Developing a Novel Index of Strong Environmental Sustainability: Preliminary Results

Developing a novel index of strong environmental sustainability: preliminary results

Authors Arkaitz Usubiaga-Liaño a Paul Ekins a a: Institute for Sustainable Resources, University College London

Abstract

Strong sustainability assumes there is limited substitution capacity between natural and other types of capital. As such, it adopts a view whereby human activities are constrained by the biophysical limits of the planet. Despite this being the predominant worldview today, there is a mismatch between the theory and practice when it comes to measuring progress towards environmental sustainability.

This paper provides an overview of some of the most prominent environmental indicators in use (e.g. planetary boundaries, ecological footprint, environmental performance index, Sustainable Development Goals index) and argues that all of them face significant limitations when used to characterise strong sustainability at country level.

Against this background, we present the Environmental Sustainability Gap framework, which builds on the concept of critical natural capital – i.e. natural capital that performs important and irreplaceable functions – and strong sustainability. Within the framework, environmental sustainability is defined as the maintenance of important environmental functions over time, and consequently of the potential of natural capital to provide useful services for humans. These concepts are operationalised through a single policy-relevant index of environmental sustainability for nations.

The index comprises around 20 distance-to-target indicators for the relevant elements of natural capital, where the target is defined using science-based environmental standards. These standards are compiled from the scientific literature and cover issues such as critical loads of air pollutants, tolerable soil erosion rates, environmental flow requirements, tolerable health impacts, minimum acceptable biodiversity levels, etc. Following a normalisation, weighting and aggregation process, we generate a single index that provides information on absolute environmental sustainability by measuring the distance between current and sustainable conditions of the natural capital stock. Computing the indicator for different years also allows the extrapolation of trends to provide a general indication of whether countries are in the right track to achieve relevant environmental standards. This framework has been tested with the 28 European Member States.

1. Introduction

Human well-being depends on a mixture of natural capital and other types of capital (Ekins 1992). The contribution of natural capital rests on the operation of a wide range of ‘environmental functions’ that ultimately represent subsets of ecological processes and ecosystem structures that determine the capacity of natural capital to provide goods and services (de Groot et al. 2002).

Environmental functions are currently threatened as a result of widespread environmental degradation (IPCC 2014; IPBES 2019; UN Environment 2019). This situation demands lowering pressures to levels that do not jeopardise the functioning of natural capital or to develop alternatives that can compensate for the loss of environmental functions. This feasibility of substituting the functions of natural capital by by other types of capital has been a hot topic in economics for a long time. While some argue that substitution is generally possible, others are more sceptical and argue that some functions provided by natural capital cannot be replaced by manufactured capital, which makes them ‘critical’ for human well-being (Ekins et al. 2003a). The latter position is commonly termed ‘strong sustainability’ and is consistent with the notion of biophysical limits.

While reviewing the progress made in realising the vision for sustainable development brought forward in the well-known Brundtland report (Brundtland et al. 1987), Ekins and Usubiaga (2019) concluded that countries still lack meaningful metrics to track progress towards environmental sustainability if this is to be understood as the maintenance of environmental functions at such a level that they will be able to sustain their contribution to human well-being in the long-term. To monitor countries’ performance in the context of environmental sustainability, the authors argued, an indicator needs to measure the distance between the current situation and a reference situation that represents a sustainable condition of an element of natural capital at the national level. To date, the most prominent indicator sets and indices fail to completely fulfil this criterion either because they either lack a national focus or because the reference point used is not representative of environmental sustainability conditions (Table 1).

Table 1: Overview of selected distance-to-target environmental indicators

Indicator set Type Focus Measures Scale References

Performance against SDG Index internationally agreed National Lafortune et al. (Environmental Composite Environment targets or best and global (2018) SDGs) performing countries

Performance against Environmental internationally agreed Yale University Performance Composite Environment National targets or best (2018) Index (EPI) performing countries

Environmental sustainability at Performance against Borucke et al. Ecological National Composite global level; self- country’s or Earth’s (2013); Lin et Footprint and global sufficiency at regenerative capacity al. (2016) national scale

Rockström et Planetary Environmental Performance against al. (2009); Set Global Boundaries sustainability environmental limits Steffen et al. (2015)

The Environmental Sustainability Gap (ESGAP) framework was developed to respond to this indicator gap already in the late 1990s (Ekins and Simon 1999) and was operationalised once with the limited data available at the time (Ekins and Simon 2001). The framework describes a set of physical and monetary metrics to track countries performance towards or away from environmental sustainability. This paper proposes a new version of the physical ESGAP index – hereinafter ESGAP index – and calculates it for data-rich European countries. Thus, section 2 describes the indicators and the methodology used to transform them into an index. Section 3 presents preliminary results, which are discussed in section 4. Section 5 concludes.

2. Methodology and data sources

2.1. Environmental sustainability indicators

In the ESGAP framework, environmental sustainability entails the maintenance of the environmental functions at such a level that they will be able to sustain their contribution to human benefits. Given the impossibility of identifying all the critical functions of natural capital, the ESGAP index (not to be confused with the underlying ESGAP indicators that the index is based on) is arranged around four dimensions that reflect broad environmental function categories as defined in earlier work by Ekins et al. (2003b)1:

 Source functions represent the capacity of natural capital to sustain the supply of resources and therefore cover the provision of different type of resources used by humans, which include the formation of topsoil, the provision of space for human activities, the supply of water, minerals, fossil fuels, and biomass, etc.  Sink functions represent the capacity of natural capital to neutralise wastes without incurring ecosystem change or damage. This includes the regulation of the chemical composition of the atmosphere and oceans and the assimilation of waste.  Life support functions refer to the capacity of natural capital to maintain ecosystem health and function, which covers functions from the provision of quality habitat to the regulation of runoff and climate or the maintenance of biodiversity.  Human health and welfare functions represent the capacity of natural capital to provide other services to humans, very often of a non-economic kind, which maintain health and contribute to human well-being in other ways. These could be related to amenity as in sites that have aesthetic, spiritual, religious or scientific value, or the capacity to provide space for recreation.

In this context, source, sink and life support functions are closely linked to the integrity of the system and therefore approach functioning from the lens of the supplier of goods and services. Human and welfare functions, on the other hand, reflect functions from the receiver´s side; in this case humans.

As argued above, the characterisation of environmental sustainability requires measuring performance against a reference points that reflect the conditions under which the

1 A detailed list of the environmental functions covered in those four broad categories is given in Ekins and Simon (2003), while a detailed description of functions can be found in De Groot (1992).

3 capacity of natural capital to function is not compromised. Here we refer to these reference points as environmental standards. In this context, we have identified environmental standards applicable to different elements of natural capital that are aligned with the broad set of sustainability principles proposed by Ekins et al. (2003b) (Table 2). These principles require to ensure that renewable resources such as fish or forests are exploited at a level that allows them to be renewed over time, to exploit non- renewable resources at a rate that allows their future use, to keep pollution at a level at which ecosystems cannot neutralise it without incurring in excessive damage, to maintain the capacity of ecosystems to support life, to respect human health standards and to conserve the elements of natural capital that provide additional services to humans.

Table 2: Functions of natural capital and environmental sustainability principles

Function Objective Principle Description

The renewal of renewable resources must be fostered through the maintenance of soil fertility, hydrobiological cycles and necessary vegetative cover and the rigorous enforcement of sustainable harvesting. The latter implies basing harvesting rates Renew renewable on the most conservative estimates of stock levels resources for such resources as fish; ensuring that replanting Maintain the capacity Source becomes an essential part of forestry; and using to supply resources technologies for cultivation and harvest that do not degrade the relevant ecosystem and deplete neither the soil nor genetic diversity.

Depletion of non-renewable resources should seek to Use non- balance the maintenance of a minimum life- renewables expectancy of the resource with the development of prudently substitutes for it.

Prevent global Anthropogenic destabilisation of global environmental Maintain the capacity warming, ozone processes, such as climate patterns or the ozone to neutralise wastes, depletion layer, must be prevented. Sink without incurring Emissions into air, soil and water must not exceed Respect critical ecosystem change or their critical load, that is the capability of the loads for damage receiving media to disperse, absorb, neutralise and ecosystems recycle them, without disturbing other functions.

Maintain Critical ecosystems and ecological features must be biodiversity absolutely protected to maintain biological diversity, Maintain the capacity (especially species which underpins the productivity and resilience of Life- to sustain ecosystem and ecosystems) ecosystems. Support health and function Apply the Uncertainties should result in a precautionary precautionary approach in the adoption of safe minimum standards. principle

Respect standards Emissions into air, soil and water must not exceed Maintain the capacity Human for human health dangerous levels for human health. to maintain human Health Landscapes of special human or ecological health and generate Conserve and significance, because of their rarity, aesthetic quality human welfare in landscape and Welfare or cultural or spiritual associations, should be other ways amenity preserved. Source: Adapted from Ekins and Simon (1999); Ekins et al. (2003b)

Because of the diverse set of principles used the set of environmental standards incorporated in the index (fifth column in Table 3) do not have a homogeneous meaning in that they can refer to acceptable health risks, acceptable environmental impacts, precautionary expert guesses or safe distance from tipping points. In all cases though, their transgression flags a potential problem that requires further policy attention.

Table 3 contains the set of 19 environmental sustainability indicators that have been used to test the environmental sustainability index in data-rich European countries. The indicators (column seven and further described in the Supplementary Material) and environmental standards have been arranged around the environmental functions and principles described above. Each of them represents compliance with environmental sustainability conditions by measuring the distance to the appropriate environmental standard. The table only includes indicators that are relevant at the national level and for which an environmental standard and data have been found. Thus, they do not cover all policy-relevant topics. For instance, indicators for non-renewables are limited to soil resources in this version thereby leaving out fossil fuels, metallic and non-metallic minerals, for which an appropriate standard has not been found. The ecological status of marine ecosystems has not been included in life-support functions due to lack of data, and indicators for oceans have been left out for not falling under countries’ sovereignty.

The index has been calculated for the 28 European Member States for two data points (see data sources in Table 3, more details in the Supplementary Material). Since each of the underlying indicators is reported for different years and updated in different timeframes (e.g. data on forest fellings is reported every five years, while human exposure to air pollution is reported annually), it is not currently possible to calculate the index for a specific year. Instead, we have used the latest data point available in each case to calculate the index. The data has been obtained in most of the cases from recognised international institutions such as the European Environment Agency, the European Commission or United Nations. In a few cases, data has been obtained from academic sources.

Table 3: Environmental sustainability principles, standards and indicators

Function Principle Topic Pressure/State Standard References ESGAP Indicator Data source

Forest resources Annual fellings Fellings / Net Annual Increment EEA (2017) Forest utilization rate EEA (2017)

Fishing mortality consistent with Maximum Sustainable Yield Condition of fish Fish stocks within safe EEA (2018b, Renew Fish resources EC (2010) stocks Spawning stock biomass biological limits 2019b) renewable consistent with Maximum resources Sustainable Yield Source Groundwater bodies in Groundwater Status of Good quantitative status as EC (2009) good quantitative EEA (2018c) resources groundwater body defined in European legislation status

Jones et al. (2004); Use non- Huber et al. (2008); Area with tolerable soil Borrelli et al. renewables Soil Soil erosion rate Tolerable soil erosion rate Verheijen et al. erosion (2017) prudently (2009)

Prevent global Per-capita GHG emissions Greenhouse gas See Supplementary Emissions / annual Eurostat warming, Climate change consistent with global climate emissions Material allowance (2019) ozone targets depletion

Horálek et al. (2015, Cropland area exposed Critical levels of O Mills et al. (2007) 2016b); 3 to safe ozone levels Concentration of air Horálek et al. pollutants in (2016a, 2018) Sink terrestrial Horálek et al. ecosystems Karlsson et al. (2015, Respect Forest area exposed to Critical levels of O (2003); Karlsson et 2016b); critical loads Terrestrial 3 safe ozone levels for ecosystems al. (2007) Horálek et al. ecosystems (2016a, 2018) Ecosystems not Hettelingh et al. exceeding the critical Hettelingh et Critical loads of heavy metals (2015); Hettelingh et Load of air pollutants loads of cadmium / al. (2015) al. (2017) in terrestrial lead / mercury ecosystems Hettelingh et Critical load of eutrophication CLRTAP (2017) Ecosystems not exceeding the critical al. (2017)

loads of eutrophication

Ecosystems not Hettelingh et Critical load of acidification CLRTAP (2017) exceeding the critical al. (2017) loads of acidification

European Parliament Surface water Good chemical status as defined Surface water bodies in Chemical status and European Council EEA (2018c) bodies in European legislation good chemical status (2008)

Good chemical status as defined Groundwater bodies in Groundwater Chemical status EC (2009) EEA (2018c) in European legislation good chemical status

Terrestrial area with Usubiaga- Terrestrial Local Biodiversity Local Biodiversity Intactness Steffen et al. (2015) acceptable biodiversity Liaño et al. ecosystems Intactness Index Index levels (2019) Maintain Good ecological status as biodiversity Life defined in European legislation (especially Surface water bodies in support Ecological status based on biological, EC (2003) EEA (2018c) species and good ecological status Freshwater physicochemical and ecosystems) ecosystems hydromorphological parameters

Blue water Blue water consumption / Mean Freshwater bodies not Raskin et al. (1997) EEA (2018a) consumption quarterly flows under water stress

Horálek et al. Population exposed to (2015, Concentration of air Air pollution Critical levels of air pollutants WHO (2005) safe levels of PM , 2016b); pollutants 2.5 Respect PM10 and NO2 Horálek et al. standards (2016a, 2018) for human health Safe drinking water criteria as defined in European legislation European Council Samples that meet the Drinking water Water samples EC (2016) based on microbiological, (1998) drinking water criteria chemical and other parameters Human health and ‘Excellent’ quality criteria as welfare defined in European legislation Recreational water Concentration of based on the concentration of Bathing waters EC (2002) bodies in excellent EEA (2019c) bacteria Intestinal Enterococci and status Conserve Escherichia Coli in recreational landscape waters and amenity Good conservation outlook Natural and mixed Osipova et al. Natural and based on three elements: the world heritage sites in (2014); mixed world Conservation outlook Osipova et al. (2014) current state and trend of good conservation Osipova et al. heritage sites values, the threats affecting outlook (2017) those values, and the

7 effectiveness of protection and management

2.2. Building the ESGAP index

Figure 1 shows the structure of the ESGAP index. 19 indicators sit at the bottom of the structure and are aggregated through three levels: principles, functions and index.

Figure 1: Structure of the ESGAP index

The figure shows the nested structure of the ESGAP index, where the indicators in the outer layer are arranged around sustainability principles (middle layer) and environmental functions (inner layer). Note: The labels in the middle layer are equivalent to the following principles in Table 3. Renewables: renew renewable resources; Non-renewables: use non-renewables prudently; Global warming: prevent global warming; Critical loads: respect critical loads for ecosystems; Biodiversity: maintain biodiversity (especially species and ecosystems); Human health: respect standards for human health; Landscape & Amenity: conserve landscape and amenity.

The construction of the index has been guided by the OECD manual on composite indicators (OECD and JRC 2008). Here we document the choices made to convert the individual ESGAP indicators that characterise the environmental sustainability conditions of individual items of natural capital to the ESGAP index, which aims to provide a high level picture. This process is undertaken in three steps: normalisation, weighting and aggregation.

Normalisation requires converting all the indicator to a common scale, since each of them generally have different units. Because most indicators in Table 3 measure the percentage of an asset that meets an environmental standard, they are implicitly normalised with a score from 0 to 100, where in all the cases 0 is the worst possible

9 performance and 100 the best. In other instances, we use a modified version of the min- max technique as described in the Supplementary Material.

Weights are intended to reflect the importance of each indicator, although this does not necessarily represent how much they impact the final score (Becker et al. 2017). Different endowments in natural capital would warrant country-specific weights for the elements covered in the index. Nonetheless, the weighting process is as much of a political process as it is a scientific process and therefore can be easily challenged irrespective of the method used (Hsu et al. 2013). Hence, similar to other indices such as the SDG index we use equal weights across countries to ensure the comparability of the results.

The aggregation across different levels is done using a geometric mean (equation 1), wherex, xi and w represent the geometric mean, the value of indicator i and weight assigned respectively. As opposed to the arithmetic mean, which linearly compensates poor performance in one dimension by high achievement in another, with a geometric mean low scores in any dimension are directly reflected in the final score of the index. Thus, a geometric mean seems more appropriate to the limited substitution capacity assumed between different types of capital and within the different elements of natural capital that is at the core of the strong sustainability perspective. In order to avoid biases from using a geometric mean, we have assigned an arbitrary score of 5 to the normalised values below that threshold.

(eq. 1)

The resulting index has a value from 5 to 100, where 5 represents the lowest possible performance and 100 shows compliance with all the environmental standards assigned to the indicators. The environmental sustainability gap would be the distance of the country value to 100.

3. Results

Figure 2 ranks EU28 countries according to their index scores in the most recent data point. Generally speaking, Scandinavian countries, former Soviet Union countries and the Anglo-Celtic isles seem to perform better than Mediterranean, and central and eastern European countries, although absolute scores are low in the vast majority of the cases, suggesting that one or more environmental functions are currently jeopardised.

Figure 2: Environmental sustainability score for EU28 Member States

The ESGAP index scores countries from 0 to 100 in terms of their environmental sustainability performance. A score of 100 indicates the compliance of all the indicators across the four environmental functions with their corresponding environmental standard. A score of 0 indicates the opposite. Countries are sorted by the score from higher to lower.

As with any index, the total score can hide disparities in the performance at lower levels. In this context, Figure 3 and Figure 4 show country scores for the four broad environmental functions and the seven sustainability principles used to characterise environmental sustainability. Countries perform very differently in source, and health and human welfare functions, with countries in the first positions scoring relatively high. This is not the case in the sink and life support functions where scores are more homogeneous with almost every country performing poorly. The scores of those functions are mainly driven by poor performance in GHG emissions and terrestrial biodiversity, which seem to be widespread except for a very limited set of countries.

Figure 3: Heatmap of the country scores by environmental function

The figure shows the scores of each country for the four environmental functions. Dark red indicates low scores, while light orange indicates high scores. Countries are sorted by the total score from higher to lower.

Figure 4: Heatmap of the country scores by sustainability principle

The figure shows the scores of each country for seven sustainability principles. Dark red indicates low scores, while light orange indicates high scores. Countries are sorted by the total score from higher to lower. Note: The labels in the y axis are equivalent to the following principles in Table 3. Renewables: renew renewable resources; Non-renewables: use non-renewables prudently; Global warming: prevent global warming; Critical loads: respect critical loads for ecosystems; Biodiversity: maintain biodiversity (especially species and ecosystems); Human health: respect standards for human health; Landscape & Amenity: conserve landscape and amenity. The label nd in the heatmap indicates that no data was available for any of the underlying indicators.

Figure 5 represents the scores and trends of each individual indicator. Upon closer examination some general patterns emerge. In the indicators associated with the source function, overexploitation of fish resources (So_Fi) seems to be the rule rather than the exception. This problem is particularly severe in the Mediterranean Sea. Mediterranean countries are also those exposed most intensively to soil erosion (So_SE).

Regarding the neutralisation of waste, all countries except two have not reached meaningful GHG emission reductions after the adoption of the Paris agreement that are in line with the goal of reaching net zero emissions around the year 2050 (Si_CC). When choosing 2015 as a baseline, getting to net zero by 2050 requires annual emission reductions of around 2.50-3.33% without considering offsets. There are several caveats to be acknowledged in this regard, after all there are multiple ways of defining the mitigation responsibilities of countries (Höhne et al. 2014). For pragmatic reasons, we have selected a simple linear extrapolation between the current situation and 2050. It should be noted though that the starting point as well as the evolution since the commitments adopted under the Kyoto Protocol differs considerably among European countries. From an absolute sustainability perspective, the emission levels of none of the countries could be sustained indefinitely at the global level without incurring in severe environmental impacts.

Scandinavian countries, former Soviet Union countries and the Anglo-Celtic isles generally perform better in pollution related to ozone (Si_Ag, Si_Fo) and eutrophication (Si_Eu) in terrestrial ecosystems, although with some exceptions in the latter. Exceedance of critical loads of heavy metals (Si_HM) in terrestrial ecosystems seems widespread. The neutralisation of waste in freshwater ecosystems (Si_SW, Si_GW) shows very different patterns among countries.

As for life-support functions, only Nordic countries and Latvia are dominated by terrestrial ecoregions where acceptable local species abundance levels (LS_BD) are above the precautionary levels proposed in the literature. The situation in freshwater ecosystems is generally negative with all countries having more than a third of their systems (weighted by area) not meeting good quality criteria (LS_SW). This percentage is much higher in many Member States.

Countries seem to perform better in those indicators that affect human health, especially when it comes to meeting drinking water standards (HW_DW). As a general rule, countries also perform relatively well in maintaining good water quality in bathing sites (HW_BW). This is not the situation with regard to air pollution (HW_AP), where a very high percentage of the population does not meet the guideline values proposed by the World Health Organisation for particulate matter. No distinguishable patterns arise in the conservation of World Heritage sites related to nature (HW_WH).

Figure 5: Bivariate heatmap of the country scores and trends by indicator

The figure shows the scores and trends of each indicator. The scores and trends of each indicator have been jointly classified in the nine categories shown in the legend. Scores were grouped in 0-50, 21-80 and 81-100 ranges, while annual trends (obtained as a linear intrapolation of the scores obtained in the years shown in the Supplementary Material) were assigned to the ‘worsen’ (<-1% annually), constant (±1% range annually) and improve (>+1% annually) categories. Note: The So, Si, LS and HW prefixes in the labels of the y axis refer to the Source, Sink, Life-support and Human health and welfare functions. The correspondence between the labels and indicators is given in Table SX. The label nd in the heatmap indicates that no data was available for any of the underlying indicators.

4. Discussion

Our results suggest that the functioning of different elements of natural capital is impaired as a result of excessive environmental degradation in Europe. The vast majority of European countries obtain index scores below 50, where only a score of 100 reflects compliance with the environmental standards of each indicator. Even in the case of the highest scoring country Latvia, the gap between the current and the target situation is of 27 points.

The indicators on GHG emissions and local species abundance in terrestrial ecosystems seem to affect the ranking of the countries, since normalised country scores seem to be at the end of the sustainability range. In the case of GHG emissions, two countries (Latvia and United Kingdom) obtain a score of 100 as a result of aligning their post-2015 emission trajectories with reaching net zero emissions by 2050, while the rest obtain a

13 score of 5 (the minimum assigned). Of course, this metric is highly sensitive to the baseline chosen. In addition, total scores are particularly sensitive to the use of geometric means to aggregate the data. It remains to be seen if the emissions of these countries will follow this downward trajectory in 2018. For biodiversity, the situation has remained constant over the period 2000-2015, with barely any country in the middle ground. Coincidentally, these two indicators are linked to key aspects of the functioning of the Earth system (Steffen et al. 2015).

Performance across environmental functions is quite uneven, with those related to environmental integrity being the most affected. Functions associated with the provision of resources seem to be in better shape than those associated with the neutralisation of waste and life-support. One can only hypothesise if the fact that biotic and abiotic resources have a market value can partially explain this pattern, which is does not necessarily hold in every country. An exception in the source function are fish stocks, which are consistently overexploited across countries.

Countries tend to obtain relatively high scores when health standards are on the line as in the case of drinking water and bathing waters. Air pollution is an exception, arguably because the policy targets set are more permissive than the guideline values proposed by the World Health Organisation. When it comes to the amenity function in relation to world heritage sites, performance is very uneven with many countries not having any natural site within their territory.

The results discussed above need qualification of various grounds. First, the level of consensus around the standards chosen differs considerably. Some are subject to period reviews (e.g. health standards by the World Health Organisation), while others are still subject to greater uncertainty (e.g. minimum local species abundance levels). In all cases though, the standards adopted are intended to represent the latest understanding in the scientific community around the levels at which the environmental functions of natural capital can be maintained over time. In this context, not all relevant elements of natural capital are currently addressed by the set of indicators chosen. After all, there are some cases in which no relevant environmental standard has been found (e.g. soil organic matter, solid waste, extraction of non-energetic abiotic materials) or in which no data was available for most European countries (e.g. quality of marine waters). The focus on broad elements of natural capital that are included to create a comparable index among countries leads to the exclusion of very specific elements of natural capital that are context-dependent and that can be subject to tipping points, e.g. coral reefs or glaciers. Second, when it comes to computing and comparing ESGAP country scores, data gaps exist for some countries (which have not been imputed) or in some cases there are indicators that do not apply to certain countries (e.g. some countries do not have world heritage natural sites or access to marine waters in relation to fish resources). Comparability between some indicators or data points is also problematic in the case of the chemical and ecological status of freshwater ecosystems (EEA 2018c).

5. Conclusions

It is remarkable that countries still lack meaningful metrics that allow them to measure progress towards or away environmental sustainability from a strong sustainability perspective. This paper a framework that addresses this gap, from which an index that

14 of environmental sustainability can be calculated, as opposed to other indices that focus on environmental policy targets and environmental performance more broadly.

At this moment, the ESGAP index has been calculated for European Member States for two data points that differ from indicator to indicator. Hence, the ESGAP index remains at the moment a proof of concept. Nonetheless, the ESGAP index the underlying indicators are novel indicators that can provide policy-relevant information at different levels.

At the lower level of bottom of Figure 1, the set of 19 indicators show the extent to which science-based environmental standards are met. Although there might be some overlaps with policy targets, the environmental standards adopted are meant to reflect the scientific understanding of good environmental quality. Hence, all of these standards have either been taken from the scientific literature or from relevant environmental legislation informed by expert input. The resulting index is expected to differ from a potential policy gap index that could measure the gap between the current performance and existing environmental policy targets. The magnitude of the difference would depend on the extent to which environmental targets are aligned with science-based environmental targets.

At higher levels, the ESGAP index and the sub-indices for environmental functions (source, sink, life-support, and health and human welfare) could be used as headline indicators when assessing progress towards sustainable development at country level, thereby complementing the narratives around social and economic welfare. A single index such as the ESGAP shows the absolute performance of countries with regard to environmental sustainability and responds to the demands made from the ‘Beyond GDP’ community on the need for a single environmental sustainability metric that can complement GDP in its (mis-)use as a headline indicator for development.

In the future, an increased availability of relevant data or scientific evidence that supports changes in existing standards or the inclusion of different ones will require the structure and indicator selection to be revisited. Hopefully, the potential usefulness of the framework will create the momentum for such review of the evidence and for relevant data to be generated.

References

Amann, M., I. Bertok, J. Borken‐Kleefeld, J. Cofala, C. Heyes, L. Hoglund‐Isaksson, G. Kiesewetter, Z. Klimont, W. Schöpp, N. Vellinga, and W. Winiwarter. 2015. Adjusted historic emission data, projections, and optimized emission reduction targets for 2030 – A comparison with COM data 2013. Part A: Results for EU-28 Laxenburg: International Institute for Applied Systems Analysis. Becker, W., M. Saisana, P. Paruolo, and I. Vandecasteele. 2017. Weights and importance in composite indicators: Closing the gap. Ecological Indicators 80: 12-22. Borrelli, P., D. A. Robinson, L. R. Fleischer, E. Lugato, C. Ballabio, C. Alewell, K. Meusburger, S. Modugno, B. Schütt, V. Ferro, V. Bagarello, K. V. Oost, L. Montanarella, and P. Panagos. 2017. An assessment of the global impact of 21st century land use change on soil erosion. Nature Communications 8(1): 2013. Borucke, M., D. Moore, G. Cranston, K. Gracey, K. Iha, J. Larson, E. Lazarus, J. C. Morales, M. Wackernagel, and A. Galli. 2013. Accounting for demand and supply of the biosphere's regenerative capacity: The National Footprint Accounts’ underlying methodology and framework. Ecological Indicators 24: 518-533. Brundtland, G., M. Khalid, S. Agnelli, S. Al-Athel, B. Chidzero, L. Fadika, V. Hauff, I. Lang, M. Shijun, and M. M. de Botero. 1987. Report of the World Commission on Environment and Development: Our Common Future. CLRTAP. 2017. Mapping critical loads for ecosystems, Chapter V of Manual on methodologies and criteria for modelling and mapping critical loads and levels and air pollution effects, risks and trends. UNECE Convention on Long-range Transboundary Air Pollution. De Groot, R. S. 1992. Functions of Nature: Evaluation of Nature in Environmental Planning, Management and Decision Making. Groningen: Wolters-Noordhoff. de Groot, R. S., M. A. Wilson, and R. M. J. Boumans. 2002. A typology for the classification, description and valuation of ecosystem functions, goods and services. Ecological Economics 41(3): 393-408. EC. 2002. Proposal for a Directive of the European Parliament and of the Council concerning the quality of bathing water. COM(2002) 581 final. Brussels: European Commission. EC. 2003. Overall approach to the classification of ecological status and ecological potential. No. 13. Brussels: European Commission. Common Implementation Strategy for the Water Framework Directive (2000/60/EC) Guidance Report. EC. 2005. Guidance on the intercalibration process 2004 - 2006. No. 14. Brussels: European Commission. Common Implementation Strategy for the Water Framework Directive (2000/60/EC) Guidance Report. EC. 2009. Guidance Document No. 18. Guidance on Grounwater Status and Trend Assessment. Technical Report - 2009 - 026. Luxembourg: European Commission. EC. 2010. Commission Decision of 1 September 2010 on criteria and methodological standards on good environmental status of marine waters. Brussels. EC. 2011. Guidance Document No. 27 - Technical Guidance For Deriving Environmental Quality Standards. Brussels: European Commission. EC. 2016. Synthesis Report on the Quality of Drinking Water in the Union examining Member States' reports for the 2011-2013 period, foreseen under Article 13(5) of Directive 98/83/EC. COM(2016) 666 final. Brussels. EC. 2018. In-depth Analysis in Support of the Commission Communication COM(2018) 773: A Clean Planet for all A European long-term strategic vision for a prosperous, modern, competitive and climate neutral economy. Brussels: European Commission. EEA. 2017. Forest: growing stock, increment and fellings. Copenhagen: European Environment Agency. EEA. 2018a. Use of freshwater resources. Copenhagen: European Environment Agency.

EEA. 2018b. Status of the assessed European fish stocks in relation to Good Environmental Status per regional sea. Copenhagen: European Environment Agency. EEA. 2018c. European waters. Assessment of status and pressures 2018. No 7/2018. Copenhagen: European Environment Agency. EEA Report. EEA. 2019a. European Bathing Water Quality in 2018. No 3/2019. Copenhagen: European Environment Agency. EEA Report. EEA. 2019b. Status of the assessed European commercial fish and shellfish stocks in relation to Good Environmental Status (GES) per EU marine region in 2015-2017. Copenhagen: European Environment Agency. EEA. 2019c. Country reports 2018 bathing season. Copenhagen: European Environment Agency. Ekins, P. 1992. A Four-Capital Model of Wealth Creation. In Real-Life Economics: Understanding Wealth-Creation, edited by P. Ekins and M. Max-Neef. London: Routledge. Ekins, P. and S. Simon. 1999. The sustainability gap: a practical indicator of sustainability in the framework of the national accounts. International Journal of Sustainable Development 2(1): 32-58. Ekins, P. and S. Simon. 2001. Estimating sustainability gaps: methods and preliminary applications for the UK and the Netherlands. Ecological Economics 37(1): 5-22. Ekins, P. and S. Simon. 2003. An illustrative application of the CRITINC framework to the UK. Ecological Economics 44(2-3): 255-275. Ekins, P. and A. Usubiaga. 2019. Brundtland+30: the continuing need for an indicator of environmental sustainability. In What Next for Sustainable Development? Our Common Future at Thirty, edited by J. Meadowcroft, et al.: Edward Elgar Publishing,. Ekins, P., C. Folke, and R. De Groot. 2003a. Identifying critical natural capital. Ecological Economics 44(2-3): 159-163. Ekins, P., S. Simon, L. Deutsch, C. Folke, and R. De Groot. 2003b. A framework for the practical application of the concepts of critical natural capital and strong sustainability. Ecological Economics 44(2-3): 165-185. European Council. 1998. Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption. European Parliament and European Council. 2008. Directive 2008/105/EC on environmental quality standards in the field of water policy, amending and subsequently repealing Council Directives 82/176/EEC, 83/513/EEC, 84/156/EEC, 84/491/EEC, 86/280/EEC and amending Directive 2000/60/EC of the European Parliament and of the Council. Eurostat. 2019. Greenhouse gas emissions by source sector. Luxembourg: Eurostat. Hettelingh, J.-P., M. Posch, and J. Slootweg. 2017. European critical loads: database, biodiversity and ecosystems at risk. CCE Final Report 2017. RIVM Report 2017-0155. Bilthoven: Coordination Centre for Effects. Hettelingh, J.-P., G. Schütze, W. de Vries, H. Denier van der Gon, I. Ilyin, G. J. Reinds, J. Slootweg, and O. Travnikov. 2015. Critical Loads of Cadmium, Lead and Mercury and Their Exceedances in Europe. In Critical Loads and Dynamic Risk Assessments: Nitrogen, Acidity and Metals in Terrestrial and Aquatic Ecosystems, edited by W. de Vries, et al. Dordrecht: Springer Netherlands. Höhne, N., M. den Elzen, and D. Escalante. 2014. Regional GHG reduction targets based on effort sharing: a comparison of studies. Climate Policy 14(1): 122-147. Horálek, J., P. d. Smet, P. Kurfürst, F. d. Leeuw, and N. Benešová. 2015. European air quality maps of PM and ozone for 2012 and their uncertainty. 2014/4. Bilthoven: European Topic Centre on Air Pollution and Climate Change Mitigation. ETC/ACM Technical Paper. Horálek, J., P. d. Smet, F. d. Leeuw, P. Kurfürst, and N. Benešová. 2016a. European air quality maps for 2014 PM10, PM2.5, Ozone, NO2 and NOx spatial estimates and their uncertainties. 2016/6. Bilthoven: European Topic Centre on Air Pollution and Climate Change Mitigation. ETC/ACM Technical Paper.

Horálek, J., P. d. Smet, P. Kurfürst, F. d. Leeuw, and N. Benešová. 2016b. European air quality maps of PM and ozone for 2013 and their uncertainty. 2015/5. Bilthoven: European Topic Centre on Air Pollution and Climate Change Mitigation. ETC/ACM Technical Paper. Horálek, J., P. d. Smet, F. d. Leeuw, P. Kurfürst, and N. Benešová. 2018. European air quality maps for 2015 PM10, PM2.5, Ozone, NO2 and NOx spatial estimates and their uncertainties. 2017/7. Bilthoven: European Topic Centre on Air Pollution and Climate Change Mitigation. ETC/ACM Technical Paper. Hsu, A., L. A. Johnson, and A. Lloyd. 2013. Measuring Progress: A Practical Guide From the Developers of the Environmental Performance Index (EPI). New Haven: Yale Center for Environmental Law & Policy. Huber, S., G. Prokop, D. Arrouays, G. Banko, A. Bispo, R. J. A. Jones, M. G. Kibblewhite, W. Lexer, A. Möller, R. J. Rickson, T. Shishkov, M. Stephens, G. Toth, J. J. H. Van den Akker, G. Varallyay, F. G. A. Verheijen, and A. R. Jones. 2008. Environmental Assessment of Soil for Monitoring. Volume I: Indicators & Criteria. Luxembourg: Joint Research Centre - Institute for Environment and Sustainability. IPBES. 2019. Global assessment report on biodiversity and ecosystem services. Bonn: Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. IPCC. 2014. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. The Intergovernmental Panel on Climate Change. Jones, R. J. A., Y. L. Bissonnais, P. Bazzoffi, J. Sánchez, O. D. Díaz, G. Loj, L. Øygarden, V. Prasuhn, B. Rydell, P. Strauss, J. B. Üveges, L. Vandekerckhove, and Y. Yordanov. 2004. Soil Erosion. In Reports of the Technical Working Groups Established under the Thematic Strategy for Soil Protection. Volume II: Erosion, edited by L. Van-Camp, et al. Luxembourg: Joint Research Centre - Institute for Environment and Sustainability,. Karlsson, P. E., J. Uddling, S. Braun, M. Broadmeadow, S. Elvira, B. S. Gimeno, D. Le Thiec, E. Oksanen, K. Vandermeiren, M. Wilkinson, and L. Emberson. 2003. New Critical Levels for Ozone Impact on Trees Based on AOT40 and Leaf Cumulated Ozone Uptake. In Establishing Ozone Critical Levels II, UNECE Workshop Report, edited by P.-E. Karlsson, et al. Gothenburg. Karlsson, P. E., S. Braun, M. Broadmeadow, S. Elvira, L. Emberson, B. S. Gimeno, D. Le Thiec, K. Novak, E. Oksanen, M. Schaub, J. Uddling, and M. Wilkinson. 2007. Risk assessments for forest trees: The performance of the ozone flux versus the AOT concepts. Environmental Pollution 146(3): 608-616. Lafortune, G., G. Fuller, J. Moreno, G. Schmidt-Traub, and C. Kroll. 2018. SDG Index and Dashboards. Detailed Methodological paper. New York: Bertelsmann Stiftung and the Sustainable Development Solutions Network (SDSN). Lin, D., L. Hanscom, J. Martindill, M. Borucke, L. Cohen, A. Galli, E. Lazarus, G. Zokai, K. Iha, D. Eaton, and M. Wackernagel. 2016. Working Guidebook to the National Footprint Accounts: 2016 Edition. Oakland: Global Footprint Network. Mills, G., A. Buse, B. Gimeno, V. Bermejo, M. Holland, L. Emberson, and H. Pleijel. 2007. A synthesis of AOT40-based response functions and critical levels of ozone for agricultural and horticultural crops. Atmospheric Environment 41(12): 2630-2643. OECD and JRC. 2008. Handbook on Constructing Composite Indicators: Mehodology and User Guide. Paris: Organisation for Economic Co-operation and Development. Osipova, E., Y. Shi, C. Kormos, P. Shadie, Z. C., and T. Badman. 2014. IUCN World Heritage Outlook 2014: A conservation assessment of all natural World Heritage sites. Gland: International Union for the Conservation of Nature. Osipova, E., P. Shadie, C. Zwahlen, M. Osti, Y. Shi, C. Kormos, B. Bertzky, M. Murai, R. Van Merm, and T. Badman. 2017. IUCN World Heritage Outlook 2: A conservation assessment of all natural World Heritage sites. Gland: International Union for the Conservation of Nature.

Panagos, P., P. Borrelli, J. Poesen, C. Ballabio, E. Lugato, K. Meusburger, L. Montanarella, and C. Alewell. 2015. The new assessment of soil loss by water erosion in Europe. Environmental Science & Policy 54: 438-447. Raskin, P. D., P. Gleick, P. Kirshen, G. Pontius, and K. Strzepek. 1997. Comprehensive assessment of the water resources of the world. Stockholm: Stockholm Environment Institute. Rockström, J., W. Steffen, K. Noone, Å. Persson, I. F. S. Chapin, E. Lambin, T. M. Lenton, M. Scheffer, C. Folke, H. Schellnhuber, B. Nykvist, C. A. D. Wit, T. Hughes, S. v. d. Leeuw, H. Rodhe, S. Sörlin, P. K. Snyder, R. Costanza, U. Svedin, M. Falkenmark, L. Karlberg, R. W. Corell, V. J. Fabry, J. Hansen, B. Walker, D. Liverman, K. Richardson, P. Crutzen, and J. Foley. 2009. Planetary boundaries:exploring the safe operating space for humanity. Ecology and Society 14(2). Scheidleder, A. 2012. Groundwater threshold values: In-depth assessment of the differences in groundwater threshold values established by Member States. Vienna: Umweltbundesamt. Slootweg, J., M. Posch, and J. P. Hettelingh. 2010. Progress in the Modelling of Critical Thresholds and Dynamic Modelling, including Impacts on Vegetation in Europe. CCE Status Report 2010. Bilthoven: Coordination Centre for Effects. Steffen, W., K. Richardson, J. Rockstrom, S. E. Cornell, I. Fetzer, E. M. Bennett, R. Biggs, S. R. Carpenter, W. de Vries, C. A. de Wit, C. Folke, D. Gerten, J. Heinke, G. M. Mace, L. M. Persson, V. Ramanathan, B. Reyers, and S. Sorlin. 2015. Planetary boundaries: guiding human development on a changing planet. Science 347(6223): 1259855. UN Environment. 2019. Global Environment Outlook – GEO-6: Healthy Planet, Healthy People. Nairobi. Usubiaga-Liaño, A., G. M. Mace, and P. Ekins. 2019. Limits to agricultural land for retaining acceptable levels of local biodiversity. Nature Sustainability 2(6): 491-498. Verheijen, F. G. A., R. J. A. Jones, R. J. Rickson, and C. J. Smith. 2009. Tolerable versus actual soil erosion rates in Europe. Earth-Science Reviews 94(1–4): 23-38. WHO. 2005. WHO Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulfur dioxide. Global update 2005. Summary of risk assessment. Geneva: World Health Organisation. Yale University. 2018. Environmental Performance Index: 2018 Technical Appendix. New Haven: Yale Center for Environmental Law & Policy.

Supplementary material

1. Source function

1.1. Renew renewable resources

So_Fo

Environmental sustainability indicator

Indicator Forest utilization rate

The utilization rate is represented as the ratio between fellings and net annual increment, Description the latter being equal to gross increment minus natural losses.

Range 0-∞

Unit %

Standard 70

Time 2005, 2010

Source EEA (2017)

Because the standard for the utilization rate (UR) is defined at country level, the indicator needs to be normalised with a score between 0 and 100. To that end we can use the min- max method as follows: Notes if UR ≤70, then normalised indicator = 100 if 70 < UR ≤100, then normalised indicator = 100 * (100 - UR) / (100 – 70) if UR > 100, then normalised indicator = 0

Science-based standard

Indicator Fellings / Net Annual Increment

An utilization rate below the standard improves the forest’s potential for wood production, Description and the conditions it provides for biodiversity, health, recreation and other forest functions.

Value / Range 70

Unit %

Scale Country

Time N/A

Source EEA (2017)

Notes -

So_Fi

Environmental sustainability indicator

Indicator Fish stocks within safe biological limits

The indicator shows the % of commercial fish and shellfish stocks that fall within European Description jurisdiction that are in good environmental status as defined in the Marine Strategy Framework Directive.

Range 0-100

Unit %

Standard 100 (*)

Time 2015, 2016 (**)

Source EEA (2018b, 2019b)

(*) Because of interactions between fish stocks, it is not possible for all stock to reach the science-based standard below. As a general rule-of-thumb, we consider 100% of stocks in good status as target. (**) The data is not always comparable across time. For instance, the assessment of the stocks in the Mediterranean are carried out in a multiannual cycle, so the amount of stocks for which data is available at different points in time varies. Notes Good environmental status is currently assessed using two criteria related to fishing mortality and reproductive capacity. Because of data availability, this information is not always available for all stocks, so sometimes judgements have to be done based on information for fishing mortality or reproductive capacity. There is a third criterion (population age and size distribution) that is not assessed due to the absence of reference points.

Science-based standard

Good environmental status is characterised through two standards: Indicator  Fishing mortality consistent with Maximum Sustainable Yield  Spawning stock biomass consistent with Maximum Sustainable Yield

The Maximum Sustainable Yield represents the maximum average biomass that can be harvested in the long-term without impeding the remaining stock in fisheries to reproduce itself. Fishing mortality higher the maximum sustainable yield and spawning stock biomass Description lower than those consistent with the maximum sustainable yield are considered to jeopardise the sustainable long-term exploitation of the fishery and to increase the risk of compromising the recruitment potential of the stock. Value / Range Stock-specific Units Unit Tons Scale Stock Time N/A

Source EC (2010)

ICES recommends an approach based on precautionary mortality and spawning stock Notes biomass. Nonetheless, the Directive uses mortality and spawning stock biomass consistent with maximum sustainable yield as references.

So_GW

Environmental sustainability indicator

Indicator Groundwater bodies in good quantitative status

The indicator shows the % area or number of groundwater bodies that are in good Description quantitative status as defined in the Water Framework Directive.

Range 0-100

Unit %

Standard 100

Time 2006 (need to check this) and 2012 (based on 2010-2014 data)

Source EEA (2018c)

The data has been generated as part of the first and second River Basin Management Plans (RBMPs) of the Water Framework Directive. Caution is advised when comparing Member Notes States and when comparing the first and second RBMPs, as the results are affected by the methods Member States have used to collect data and often cannot be compared directly.

Science-based standard

Indicator Good quantitative status

For a groundwater body to be of good quantitative status each of the following criteria:  available groundwater resource is not exceeded by the long term annual average rate of abstraction;  no significant diminution of surface water chemistry and/or ecology resulting from anthropogenic water level alteration or change in flow conditions that would lead Description to failure of environmental quality objectives for any associated surface water bodies;  no significant damage to groundwater dependent terrestrial ecosystems resulting from an anthropogenic water level alteration;  no saline or other intrusions resulting from anthropogenically induced sustained changes in flow direction.

Value / Range Poor / Good

Unit -

Scale Groundwater body

Time N/A

Source EC (2009)

Notes -

1.2. Use non-renewables prudently

So_SE

Environmental sustainability indicator

Indicator Area with tolerable soil erosion

The indicator shows the % of terrestrial area that is not subject to excessive water soil Description erosion.

Range 0-100

Unit %

Standard 100

Time 2001, 2012

Source Panagos et al. (2015) / Borrelli et al. (2017)

Notes -

Science-based standard

Indicator Soil erosion rate

Rates higher than the reference value lead to loss of agricultural productivity and decrease Description in water quality.

Value / Range 1

Unit t ha-1 yr-1

Scale Local

Time N/A

Source Jones et al. (2004); Huber et al. (2008); Verheijen et al. (2009)

Notes -

2. Sink function

2.1. Prevent global warming

Si_CC

Environmental sustainability indicator

Indicator Per-capita GHG/CO2 emissions This indicator shows the deviation of per-capita emissions from a lineal trajectory starting Description in 2015 that leads to net zero emissions around 2050.

Range 0-∞

Unit % reduction compared to 2010 (current baseline year)

Standard 0

Time 2016, 2017

Source -

Normalisation is carried out with the min-max technique where maximum and minimum Notes values are defined by the trajectories consistent with reaching net zero GHG emissions by 2045 and 2055.

Science-based standard

Indicator Per-capita GHG/CO2 consistent with global climate targets Reaching net zero emissions in Europe by 2050 is considered to be consistent with the Description commitment of the Paris Agreement.

Value / Range 0-∞

Unit t per capita

Scale Country

Time 2015-2050

Source EC (2018)

Notes -

2.2. Respect critical loads for ecosystems

Si_Ag

Environmental sustainability indicator

Indicator Cropland area exposed to safe ozone levels

Description The indicators shows the % of cropland area not exposed to critical levels of ozone

Range 0-100

Unit %

Standard 100

Time 2014, 2015

Source Horálek et al. (2015, 2016b); Horálek et al. (2016a, 2018)

Notes -

Science-based standard

Indicator AOT40

AOT40 gives an indication of accumulated ozone exposure, expressed in μg m-3 h, over a threshold of 40 ppb. It is the sum of the differences between hourly concentrations > 80 -3 -3 Description μg m (40 ppb) and 80 μg m accumulated over all hourly values measured between 08:00 and 20:00 (Central European Time) between May and July. The environmental standard is linked to a 5% decrease in yield in wheat.

Value / Range 3 (6000)

Unit ppm h (μg m-3 h)

Scale Local

Time N/A

Source Mills et al. (2007)

Notes -

Si_Fo

Environmental sustainability indicator

Indicator Forest area exposed to safe ozone levels

Description The indicators shows the % of forest area not exposed to critical levels of ozone

Range 0-100

Unit %

Standard 100

Time 2014, 2015

Source Horálek et al. (2015, 2016b); Horálek et al. (2016a, 2018)

Notes -

Science-based standard

Indicator AOT40

AOT40 gives an indication of accumulated ozone exposure, expressed in μg m-3 h, over a threshold of 40 ppb. It is the sum of the differences between hourly concentrations > 80 -3 -3 Description μg m (40 ppb) and 80 μg m accumulated over all hourly values measured between 08:00 and 20:00 (Central European Time) between April and September. The environmental standard is linked to a 5% decrease in biomass.

Value / Range 5 (10000)

Unit ppm h (μg m-3 h)

Scale Local

Time N/A

Source Karlsson et al. (2003); Karlsson et al. (2007)

Notes -

Si_HM

Environmental sustainability indicator

Indicator Ecosystems not exceeding the critical loads of cadmium / lead / mercury

This indicators represents the % of area-weighted ecosystems not at risk of transgressing Description the critical loads of Cd / Pb / Hg

Range 0-100

Unit %

Standard 100

Time 2010, 2020

Source Hettelingh et al. (2015)

The same indicator has been computed separately for three heavy metals (Cd, Pb and Hg). A single map that considers the exceedance of the critical loads of these substances at the same time does not seem to be available. Thus, we select the indicator with the highest exposure as proxy. The indicator is computed for two years, one of which is 2020. The latter refers to a scenario that assumes the full implementation of the heavy metals protocol. According to Hettelingh et al. (2015), the scenario leads to a -29%, -33% and +10% change in the emissions of Cd, Pb and Hg respectively between 2010 and 2020. The extrapolation of the 2010-2016 EEA data leads to a -16%, -28% and -13% change in emissions. Despite the discrepancies, both time points are used as an illustrative example. Critical load exceedance has been allocated to the sink function in terrestrial ecosystems. Notes Nonetheless, the critical loads of used in the original source consider five effects of heavy metal deposition:  human health effect (drinking water) via terrestrial ecosystem;  human health effect (food quality) via terrestrial ecosystems;  eco-toxicological effect on terrestrial ecosystems;  eco-toxicological effect on aquatic ecosystems;  human health effect (food quality) via aquatic ecosystems. The maps in Slootweg et al. (2010) show that as a general rule, exceedance of critical loads related to eco-toxicological effects occurs much more often than that related to human health effects. The effects of heavy metals in surface and groundwater are already covered by the chemical status indicators.

Science-based standard

Indicator Critical load of Cd / Pb / Hg

The critical load is the highest total metal input rate (deposition, fertilisers, other anthropogenic sources) below which harmful effects on human health as well as on ecosystem structure and function will not occur at the site of interest in a long-term Description perspective, according to present knowledge. Critical loads are receptor-specific, so it is not possible to provide a detail account of the specific impacts exceeding critical loads would lead to.

Value / Range 0-∞

Unit g ha−1 yr−1

Scale Ecosystem

Time N/A

Source Hettelingh et al. (2015); Hettelingh et al. (2017)

Notes -

Si_Eu

Environmental sustainability indicator

Indicator Ecosystems not exceeding the critical loads of eutrophication

This indicators represents the % of area-weighted ecosystems not at risk of transgressing Description the critical loads of eutrophication (modelled as deposition of N).

Range 0-100

Unit %

Standard 100

Time 2005, 2020

Source Hettelingh et al. (2017)

The indicator is computed for two years, one of which is 2020. The latter represents a scenario that assumes the full implementation of the Gothenburg protocol. According to Amann et al. (2015), the scenario leads to a -59% and -42% change in the emissions of

SO2 and NOX respectively between 2005 and 2020. The extrapolation of the 2005-2016 EEA data for EU33 leads to a -78% and -51% change in emissions (-52% and -35% Notes between 2005 and 2016). Despite the discrepancies, both time points are used as an illustrative example. The indicator has been allocated to the sink function of terrestrial ecosystems, yet it covers both terrestrial and aquatic ecosystems. The acidification and eutrophication effects of N and S compounds should already be considered in the chemical status of surface waters.

Science-based standard

Indicator Critical load of eutrophication

Critical loads represent the pollutant deposition levels that lead to significant harmful effects on specified sensitive elements of the environment. In the case of nitrogen compounds they are set considering that an increase availability of nutrients that can affect the composition of species in low-nutrient ecosystems and lead to an increase the Description nitrate concentrations in water bodies. In the case of acidifying substances, critical loads consider the impacts on flora and fauna resulting from the release of toxic metals such as Al and the leaching of nutrients from soils.

Value / Range 0-∞

Unit nitrogen eq ha-1 yr-1

Scale Ecosystem

Time N/A

Source CLRTAP (2017)

Notes -

Si_Ac

Environmental sustainability indicator

Indicator Ecosystems not exceeding the critical loads of acidification

This indicators represents the % of area-weighted ecosystems not at risk of transgressing Description the critical loads of acidification (modelled as deposition of N and S).

Range 0-100

Unit %

Standard 100

Time 2005, 2020

Source Hettelingh et al. (2017)

Science-based standard

Indicator Critical load of acidification

Value / Range 0-∞

Unit acid eq ha-1 yr-1

Scale Ecosystem

Time N/A

Source CLRTAP (2017)

Notes -

Si_SW

Environmental sustainability indicator

Indicator Surface water bodies in good chemical status

The indicator shows the % area or number of surface water bodies that are in good Description chemical status as defined in the Water Framework Directive. Rivers have been chosen as the representative body.

Range 0-100

Unit %

Standard 100

Time 2011, 2014

Source EEA (2018c)

Science-based standard

Indicator Good chemical status

Good chemical status means that the concentration of priority substances does not exceed the relevant environmental quality standards specified in the European legislation, which Description are intended to protect the most sensitive species from direct toxicity, including predators and humans via secondary poisoning.

Value / Range Poor / Good

Unit -

Scale Surface water body

Time N/A

Source European Parliament and European Council (2008)

The Directive on Environmental Quality Standards (European Parliament and European Council 2008) contains the list of substances and standards that are used to assess the chemical status of surface waters. These standards refer to pollutant concentration in Notes waters. Based on guidelines provided by the European Commission (EC 2011), Member States can establish their own standards for sediment and/or biota, and use them instead of the water-based standards, which can ultimately lead to differences in the standards adopted across countries.

Si_GW

Environmental sustainability indicator

Indicator Groundwater bodies in good chemical status

The indicator shows the % area or number of groundwater bodies that are in good Description chemical status as defined in the Water Framework Directive.

Range 0-100

Unit %

Standard 100

Time 2011, 2014

Source EEA (2018c)

Science-based standard

Indicator Good chemical status

Good groundwater chemical status is achieved when:  there is no sign of saline intrusion in the groundwater body;  the concentrations of pollutants do not exceed those permitted under the applicable groundwater quality standards or threshold values, including those for Description drinking water protected areas;  the concentrations of pollutants do not result in failure to achieve the environmental objectives of associated surface waters (as specified in the Water Framework Directive), nor in any significant damage to terrestrial ecosystems that depend directly on the groundwater body.

Value / Range Poor / Good

Unit -

Scale Groundwater body

Time N/A

Source EC (2009)

Following on the comment above, countries use different threshold values for chemical Notes substances (Scheidleder 2012) and they monitor a different amount of substances (EEA 2018c), which limits the comparability of the country results.

3. Life-support function

3.1. Maintain biodiversity

LS_BD

Environmental sustainability indicator

Indicator Terrestrial area with acceptable biodiversity levels

The indicators shows the % of area-weighted ecosystems (subecoregions) above a certain Description biodiversity (mean species abundance) level

Range 0-100

Unit %

Standard 100

Time 2000, 2015

Source Usubiaga-Liaño et al. (2019)

Notes -

Science-based standard

Indicator Local Biodiversity Intactness Index

The indicator estimates how much of a terrestrial site's original biodiversity remains in the Description face of human land use and related pressures. It is reported in mean species abundance compared to undisturbed baseline.

Value / Range 90

Unit %

Scale Global and biome/large region

Time N/A

Source Steffen et al. (2015)

Notes -

LS_SW

Environmental sustainability indicator

Indicator Surface water bodies in good ecological status

The indicator shows the % size or number of surface water bodies that are in good (or Description high) ecological status as defined in the Water Framework Directive. Rivers have been chosen as the representative body.

Range 0-100

Unit %

Standard 100

Time 2011, 2014

Source EEA (2018c)

Science-based standard

Indicator Good ecological status

The ecological status of surface waters (including artificial and heavily modified water bodies) is determined based on biological, physicochemical and hydromorphological Description criteria. There are no absolute environmental standards applicable across water bodies, so the ecological status is defined based on the extent to which current values deviate from those attributable to undisturbed conditions.

Value / Range Bad / Poor / Moderate / Good / High

Unit -

Scale Surface water body

Time N/A

Source EC (2003)

Except for certain chemical substances, there are not hard fixed standards to determine the overall status of water bodies. The WFD provides a normative definition of high and good ecological status. Ultimately, the characterisation of water bodies depends on how Notes Member States characterise the undisturbed conditions and on the intercalibration process aimed at ensuring that the high-good and the good-moderate boundaries in all assessment methods for biological quality elements correspond to comparable levels of ecosystem alteration (EC 2005).

LS_Sc

Environmental sustainability indicator

Indicator Freshwater bodies not under water stress

The indicator represents the % of freshwater bodies that is not subject to excessive water Description consumption at any season.

Range 0-100

Unit %

Standard 100

Time 2014, 2015

Source EEA (2018a)

The indicator is computed quarterly to reflect seasonality. It covers all types of freshwater, Notes namely rivers, lakes, reservoirs and groundwater.

Science-based standard

Indicator Blue water consumption / Mean quarterly flows

Consumption over mean runoff exceeding 20% is commonly used to distinguish water Description stressed bodies.

Value / Range 20

Unit %

Scale (Sub)river basin

Time N/A

Source Raskin et al. (1997)

Notes -

4. Human health and welfare function

4.1. Respect standards for human health

HW_AP

Environmental sustainability indicator

Population exposed to safe levels of particulate matter lower than 2.5/10 micrometres or Indicator less in diameter

The indicator shows the % of population exposed to lower PM or PM levels than the Description 2.5 10 WHO guideline values.

Range 0-100

Unit %

Standard 100

Time 2014, 2015

Source Horálek et al. (2015, 2016b); Horálek et al. (2016a, 2018)

Notes The indicator represents the highest exposure to PM2.5 or PM10 Science-based standard

Indicator Average annual PM2.5 or PM10 concentration The standard refers to the lowest level at which total, cardiopulmonary and lung cancer Description mortality have been shown to increase with more than 95% confidence in response to long-term exposure to PM2.5.

Value / Range 10 (PM2.5) and 20 (PM10) Unit μg m-3

Scale Local

Time N/A

Source WHO (2005)

Notes -

HW_DW

Environmental sustainability indicator

Indicator Samples that meet the drinking water criteria

The indicators shows the % of samples that meet the drinking water criteria specified in Description the European legislation

Range 0-100

Unit %

Standard 100

Time 2012, 2013

Source EC (2016)

Notes -

Science-based standard

Indicator Safe drinking criteria

Environmental standards in the European legislation are in most cases based on the WHO guideline values available at the time and the input from the Commission's Scientific Advisory Committee. The latest evidence calls for a revision of some of these standards. Description Standards at country level can be more restrictive and cover additional parameters. Drinking water quality is determined based on 48 parameters grouped in three categories: microbiological parameters, chemical parameters and indicator parameters.

Value / Range Multiple

Unit Multiple

Scale Sample

Time N/A

Source European Council (1998)

Notes -

4.2. Conserve landscape and amenity

HW_BW

Environmental sustainability indicator

Indicator Recreational water bodies that meet the ‘excellent’ quality criteria

The indicators shows the % of marine and inland water bodies used for recreational uses Description that meet the reference values in European legislation.

Range 0-100

Unit %

Standard 100

Time 2007, 2018

Source EEA (2019a)

The classification of European waters has the following categories: excellent, good, sufficient, poor and insufficiently sampled. Before 2015 the EEA reports do not distinguish Notes between excellent and good, which are reported as a single category. The European legislation did not adopt the no-effect standard specified by WHO and instead adopted a tolerable risk approach, which is supported by different sources.

Science-based standard

Indicator Concentration of Intestinal Enterococci and Escherichia Coli in recreational waters

The standard is associated with 3% of gastrointestinal illness risk and 1% of acute febrile Description respiratory illness risk after repeated exposure to water containing the abovementioned bacteria.

200 (intestinal enterococci, inland waters), 500 (Escherichia Coli, inland waters), 100 Value / Range (intestinal enterococci, coastal and transitional waters), 250 (Escherichia Coli, coastal and transitional waters),

Unit cfu / 100 ml

Scale Water system

Time N/A

Source EC (2002)

Notes -

HW_WH

Environmental sustainability indicator

Indicator Natural and mixed world heritage sites that have a good conservation outlook

The indicators shows the % of natural and mixed world heritage sites that are considered Description to have a good conservation outlook.

Range 0-100

Unit %

Standard 100

Time 2014, 2017

Source Osipova et al. (2014); Osipova et al. (2017)

Notes -

Science-based standard

Indicator Good conservation outlook

Good conservation outlook based on three elements: the current state and trend of values, Description the threats affecting those values, and the effectiveness of protection and management.

The conservation outlook of each site is classified as being good, good with some concerns, Value / Range significant concern or critical.

Unit -

Scale Individual sites

Time N/A

Source Osipova et al. (2014)

Notes -