zones of maximum benefit for adaptation and mitigation. The right side shows likelihood based on threshold exceedance as a function of global warming and the consequences of global warming reaching that particular level based on the conclusions of IPCC WG II3. Risk is a function of probability and consequence.
Risk Management
Mitigation and adaptation are the two major forms of risk management for climate change. Mitigation reduces the likelihood of climate hazards increasing under climate change, while adaptation reduces the consequences of a given climate hazard. There are two main steps to adaptation. The first is prioritise adaptations based on the assessment of current and future conditions, and the second step is implementation and monitoring (Figure 1.7). Figure 1.7 is a flowchart constructed for the Adaptation Policy Framework under the auspices of the United Nations Development Program (UNDP) that can be used for designing adaptation projects in both developing and developed countries.
While some prioritisation of adaptation options has been undertaken (IPCC, 2001b), these have tended to be independent of location and socio-economic context. In Figure 1.7, adaptive capacity (the ability to adapt) is enhanced at all steps of the project, but specific adaptation options need to be developed under a risk assessment process.
19 1. Scope Project • Identify policy objectives of national plans for key systems: •existing assessments •expert workshops •national consultations
2. Assess Current Vulnerability •Climate risks, impacts and damages
•Socio-economic drivers Capacity Adaptive •Natural resource drivers •Adaptation experience and capacity •Policy and development needs
3. Characterise Future Conditions •Climate (scenarios, trends, risks and opportunities) •Socio-economic (scenarios, trends) Stakeholders •Environment (trends) •Adaptation policy & development options
4. Prioritise Policies and Measures •Broad adaptation strategy •Priority measures and projects among sectors
5. Facilitate Adaptation •Incorporate climate risks into development plans •Evaluate and monitor policies, measures and projects
Figure 1.7 Adaptation Policy Framework (From UNDP-GEF Workshop, Montreal June 2001).
20 Chapter 2 Catchments and Water
Introduction
Victoria’s surface water resources are already highly utilised. The current average annual water use in Victoria represents around 87% of the estimated sustainable yield for surface water (NLWRA, 2001). The sustainable yield has already been reached in many river systems, and will be very soon reached in others if extractions continue to increase. Any change in resource availability as a result of climate change will therefore have potentially significant impacts on a wide range of water users and on the environment.
Water resources are generally sensitive to climate but the major issue for impact assessment is whether such changes are likely to result in increased stress (Arnell and Liu, 2001). This relates to perceptions (scientifically based or otherwise) as to whether future climate is likely to remain within the normal coping range associated with resource use and how the coping range may change over time (whether the capacity to adapt increases or decreases).
Victoria’s surface water resources fall into three zones as defined by Australian Rainfall and Runoff (Pilgrim, 1987). Zone 2 forms part of The Murray-Darling Basin north of the Great Dividing Range. The rivers of the South-east Coast Division in Zone 1 flow south of the divide and extending from the NSW border to the Otways. In Zone 6 the catchments of the western plains extend from the Corangamite catchment to the Glenelg in western Victoria.
A detailed assessment of the current, and likely future, status of Victoria’s surface and groundwater resources was undertaken in 2000 for the National Land and Water Resources Audit (NLWRA, 2001). Results from this audit can be found in the Australian Natural Resources Atlas (see http://www.nlwra.gov.au/atlas). In the context of the NLWRA, Victoria’s catchments were divided into 32 surface water management areas (SWMAs), which closely reflected the boundaries of the main Australian Water Resources Council drainage basins, but with some basins being subdivided into two for assessment purposes.
This chapter is based on the workshop on Catchments and Water held on April 30 2001 to examine the issues surrounding climate change and water resources. This workshop undertook several of the tasks described in the previous chapter, exploring: • The relationship between key climate variables and performance criteria to define the basis of coping ranges affecting the management of catchments and water supply. • The relationships between climate and non-climatic drivers of change. • The institutional and policy environment influencing the planning of catchments and water supply. Previous research
Climate change impacts on water resources in Victoria have been investigated by Chiew et al. (1995), Schreider et al. (1996, 1997), Wang et al. (1999) and Chiew and McMahon (2002). Climate scenarios for all these studies were constructed from an earlier generation of climate models containing a ‘mixed-layer’ ocean: a 50-m layer with flux adjustments to simulate deep ocean effects. However, the only credible projections for rainfall are from the later generation of coupled ocean atmosphere GCMs. These are dominated by decreases in Victorian rainfall (Whetton et al., 2002).
21 Chiew et al. (1995) constructed scenarios from five different climate models simulating increases in decreases in rainfall. These, in turn, produced large increases and decreases in runoff and streamflow for five ungauged Victorian catchments. This work was repeated using both mixed-layer and coupled model scenarios from CSIRO (1996) by Chiew and McMahon (2002). They also tested changing daily rainfall in the Bass catchment showing increases in high flows relative to changes in mean flow (Chiew and McMahon, 2002). Although the ranges used included a marked increase in rainfall, increases in extreme rainfall are considered likely, even with mean rainfall decreases.
Schreider et al. (1996, 1997) investigated changes in the Goulburn, Ovens, Mitta Mitta and Kiewa catchments using “most wet” (+1.5°C, +20% summer, +10% winter) and “most dry” (+2°C, 0% summer, –10% winter) scenarios for 2030 from CSIRO (1992). These scenarios produced neutral to negative changes in streamflow of much greater variability in the snow-free catchments, and slightly positive to negative changes in the snow-affected catchments. Despite using similar climate scenarios to Chiew et al. (1995), these results were substantially ‘drier’.
Wang et al. (1999) investigated the Campaspe system water supply using a climate change scenario derived from the CSIRO DARLAM model nested in a mixed-layer GCM, in which rainfall decreases in the first half of the year and increases in the second half producing a net annual decrease. In that system, irrigation water is allocated based on 100% water right with up to a further 120% of sales water in years when supply is not limited. The simulated security of the water right was reduced by
1% in 2030 (0.8°C global warming), 4% in 2070 (1.8°C global warming) and 16% at 2×CO2 (4.1°C global warming). However, this relatively effective maintenance of security was at the expense of downstream environmental flows.
The most recent CSIRO projections and detailed changes for Victoria summarised in Whetton et al. (2002) show a much more cohesive picture of climate change. Coupled ocean-atmosphere GCMs simulate a largely consistent pattern of mean seasonal rainfall change. Decreases dominate the winter– spring period, whereas the summer-autumn period show slight decreases to increases. Potential evaporation scenarios are inversely correlated with precipitation. Potential evaporation increases in all cases, but these increases are lowest where rainfall increases and higher when rainfall decreases. The addition of scenarios for potential evaporation will reduce the uncertainties apparent between the Chiew et al. (1995) and Schreider et al. (1996, 1997) studies, where similar rainfall scenarios produced very different outcomes, due in part to differences in the handling of temperature and potential evaporation in the rainfall-runoff modelling. Initial modelling of the Ryan’s Creek catchment, near Benalla shows decreases in streamflow ranging from –8% to -64% by 2030. Climate-impact relationships
Part two of the catchments and water workshop related climate variables with impacts. The results are summarised here in an interaction matrix. Climate variables were divided into different components where necessary (e.g, rainfall was divided in five aspects ranging from mean annual rainfall to probable maximum precipitation associated with single flood events). Climate variables are classified as primary variables and those that are a direct consequence of climate such as runoff, recharge and fire are classified as secondary variables.
In Table 2.1, the interactions between primary and secondary climate variables on the vertical axis with activities listed on the horizontal axis are shown. These interactions are weighted using a score of one to three denoting a weak to strong relationship. The weighting is subjective and is based on expert opinion, so is open to wide interpretation. In some cases, the variables on the left axis are related (e.g. rainfall and runoff effects on streamflow), so both may be given the same rating although it may be unclear the strength of a particular interaction should be rated. Where such variables influence a particular activity (e.g., water supply) all should be included in any model-based assessment of impacts.
22 Table 2.1 Climate variables/activities matrix. Interactions are weighted on a score of one to three denoting a weak to strong relationship. Urban Water Supply Rural Water Supply Catchment Management Waterway Management
CLIMATE VARIABLES / ACTIVITIES MATRIX sequestration 2 Groundwater recharge Groundwater management Waterway Flood management Wetland management Environ. Flow (SEPP's) Water quality uses Recreational Urban water demand water Urban supply water Urban Industrial uses Storm water management Sewerage infrastructure design Urban Irrigation entitlements Bulk On-farm storage infrastructureRural design Hydropower management Catchment Watershed management Forestry farming practice Dryland CO Temperature (av.) 2 1 22211111111 1 1 11 21 Temperature (daily max.) 3221111 2 1 2218 Evaporation (ann./seas.) 221 213222 2212 1 111 28 Evaporation (daily) 3 1 122111211 1 1111 21 Humidity 11 1 14 Rainfall (annual total) 1112333332332312222222 48 Rainfall (daily) 2213222 21112 2 3232332 41 Rainfall variability (annual) 23122133313331212232322 50 Rainfall variability (decadal) 12111122112222111121211 32 Rainfall (pmp) 1 333 112311 3231232 35 Runoff 131322132211312 2232222 43 Runoff (winter/spring) 2 222121111111 2111222 29 Runoff (summer base flow) 1 111 11111111 1111111 19 Streamflow 3 12113213231 1332332 40 River height 1122111 1312 1232222 30 Flooding21323223322311 2332332 48 Water temperature 2 3 1 2 2131 15 Drought 33222233323231212223333 55 Fire 12 1 1 133313 2 2 21 26 Soil moisture 32 1113111 121212 22 11 29 Landcover 2 1 11111 333232222121 34 Evapotranspiration/LAI 3 22322211211 22 Recharge 11111111111 1 12 Discharge 1 11 1 1 1111 11112 15 Water table height 1111 1 1 11 11111 13 Dryland salinity 1 111 22121 213321 24 Water salinity 2 1 31 11 213232 22 Atmospheric CO2 11223 1 10
24 37 16 29 38 33 42 32 30 27 29 40 48 31 37 17 28 40 38 44 40 49 35
An interaction matrix illustrates which climate variables affect various activities, how strongly those activities are affected and whether they are affected by a wide or a narrow range of climate variables. The results are summarised in Table 2.2. The left-hand column shows the relative importance of key climatic drivers affecting catchment and water activities and the right-hand column shows the sensitivity of various activities affected by climate. Not surprisingly, rainfall and closely related variables affect almost all aspects of catchment-based processes. Drought is the highest concern followed by various aspects of rainfall and the secondary variables, flooding and runoff. Atmospheric CO2 and humidity are largely unimportant.
Most catchment-related activities are highly sensitive to climate. The highest possible tally is 84, and many activities total about half that. Even the third lowest-rated activity (urban water demand) is strongly affected by variations in external water demand, which is affected by climate. Only CO2 sequestration and industrial water use are relatively unaffected. In the workshop, watershed management was distinguished from catchment management by its greater emphasis on water harvesting as opposed to the integrated management of both land and water.
This type of assessment, beginning with impacts and working back to climate poses a particular challenge for those who build climate scenarios. The challenge becomes to represent the most important aspects of climate as they impact on various activities, particularly climate variability and extremes, in climate models and scenarios.
23 Table 2.2 Prominence of key climatic drivers affecting catchment and water activities on the left and those activities affected on the right, showing the total weightings from Table 2.1. Key Climatic Drivers Activities Affected 55 Drought Water quality 49 50 Rainfall variability (annual) Watershed management 48 48 Rainfall (annual total) Wetland management 44 48 Flooding Irrigation 42 43 Runoff Catchment management 40 41 Rainfall (daily) Waterway management 40 40 Streamflow Environ. flow (SEPP's) 40 35 Rainfall (pmp) Sewerage management 38 34 Landcover Flood management 38 32 Rainfall variability (decadal) Urban water supply 37 30 River height Dryland farming practice 37 29 Runoff (winter/spring) Recreational uses 35 29 Soil moisture Urban infrastructure design 33 28 Evaporation (ann./seas.) Bulk entitlements 32 26 Fire Forestry 31 24 Dryland salinity On-farm storage 30 22 Evapotranspiration/LAI Storm water 29 22 Water salinity Hydropower 29 21 Temperature (av.) Groundwater recharge 28 21 Evaporation (daily) Rural infrastructure design 27 19 Runoff (summer base flow) Urban water demand 24
18 Temperature (daily max.) CO2 sequestration 17 15 Water temperature Industrial uses 16 15 Discharge 13 Water table height 12 Recharge 10 Atmospheric CO2 4 Humidity
Forcing variables Relay variables
Catchment management Rainfall (decadal) Drought Rainfall (annual var.) Forestry
Soil moisture Landcover Watershed management Rainfall (daily) Rainfall (average) Winter/Spring Runoff Runoff Flooding Dryland farming Irrigation Rainfall (PMP) Annual Ep Temperature (av.) Streamflow Rural infrastructure Runoff (summer basef) Waterway plan Atmospheric CO2 Flood plan Discharge Fire Actual Et Irrigation Wetland plan Watertable Daily Ep River level Industrial demand Water storage Urban water demand Recharge Hydropower Dryland salinity On-farm storage Env. flows CO2 mitigation Water quality Bulk entitles Sewerage Forcing Power Temperature (max) Water salinity Recreation Urban infrastructure Water temp Humidity Storm water
Dependent variables Dependency (Sensitivity)
Figure 2.1 Forcing/dependency diagram. Forcing increases up the vertical axis and dependency along the horizontal axis. Forcing variables (solid squares) act on the system and are little modified by it. Relay variables (diamonds) force the system but are also modified by it. Dependency variables (open squares) have limited interactions within the system but may be important for individual processes. Dependent variables (circles) do not significantly affect the system but are greatly affected by it.
24 A cross impacts analysis can add structure to a complex system where there are multiple interactions. All of the climate variables and related activities were compiled into one long list which was then repeated in both the horizontal and vertical axes of an interaction matrix. If an element on the vertical axis produces a reaction in another element on the horizontal axis, then its tally (forcing power) is increased by one. The tally for dependency of the element located along the horizontal axis is also increased by one. The result is a forcing/dependency score for each variable that can then be charted (Figure 2.1).
Forcing variables in the upper left quadrant are largely external to the system but have a significant effect on that system. Relay variables force many elements within the system but are also themselves forced by other variables. This is the area where feedback effects between processes are most common. Dependent variables tend not to affect other variables very much but are themselves acted on by a large number of processes. These are the variables most closely related to the criteria linked to thresholds and risk. Autonomous variables occupy the lower left quadrant and have only limited impact within the system. Performance criteria / thresholds
Performance criteria in the form of a continuous function or in terms of limits or thresholds are needed to assess risk. Criteria that could be used to mark a level of performance were nominated by the workshop and subsequent discussions allowing the links between key climatic variables and performance criteria to be evaluated. Table 2.3 shows the activities from Table 2.2 broken down into individual criteria. Thresholds for a number of these activities are locally or system specific, but many remain unquantified.
Table 2.3. Activities and areas from which performance criteria can be constructed. Urban Water Systems Performance criteria Supply Annual catchment streamflow Bulk supply (Volume or % of storage) Supply quality Demand External demand as proportion of total annual demand Total demand Per capita demand Internal demand (domestic and industrial) Supply and Demand System security/Restrictions (frequency, severity and duration) Stormwater Urban flooding (frequency, severity, location) Re-use (volume, percentage) Water quality (system quality targets, within exceedance limits) Infrastructure Re-use infrastructure (coverage, treatment standards) Peak demand operation (ability to meet peaks) Sewerage Uncontrolled release (flooding) Re-use/controlled release (proportion, treatment standards)
Rural water systems Supply System security (frequency of supply) Bulk entitlements met Irrigation cap Water quality Environmental flows (volume and frequency) Demand Proportion of cap allocation Spot pricing On-farm storage On-farm dams (numbers and coverage) Infrastructure Saline discharge (drainage, re-use) Groundwater recharge Short-term peak demand
25 Hydropower Flow volume Peak power demand
Catchments Catchment Management Land-use systems (targets for quality, e.g. biodiversity, forest, grassland) Salinity affected (area, trends, improvement) Degraded land (area, trends, improvement) Nutrient runoff (flux per unit area) Watershed management Runoff yield Runoff quality Forestry Fire (frequency, magnitude, wildfire and controls) Environmental buffers (compliance rates) Regrowth/runoff relationship Dryland farming Production/water use relationship Runoff quality/yield CO2 mitigation Tonne C per ha/yr fixed Groundwaterwater recharge Estimated mm pa
Waterways Waterway management Water quality (system targets) Riparian vegetation quality (condition, bank length) Aquatic fauna/indicator species Water quality (SEPPs) Flood management Flood frequency Flood height Wetland management Volume/frequency relationships (set by management plans) Water level (safe limits of time and duration) Water quality Aquatic flora & fauna quality Bird breeding events (population size and health) Environmental flows Volume/frequency relationships Water quality Quality indicators Recreational uses Water level Water quality (especially algal blooms) Workshops
Breakout groups were formed to investigate the following questions for the general topics of: • Urban water supply • Rural water supply
Each breakout group was asked to discuss the following 1. What activities are resilient/vulnerable to climate? What are the adaptations and critical thresholds? 2. What are the planning horizons in use/should be considered? 3. Who manages these activities, who is affected and what are the gaps in management? 4. What policies affect these activities?
Urban Water Systems
1. What activities are resilient/vulnerable to climate? What are the adaptations and critical thresholds?
Victoria’s urban water systems are generally resilient to variations in interannual variability. Melbourne’s urban water supply is one of the few places in the world where a system of closed catchments supplies a major urban centre. Since the construction of the Thomson Dam in the late 1980s, high per capita storage rates have largely quarantined Melbourne from restrictions. The last
26 five years has seen below average rainfall, but restrictions were not implemented until November 2002. The Barwon-Geelong system and others have not been as resilient over the same period. Some other smaller systems are more prone to restrictions and water quality problems than are the major systems.
Although climate change is expected to increase demand due to higher temperatures and evaporation rates, external (outdoor) demand can be managed through encouraging greater efficiency of use and water recycling. The picture for supply is less clear. Urban water supply systems face the greatest risk from sequences of dry years. These can arise from declining trends in rainfall, combinations of El Niño episodes and or changes in decadal rainfall regimes. The recent recognition of past changes in decadal rainfall and modelling that shows how such events may combine with changes in mean rainfall will be a most critical issue for future water supply in Victoria.
The following activities were nominated as providing criteria from which thresholds may be constructed: System security – all systems are designed and operated to meet a given level of security under normal operations (e.g., a stationary climate). Water rights – customers are guaranteed a level of supply based on a water right, which is increasingly being recognised as a property right (The Crown has title to runoff which it can licence or grant as a right which is made tradeable under the COAG water reform process). Sales water – the frequency with which varying volumes of sales water (in addition to water right) is made available. Sale/spot prices – trading of sales water is subject to demand, with higher value activities pricing out lower value activities. This is an issue for systems carrying both urban and rural water supply. State Environment Protection Policies (SEPP) – these policies contain regulations governing many areas of the environment but of relevance here are those governing waste discharges, water quality and the aquatic environment. In general, these regulations specify levels of quality that should be maintained. Bulk entitlements – entitlements made available to different water authorities. These entitlements are designed as having a specified level of security and also contain associated requirements for sustaining environmental flows. Water quality – mainly related to land-use, changes in farming from extensive to intensive land-use can alter water quality of agricultural runoff. Criteria can be designed to manage nutrient fluxes from different land-uses as they relate to nutrient loads in runoff and streamflow. Salinity – salinity criteria are twofold: salt loads affecting water quality, measured by concentration and end of valley targets for salinity management plans, and area of the catchment affected by high water tables. Regulations and targets – consumption targets setting limits on per capita water use and proportion of recycled water are increasingly being used by governments to limits resource use and increase efficiency. Water quality targets (e.g. the WHO limit for fresh water) can also be imposed. Catchment streamflows – changes in catchment yield can also be a useful measure as they impact on many of the above criteria.
2. What are the planning horizons in use/should be used
• Water Resource Planning Strategy for Melbourne is foresighting the next 20 years (reference). • Engineering design lives can exceed 100 years for major trunk systems. • Urban planning horizons are about 20 years (Melbourne strategy). • Peak flow design needs to follow and anticipate development.
3. Who manages this area, who is affected and what are the gaps?
• Melbourne Water • Water Supply Companies (South East Water, City West Water, Yarra Valley Water), also regional authorities (North East Water, Murray-Goulburn Water etc)
27 • Catchment Management Authorities • DSE • EPA • Department of Infrastructure • Developers • Agricultural Industry • Consumers
Gaps in knowledge include: • Social resilience – e.g. how do people adjust to water restrictions or planned limits? • Scientific unknowns regarding climate – particularly impacts at the regional and local level.
4. What policies affect this area?
• Strategy for Melbourne • EPA • Department of Infrastructure Development Policies • Local Government / Urban Land Authority / Major developers • Government requirements for drought planning, levels of service provided by water authorities, business planning/performance requirements for water authorities.
Issues for the Urban Sector • Sustainability of the built environment • Social acceptance of climate variability (e.g. drought is normal) is only partial • Increased expectations of natural resource management as they affect service delivery • High treatment standards for recycled water may not always be required, as only a small amount of total water use is for human consumption, i.e. water quality could be much better matched with end-use. • Environmental quality of the catchment, greater awareness of environmental flows • Climate change may accelerate the pace of environmental management (speeding up so-called • “no regrets”).
Rural Water Systems
The regulatory responsibility of rural water systems is listed in Table 2.4. The other questions were explored through the use of six critical control points (CCP) and are listed in Table 2.5.
Table 2.4 Regulatory Environment for the Water Industry in Victoria Function Metropolitan Water Sector Non-Metropolitan Urban & Rural Water Sectors Pricing Minister for E&C Minister for E&C Customer Service ORG Minister for E&C Resource Allocation Minister for E&C Minister for E&C Environmental EPA EPA Drinking Water Quality Minister for Health, Minister for Health, Minister for E&C Minister for E&C Notes: E&C: Environment and Conservation EPA: Environment Protection Authority ORG: Office of the Regulator-General
28 Table 2.5 Critical control points for the rural water system Area Critical control point Catchment and watershed 1. Climate inputs 2. Land-use, catchment management, runoff, streamflow, storage Infrastructure and environment 3. System losses Allocations 4. Allocations to environmental flows, and irrigation and urban diversions Streams and wetlands 5a. Environmental flows Diversions 5b. Reticulated and gravity-fed diversions Water use 6. Use at enterprise level e.g. farming, industry
CCP Resilience/ Planning Horizon Who, What, Policy vulnerability Where? Environment CCP1 Resilient and 20–50 years State Gov., Intensity flexible in the past water Amount authorities, Variability general Seasonality community, government research CCP2 Highly sensitive to 20–50 years Research: Land use climate change CRCCH, Stream function Relatively CSIRO, DSE Forestry vulnerable due to infrastructure Ris considerations CCP3 Increase in Salinity targets State Restoring Flow Seepage evaporation, 2015 government, to the Snowy Evaporation decrease in rainfall has made system water authorities River, loss more Environmental problematic Flow reform CCP4 Environmental Water review every State Water Industry Allocation flows are most five years government Act 1994 (Urban between vulnerable water) environment, rural Water Act 1989 and urban (Rural water) CCP5a & b As above. Managed EPA National Management of diversions fairly Competition environmental resilient Policy (Part IV flows/diversions of the Trade Practices Act 1974) Water Service Agreements Restoring Flow to the Snowy River CCP6 Ongoing to 5 years Use at enterprise level
29 Conclusion
Projections of rainfall change and potential evaporation for Victoria (Whetton et al., 2001; CSIRO, 2001a) and modelling based on those changes (Jones et al., 2000; CSIRO, 2001b) indicate that reductions in water supply are likely for much of Victoria. The adaptive capacity of water management on both urban and rural supply systems to interannual climate variability is high, but the risks of longer-term, sustained reductions of water supply remain unknown.
As noted in the Introduction, Victoria’s surface water resources are already highly utilised. Of the Surface Water Management Areas defined for the purposes of the NLWRA, in relation to volumes of water already allocated, one SWMA was assessed as being over developed (the Wimmera-Avon), 21 were assessed as being fully developed, three as highly developed, three as having a medium level of development and four as having a low level of development. (Fully developed catchments include the remaining SWMAs in the MDB; SWMAs in the Gippsland Area – pending the outcome of the Gippsland Lakes Environmental Study; the Yarra and Moorabool Rovers – pending the outcome of the Streamflow Management Plan Process; and the Hopkins and Lake Corangamite SWMAs – due to water quality constraints).
While the Bulk Entitlement Market Conversion process has lead to improvements in environmental flows for various rivers around the State (in about 90% of the systems where entitlements have been converted to date), it does not typically result in environmental flow provisions that fully meet the needs of the environment. Any decreases in resource availability due to climate change therefore have the potential to erode security of supplies for existing water users and to further stress the environment. Water reform is continuing under the jurisdiction of the Council of Australian Governments (COAG), with parallel efforts to ensure sustainable use of both surface and groundwater. The exploration of ecosystem services is also raising the issue of both wetland and stream quality for services such as recreation and water quality with direct benefits to the economy and non-economic criteria in terms of quality of life.
Water futures have become a highly political issue in Victoria. For instance, the issue of securing increases in flow for the Snowy River from diversions to the Murray-Darling Basin. The level of concern within the community about water resources, salinity and water quality, particularly in rural regions, mean that water is a very high profile issue. The water reform process has contributed to significant increases in high-value agricultural productivity (see Agriculture Chapter) but increases in sustainability are more difficult to achieve. Ongoing decisions are being made that will have ramifications for decades, and the possibility that climate may reduce supply has not yet been explicitly factored into such decision-making due to large uncertainties. The current drought has raised the issue of long-term water security in a changing environment increasing the need for information about long-term risks to water supply.
The issue of catchment management is pervasive and complex. The post-workshop analysis showed how tightly land and water management tied to catchment issues. Major catchment interactions, such as those between climate change and salinity, and how climate may affect salinity management options, is a key issue for catchment management. Land-use changes pursuing greater productivity, salinity amelioration, habitat improvements and carbon sequestration will affect water quality and supply, and climate change will in turn affect all of these factors. Future research needs to investigate how the external drivers to the system (rainfall, evaporation) are likely to affect water resources but Figure 2.1 shows how important integrated assessment is. Internal drivers in the system (land-use change, catchment management) interact with the external drivers and are themselves be modified to produce complex interactions affecting factors such as productivity, water quality and water supply.
Integrated assessment of climate risks will need to be factored into ongoing market reform of water resources, land-use planning and catchment based strategies for improving water quality, river health and environmental flows.
30 Chapter 3 – Agriculture
Introduction
Victorian has a diverse agricultural industry, consistent with its wide range of climates and soils. Agricultural activities range across a broad range of climates, from semi-alpine to semi-desert environments. To thrive, agriculture has had to adapt to these diverse environments along with high climate variability. However, production rates are generally higher than the Australian average due to comparatively good soils and climate. The agricultural sector is vital to Victoria’s economic, social and environmental outlook, accounting for about 35% of Victoria’s exports. Previous research
Research describing Australian agricultural impacts is described in Pittock and Wratt (2001). Although most of the study sites discussed are not in Victoria many of the conclusions are relevant to Victorian conditions. The role of agriculture regarding ecosystem goods and services is described in Gitay et al. (2001). Generic results can also be obtained from other regional chapters in the IPCC TAR (McCarthy et al., 2001) and previous IPCC reports (Watson et al., 1998; Watson et al., 1996). Although there is a great deal of knowledge in Victoria about the relationship between agricultural performance and current climate there has been little work extending this to climate change. The broader interactions relating climate, land capability and current activities at the landscape scale are poorly known, and need to be interpreted in the light of studies carried out elsewhere.
Plant growth rates and drought tolerance is expected to increase due to the fertilisation effect of increased atmospheric CO2, but the benefits to agriculture may be counterbalanced by decreases in moisture availability in some regions and seasons. Because climate change and its impacts relative to greenhouse gas emissions are delayed by several decades, initial benefits of higher CO2 may later be outweighed by later losses. Later this century, increases in temperature exceeding 2–4°C accompanied by decreases in rainfall may result in net losses in productivity compared to current levels (Pittock and Wratt, 2001). Therefore, although there may be net benefits in the short term, these may not continue over the longer term.
Potential adaptation to changes in agriculture tends to be highest where the industry has good access to technology, the ability to diversify and the economic capacity to apply them (Gitay et al., 2001). Compared to many other counties and regions, Australian agriculture is well adapted to climate variability, and this capacity will be a great benefit under climate change. However, as both mean and variability change, new extremes of variability will test this capacity, which needs to anticipate such changes.
The greatest risks are not those faced by individual activities but come from the integrated affects of a number of factors, of which climate change is only one. The negative impacts of agriculture, for instance effects on stream quality, dryland and irrigation salinity, greenhouse gas emissions, and degradation and loss of natural habitat all require changes to be made. Previous research has mainly concentrated on single elements of this list. Climate change adaptation could also deal solely with climate but it makes much more sense to take a much broader approach that deals with agriculture in a more holistic manner. Climate-impact relationships
We report here on the relationship between climate variables and impacts explored in the workshop. Aspects of particular climate variables were chosen for their relevance to the agricultural sector (Table 3.1). For instance, mean temperature of the growing season was explored in preference to annual mean
31 temperature. Primary and secondary climate variables are situated on the vertical axis. The agricultural variables on the horizontal axis were chosen as farming sectors that show a similar range of characteristics with respect to climate (except hobby farming). The last four variables are process oriented. The interactions between climate variables and individual activities listed in rows are shown. These interactions are subjectively weighted on a score of one to three denoting a weak to strong relationship.
Table 3.1 Key climate variables / activities matrix. Interactions are weighted on a score of one to three denoting a weak to strong relationship.
KEY CLIMATE VARIABLES / ACTIVITIES MATRIX Viticulture Horticulture (fruit) Vegetables Agroforestry land) (state Forestry Crops Perennial Large scale cropping (grains) crops irrigated Summer Grazing Pastures (dryland) (irrigated) Pastures Livestock industry Dairy Pigs) & (Chickens Livestock Intensive Aquaculture? Hobby farming (soil) matter Organic Nutrient balance Weeds Salinity Rainfall (av.) 22132331 232221121122 38 Rainfall (seasonal/variability) 32211231 23122 111123 34 Summer drought 232 2 2 2212 1 1 20 Autumn break 1 13 122 2 11111 17 Post anthesis rainfall 2 11116 R (sowing/growth/harvest) 213 2321115 Rainfall (daily intensity) 111 1 11 1 1 13 12 T (growing season) 33311232 221211229 Temp (daily) 11 1 1 1 5 T ( >35°C) 223 111 1133311 1 24 Frost 3221 112 1111 16 Chilling/vernalisation 121 15 Humidity/Temp 33211122 111332 1 1 28 Evaporation22211 12 22 21111 21 Wind 22111 1 22111 15 Hail 332 111 11 13
CO2 22233222 111 2 11121 29 Sunshine/cloudiness 22111111 1111 1122121 UV exposure 22211111 11122 1 1 20 Weather changeability 11 22 1 1 8 Water availability 223111133133333212 240 Irrigation supply 333 3 3 12211111 25 Flood 113 1 11111132 1 22 22 Soil moisture 33322233 22313 22122 41 Waterlogging 11 1 11111 11113 15 Fire 1 23111 211121111 20
48 46 43 19 18 27 34 32 20 26 25 27 36 13 18 26 16 17 26 22
Table 3.2 shows the results from Table 3.1 ranked in order of significance. Totals of the primary and secondary climatic variables are in the left-hand column and the agricultural variables are on the right. The large totals for moisture-related variables show how Victorian agriculture is generally rainfall, rather than temperature, related. Also important are the growing season temperature, stock comfort levels and atmospheric CO2. The climate drivers with less weight tend to show some important interactions, but they are less widespread in their impact. The agricultural variables in Table 3.2 tend to decrease in economic yield per unit area from the top of the page, showing that most high yield activities are affected by many climate hazards. Although all agriculture focuses closely on climate, for these activities, climate hazards are numerous and the financial risks are high.
32 Table 3.2 Prominence of key climatic drivers affecting catchment and water activities on the left and those activities affected on the right, showing the total weightings from Table 3.1.
Key Climatic Drivers Activities Affected 41 Soil moisture Viticulture 48 40 Water availability Horticulture (fruit) 46 38 Rainfall (av.) Vegetables 43 34 Rainfall (seasonal/variability) Dairy industry 36 29 T (growing season) Large scale cropping (grains) 34
29 CO2 Summer irrigated crops 32 28 Humidity/Temp Perennial Crops 27 25 Irrigation supply Livestock 27 24 T ( >35°C) Pastures (dryland) 26 22 Flood Hobby farming 26 21 Evaporation Weeds 26 21 Sunshine/cloudiness Pastures (irrigated) 25 20 Summer drought Salinity 22 20 UV exposure Grazing 20 20 Fire Agroforestry 19 17 Autumn break Forestry (state land) 18 16 Frost Aquaculture? 18 15 R (sowing/growth/harvest) Nutrient balance 17 15 Wind Organic matter (soil) 16 15 Waterlogging Intensive Livestock 13 13 Hail 12 Rainfall (daily intensity) 8 Weather changeability 6 Post anthesis rainfall 5 Temp (daily) 5 Chilling/vernalisation
Forcing variables Relay variables
CO2
Rainfall variability
Rainfall average Sunshine/cloud Soil moisture Salinity Temperature (season) Weeds Autumn break Water avail. Summer drought Daily rain Hobby farming Soil organics Temp (>35) Flood Irrig. supply Evaporation Hum/temp Waterlogging Wind Nutrient balance Rainfall (grow) Fire UV exposure Frost Irrigated crops Temp (daily) Agroforestry
Forcing Power Weather change Forest (state) Grazing Rainfall (post-anth.) Pasture (dry & irrig.) Perennial crops Hail Broadacre cropping Dairy Viticulture Livestock Horticulture Chilling Intensive stock Vegetables Aquaculture Dependent variables Dependency (Sensitivity)
Figure 3.1 Forcing/dependency diagram. Forcing increases up the vertical axis and dependency along the horizontal axis. Forcing variables (solid squares) act on the system and are little modified by it. Relay variables (diamonds) force the system but are also modified by it. Dependency variables (open squares) have limited interactions within the system but may be important for individual processes. Dependent variables (circles) do not significantly affect the system but are greatly affected by it.
33 A cross-impacts matrix was constructed from both the climatic and agricultural variables. The matrix is not shown but has been integrated into a forcing dependency diagram (Figure 3.1). The key climate variables and agricultural activities from Table 3.2 are combined into the one series, which is repeated as a series forcing variables on the vertical axis and dependent variables on the horizontal axis. If a variable on the forcing axis produces a reaction on the dependent axis then one is added in the corresponding matrix square. The totals are shown in Figure 3.1. The forcing variables in the upper left quadrant are largely external to the system and are dominated by climate variables. If any of these change then a significant system response would be expected. The relay variables that contain most of the major feedbacks within the system consist of environmental variables, and climate variables that are themselves modified by the system (e.g. through land surface – climate feedbacks). Autonomous variables occupy the lower left quadrant and have only limited impact within the system. However, there are a number of variables in Figure 3.1 that are important in specific situations, such as frost, hail and abrupt changes in weather. As might be expected, the majority of agricultural sectors are dependent variables. These have a limited impact on the system but are dependent on both the forcing and relay variables. These are the variables most closely related to the criteria linked to thresholds and risk. Performance criteria / thresholds
The agricultural sector utilises numerous production- and quality-related thresholds to measure output performance. The links between many of these thresholds and climate variables are well known. Table 3.3 shows a number of quality-related criteria for agricultural yield and performance nominated at the workshop. There are a number of available models, capable of representing these relationships in terms of current climate.
Table 3.3 Agricultural activities and performance criteria Activity Performance criteria Viticulture/horticulture 10/10/10 threshold Colour Brix Yield Sugar content Health/Disease Size Pests Grains Pesticide/herbicide contents Weed contamination Grain protein Oil content Screenings Grazing (stock) Disease Wool quality (fineness, weathering and contaminants) Stock losses Age at maturity Carcass quality (size, shape, yield and fat content) Grazing (pasture) Carrying capacity (normal and drought) Seed production and soil seed store Toxic plants Weeds Dairy Milk yield (also Grazing – pasture and Butterfat stock) Protein
34 Workshops
Breakout groups were formed to investigate the following questions for the general topics of: • Extensive agriculture • Intensive agriculture
Extensive agriculture
1. What areas are resilient/vulnerable to climate?
• While much of the extensive grazing/cropping agriculture industry is well adapted to climate variability there are gains to be made in relation to productivity. • Improvements in sustainability still need to be made, especially in the area of soil degradation, salinity, fertiliser application, biodiversity in agriculture, water use and farm chemicals but this an ongoing process that is consistent with many of the aims of adaptation in agriculture.
The socio-economic areas of agricultural resilience were concentrated on: • Farming community demographics • Family farming structure • Corporate farming • Debt loads, financing, off-farm income • Economic reform is a huge driver, often masking other impacts • How farmers manage high income variability • Supply infrastructure and price • Land tenure • Supporting industrial infrastructure (post-processing etc)
2. What are the planning horizons in use/should be used?
The Individual – ongoing: seasonal to yearly Whole farm planning – 5 to 10 years+ Herd Planning – 10 years+ Industry/organisation – 5 to 25 years Agroforestry/Tree crops – 12 to 30+ years Sustainability – Intergenerational Salinity – 15 to 500 years Soil formation – hundreds to thousands
3. Who manages this area, who is affected and what are the gaps?
Managers include individual farmers, farmers’ groups, CMAs, R&D corporations (including DPI), DPI and DSE policy, government and industry through planning and infrastructure. One of the largest gaps is the mismatch between institutional timeframes and policy/funding timeframes. The industry needs sufficient cashflow to invest in adaptation, especially to use productivity increases to enhance sustainability.
4. What policies affect this area?
DPI has significant research capacity and, Purchaser – Provider relationships determine research priorities by commissioning research (a research policy relationship). The line between researchers and managers is also becoming blurred, as partnerships and stakeholder interactions become more prominent.
35 The following sample of current policies affect agriculture: • Forestry Rights Amendment Bill • Environmental Flows in the Snowy River • Clean and Green • Organic Farming Strategy • Water Allocations Bill • Triple Bottom Line policy • Farmsmart • Drought Exceptional Circumstances and various reform and deregulation plans.
Intensive agriculture
Perennial horticulture
1. What areas are resilient/vulnerable to climate?
• Well adapted through irrigation (6% of the water to high return activities). This high return will allow perennial horticulture to compete with lower value activities for reduced water supply. • May be vulnerable to higher temperatures (e.g. cherries can be marginal at present) • Stone fruit in many areas is also close to temperature limits for chilling • Frost, humidity, hail are all short-term sources of climatic vulnerability
2. What are the planning horizons in use/should be used
• Breeding low chill takes ~20 years • Productive life of trees generally 20–40 years • Annual (for water supply) • Turnover at 10–20% per year
3. Who manages this area, who is affected and what are the gaps?
• All members of industry • Growers/producers associations • RDCs as research commissioners • DPI as resource manager and researcher
Gaps • No climate change breeding • Reduced chilling breeds generally lower quality • Change in length of growing season on quality • High CO2 varieties
4. What policies affect this area?
See extensive agriculture above for policies. The push towards high value agriculture was noted. Further suggestions included managing current disease problems better, and taking account of changing relationship between disease and chemical use under climate change.
Annual horticulture Winter grains under irrigation, vegetables and strawberries
1. What areas are resilient/vulnerable to climate?
• Less vulnerable than perennial horticulture.
36 • More able to cope with higher temperatures (esp. less frost) except cold weather varieties • Relatively straightforward to breed • Pest and disease issues similar to perennials • Vegetables are less planned as an industry, and the pressure on reducing chemicals is significant • Prices under pressure from processing industry buyers
2. What are the planning horizons in use/should be used
Mostly short-term horizons. Longer-term financial horizons are required to service capital costs.
3. Who manages this area, who is affected and what are the gaps?
Vegetable growers/product groups Horticulture Australia Ltd. DPI as resource manager and researcher CSIRO Consultants
Gaps Relationship between biocontrol and pests Reduced chilling breeds generally lower quality in Brassicas, garlic etc Knowledge of temperature tolerance of current varieties High CO2 varieties
4. What policies affect this area?
As for perennial horticulture Conclusion
Victorian agriculture is highly resilient, having adapted to large climate variability, but more importantly, to ongoing social and environmental change. From being the largest employer and sector of Victoria’s economy for much of the 19th and 20th century, economic intensity per unit area is increasing, but agriculture as a proportion of the total workforce and the ratio of economic intensity to number of people supported per unit area have never been lower. However, agriculture remains the most widespread activity in terms of land area, shaping the Victorian landscape, rural economy and rural society. Social or “lifestyle” factors rate very highly in agriculture, as do the demands in terms of workload. Financial security has been a negative in terms of recruitment to the industry.
The challenge for agriculture in the 21st century is to envision and construct an industry that is productive and sustainable. During much of its history, agriculture has been conducted as if many things would remain unchanged: the climate, the natural resource base and even social and community structures (e.g., land being held in the same family for generations) have all been assumed as constants. Yet, the future brings the challenges of climate change, land and water degradation, and social change as well as changes in the economy and in technology. Sustainability, or the transition to sustainability, is not to anticipate some future state of equilibrium but should be looked at in terms of ongoing adaptation to projected changes and building resilience to surprises.
The following ten factors were offered as contributing to resilience in agriculture (Mark Howden, pers comm.): 1. Knowledge 2. Technical options 3. Governance: policies and institutions, property rights and tenure 4. Financial and social capital
37 5. Rural services 6. Off farm income/debt 7. Changes in supply and demand / trade balance 8. Fossil fuel prices (inc. fertilisers) 9. Pests and diseases / quarantine 10. Technology / natural capital relationship None of these factors are climatic, but all contribute to adaptation, and are also agents of change in themselves.
Two scales of engagement between agriculture and climate change can be discerned. At the enterprise level, the relationships between climate variability and criteria such as yield and quality are fairly well known. These relationships can be simulated using models allowing forecasts and quantified estimates of risk to be made. An improved understanding of management systems on short-term planning horizons will benefit agriculture at this scale. The further development of critical thresholds for stock and crops will allow for planning activities with longer-term horizons (e.g. horticulture, agroforestry).
At the landscape scale, where biophysical, economic and social systems all interact, accurate forecasts are not possible, especially over longer time scales. Tools such as scenario-building, foresighting and risk assessment utilising expert judgement need to be developed to manage on this scale. Their application requires interdisciplinary development in the sciences (biophysical, social and economics) along with the improvement of formal and informal links between government and the community. A major element of sustainability concerns the relationship between technology and natural capital. In the past, loss of natural capital has been accepted as part of technological development, and technological development has been accepted as a substitute for the loss of natural capital. Choices about the future of this relationship, and how it may respond with large-scale changes such as climate change, need to be investigated, and scientific frameworks developed to carry out those investigations.
The largest benefit agriculture is likely to face under the enhanced greenhouse effect is from increases in plant water use efficiency and growth rates due to higher levels of atmospheric CO2. This benefit is comparatively larger in water-limited conditions. CO2 forcing is immediate, because emissions mix fully in the global atmosphere in less than a year. Climate changes ensuing from higher rates of CO2 are delayed by several decades and sea-level changes by even longer. The downside is that higher rates of CO2 growth produce greater warming risks. The direction of rainfall change is not likely to be affected by the magnitude of CO2 growth but the amount of rainfall change will be. This delay in the benefit – cost relationship of CO2 growth and climate change leaves a window for adaptation, where higher productivity benefits can be used to adapt to coming climate changes. This will not be possible if those benefits are required to maintain current income in a world of increasing costs and decreasing real commodity prices.
The agricultural sector is also a significant emitter of greenhouse gases and will need to reduce emissions and sequester carbon in plants and soil to reduce the risks associated with climate change. Sequestration will be benefited by the delay in impacts also. Adaptation and mitigation in agriculture will be tightly intertwined at the operational level for such risks to be reduced. For example, higher atmospheric CO2, and changes in temperature and rainfall may increase wheat yields in the short-term at the expense of quality. One response is to add extra nitrogen fertiliser to increase the protein yield but which will also increase nitrous oxide emissions (a greenhouse gas).
The Agricultural R&D capacity within DPI is substantial but is mainly geared towards the shorter- term management aspects. This capacity could be increased to deal with changes to key climatic variables using the techniques described in this report and standard techniques addressed by McCarthy et al. (2001). The development of frameworks to investigated paths and goals for sustainability need to be developed but our understanding of how those frameworks could be constructed is very preliminary. The links between the agriculture sector, forestry, biodiversity, and catchments and water at the landscape scale are part of this and also need to be developed.
38 Chapter 4 – Biodiversity
Introduction
Victoria has a diverse biota, containing eleven Interim Biogeographic Regionalisation Zones (IBRA) developed at the request of the Australian and New Zealand Environment Conservation Council (ANZECC). These have been divided into a further 21 Victorian bioregions. Victoria’s biodiversity: directions in management (DNRE, 1997) sets out a framework for responding to the challenges in the management of biodiversity. One of these challenges is climate change. Nationally and internationally, one of the three aims of the UNFCCC in limiting dangerous anthropogenic climate change is to allow ecosystems to adapt naturally to climate change. This aim is reinforced in the National Greenhouse Strategy (AGO, 1998).
It is not yet clear how this can be achieved. Many of Victoria’s bioregions are in a depleted state after 165 years of post-European settlement, and some of the most threatened communities (e.g. temperate grasslands) are still being cleared. There is no doubt that recent years have seen reduced degradation in many ecological communities, while some, such as riparian vegetation, are being improved by activities such as Landcare, funded by community efforts and state and federal government funds. In Victoria, about 600 of the 4,000 vascular plant species are listed are rare, threatened or depleted. Under the Flora and Fauna Guarantee 193 plant species, 169 animal species and 33 ecological communities are listed on Schedules as threatened, and 27 processes are listed as potentially threatening. One such process is Loss of terrestrial climatic habitat caused by anthropogenic emissions of greenhouse gases. With regard to adaptation, two major questions can be raised: 1. What are the autonomous adaptations likely under climate change? 2. How can planning of future human activities enhance ecosystems’ natural ability to adapt to climate change? Previous research
Biodiversity issues are summarised in the IPCC WGII TAR Chapter on “Ecosystems and their Goods and Services” (Gitay et al., 2001). This chapter places climate change within the broader issue of global change, climate change being just one of a series of stresses on ecosystems and their services. Most climate change research in Australia has utilised bioclimatic models, most often BIOCLIM (Busby, 1988). In Victoria, a landmark study on 42 species of vertebrate fauna by Brereton et al. (1995) showed that all but one suffered reductions in their bioclimatic envelopes under a suite of six scenarios of temperature and rainfall change.
Changing areas of bioclimatic envelopes in Brereton et al. (1995) are tightly coupled to temperature change. We used linear regression on the warming / area relationships to estimate the temperature at which the envelope disappears. These thresholds were then related to the range of warming expected for Victoria to 2100. The results take into account the range of regional warming expected in Victoria (0.8 to 1.2ºC) and are illustrated as a function of global warming (refer to Figure 1.4). The horizontal lines show the range of species’ bioclimatic envelopes that may be exceeded for a given level of global warming. The boxes show the ranges of global warming projected for 2030, 2070 and 2100. The level of warming represented at base of each box is most likely to be exceeded, those at the top are the least likely to be exceeded. Although this provides an analysis of the risk of bioclimatic envelopes, the relationship with habitat and how habitat may change remains unknown. The risk will remain precautionary until more is known about how the ecophysiology of given species and the relationship with their bioclimatic envelopes.
39 Although this analysis applies some significant simplifications, it indicates a high level of vulnerability of the species assessed to global warming in the second half of this century (Figure 1.7), raising the following questions: • Will ecosystems migrate intact or recombine in new ways, perhaps in combinations that have no current or palaeo-analogues. • Will flora and fauna adapt, changing their climatic envelopes, perhaps in response to increased level of atmospheric CO2? • Will disturbance regimes, increased nutrient fluxes and higher CO2 result in certain groups of plants being favoured at the expense of others (especially weeds}? • What are the dynamics of migrating species over fragmented landscapes? • Will ecosystem services stay intact during migration, enhance or degrade? • Are species and ecosystems at risk of extinction under climate change?
8
7
6
5
4 2100 3
Warming (°C) Warming 2050 2
1 2030 0 010203040 Number of Species Date Range No of species’ envelopes exceeded 2030 Lower limit 0 Median 0–1 Upper limit 1–2 2070 Lower limit 1–2 Median 5–18 Lower limit 22–33 2100 Lower limit 1–5 Median 16–34 Lower limit 36–41
Figure 4.1. Temperature of exceedance of bioclimatic envelopes for 42 vertebrates species with results for ranges (lower, median and upper) in 2030, 2070 and 2100 (data adapted from Brereton et al., 1995). Climate-impact relationships
At the Biodiversity Workshop, climatic variables were linked with specific activities utilising or managing the natural biota. Particular climate variables were chosen for their relevance to ecosystem processes. Primary variables are climate variables and secondary variables are those that are a direct consequence of climate such as flood and fire and derived variables such as the climatic envelope.
40 Three major types of biodiversity variable were chosen: broad vegetation types, major processes or descriptors and human activities either managing biodiversity, or significantly affecting natural systems. An interaction matrix was created to show how strongly climate variables affect different activities and how widely those activities are affected (Table 4.1).
Table 4.1 Key climate variables / activities matrix. Interactions are weighted on a score of one to three denoting a weak to strong relationship. o d
KEY CLIMATE VARIABLES / ACTIVITIES MATRIX Alpine Grasslands ecosystems woody Alpine/subalpine Wet sclerophyll forests forests Sclerophyll Dry Woody grasslands Temperate grasslands Heathlands Shrublan Chenopod and heath Mallee Mallee, Wetlands Streams ecosystems Coastal Weed/Pest Infestation (gross disturbance) abundance/composition Species cover Area Fire Regime migration Species disturbance mechanical Gross Management strategies (incl. Tourism/recreati Recreation Park management Alpine tourism (+off season) sequestration) (carbon Mitigation Forestry Agriculture Urbanisation Landcare and bushcare Habitat destruction Duration of growing season 33211111 122 12 2 11223 1 33 Temperature extremes (minima) 22 111 12 11 2 2 1 17 Temperature extremes (maxima) 11111111 11 2 11 1 111 18 Temperature 3322222322223233 123222212 55 Frost frequency 23112211 111 11 2111211 27 Rainfall 11332223332333221222233323261 Climate variability (ENSO) 22232223321222232211222313254 Seasonal extremes 3311111211 12222 11 21 2 1132 Climatic envelopes 33322223112232121322323313 57 Fog drip/humidity 222111111112212 11 23 Extreme winds 22112222 3222123222312211245 Prevailing winds (species migrations) 1 112 211 3 1 1 14 Lightning 11111111 111 2 21111 1 1 121 UV 11 11111 1 1 111 1 113
CO2 fertilisation 2333323331233222 2 2133313?58 Atmospheric nutrient flux111111111 2111 2122 21 Duration of snow cover 331 111113 15 Soil/water temperature 22111111221221 1 1 22 Soil condition (temp/mois) 222222221112221 21222 2 37 Soil nutrients 222222323323321 2 1132322350 Soil acidification (human induced) 111 231221 1 1 2 3 2123 Groundwater depth/flow 1111223322212 1 2 11212133 Runoff 22222211231111 2222122332 44 Water flow 33 22 1211 15 Floods (red gum regen) 121 33 321 12222 231131 Salinity 121 3221223 2322 22313339 Fire 211233331 11323 2323133323254 Mean sea level 12 3 Storm surge 22 4 43 43 33 34 39 36 35 41 43 34 34 43 49 32 28 24 21 33 27 35 29 35 34 51 26 37 20
The interactions between primary and secondary key climate variables on the vertical axis with activities listed in horizontal axis are shown. These interactions are weighted on a score of one to three denoting a weak to strong relationship. The weighting is subjective and meant to be interpreted based on the pattern of results rather than through individual interactions. Table 4.2 shows the totals of the primary and secondary climatic variables in the left-hand column and the biodiversity variables on the right. The primary climatic variables have the largest effect, but closely related variables such as fire and soil condition are also important. Atmospheric CO2 is a large driver but its impacts are poorly known. All the activities taking place within or interlinked with the biodiversity sector rated highly. Grouped variables such as agriculture and species abundance/composition (related to population and structure) rating the highest with alpine ecosystems, wetlands and weeds and pests all being prominent.
41 Table 4.2 Prominence of key climatic drivers affecting catchment and water activities on the left and those activities affected on the right, showing the total weightings from Table 4.1. Key Climatic Drivers Activities Affected 61 Rainfall Agriculture 51 58 CO2 fertilisation Species abundance/composition 49 57 Climatic envelopes Alpine Grasslands 43 55 Temperature Alpine/subalpine woody ecosystems 43 54 Climate variability (ENSO) Wetlands 43 54 Fire Weed/Pest Infestation (gross disturbance) 43 50 Soil nutrients Mallee, Mallee heath and Chenopod Shrublands 41 45 Extreme winds Woody grasslands 39 44 Runoff Landcare and bushcare 37 39 Salinity Temperate grasslands 36 37 Soil condition (temp/mois) Heathlands 35 33 Duration of growing season Park management 35 33 Groundwater depth/flow Mitigation (carbon sequestration) 35 32 Seasonal extremes Dry Sclerophyll forests 34 31 Floods (red gum regen) Streams 34 27 Frost frequency Coastal ecosystems 34 23 Fog drip/humidity Forestry 34 23 Soil acidification (human induced) Wet sclerophyll forests 33 22 Soil/water temperature Management strategies (incl. Tourism/recreation) 33 21 Lightning Area cover 32 21 Atmospheric nutrient flux Alpine tourism (+off season) 29 18 Temperature extremes (maxima) Fire Regime 28 17 Temperature extremes (minima) Recreation 27 15 Duration of snow cover Urbanisation 26 15 Water flow Species migration 24 14 Prevailing winds (species migrations) Gross mechanical disturbance 21 13 UV Habitat destruction 20 4 Storm surge 3 Mean sea level
Forcing variables Relay variables
Climate variability (ENSO) Rainfall Urbanisation Habitat destruction Agriculture Seasonal extremes Spp abund. & comp. Temperature Forestry Management Park management Landcare and Bushcare Area cover CO fertilisation Recreation 2 Extreme winds Disturbance Soil cond. Runoff Fire Weeds & pests Climatic envelope Mitigation Fire regime Growing season Groundwater Soil nutrients Extreme max T Lightning Salinity Frost Extreme min T Soil&Water temp Wetlands Floods Atmos. nutrients Fog/Hum. Wet forest Coastal Snow cover Alpine tourism Dry forest Woody grassland Utraviolet Soil acid. Streams Forcing Power Forcing Prevailing winds Spp. migrat. Temp. grassland Heathlands Water flow Alp. grassland Alpine forests Mallee
Sea level Storm surge Dependent variables Dependency (Sensitivity)
Figure 4.2. Forcing/dependency diagram. Forcing increases up the vertical axis and dependency along the horizontal axis. Forcing variables (solid squares) act on the system and are little modified by it. Relay variables (diamonds) force the system but are also modified by it. Dependency variables (open squares) have limited interactions within the system but may be important for individual processes. Dependent variables (circles) do not significantly affect the system but are greatly affected by it.
42 A cross-impacts matrix was constructed from both the climatic and biodiversity variables. Due to its complexity, the matrix is not shown, but the results have been integrated into a forcing dependency diagram (Figure 4.2). If a variable in the forcing column produces a reaction in the dependent row then one is added in the corresponding matrix square. All scores were then tallied and plotted. The forcing variables in the upper left quadrant are largely external to the system and are dominated by climate variables. If any of these change then a significant system response would be expected. The relay variables are dominated by process- and management-related variables, and secondary climate variables such as fire that are themselves modified by the system. Autonomous variables occupy the lower left quadrant and have only limited impact within the system, although individual interactions can be important (e.g., snow cover is vital for alpine systems).
Broad Vegetation Types are dependent variables within this system. These have a limited impact on the system but are dependent on both the forcing and relay variables. These are the variables most closely related to the criteria linked to thresholds and risk. Performance criteria / thresholds
Biophysical thresholds that mark a sudden shift on a spatial or temporal scale, or a change in state, are important in the observation and measurement of ecological processes. Biological thresholds range from ordinary events such as breeding and migration (including most phenological behaviour), to extraordinary events such as extinction. Management thresholds involve a behavioural trigger that is activated by a given sequence of events, often structured around biophysical thresholds. The use of thresholds as criteria for assessing risks to biodiversity under climate change have been discussed by Markham (1996), and Jones and Pittock (1997).
The many studies of biodiversity impacts that have so far taken place generally involve the application of one or a few climate scenarios and have not been able to quantify the likelihood of outcomes. Despite this, some Australian species of flora and fauna are highly sensitive to even small changes in climatic envelope, where thresholds such as ranges within reserves, or current suitable habitat have been exceeded with several degrees of warming and limited rainfall change (e.g. Figure 4.1. Other species appear to be quite robust.
The use of performance criteria in measuring biodiversity either within a biodiversity sector or in conjunction with other activities such as agriculture is in its infancy. The recent discussion paper on Incorporating Biodiversity into Environmental Management Systems (EMS) for Victorian Agriculture (Anderson et al., 2001) discusses the need to develop specific performance standards to manage the impact of agriculture on biodiversity. Such standards can also be used to assess risk and to set targets used to monitor the performance of adaptation to climate change. The Biodiversity Reporting Framework flagged in the Victorian Biodiversity Strategy (DNRE, 1997) would also develop and use the criteria from which thresholds for climate change could be constructed. Workshops
Fire and biodiversity
Definitions 1. Wildfire 2. Control burns • Fuel reduction • Ecological • Regeneration
43 1. Investigate current impact thresholds to understand how well each sector is adapted to current climate (e.g. system resilience)
Baseline resilience to current patterns of wildfire/uncontrolled fire is high. Contributing to that resilience are: • Fast fire response • Improved management of power lines, etc. • Good resident education • Role of CFA as community volunteer organisation
Potential vulnerabilities under climate change include: • New areas that burn – limited resources for response and poor recovery • Fire sensitive areas at risk • Increase in critical fire factors • Altered fire behaviour • Shifts in flora and fauna to greater fire tolerance • Tourism patterns change • Greater air pollution concerns affecting control burns • Increase in Total Fire Bans • Longer restriction season • Benefit for some fire-dependent communities • Altered number of safe days for control burns • Insurance cover changes • Sequestration at risk • Decision-making becomes more complex • Smoke in biomass burning increases as part of carbon cycle • Fire-regrowth-water production relationship changes • Urbanisation affecting fuel reduction burns, increases in mowing, weeds etc • Increases in tree mortality • Changes in NPP/litter production • Water availability for fire fighting • Increased demand on control of wildfire/“hot” burns
2. Link stakeholders and policies with relevant planning horizons
• Ecological requirements (burning intervals for EVCs) • Short-term ENSO – Fuel load responses (seasonal fire danger) • Ecological and fuel reduction needs operate on different planning horizons • Planning tasks need to account for different pressures • Long-term plans better accounting for these factors are needed
3. Identify sources of data and knowledge
• Local government • DSE – public land • Parks Victoria (ecological burns) • CMAs and Water Supply Companies • Private landholders • Forestry Industry • Insurance Industry • Health Industry
4. Identify important gaps in responsibilities, data and knowledge
• Past fire regimes (wetland cores, sedimentology etc)
44 • Post fire succession • Post fire regrowth and water production • Lack of historical data • Understanding of refugia dynamics • Integrated knowledge of fire futures related to biodiversity, public health and property and planning
Regional habitat management
Priorities: Protect – Enhance – Restore Protection is the starting point but may be the only step in some cases
1. Investigate current impact thresholds to understand how well each sector is adapted to current climate (e.g. system resilience)
• Water and riverine habitats are perhaps the most vulnerable areas, e.g.: • Plains areas are the most highly fragmented, where most remnants are associated with streamlines and it is easy to get down to level of threatened species in such areas. • Salinity impacts are important but will depend on dryland revegetation and agricultural production • Allocation of water in maintaining freshwater habit is under threat because of reduced streamflow • Low productivity agricultural land doesn’t offer the best productivity response for sequestration and has limited current value for biodiversity • Migration is problematic in the time available, and corridors may not be sufficient for dispersal.
2. Link stakeholders and policies with relevant planning horizons
• Planning horizons for habitat management were considered too short, and are driven by political considerations. Fifty to 100 year planning time frames (and longer) are needed. • There is a need to build better community support for responses to greenhouse • Need planning over climate change timeframes. • Bulk water regime assumes stationary climate but there is likely to be less water – what are the operational planning horizons for these arrangements? • Political horizons are very short but property/water rights are long-term or in perpetuity • Greenhouse climate change needs broad agreement between different stakeholders with various planning horizons • Greenhouse is a driver to get better outcomes through the political process e.g. better water management, but the planning horizon needs to be about a century • Must treat greenhouse as a country and city problem for the environment • Management is very fragmented on public land, especially in aquatic and riverine management. • Problems often occur on private land, but there are very few regulatory controls available.
3. Identify sources of data and knowledge
Sources of knowledge are Arthur Rylah Institute, the Flora and Fauna management structure of DSE, Parks Victoria, Field Nats groups, Landcare, Conservation NGOs and the tertiary sector.
4. Identify important gaps in responsibilities, data and knowledge
The working group raised a large number of questions about biodiversity under climate change. Some of them are as follows:
• Is it possible to identify types of habitat, rather than individual species, that are likely to be vulnerable?
45 • Are forested areas particularly vulnerable to climate change? Need to know what the climatic envelopes of forest species are. • Is it possible to identify the most depleted, therefore the most vulnerable areas? • If riparian communities are vulnerable do they offer the best opportunity because of connectivity along streamlines (dispersal)? • Allowing ecosystems to move naturally may not be enough • Is the area of non-agricultural land sufficient to allow adaptation to climate change? • How do we overcome the lack of biodiversity in agricultural areas? • What are socio-political decisions implicated in buy-back? • Patch size is important but patch dynamics are less well known
Big Issues • How do we ensure that biodiversity is not lost when climate change becomes significant? • Biodiversity management is too often concerned with other (short-term?) issues when the substantial long-term impacts are poorly addressed. This includes total sequestration, not just managing for carbon credits, which is more a financial than physical mechanism. • Need to look to long-term planning for policy but also take advantage of short-term payoffs. Conclusion
Attendees to the workshop demonstrated the greatest lack of awareness of the relationship between climate processes and outcomes in the sector being investigated. In the second session, linking key climatic variables to impacts and outcomes was hampered (1) by a lack of general knowledge about climate–ecosystem links and (2) by the participants being unused to thinking of biodiversity as an active sector. Biodiversity was seen as a passive sector that is affected by most elements of the wider economy but not as part of it. Tourism, and to a lesser extent, forestry (although forestry is largely considered separate), were seen as the only actively commercial aspects of the sector. DSE and CSIRO have agreed to carry out another workshop for the biodiversity sector at the Arthur Rylah Institute involving professional participants to jointly explore the biophysical aspects of climate– biodiversity links (Held in March 2002).
The science of predicting the responses of both individual species and ecological communities to climate change, and how other processes (land degradation, fire, pests and weeds) may interact with climate change needs to be developed in Victoria. Both autonomous and planned responses need to be investigated. For example, Noss (2001) describes the following options with regard to forest management under climate change: (1) representing forest types across environment gradients in reserves; (2) protecting climatic refugia at multiple scales; (3) protecting primary forests; (4) avoiding fragmentation and providing connectivity, especially parallel to climatic gradients: (5) providing buffer zones for adjustment of reserve boundaries; (6) practising low-intensity forestry and preventing conversion of natural forests to plantations; (7) maintaining natural fire regimes; (8) maintaining diverse gene pools; and (9) identifying and protecting functional groups and keystone species.
The socio-economic aspects of the biodiversity sector also need to be investigated. Most people view the biodiversity sector as a passive, not as an active, sector of the economy. This is a significant obstacle to the assessment and implementation of planned adaptation to climate change, because it will require adaptation measures that incorporate economic factors being implemented through other activities (e.g., agriculture). The gulf between the environment and the economy in the public and political mind needs to be bridged before biodiversity can be treated as an active sector within the broader socio-economic landscape. This does not mean that all ecosystem elements and functions need to be translated into monetary terms but that the broader values of ecosystem services need to be addressed as a valid part of the physical and monetary economy. Some of the recent developments in assessing ecosystem services, incorporating non-monetary metrics into valuations and triple bottom line accounting that address stocks and flows in ecosystems will aid this process.
46 Chapter 5 Coasts
Introduction
The boundary between the ocean, atmosphere and terrestrial landscape at the coast creates a particularly complex region of interactions. Competing demands on coastal resources for food, energy, housing and recreation alongside the need to preserve natural ecosystems makes management of coastal regions a challenge for the appropriate authorities. The prospect of additional stresses brought about by the enhanced greenhouse effect serve to increase the complexity of issues and potential vulnerabilities facing coastal regions.
Various vulnerability assessments have been undertaken within Victoria. They have focussed mainly on the impact of a mean rise in sea level on tidal ranges in Port Phillip Bay (Black et al., 1990), the 1 in 100 year flood lines (Crapper and Wood, 1991), beach erosion (Coastal Vulnerability Study, 1992; Woodward-Clyde, 1995; Lawson and Treloar, 1995), inundation due to storm surges (McInnes and Hubbert, 1996; Woodward-Clyde, 1995). With the exception of the Coastal Vulnerability Study, all studies have tended to be location specific. In some cases the sensitivity of some of the findings of these studies have limited their dissemination and consequently resulted in little or no action taken upon their recommendations. Furthermore, a lack of data and information pertaining to current climate conditions can often cause difficulty in designing and conducting vulnerability studies under future climate change scenarios Climate-impact relationships
The key climatic variables used to link specific activities in the coastal sector affected by climate are shown in Table 5.1. These variables and activities were constructed in the stakeholder workshop and subsequently reviewed and modified. The key climate drivers are broadly grouped as meteorological, oceanographic and terrestrial. The impact areas, activities and issues are broadly grouped into coastal morphology, operations, artificial structures, legal issues and natural ecosystems. The weighting is subjective, the weighting coefficients have been based on expert opinion and each conclusion is open to different interpretations. The interaction matrix shows how strongly each climate variable affects and activity and whether each activity is affected by a wide or narrow range of climate variables.
Table 5.2 shows the prominence of key climatic drivers affecting coastal issues on the left and how much various activities are affected by climate on the right. The most important climatic variables are weather events that affect sea-level or aspects of sea-level itself. Mean sea-level rise is analogous to mean climate change while waves, surge and tides are analogous to climate variability. Combinations of those variables, occurring as extreme events, cause most severe impacts.
A cross-impacts matrix was constructed from the climatic variables and coastal elements shown in Tables 5.1 and 5.2. The matrix is not shown, but has been integrated into a forcing/dependency diagram (Figure 5.1). For an explanation of this diagram, see Chapter 2. The forcing variables in the upper left quadrant are dominated by climate and closely related marine variables. If any of these variables change significantly then a sizeable response in the relevant activity would be expected. Coastal processes and key coastal formations such as estuaries and bays dominate the relay variables. These are the sources of major system feedbacks. When external drivers, such as urban development, significantly modify relay variables changes cascade through coastal systems affecting the dependent variables in the lower right quadrant. The lower left quadrant contains climate and marine variables that have
47 only a limited affect on the rest of the coastal system along with activities that are sensitive to a limited number of drivers. On the lower right are activity and coastal elements important to human activities. These have a limited impact on the system but are dependent on both the forcing and relay variables.
Table 5.1. Key climate variables / activities matrix. Interactions are weighted on a score of one to three denoting a weak to strong relationship. w
KEY CLIMATE VARIABLES
/ ACTIVITIES MATRIX ility Bays coast Sandy coast Rocky Soft rock coast Estuaries stab Dune ICOLLS Recession/accretion beach Surf Breakwaters (groynes) Seawalls areas coastal Urban walls Tide Tourism Ports Boating fishing Amateur energy Alternative and gas Oil access Boat replenishment Beach Coastal title by-la government Local Public liability Biodiversity Wetlands parks Marine vegetation Coastal Fisheries habitat Significant aquifers Coastal Macrofauna pests Marine blooms Algal Extreme rainfall 1 332 31213 2 21 Storms 13122 3233 223 3332133 3 2 1 322232 22271 Mean winds 222 222 2 222311 25 Extreme winds 2333 333 2 3 333 3 3 2 111 45 Sea-level rise 23331 3232 3 22 12 2 3 3 21212 48 Sea-level variability 2333 3 2 2 22 12 2 3 2211137 Tides 21 13 21 3 2 1 211 20 Surge 33333 3233 3 3333113 3 3 3 131 60 Currents 23331 3332 312 3 2212 12 3 21250 Waves23332 3333331 3313322 32 2 32 61 Wave climates 333 3333 311112 3 111 36 Water temperature 12 23 121 32 22324 Salinity 12 2 1 22 211 22220 Upwelling 31333316 Longshore drift 1313 2321 33 3 111 1 3 11 34 Turbidity 22 33 23 2219 Runoff 2 3 2 33 3 2 1 321213 22237 Water quality 23 333 222331333 22242 Sedimentation 13132 3 223 13 1 2 2 11132 Mobilisation of nutrients 222333 2 22 322 3 31 Stream inflow 32 23 13222133132 33 Drought 23233215 Drainage 31 33 22 1 13121 23 Pollution 32 3 3 3 3 3 332 3 333 33349 37 35 26 31 34 28 20 28 31 18 10 43 21 45 26 15 43 22 7 27 30 20 5 12 7 37 31 13 43 27 19 16 18 24
48 Table 5.2. Prominence of key climatic drivers affecting catchment and water activities on the left and those activities affected on the right, showing the total weightings from Table 5.1. Key Climatic Drivers Activities Affected 71 storms tourism 45 61 waves urban coastal areas 43 60 surge rec fishing 43 50 currents fisheries 43 48 sea level rise bays 37 47 pollution wetlands 37 45 extreme winds sandy coast 35 40 water quality estuaries 34 37 sea level variability soft rock 31 37 runoff surf beach 31 36 wave climates marine parks 31 34 long shore drift beach replenishment 30 32 sedimentation dune stability 28 32 stream inflow recession/accretion 28 31 mobilisation of nutrients boat access 27 25 mean winds significant habitat 27 23 water temperature hard rock 26 23 drainage ports 26 21 extreme rainfall algal blooms 24 20 tides alt energy 22 19 salinity training walls (tides) 21 19 turbidity ICOLLS 20 16 upwelling coastal title 20 15 drought coastal aquifers 19 breakwaters (groynes) 18 marine pests 18 macrofauna 16 rec boating 15 coastal veg 13 public liability 12 seawalls 10 oil gas 7 diversity 7 local government by-laws 5
Forcing variables Relay variables
Storm
Surge Currents Rainfall (average) Sea-level rise Runoff Wave climate Streamflow Extreme winds Coastal vegetation Tides Erosion/sedimentation Recession/accretion Av. winds Tourism Estuaries SLR var. Drainage Pollution Wetlands Bays Water temp. Groynes Extreme rain Nutrient mobil. Urban coast Drought Seawalls L'shore drift Ports Marine parks Salinity Fauna Boating Forcing Power Tide walls Dunes Biodiversity Key habitat Am. fishing Upwelling By-laws Turbidity Algal blooms Marine pests Fisheries Pub. liabilityBeach replen. Sandy coast Alt. energy ICOLLS Boat access Oil&gas Title Surf beach Water quality Hard rock Soft rock Aquifers Dependent variables Dependency (Sensitivity)
Figure 5.1 Forcing/dependency diagram constructed from a cross-impacts matrix, built using the elements shown in Tables 5.1 and 5.2.
49 Performance criteria/thresholds
Quantifying climate change impacts in the coastal and marine sector has concentrated most on mean sea-level rise, but most impacts will occur due to a combination of variability superimposed on sea- level rise. Sea-level variability will have an impact both spatially and temporally. Regional eustatic sea-level rise is subject to warming patterns, currents and vertical mixing of the water column. A number of models runs are becoming available which will give a range of regional change similar to those produced by CSIRO for climate. Temporal variability such as surge and tides are additive on sea-level rise, so the creation of a coping range of sea-level variability for a site requires a knowledge of the response to historical variability, and relative trends in mean sea-level rise (relative to land- surface movements). Few sites have access to this type of data. Planning thresholds have been constructed for South Australia and the Gold Coast but not for Victoria. Even a broad approach to constructing thresholds for coastal planning purposes utilising a combination of IPCC projections for mean sea-level rise, selected local studies and the precautionary principle would be a useful beginning. Workshop discussions
Urban Coastal Areas
1. Investigate current impact thresholds to understand how well each sector is adapted to current climate (e.g. system resilience)
Four issues relevant to urban coastal areas were discussed:
1. Beach erosion and residential flooding Port Phillip Bay has sufficient dunes to cope with sea-level rise, and re-nourishment provides resilience. Victorian coasts have a relatively low tidal range, so there’s relatively low vulnerability to extreme flooding from a storm surge on a high tide. However, some areas are more vulnerable than others. Aspendale North was considered highly vulnerable since this stretch of beach is adjacent to residential properties (houses and bathing boxes) and needs re-nourishment. Elwood and St Kilda were also considered vulnerable due to flooding from Elwood Canal.
2. Ports and channel depth Dredging of the Port Phillip Bay channel is needed every 5 –6 years. With sea-level rise, the Bay will deepen. This will improve flushing of the Bay and provide access to larger ships. However, it will also reduce frictional effects at the Heads, leading to a larger tidal range including lower tides that may restrict port access for larger ships. The net effect is uncertain. Sea-level rise and greater tidal variability may be require reinforcement of port infrastructure (docks and storage).
3. Drainage Port Phillip Bay drainage is affected by sea level, so storm water drainage is vulnerable to sea-level rise. However, current drainage infrastructure is based on flow rates, not sea level or probable maximum flood. Increased rainfall intensity will mobilise more litter and sediment, reducing water quality in oceans. Retaining basins are designed for the 1-in-5 year flood event that captures about 90% of the flow, with the remainder and excess from heavier events allowed to bypass through pipes. More retaining basins and on-site storage should be encouraged to lessen the volume into streams and pipes. Revision of drainage design standards would have expensive consequences for re-engineering.
4. Beach health. Warnings and closures are occasionally issued for Victorian beaches due to the presence of stinging jellyfish or high levels of E-coli. Levels of E-coli rise after heavy rain, which is predicted to become more frequent. Protection of biodiversity in urban estuaries and wetlands was seen as an important issue. A Board of Works study has estimated that inundation of the Werribee Sewage Farm would cost $4.5 billion. Beach width would be affected by storm surges, yet there has been no mapping of the 1 in
50 100 year storm surge height. This is needed in order to determine a baseline against which changes can be compared for planning purposes.
2. Link stakeholders and policies with relevant planning horizons
A 30 cm rise in mean sea-level by the year 2050 is a mid-range estimate from the Intergovernmental Panel on Climate Change (IPCC). Most participants in the workshop considered this level an appropriate planning target for adaptation.
Planning schemes and authorities • Local Government Planning Schemes • Melbourne Water – 1-in-100 year flood lines, flood-prone land zones • State Government Policy and Minister for Planning • Victorian 2001 Coastal Strategy • Insurance companies • Building Code of Australia includes environmental aspects including energy performance • Metropolitan Strategy for Melbourne in 2020 projects 420,000 new homes on Melbourne’s fringe in 20 years. There is a 3-phase consultation process, and we’re now in Phase 2. Climate change is a significant issue – one of the top 3. The Victorian Greenhouse Strategy and the Vegetation Protection Strategy influence this strategy.
3. Identify important gaps in responsibilities, data and knowledge
Australian Coastal Atlas – online data holdings from the States and Commonwealth http://www.nrsc.com.au/atlas3/atlaspage.html Data is held by Queenscliff Marine Science Laboratories, Port Authorities, Melbourne Water (Port Phillip Bay), the National Tidal Facility (Flinders University) and the EPA.
• Benchmarking of current climate and ocean variability is inadequate. • Poor understanding of set-backs for extreme events, i.e. the 1-in100 year flood or storm surge line. Current set-backs are not well founded on research • Inadequate exploration of potential impacts and adaptive responses • What is the effect on residential house prices and insurance premiums if we do nothing? • What are the costs and benefits of building barriers from sand, rock or concrete? Would the costs be borne by government, insurance or building owners? • What is the cost of retreat or abandonment? Would it be borne by government, insurance or building owners? • What is the impact of calm inundation versus storm inundation • In the absence of sufficient data, should the Precautionary Principle apply? • What degree of “certainty” is needed to affect decisions?
4. What policies affect this area?
The state government has jurisdiction of about 96% of the coastline (DSE) and of coastal waters from the high water mark to the 3 nautical mile limit. The federal government has jurisdiction of the waters further offshore and all oil and gas operations. Many foreshore reserves are operated by Parks Victoria or committees of management, often under the auspices of local government. Private land is controlled by local government regulation. The EPA administers State Environment Protection Policies and individual site and works agreements for the maintenance of water quality in coastal waters. To bring all of these jurisdictions together and to implement Integrated Coastal Zone Management (ICZM), The Coastal Management Act 1995 provided for the creation of the Victorian Coastal Council and Regional Coastal Boards. The council co-ordinates a number of program including CoastCare, and applies the Victorian Coastal Strategy (Victorian Coastal Council, 2002).
51 In 2001, a draft Victorian Coastal Strategy (DNRE, 2001) was released for public comment. It commits the government to sustainable management of the coast in partnership with the community. The draft strategy contains a comprehensive list of policies and players involved in coastal management. The final strategy was released in 2002 (Victorian Coastal Council, 2002).
Estuaries
1. Investigate current impact thresholds to understand how well each sector is adapted to current climate (e.g. system resilience)
Estuaries were thought to be more vulnerable to temperature and extreme events rather than to sea- level rise. Such events include storms and breach events, and may see the return frequency of a given effect increase. Vulnerabilities include: • Southern limit of cool water coastal species in Victoria • Extreme events that open niches, especially where pests are prevalent • Nutrient flushing from adjacent catchments • Combinations of algal blooms, high temperature and low flow • Ecological succession with sea-level rise • Extinction of rare and threatened species • Nursery functions of estuaries • Ecological specialisations
Resilience to changing conditions were noted for mangroves and other warm climate species
2. Link stakeholders and policies with relevant planning horizons
All of the stakeholder policy links made for the previous topic are relevant also for estuaries. Also noted was the immense human use of estuaries for tourism, boating, fishing and urban development which threatens to reduce their resilience to environmental change, as degrading processes reduce ecosystem function. Despite the heavy use of estuaries by stakeholders, there is a low public awareness of the importance of estuaries and estuarine processes.
3. Identify important gaps in responsibilities, data and knowledge
• Ecosystem processes and functions in estuaries • Risks of establishment and spread of marine pests • Link between development and ecosystem function • No link between local economy around the estuary and the provision of ecosystem services • Large uncertainties about climate change • Need to provide a more established system for the generation of new knowledge and its dissemination between researchers, managers and the community • Insufficient monitoring • Integration of community and scientific data
4. What policies affect this area?
Policies are as for the previous questions 4, with added emphasis of the Ramsar Convention. Development futures are very important, as is the question of setback for estuaries and coastal wetlands with sea level rise.
52 Conclusions
The last major study of the impacts of climate change on coasts was the Victorian Coastal Vulnerability Study (Coastal Investigations Unit, 1992) that identified a number of vulnerable areas around the state. It would be possible to revisit this and other studies with our improved knowledge of the science.
Since 1992, projections of global mean sea-level rise have been much improved with narrowed ranges of uncertainty for aspects such as thermal expansion, the melting of glaciers and ice caps and reductions of runoff into the ocean. Large uncertainties surround greenhouse gas emissions and climate sensitivity contributing to increases in global mean temperature. The latest IPCC estimate of sea-level rise by 2100 is 9–88 cm, a figure that is slightly lower than previous estimates however, modelling over the longer-term shows sea-level rise continuing for centuries (Houghton et al., 2001). The inertia that ice sheets and the deep ocean gain from climate change is substantial and the longer that greenhouse gases continue to rise, the more substantial this inertia will be. Long-term increases in greenhouse gases will also increase the likelihood of extreme one-off events, such as the collapse of the West Antarctic Ice Sheet; although this risk is thought to be very low this century (IPCC, 2001a). Some consideration of what these very long-term changes may be for water bodies such as Port Phillip Bay may be warranted.
An understanding of sea-level variability is also being developed but is in its early stages. Sea-level rise will not be uniform but will vary according to factors such as currents and warming patterns. Climate scenarios are being developed for regional sea-level rise from coupled GCMs and CSIRO has plans to develop regional projections of sea-level rise similar to those developed for climate. Relative movements of the land surface are also much more variable than once thought, requiring a better knowledge of local seismology and tectonics to determine the directions and rates of regional land movements. However, as confirmed by the workshop analysis, most coastal impacts will continue to be event-based, requiring an improved understanding of frequency-based changes such as storms and surges.
The workshop highlighted the following points: • Knowledge of how the ecology of coasts, especially estuaries, would be affected by climate change is lacking. • Monitoring, data archiving, management and retrieval all need to be improved. • The importance of the coast to the Australian lifestyle seems to be inversely proportional to community understanding of the coast and its most critical issues. • Development has an enormous impact on coasts, but planning has yet to come to grips with how the coast may change, or how important coastal systems are being threatened by lack of opportunity to adapt when sea-level rises, because of the encroachment of development. • The slow rate of sea level rise in the coming decades should allow sufficient time for adaptation in many areas.
53 References
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