An Interdisciplinary Approach to Sea Level Rise

Planning for Uncertainty in Bremen and Gothenburg: An Interdisciplinary Approach to Sea Level Rise

Osäkerhetsplanering i Bremen och Göteborg: En interdisciplinär studie av stigande havsnivåer

Degree project in strategies for sustainable development, Second Cycle AL250X, 30 credits

Author: Per Björklund

Supervisor: Jacob von Oelreich

Examiner: Måns Nilsson

Division of Environmental Strategies Research (fms) Department of Sustainable Development, Environmental Science and Engine- ering School of Architecture and the Built Environment KTH Royal Institute of Technology

TRITA TRITA-INFRA-FMS-EX-2016: 16

Table of Contents

Abstract / Sammanfattning 3

Introduction 3

Methodology 4 Quotes, figures and text boxes 5 Relationship between theory and case study 5 Methodological limitations 6

Chapter 1: The psychology and practice of risk assessment 8 Risk as a variable in urban planning 8 General principles of risk assessment 9 Psychological heuristics 10 Heuristics relevant to the perception of risk 11 Conservatism, culture and incentives 13 The risk professional 13 The natural scientist 14 The practitioner/decision maker 15 Reducing bias in decision making 16

Chapter 2: The science of climate change and sea level rise 18 Understanding the drivers of climate change 20 How much will the climate system warm? 21 The Paris agreement and the 1.5 degree goal 23 Global sea level rise over the long term according to current scientific understanding 24 Global sea level rise in the 21st century according to current scientific understanding 27 Localizing global average sea level rise 28 Currently unknown science 29 The West Antarctic 30 Arctic Sea Ice, Greenland and the Gulf Stream 33 “The Cold Spot” and changing weather patterns 35

Chapter 3: Overview and comparison of Bremen and Gothenburg 37 Bremen, Bremerhaven and the North Sea Coast 37 The organization of coastal defense 40 Sea level rise along the German North Sea Coast 41 Future plans 42 Possible future alternatives 43 Gothenburg 45 The organization of sea level rise adaptation 46 Sea level rise along the Swedish West Coast 47 Future plans 48 Country guidelines and city plans 49 Comparative analysis 51 Conclusion 53

References 55 Interview references 65

Abstract This thesis examines the readiness and perception in the regions of Gothenburg and Bremen towards future sea level rise. It does so through the theoretical lens of risk psychology / policy research and of climate science research. Results are built on some of the most recent research of these fields, as well as interviews with 14 people on the local, regional and national level in Germany and Sweden. Key findings of this thesis are that both contexts struggle to deal with the great uncertainties inherent in sea level rise. On the German North Sea coast, there is long experience with sea level variation and extensive civil institutions created to deal with storm surges, dikes and sea level rise which may partially compensate for inherent vulnerability to future sea level rise in this region. The novelty of sea level rise in Gothenburg and Sweden means that it is in the process of creating similar institutions and national-regional divisions of responsibility from scratch. The great uncertainty around the pace and extent of future sea level rise is however an obstacle which may have to be overcome before a more coherent response may be developed.

Keywords: Gothenburg, Bremen, Sea Level Rise, Uncertainty, Heuristics, Risk Assessment, Climate Change Adaptation, Climate Science, Earth System Science

Sammanfattning Denna uppsats undersöker beredskap och uppfattningar kring framtida havsnivåhöjningar i Göteborg och Bremen. Detta görs med de teoretiska ansatserna riskpsykologi / beslutspsykologi och grundläggande klimatvetenskap. Uppsatsens resultat bygger på de senaste resultaten inom dessa fält, samt intervjuer med 14 personer på lokal, regional och nationell nivå i Tyskland och Sverige. Efter genomförd studie kan konstateras att bägge kontext har svårigheter att hantera de stora osäkerheter som havsnivåhöjningen medför. Tyska Nordsjökusten har mycket lång erfarenhet och kapabla offentliga institutioner vilka skapats för att hantera skyddsvallar, sjunkande landnivåer och stormfloder, vilket balanserar det prekära läge som området annars står inför. I Göteborg och i Sverige är havsnivåhöjning något fundamentalt nytt, vilket innebär att man nu försöker skapa liknande institutioner och ansvarsfördelning mellan nationellt och regionalt som de Bremen och Tyskland redan har. Ett hinder för detta är de stora osäkerheter som råder kring hastighet och absolut nivå på framtida havsnivåhöjningar. Dessa osäkerheter kan komma behöva reduceras innan problemet börjar hanteras på ett mer samordnat sätt.

Nyckelord: Göteborg, Bremen, Havsnivåhöjning, Osäkerhet, Heuristik, Riskbedömning, Klimatanpassning, Klimatvetenskap.

Introduction “When we look at any of the major impacts of climate change, they one way or another come through water… So it will be no exaggeration to claim that climate change is really in fact about hydrological change.” Richard Damania, lead author of the World Bank report “High and dry, Climate Change, Water and the Economy” (Mooney 2016).

70% of our planet is covered by water, and an entire continent (Antarctica) is covered by 30 million cubic kilometers of ice. Were all the great glaciers on earth to melt, it would equal 70 meters of average global sea level rise (NSIDC 2015a).

But how much, and how quickly, may it melt? When studying adaptation, it is unavoidable to encounter the concepts of risk and uncertainty. If anything can be said with certainty, it is that climate change mitigation will not be completely successful or unsuccessful. Rather, it will be somewhere in between. Furthermore, whatever success we achieve will have different impact in

different regions, which may or may not be ready to deal with them.

While all climate change is in some ways directly or indirectly about water, the study of sea level rise is obviously so. This thesis is about how two regions (the sedimentary and sinking German North Sea coast and the rocky and rising Swedish West Coast) deals with the uncertainty that surrounds it, and what differences and parallels there are between the port cities of Bremen and Gothenburg. On first glance, this comparison may seem curious, as there are quite a few obvious differences. But there are many similarities as well. They are of similar size, are economically dependent on trade and shipping, and both are notable for their vulnerability to sea level rise within their countries. This combination of similarity and difference seemed to promise a dynamic final result.

The goal of this thesis is to uncover what sort of assumptions about the future that exist in these two contexts, compare them, and assess them in light of risk psychology, policy research and climate science research. This interdisciplinary approach was decided upon as a way of making this thesis applicable not only in the context of Bremen and Gothenburg, but also as more general examples of the world-wide challenge of sea level rise and universal psychological tendencies when it comes to how humans tries to deal with risk and uncertainty.

Methodology When it comes to thinking about how the world will respond to projected changes in the climate…it is important to guard against a failure of imagination… Failure to think about how climate change might impact globally interrelated systems could be stovepipe thinking. (King et al 2015: 23)

This thesis has an interdisciplinary approach1, blending insights from areas such as urban planning, history, geology, intelligence studies, risk psychology, social anthropology and earth system science / climate science in order to study adaptation to sea level rise in a holistic manner. Social anthropology and closely related fields such as Intelligence Studies and Development Studies has been especially important2. There it is not uncommon to shape the approach after what is being studied and both put a heavy emphasis on contextual information.

In the case of this thesis, it was deemed that the critical context was (1) The regions of Bremen and Gothenburg, (2) The planners, scientists and risk-analysts set to improve and protect them, and (3) The science of predicting future sea level rise. While taking an interdisciplinary approach always risks spreading attention too thinly over too many subjects, this concern must be balanced against the nest of complexity-upon-complexity that is future human-climate interaction. A very important inspiration has been the approach taken by the report “Climate Change: A Risk Assessment” (King et al 2015).

The principles behind that report can be found on page 9, and helped guide how to write chapter 1 and 2. Wilhelm Agrell’s book Konsten att gissa rätt, underättelsevetenskapens grunder (The art of guessing right: The foundations of Intelligence Studies) (Agrell 1998) has been very useful for helping provide some of the tools necessary for investigating the relationship between producers and consumers of uncertain information (such as climate science and risk assessments). This thesis takes the point of view that the sort of methodical thinking practiced by risk professionals is

1 ”Interdiciplinary” being defined as: integrating knowledge and methods from different disciplines, using a real synthesis of approaches (Stember 1991). 2 Works of particular importance include ”Europe and the People Without History” (Wolf 1982), ”City: Urbanism and its End” (Rae 2005), ”Seeing Like a State” (Scott 1998) and ”Analytical Culture in the U.S. Intelligence Community” (Johnston 2005). 4

necessary for approaching complex and emotionally draining topics such as climate change in a dispassionate, scientific and constructive way. This does not mean that intuitive ways of understanding risk can be ignored, but must be understood.

Quotes, figures and text-boxes In chapters 1 and 2 there is a heavy use of quotes located before the main text. These are used as a form of textual illustrations, intended to introduce and reinforce the point the main body of text is making. Graphical figures are used in a similar way, especially in chapter 2. Text boxes are used in chapters 1 and 2 to explain critical concepts and present source material that reinforce and puts the main text in context.

Relationship between theory and case study Chapters 1 and 2 constitute theoretical chapters, and are necessary to understand Chapter 3. The thesis is meant to be read in a chronological order, with each chapter building on top of those that came before it. The chapters move from the general to the specific, the former chapter giving context to the latter.

Chapter 1 is a very general comment on psychological and cultural tendencies in dealing with risk. It looks at common mistakes and ways of avoiding these. It is essential for broadly understanding the actions and reasoning of people in Bremen and Gothenburg. It uses concepts and theory from risk psychology in works such as The Perception of Risk (Slovic 1987) and Thinking Fast and Slow (Kahneman 2011). This chapter also looks at professional cultures and incentives, building on the framework from King et al 2015, as well as the conflicts between consumers of information and those that produce is as described by Agrell (2009). In this particular case, the producers of information are the stereotypical Risk Professional as compared to the stereotypical Natural Scientist. It will then look at how these interact with the consumers of information, the stereotype of the Practitioner/Decision Maker. The two first stereotypes are adapted from King et al (2015), while the characteristics of the Practitioner/Decision maker is adapted from Agrell (2009) and Gluckman (2014).

The theoretical approaches in Chapter 1 are used to give context to the underlying psychological and cultural tendencies that are found in Chapter 2 and 3. While it may seem tempting to explicitly apply stereotypical labels to individual organizations and people, this is generally avoided. It is the judgement of the author that the source material is too limited for such an exercise, and that it would be unethical to risk pathologize readily identifiable, complex individuals.

Chapter 2 is a look on the global problem of climate change and an in-depth look at the significant uncertainties that exist over both the long term and the short term. This chapter tries to understand the problem of sea level rise from first principles, which is necessary in order to understand what the range of uncertainty is, what science does and does not know, and what the current understanding of worst case scenarios are. This approach is in line with points 2 to 5 in the risk assessment framework identified in the beginning of Chapter 1.

This chapter gives as global view of sea level rise, which is of course very useful in and by itself given how central such knowledge is for gaining a scope on the issue. In the thesis, this theory is primarily used to give context to the reasoning and assumptions in Chapter 3, specifically whether individuals are aware of the factors, predictions and uncertainties that it describes, and how / if they choose to deal with them. Chapter 3 does generally not try to second-guess these decisions as that is beyond the scope of the thesis, but aim to point out when certain factors appear to be ignored.

Chapter 3 starts with a general overview and a comparative chart of Bremen and Gothenburg, giving context to the present situation and presents the different views and ideas and institutional relationships that interviews revealed as important. Chapter 3 ends with a comparison between two contexts, and with the theory found in chapters 1 and 2.

Interviews This chapter is mainly based on 14 interviews done with individuals in Germany and Sweden, both in person and over telephone (a list of these are found on page 65). The intention was to collect a sample of academics and practitioners in both contexts, representing a variety of different key institutions and professional cultures engaged in adaptation. In Gothenburg (much as in Sweden in general) the number of people both knowledgeable and willing to be interviewed proved to be quite manageable. In Bremen it was more unclear who to talk to, but discussions with my initial contacts led to several more interviews (see the section on limitations below for more information).

An initial ambition was to have at least part of each interview be of a “standardized open-ended” format (Mikkelsen 1995: 102-103). In this type of interview, questions are of identical wording and is asked in an identical order, making data easier to compare. This approach was soon abandoned as the diversity of topics and interviewees grew, making it obvious that maintaining it would be both unsuitable and probably unsustainable.

Instead a semi-structured “interview guide” (ibid.) approach was used. In this case, it entailed preparation before each interview, attempting to identify certain points of interest which the interviewee could be expected to know about. The extent to which these questions came to be used varied widely, depending on what the interview revealed. The primary factor came to be how the interviewee wanted the interview to proceed. Some interviews touched only on the questions written beforehand, while other interviews became an exercise in trying to sort information and invent questions on the fly as the interviewee forged their own path.

Most interviews ended up being around one hour in length or shorter, but a few grew significantly longer than that. All interviews were recorded, and notes over significant points were taken. The entire source material constitutes over 15 hours of audio. It has only been partially transcribed but is available on request.

In Chapter 3, the material from the interviews have been used together with literature and graphics to try and paint a coherent picture of each region. An alternate possibility would have been to split the interview material and present it in a separate section, but it quickly became apparent that the heterogeneity in interview material, sources and topics would have made this both inelegant and confusing. The chosen method also had the advantage of making it easier to contrast interview material with other sources to verify, or to highlight contradictions.

Methodological Limitations While every effort has been made to gain a representative sample of the adaptation communities in Bremen and Gothenburg, it is obvious that the sample is biased in different ways. There is an unrepresentative amount of academics in Bremen, and the perspective of practitioners became overrepresented in Sweden. The academic bias in Bremen is partly due to a cultural divide between practitioners and academics when it comes to adaptation (which will be further explored in Chapters 3 and 4) which made it hard to find the right people to talk to. Another reason was the need for the interviewee to be fluent in English (with the average academic having better language skills). In Sweden the skew towards practitioners came down to access (these simply proved to be more willing to participate) and the fact that there are relatively few academics oriented towards the study of urban planning related to sea level rise in Sweden and in Gothenburg (see Chapter 3).

In Sweden, it was my experience that practitioners (meaning those who have to design or implement policy) would be more challenging to interview than those who were pure academics. This could be because practitioners may feel obliged to adhere to company or governmental policy in their answers. The same problem was not encountered in Bremen, which can have something to do with all the different ways that coastal protection in that context is a question of citizenship and is perceived as a common public concern open for debate and disagreement. It may also partly be about the people who were willing to be interviewed, meaning a fairly small and towards activism biased sample. Chapter 3 will examine these questions more closely.

Another limitation was that there was only one woman in the sample. This was both due to a predominance of men in relevant positions and due to the fact that all but one of the women who I contacted declined to be interviewed. This bias in the sample may be problematic since quite a few studies show a significant difference in the perception of risk between genders (Slovic et al 1987: xxxiv). Using semi-structured, non-standardized interviews are, at least in some aspects, another possible limitation. But given the diverse set of participants, there wasn’t much choice. The interdisciplinary approach taken somewhat compensates for the biases identified above, as the interview material has plenty of context in Chapter 1 and 2 which potentially helps “triangulate” the data (in the sense of providing cross verification from different theoretical frameworks and data points (Given 2008: 892-894)). At the same time, such an approach introduces limitations of its own, trading focus for breadth.

Chapter 1: The psychology and practice of risk assessment

It is a truism that societies which are regularly exposed to nature’s extremes find ways of adapting. After all, if they didn’t, they would no longer be around. Solutions can be complete or merely “good enough”, depending on resources and organization, as well as the severity and duration of these adverse conditions.

For example, the rapid shift that occurs when temperature fall below zero degrees C may completely paralyze transport in subtropical climates, while most sub-arctic societies have systems, laws and procedures in place to enable society to continue functioning (Bagehot 2010). The same is true of heat. Cities in northern USA have been shown to have higher mortality during heatwaves than southern cities, even though the absolute temperatures reached in the US south are higher (Kousky 2012:37).

What brings society to a halt in one context may be seen as completely normal, if a bit annoying, in another. We have a clear tendency to be bad at dealing with events happening outside of the range we have learned to deal with. Or, if a specific event is sufficiently rare, it may make no sense to insure against it, as the opportunity-cost of insurance may well be higher than the effects of just muddling through when and if anything happens.

Another type of risk is overconfidence in our defenses. Too much skill and investment in defending against severe events can lead to a very dangerous build-up in risk if systems were to fail or be overwhelmed. This is known as the “Levee Effect” (American Rivers 2012), so named because of the tendency that protective dikes / systems over time leads to an increase in population and infrastructure at risk from catastrophic failure. Skill at adaptation, seemingly impenetrable defenses or complex systems intended to reduce risk may in this way prove to be counterproductive. Rare and / or unanticipated combinations of events can overwhelm or circumvent what we put in place to stop them (the very dramatic sinking of the “unsinkable” Titanic being a classic case).

Risk as a variable in urban planning Locating and designing housing, industry and supporting infrastructure is a commitment which is usually very expensive and difficult to change once done. The standard prescription for minimizing the impact of today's decisions on the future is careful, iterative planning (Scott 1998: 327). But if such planning is done on the assumption that tomorrow’s urban challenges are merely a gradual extension and intensification of the present, it may very well fail to anticipate the needs of the future. In the worst case, our failure to anticipate will now prevent us from setting in place the solutions we could have used had we had more foresight and built in more flexibility into our plans.

This does not mean that our preoccupation with cyclical or gradual risks is irrational. It is impossible to fortify society against every conceivable event, and gradually emerging risks can usually be discovered and adapted to when and as they occur. There are also some very rational, if dangerous, psychological reasons for ignoring risks (which will be discussed in the next section). However, in the era of climate change abrupt risks of the type we are the least prepared to deal with may become the types of risks we must be the most concerned with3. Urban planners must learn from professions that are more oriented towards anticipating and calculating risk, and which tries to reduce the consequences of change outside of the range experience has taught us is possible.

3 “A study of Earth’s climate history suggests the inevitability of “tipping points”, thresholds beyond which major and rapid changes occur when crossed that lead to abrupt changes in the climate system. The history of climate on the planet. as read in archives such as tree rings, ocean sediments, and ice cores is punctuated with large changes that occurred rapidly, over the course of decades to as little as a few years.” (NRC 2013: 8) 8

General Principles of Risk Assessment "Risk assessment begins and ends with specific objectives" (King et al 2015: 19)

As will be further explored in the next section on culture, different academic traditions and professional cultures have different ways of defining “risk”. Quantitatively, the most common definition is Impact x probability = risk, a common formula in cost benefit analysis (Kreimer et al 2003: 45). Two more qualitative definitions are:“the effect of uncertainty on objectives” and ”uncertain, generally adverse consequence of an event or activity with respect to something that humans value”. (King et al 2015: 26). As elaborated below, both definitions have their place in risk analysis.

One of the goals of this thesis is try and gain an understanding about the risk assessment procedures and strategies used in Bremen and Gothenburg. The six principles below have been adapted from the report “Climate Change, A Risk Assessment” (King et al 2015). According the authors of these six points, the framework has been constructed by a process involving literature studies and conversations with risk professionals in various fields (ibid: 22).

The points below is one way of creating a structured approach for what to include and what to leave out, as well as giving hints of what some common deviations from best practices might be. These points will form a core part of the current chapter, has been used in deciding what to write in the second chapter, and will be explicitly referred to during the discussion and analysis part.

One. Identify risks in relation to objectives The first principle is that of identifying what we are trying to protect. If we haven't identified this, we cannot know what the risks may impact this core value. From this principle follows that we first ask what might happen that could affect our interests the most, and then ask how likely that is to happen. This may seem obvious, but a common mistake is to instead start with what seems most likely to happen, and then examine the impact to our interests from that. This is dangerous because the main purpose of a risk assessment is to maximize protection from rare / uncertain events which threaten our core interests. If we instead go looking for what we think is likely / reasonable we may be left completely exposed if our assumption prove to be wrong (King et al 2015: 22-24, Lovallo & Kahneman 2003).

Two. Identify the biggest risks The second principle is an extension of the first principle. The bigger the impact of the risk, the higher the relevance for our decision-making. Simply calculating risks as the product of likelihood multiplied by impact is dangerous, since that may prevent us from taking the gravest, most irreversible risks into account (King et al 2015: 22-24, Hillson & Hulett 2004: 5)

Three. Consider the full range of probabilities In order to be able to apply the second principle, we must first identify the full range of possible risks. How low probabilities we are willing to accommodate in this process is a matter of judgement, but risks deemed to be 1 in 100 or below should not be automatically discounted if the impact poses a grave threat to the objectives identified in principle #2. (King et al 2015: 22-24, Hillson & Hulett 2004: 2)

Four. Use the best available information The sources used for the risk assessment should seek to include as many types of perspectives as possible. For example, one should not only consider risks studied quantitatively, or only risks studied qualitatively. One should strive to consider all risks, even if the span of uncertainty is wide, there are several competing interpretations, or even if no information can be found. (King et al 2015: 22-24, Hillson & Hulett 2004: 3)

Five. Take a holistic view When faced with a complex system of risks, one must consider all the parts together. This is especially true with a very complex and chaotic issue such as climate change, where the many uncertainties and unknowns makes modelling impractical. Scenarios are especially useful for these kind of problems, as these may identify the range of possibilities, if not the exact likelihood. (King et al 2015: 22-24, Schrage 2003)

Six. Be explicit about value judgements This means a transparency about the process that led to our judgements. Unless we are open about how we identify and evaluate risks (what we want to avoid) it is impossible to know what we have chosen to exclude. It is also very important to be as transparent as possible about the probabilities of the risks we identify. (King et al 2015: 22-24, Lovallo & Kahneman 2003)

It should be noted that risk assessments are cyclical and iterative. They should be done repeatedly and information uncovered during later points in the process may force a reassessment of earlier points (Stanleight 2016).

Psychological heuristics

“Essentially, all models are wrong, but some are useful” George E. P. Box (Jennings 2014)

“Evolution has shaped us with perceptions which allow us to survive. They guide adaptive behaviors. But part of that involves hiding from us the stuff we don’t need to know.” Donald Hoffman (Gefter 2016)

As dictated by principle number 5 in our principles of risk Box 1.1 Heuristic: A mental model, assessment on page 9, we need to take a holistic view a "rule-of-thumb", for reducing a when trying to understand risk. Risk Psychology is a field complex problem to a manageable which is key to understanding why people tend to make size. (Fox 2015) particular decisions under particular conditions. This section will discuss a number of psychological concepts which can help us understand how people deal with risk and uncertainty, both as individuals and groups.

Box 1.2 Bounded Rationality: The fact The first, and most basic concept is that of that human decision-making is rational heuristics (box 1.1), which captures all the ways we only within the constraints of the use to filter out information as unnecessary or available information, our cognition (Box dangerous. As Donald Hoffman puts it at the top of 1.3) and the amount of time used to tackle this page: “…the stuff we don’t need to know”. a problem. (Slovic et al 1987: 23-24) Heuristics are by definition subconscious, using instinct and experience to make very quick decisions on very complex and / or ambigious problems and situations. Heuristics are part of what can be termed bounded rationality (box 1.2).

The concept of bounded rationality implies that the Box 1.3 Cognition: The way the human all-seeing, all-knowing agent so popular in economic mind interprets the world around it theory in itself is a heuristic. Which is not a problem through a combination of senses, unless one forgets that it is a model, a necessary experience and thought. (Kahneman simplification. Real people in the real world are 2011: 59) And since our ability to dependent on using their cognition (box 1.3), which understand, process and combine this is subject to limitations. Our understanding of the information is limited, we use instinctive world cannot be perfect, but rather strives to be good mental models (simplified enough for the situations and constraints we most representations of the world), which commonly encounter. psychologists call heuristics (see Box 1.1) Heuristics relevant to the perception of risk Affect: “…people make judgements and decisions by consulting their emotions. Do I like it? Do I hate it? How strongly do I feel about it? …The affect heuristic is an instance of substitution, in which the answer to an easy question (How do I feel about it?) serves as an answer to a much harder question (What do I think about it?)(Kahneman 2011: 137) The Affect heuristic describes a tendency in which “the emotional tail wags the rational dog” (ibid.). It simplifies things by making us think that the way we feel about something is how it really is. This heuristic gives clarity to murky situations and significantly lightens the cognitive load of decision making. Affect is useful for avoiding complex and / or uncomfortable information: “creating a world that is much tidier than reality.”(ibid). This heuristic is a powerful reason to create procedures and checklists (such as our six principles of risk assessment found on page 9) that forces us to discuss and take a good look at our assumptions. Availability: Availability is a type of heuristic which tries to anticipate the future by how easily we Box 1.4 Example of Availability from the Christ- can imagine a specific event occurring. mas Tsunami disaster of 2004: ”Although the Dramatic events (especially those that small global community of tsunami researchers affected us personally) from the recent past [in the countries surrounding the Indian Ocean] have a great deal more weight than a great had expressed some concerns about the risk of number of smaller events. The ease of recall such an event, little had been done to plan for it… tends to make us think they are more likely it has been difficult to raise the money for a moni- to also happen in the future (Slovic et al toring system. 1987: 37) A very important implication of the ’Only two weeks ago it would have sounded availability heuristic is that events which we crazy… But it sounds very reasonable are unable to imagine will be considered now. The millions of dollars needed would extremely unlikely, or even impossible, to have saved thousands and thousands of lives.’ happen. This is part of the explanation of The most recent comparable event in the what prevent us from undertaking even the region took place in 1883.” (Marris 2005) most basic precautions when faced with an unfamiliar scenario of potentially catastrophic consequences, as seen in box 1.4. The mass experience of a predictable catastrophic event which was very uncertain in timing and impact suddenly sets into motion processes that would have been more useful to have before the event rather than after. The availability heuristic greatly complicates planning and implementation of sometimes cheap preventive measures, but also help us focus on problems that actually happen rather than the potentially limitless number of problems we could imagine might happen.

Temporal Parocialism/Time Horizon Bias: The lack of availability is part of what makes climate change and sea level rise are so difficult to deal with. Connected to this lack of experience with the issue is that of human time horizons. People find it very hard to relate to events which are measured in thousands, millions or billions of years. Such “Temporal Parocialism” (box 1.5) means that events removed from our everyday understanding of the world may only be understood in an abstract sense.

This time horizon heuristic is in many ways quite rational: Box 1.5 Temporal Parocialism: The Spend too much time and energy worrying about the brevity of our lives breeds a kind of future and you’re less likely to survive the present. temporal parochialism—an Shrinking your horizons has for much of human history ignorance of or an indifference to been a necessary tool for making the best we can today those planetary gears which turn and let the future take care of itself. While a very useful, more slowly than our own. (Schultz and sometimes crucial, heuristic for getting us through the 2015) short term, it can be a case of trading peace of mind today for irreversible consequences tomorrow. Temporal Discounting:

Much of the debate about climate Box 1.6 Example of Temporal Discounting: In Florida, change is not primarily about the one of the most exposed areas in the world when it comes data. Rather, it is about to sea level rise, state officials are banned from using the intergenerational economic words “climate change” and “global warming” in official interests. (Gluckman 2014) communications (Korten 2015). According to some Some psychological studies indicate estimates, Miami is the city in the world with the most that we demand a significant rate of economic assets at risk from sea level rise, and very return if we are to shift a reward to unfavorable local conditions (Tompkins & DeConcini our future selves instead of making 2014). There is ongoing construction of luxury apartments a decision which helps us in the less than 30 cm of sea level rise along the Miami present. What is more, this beachfront. According to Miami Mayor Levine “We’re tendency seem to increase if we feel going to have innovative solutions to fight back against uncertainty about the future (Soman sea-level rise that we cannot even imagine today.” et al 2005). One hypothesis is that (Kolbert 2015) people who feel that they are in control of their lives feel a greater In another interview he states that “We believe what we’re connection to their future selves, doing, this $400 million plan, could be a 30 or 40 year while people who lacks such solution…” while Susanne Torriente, Miami Beach chief confidence is more inclined to let resilience officer says: “Thinking about 2100 is their future selves take care of overwhelming… but if you think about the things we can themselves (ibid). do now, it’s a manageable challenge and an opportunity. The next person in my job is going to have to keep In the field of planning for building upon this over time.”(Weiss 2016) adaptation and climate change, one possible consequence is that people who live in chaotic societies where planning is impossible, and / or believe they face an uncertain future, may respond by decreasing their time horizon, i.e. becoming more short-term in their outlook. This heuristic may be helpful in retaining confidence and coherence in uncertain times, as shown by box 1.6. The planners of Miami have dealt with its exposed position and uncertain prospects by adopting very short time horizon. It is easy to have sympathy with this reaction. But preservation of the status quo can have very high long term costs if the kind of miracle that is clearly expected does not arrive. In the short term such a gamble makes a lot of sense, since it is the future that will have to deal with the consequences if the bet goes wrong.

Conservatism, culture and incentives Conservative: a: tending or disposed to maintain existing views, conditions, or institutions b: marked by moderation or caution c : marked by or relating to traditional norms of taste, elegance, style, or manners (Merriam-Webster 2016).

The last section looked at different heuristics that people use to deal with uncertainty. This section will look at the different cultural4 approaches organizations and professions have for dealing with risk, and what the definition of a “conservative” assessment happens to be.

What risks and timeframes are relevant? The answer to this question is at heart of what people think is the right way to deal with the many uncertainties surrounding climate change and sea level rise. According to the definitions above, it is a question of maintaining particular ways of doing things, ways which in turn were shaped by the values and incentives of a particular cultural context.

This section will look at three different stereotypes when it comes to the management of risk. Reducing the diversity of people to three stereotypes may seem unnecessarily reductive, and plenty of people and professional roles do not fit neatly into one of these slots. What gives such stereotypes explanatory power is that these respective fields are under a set of incentives which shapes how they see the world, incentives which over time have shaped the professional cultures in institutions where they dominate. Three ways of understanding what a conservative point of view really means.

All three perspectives have merit, which is why it is so important to try and have empathy with them all. Doing so can help us be aware of what cultural misunderstandings can arise or to decipher what led an individual to take a particular action.

The Risk Professional “Even very low probability events with devastating consequences must be considered and mitigation / adaptation schemes developed and employed. We operate our nuclear submarine fleet in this fashion. Some may argue that this continuing process result in overdesign and overcautiousness. Maybe so, but our U.S. submarine safety record testifies to the wisdom of this approach. That’s where we should be with climate change knowns and unknowns.” (King et al. 2015: 23).

Examples of fields where this type of perspective is dominant is the insurance industry and the military. At their core, these two types of institutions are dedicated towards handling and hedging against catastrophic events. This means that a “conservative” assessment made from this point of view tries to figure out the absolute worst case scenarios, understand them, and find ways to deal with them (ibid: 20-23). One implication of this is that the professional incentives are biased towards overestimating the chance of a particular event rather than underestimating it.

The weakness with this point of view is that since eliminating all risk is impossible, there is an infinite scope for investment into risk reduction. There is a fine line between prudence and paranoia, and too much investment into risk reduction is a risk in itself as those resources might be better used elsewhere.

4 “Culture” is a concept which is notoriously hard to define (one book listed 164 different ones (Spencer-Oatey (2012)). This thesis finds this one, by pioneering Social Anthropologist Franz Boas, to be useful: “Culture embraces all manifestations of social behavior of a community, the reactions of the individuals as affected by the habits of the group in which he lives, and the product of human activities as determined by these habits.” (Boas 1930:79) 13

The Natural Scientist “Personally, I really would be happier if we had the luxury of doing the research on this, without bothering the public until we have 95% confidence in an answer. All of us are fully aware how wrong it is to falsely yell “Fire” in a crowded theater.” (Freedman 2016)

“I agree there can be a conflict between good science and what policymakers and engineers like flood designers want to know.” Tony Payne, Lead Author of the 2013 IPCC chapter on sea level rise. (Pearce 2013)

This category is very broad, there are many academic Box 1.7 “scientists are biased not cultures and types of scientists. It is however particularly toward alarmism but rather the relevant for physical scientists doing science in fields re- reverse: toward cautious estimates, lated to climate change. Here, there is a culture of con- where we define caution as erring servatism which rewards steady progress and is suspi- on the side of less rather than more cious of dramatic claims (see box 1.7) or using credibil- alarming predictions. We call this ity built up as a researcher to advocate for political tendency ‘‘erring on the side of change.5 least drama” (Brysse et al 2013).

The definition of a “conservative estimate” among natural scientists is the opposite of that of the risk professional:”Scientists are conservative about drawing incorrect conclusions, so much so that they would rather draw no conclusion than an incorrect one. Consequently, they have developed standard practices and cultural norms to protect the scientific knowledge pool from being contaminated by falsehoods.” (King et al 2015: 47). To be precise, this means that stereotypical natural scientific culture wants to avoid Type 1 errors (false positives) and are tolerant of Type 2 errors (false negatives) (ibid 47-48).

As described by the study cited in box 1.7, there is a tendency to ”err on the side of least drama”. Climatologist James Hansen, considered by some to have become too outspoken and producing science tainted by his activism (Bagley 2016), has termed this the ”John Mercer effect” (after the first glaciologist to discuss a possible destabilization of the West Antarctic ice sheet6). According to Hansen, Mercer’s predictions brought him into disrepute and he consequently struggled to gain funding (Ball 2007).

5 “There’s definitely a strong, old school idea in the physical sciences that you do the science and only the science. You don’t do a lot of interviews or outreach or popularization of science. You certainly don’t bring your personal life into the science in any way, shape or form. Anybody who does that is not a serious scientist.” Katharine Hayhoe (Dolson 2015)

6 For further discussion on this particular issue, please consult ”Currently unknown science” on page 29 – 36. 14

The Practitioner/Decision maker “The role of the science adviser is often less about providing direct technical expertise than it is about nudging attitudes and practices… Why? Because sceptics in the policy community are surprisingly prevalent… I surveyed how our public-service personnel use evidence in making policy. Several ministries stated that their job was to design policy that met the minister’s requirements, not to advice on policy options on the basis of available evidence. Studies in Canada and Australia found similar results…

…But scientists must not overstate what is or can be known, even though the shift from a view of science as a source of certainty to a source of probability can frustrate and confuse decision-makers and the public. How many politicians or issues advocates have claimed that they can find a scientist to back any position…?“ (Gluckman 2014)

“Adaptation research often ignores the fact that adaptation is not the only priority for many stakeholders.” (Klein & Juhola 2013)

The quotes that introduce this section discuss the problem of how science is used (or abused) by policy makers, and the pressures advisors that give the wrong type of advice can be subject to. In Gluckman’s experience as science advisor for the New Zeeland prime minister’s office, science does not make policy, it informs it. If it is supportive of pre-determined policy goals, it may be considered more useful. If it disagrees with the same policy goals, it (and the institutions that produce it) risks being marginalized.

Another problem is on of time frames, where the science may be too long term or uncertain to fit into the decision making process. There is the cycle of monthly pay, the quarterly result, the four year cycle of the political career, the roughly 10 year horizon of the individual, and so forth. Issues like climate on the other hand is about decades, centuries and millennia, mostly being far too long to include in most conventional decision making or cost-benefit analysis. The heuristic of temporal discounting (see page 12) is relevant here, as are the concepts of bounded rationality and cognition (page 10-11).

Where a large amount of ambiguous decision information and competing demands exist, decision makers must rely on heuristics, rather than to try and process all available information. This is rational since time and energy are scarce resources, meaning that decision makers need information that is condensed into a format that they can apply and integrate with a minimum of effort.

Simplification and customization of information carries its own risks. As will be seen in the chapter on the science of climate change, when it comes to issues such as climate and sea level rise, it is very easy to lose sight of the scope of uncertainty, and give recommendations which instill an exaggerated sense of confidence among people who have to act on the advice given (Taylor et al 2015: 2) Climate adaptation is a novel risk, which means that the heuristic of availability (page 11) comes into play. Societies face big costs which are uncertain in dimension and timing, to which the recent past may be a poor guide.

On the one hand, acknowledging the full range of uncertainty carries the very real potential of significant disruption to established procedures and plans. As implied by climatologist Tony Payne on page 14, the kind of precision that many engineers want to know is well beyond the margin of error of the underlying science (which will be further discussed in Chapter 2).

Building in flexibility into plans may come with a very significant opportunity cost. Over- engineering solutions is very hard to explain to politicians who have to divert resources from other 15

sources with clear and proven short term needs. Under these conditions, how useful is the worst case scenario really? It is easy to say that we should use the same prudence as when we use a seat belt to insure against an unlikely accident during a car ride. But such insurance costs nothing but a moment of time. The worst case scenario may well cause paralysis, Box 1.8 In Thailand leading scientists held a meeting which may turn out to be more just minutes after the great earthquake near Sumatra in disruptive than the danger itself. It December 2004. The issue under consideration was may demand an exponential increase whether to issue a tsunami warning. The risk of such an in investment and force us to deal event had to be set against the low probability of it with eventualities which we rather actually happening. In addition, the force of the quake not consider. was estimated as low, and the direction of any wave were assessed to hit parts of Thailand that wasn’t The institutional incentives for particularly vulnerable. Issuing a warning would have a scientists to retain access to policy severe impact on the tourist industry. As one participant makers is very strong. The “No explained the ultimate decision: “If we had issued a Drama” heuristic discussed on page warning, which would have set in motion an evacuation, 14 makes sense in the common cases. and nothing had actually happened, what would have But it can prove to be dangerous been the consequence? The tourist industry would have when the rare event finally arrives. been impacted straight away. Our department couldn’t handle that, we would have been in great trouble if the For certain types of irreversible risks, tsunami didn’t arrive.” (Agrell 2009: 163), author’s alarms which ring one time too many translation from Swedish) are more useful that those that ring one time too few. Box 1.8 gives an example of where a combination of uncertainty and fear for professional survival prevented the scientists responsible for keeping watch from alerting people to the danger. Instead they chose to gamble. It is easy to condemn them for doing so, but it is very possible they were correct in their perception of what would happen had the tsunami not arrived. If so, the outcome would only have been delayed, and the scientists may have lost their jobs. Clearly, preventing such fears from establishing themselves is critical if policy-makers want honest scientific advice.

Reducing bias in decision making “We know a lot about the conditions under which groups work well and work poorly. It’s really clear that groups are superior to individuals in recognizing an answer as correct when it comes up. But when everybody in a group is susceptible to similar biases, groups are inferior to individuals, because groups tend to be more extreme than individuals... One of the major biases in risky decision making is optimism. Optimism is a source of high-risk thinking. Groups tend to be quite optimistic. Furthermore, doubts are suppressed by groups… That underlies the whole class of phenomena that go by the label of groupthink.” Daniel Kahneman (emphasis in original)(Schrage 2003)

As can be seen from the sections on psychology and professional cultures, there are many reasons, good reasons, why we make decisions which turn out to be counter to our long term interests. There are simply too many biases, short term incentives and lazy heuristics that can come into play when we deal with present and future, with complexity and uncertainty.

We cannot escape our biases, but we can learn to recognize them and try and mitigate their impact. One example of this are the General Principles of Risk Assessment found at the beginning of this chapter. Using such a structured process is key, partly because it makes it harder to “forget” to ask and answer inconvenient questions.

It also slows down our decision making process, allowing Box 1.9 “When pessimistic us to think critically about our assumptions, and allows us opinions are suppressed, while to seek out and absorb more complex information. optimistic ones are rewarded, an organization’s ability to think To counter the tendencies towards “groupthink” mentioned critically is undermined. The in the quote at the start of this section, some use a form of optimistic biases of individual “Chief Contrarian / Devil’s Advocate” tasked to challenge employees become mutually and find weaknesses in the group’s reasoning. (Ricciuti reinforcing, and unrealistic views 2014). of the future are validated by the group.” (Lovallo & Kahneman An all too common way of making the motions of a risk 2003) assessment, without actually really doing it, is to penalize those who raise uncomfortable issues and perspectives (see box 1.9). Creating a position from which people can expect contrarian perspectives has at least two advantages. One is that there is formal recognition that groupthink is a serious concern for the collective. Another is that it can help lift the understandable and often justified fears that an individual might have about raising provocative questions unprompted. (ibid.)

The greatest challenge of all might be to live up to not only the letter, but also the spirit of this type of advice, and to do it regularly and transparently (Schrage 2003).

Chapter 2: The Science of Climate Change and Sea Level Rise

“…we were all so taken in by the perfect correlation between temperature and CO2 in the ice-core analyses... it was such a temptation for everyone to say “Well, with CO2 rising in such and such a year it will be this hot.” It was a mistake we all made. We shouldn’t have forgotten that the system has a lot of inertia… the heat storage of the ocean, it’s a thousand times greater than the atmosphere and the surface. You can’t change that very quickly.” James Lovelock (Ball 2014) Earth’s climate is complex, and it is quite easy to make mistakes in our efforts to gain understanding. The above quote illustrates the perhaps most common mistake people make when thinking about climate: forgetting that the climate system is dominated by the Sun’s interaction with Earth’s oceans and water, with the atmosphere playing a supporting role. Water vapor is the primary greenhouse gas, but unlike other greenhouse gases individual water molecules does not stay in the atmosphere for very long. As illustrated in figure 1, water vapor and lesser greenhouse gases are tightly linked into a positive feedback loop. Gases such as CO2 can thus be said to regulate the atmosphere’s ability to store heat, but it is water (in various forms) that is the main actor, greatly amplifying the impact of the other greenhouse gases. Thus energy from the sun that would otherwise escape into space is retained in the climate system. Of this extra energy, approximately 90% goes into heating the oceans, while only around 2% is stored in the atmosphere (with the remainder being absorbed by ice and land) (Katz 2015). Over 70% Figure 1: CO2 – Water Vapor positive feedback loop. After Mann & Kump of our planet’s surface is covered 2015:24 by water, and as Lovelock states in the quote introducing this section, the oceans’ total storage capacity is around 1000 times more than that of all the air in the atmosphere. Measuring the heat of the atmosphere, or of the surface of the ocean, only tells us roughly what the state of the entire climate system is. But studying the vast volume and expanse of the oceans is very hard. The best historical data on ocean temperatures has been along shipping routes and is Figure 2: Ocean heat uptake as a percentage of 1865-2015. The cross shows almost non-existent in less that roughly as much heat uptake occurred after 1997 as before that year. (Gleckler et al. 2015) travelled parts of the globe. An 18

effort to rectify this is called the Argo, and has seen the deployment of thousands of autonomous floats which Box 2.1 “…when you focus on just the drifts with the currents and take temperature heat in the atmosphere… to measure measurements on depths down to 2000 meters (NOAA or describe global warming, it is like 2012). Figure 2 is taken from a study which combined tracking the tip of your dog’s tail to the data generated by the Argo with statistical error determine its location, instead of the reducing methods to compensate for the floats’ uneven body of the dog. It will work, and over distribution (Gleckler et al. 2015) time be a good approximation of global warming / dog location, but Figure 3 details past surface temperatures and a over shorter time scales, looking only prediction for the year 2016. Atmospheric heat content at the atmosphere / tail will show more sometimes move in tandem with that of the ocean, and variation than is useful in answering sometimes pause while ocean temperatures race ahead. the important questions.” (Laden Box 2.1 is a reminder that it is the ocean and not the 2013) atmosphere which directs the climate system. Oceans alternate between taking in more and less heat, something clearly seen in the famous phenomena of La Niña and El Niño, of which the latter represents a relative redistribution of heat from sea to air, and the former the opposite (SMHI 2015). But there are other cycles that operate at longer time-scales. One is the 20 to 30 year Interdecadal Pacific Oscillation (IPO) which also alternate between sequestering heat and releasing it (it is especially important as the Pacific represents such a huge share of total planetary ocean volume). Such oscillations represent vast redistributions of heat, and the last decades have been a time where the ocean’s deeper layers have been accumulating more heat than it has emitted. When this phase of accumulation ends, and reverses, we will experience it as an acceleration in the heating of the atmosphere (Katz 2015). Figure 3 shows that that 2016 may be the Figure 3: Global surface temperatures until September indicates that 2016 will be the warmest year on record, possibly by an year when that perceived acceleration unprecedented margin. Predicted temperature average at arrives. As of July 2016, the last 14 horizontal axis, actual temperature average at vertical axis. months have been the warmest on record, (Schmidt 2016, NASA 2016a) in itself the longest streak of consecutive record warmth since the start of modern measurements (NOAA 2016). The immense bulk of the world’s seas prevents us from immediately experiencing the full effects of our greenhouse gas emissions, as oscillations between accumulation and distribution sometimes hide the heat, and the inertia caused by water’s heat capacity acts as a break on the perceived pace of climate change. But as will be explained by the next section, it also adds considerable uncertainty to any prognosis of both our ultimate destination, and the path that will lead us there.

Understanding the drivers of climate change

Figure 4: Quantities and uncertainties regarding human (anthropogenic) emissions (up until 2011) heating or cooling the climate (also known as positive or negative “forcing”). Warming or cooling effects are relative to a pre-industrial baseline, measured in Watts per square meter. Uncertainty bars indicate area of 95% certainty, with the dot the most likely value. Source: IPCC AR5 Chapter 8 (Myhre et al 2013: 697)

The current pace of long-lived greenhouse Box 2.2 Aerosols: The cooling effect of these types of gas emissions is at least 10 times faster particle emissions are short term (the particles are washed than any event over at least the last 66 out of the atmosphere in a matter of days) and local, mostly million years (Zeebe et al. 2016). As cooling South East Asia while having a more marginal effect compared the last few hundred thousand in e.g. the Arctic. (Herring 2007) years, the end of the last ice age saw an Volcanic eruptions also produce these sorts of particles incremental 80 ppm (parts per million) (major events can be seen as triangles in figure 2 on page increase, which was staggered in bursts 18). Compared to human emitted aerosols which stay close over 5000 years (IPCC 2007a). The last to the ground, volcanic aerosols are more potent at cooling, 200 years have seen an increase from 280 as the heat from the eruption means they are injected much higher into the atmosphere, causing them to stay there much ppm to the 400 ppm of today, with the longer. (Wolfe 2000) current rate of accumulation being about 2 ppm per year. (NASA 2015) We will very likely hear a lot more about experimental use of aerosols in the years ahead. The US Senate has directed the Figure 4 summarizes the current US Department of Energy to investigate ways to increase the knowledge about how human Earth’s “albedo” (whiteness): "As other nations have (anthropogenic) emissions are impacting launched research programs on albedo modification, the the climate’s energy balance as compared Committee recommends the Department review the findings of the NAS report [On using aerosols as a form of “climate to pre-industrial values. (Myhre et al 2013: intervention”] (NRC 2015a)… and leverage existing 697) computational and modeling capabilities to explore potential impacts of albedo modification," (Chu 2016) As can be told from the lowest uncertainty

bar in figure 4 (under “Total anthropogenic”), the actual current heating of the climate (designated as Watts per square meter) is a matter of great uncertainty. The main reason for this uncertainty is particles and clouds (Aerosols in figure 4) which have proven very hard to measure (NASA 2010). Also note that non-CO2 long lived greenhouse gases currently provide a heating effect that is over 50% of human emitted CO2, but both the long term and the short term is subject to great uncertainty. Tropospheric Ozone (the troposphere is the part of the atmosphere that is closest to the ground) is a very reactive and complex variable which may be equal to methane in its current impact (what the emissions of these will be in the future is of course unknown). Methane decays in the Figure 5: Uncertainty ranges (using the IPCC system of probabilities) from atmosphere in a matter of different sources for a doubling in CO2 from the pre-industrial value of 280ppm. decades (EPA 2010), while “Equilibrium Climate Sensitivity” means the theoretical rise in global average Tropospheric Ozone tend to surface temperatures were the climate system to stay at 560ppm long enough to reach balance between emitting and receiving energy from space. Note that this decay within about one only concerns the long term impact of CO2, ignoring any other cooling and month (IPCC 2007a). heating effects such as those found in figure 4. Source: Mann & Kump 2015: 91 Since our emissions of CO2 and some varieties of Halocarbons (IPCC 2007b) stay in the atmosphere for hundreds to thousands of years (EPA 2010), thereby raising its heat capacity, there are very good reasons to get the emissions of these down to zero as soon as possible. But this does not mean that the emissions of Methane and Tropospheric Ozone can be disregarded. In the very short term, these may be equal to the CO2 humanity has emitted in warming the climate system, causing it to accumulate much more heat over the last 200 years than would otherwise be the case.

How much will the climate system warm? Another part of the uncertainty can be seen in figure 5, which compares the climate sensitivity from various sources, with most lines of evidence pointing towards it being in the vicinity of 3 degrees for a doubling of CO2 concentrations from pre-industrial levels. Finally, a lot of uncertainty is caused by the endless possibilities of our future actions. How much more greenhouse gases are we going to add to the atmosphere? And once we stop, how quickly and to what extent will we be able to reduce the amount that we have dumped in there? 21

After all, the heating effects of human emitted Methane and Tropospheric Ozone will go away much more quickly than CO2 if and when we stop emitting them. But the amount of methane in the atmosphere is currently increasing, and it is not clear why it is doing so: “There is no question that methane is doing some very odd and worrying things,” Euan Nisbet, Royal Holloway, University of London (Voiland 2016). There are concerns that there will be an increase in non-human emissions of methane as the arctic melts, which in the worst case scenario may equal or surpass human emissions of that gas, and which are out of our control (ibid.)

The Paris Agreement and the 1.5 degree goal Since the start of last century, the climate has warmed about 1 degrees Celsius (NASA 2016b), but this is not the whole picture. Unfortunately, the industrial revolution (and with it, CO2 emissions from fossil fuels) started a century before modern records began. This means that the IPCCs 1870 baseline for distinguishing between pre- and post-industrial temperatures does not account for nearly a century of emissions and temperature increase. During the time before 1870, temperatures increased about 0.2 degrees C, meaning that we are today at 1.2 degrees when using a 1750 baseline (Mann 2015). What is more, as seen in the previous section, there is today significant cooling effects from primarily aerosols which when removed will increase the heating the climate system is experiencing by an at present poorly understood amount (figure 4). Some scientists think that the most likely value of the cooling effect from aerosols caused by the burning of fossil fuels is near 0.5 degrees (Mann 2015, Hansen et al 2011). If that guess is correct, and the “most likely” sensitivity of the climate to a doubling of CO2 is 3 degrees C (figure 5), then we are presently already beyond 1.5 degrees in warming, and getting closer to 2 degrees7 (Mann 2015). The outcome of the Paris negotiations agreed to limit greenhouse gases and “achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century”, and that the ultimate atmospheric warming will be no more than 1.5 degrees C. (Levin et al. 2015) This goal was chosen instead of the old one of 2 degrees since there is quite a lot of science which indicates that the damages done by 2 degrees of global temperature rise would be much worse than 1.5 degrees (Pearce 2015). If one does a bit of “temporal discounting” (letting the future take care of itself, see page 12) a case can be made that the long term may not matter so much. Either, if we are lucky, accumulation of heat can be reduced and then removed before it can do too much damage. Or perhaps the pace will be so slow that adaptation can be done over centuries and millennia. Even if we heat the oceans, perhaps the great ice sheets react to this warming very slowly. If so, then we can reduce our emissions and / or use climate intervention techniques such as those described by the US National Research Council8 in two reports (NRC 2015a and NRC 2015b). Perhaps this would let us avoid the worst impacts, or at least delay them into the far future. From a risk management perspective, the agreement in Paris is not exactly best practice. But true minimization of risk has the potential for great short term costs and huge disruptions to our private and collective ways of working, consuming and travelling. Without really knowing the odds, this is a gamble humanity appears to have decided to make. Partly this may be due to the perception that it is the distant future which will have to carry the heaviest burden, a future which may be much more capable than the present. But is this perception correct?

7 That number obviously also include heating from non-CO2 greenhouse gases, which may be used to argue that the argument Mann puts forward is irrelevant. This since the long term temperature increase, once we stop emitting non- CO2 greenhouse gases, may be much lower (see page 20). On a more fundamental level, this reveals one of many reasons why it is in many ways both problematic and misleading to use global average surface temperatures as a policy tool (Victor & Kennel 2014).

8 These two reports described ways to reduce already emitted greenhouse gases (Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration (NAS 2015b)) and actively cooling the climate by replacing the aerosols currently emitted by fossil fuels (Climate Intervention: Reflecting Sunlight to Cool Earth (NAS 2015a)).

Global Sea level rise over the long term according to current scientific understanding “There are a lot of things I am uncertain of as a scientist” says [Andrea] Dutton, one of the leaders of PALSEA2, an international effort by scientists to nail down the details of ancient sea levels. But we’re certain the sea level is going to keep rising” with the extra heat already added to the climate in recent decades. “And not just a little bit. We’ve got a long way to go... we’ve warmed [our climate] so rapidly that the ice sheets are out of equilibrium. And they’re playing catch up.” (Cornwall 2015) The two great storages of land based ice in the world are the Greenland Ice Sheet in the Northern Hemisphere, and the West and East Antarctic Ice Sheets on the continent of Antarctica. Together, these contain the equivalent of 70 meters of global average sea level rise (NSIDC 2015a)9. Understanding how these great ice-sheets formed is helpful for predicting how much sea levels will rise under current and future conditions. While detailed information of past sea levels are lacking, we have a pretty good grasp of the broader outline, especially the past 65 million years or so. As can be seen in figure 6, during this period there are no records of great inland glaciers until approximately 40-35 million years ago. The ice sheets on West Antarctica and Greenland only came into existence in the last 10-5 million year period (Hansen & Sato 2011). From this perspective, we are currently in a geological ice era, where the existence of great inland glaciers is possible due to comparatively low levels of CO2. The intensification of this ice era led to the kind of more Figure 6: Global temperatures over the last 65 million years divided into three recent “ice ages” (which can steadily more recent sections. Pale blue bands in the box at the top signifies light be seen from the Pleistocene glaciation while deep blue bands equal glaciation which equal or exceed that of onwards, and in great detail the present day. Temperatures were going up at the beginning of the period as at the bottom of figure 6). At what is today India was travelling across the Indian Ocean, leading to great CO2 their most severe, these ice emissions from volcanism. Peak temperatures were reached when India finally collided with Asia. The pressure from India on Asia led to the creation of the ages saw sea levels dip to Himalayas, which helped reduce CO2 levels, leading to temperature decline. Source: Hansen & Sato 2011

9 Which isn’t necessarily the same as local sea level rise, see page 28. 24

over 100 meters below our present ones (ibid.). Recent research indicates that 30 million years ago the continental shelf of Antarctica completely separated from the other continents, which allowed the establishment of the Antarctic Circumpolar Current (ACC). The incredible strength of this new current and the jet-stream above it isolated Antarctica from the rest of the planet. Rapid mixing of deep and shallow waters at aided in drawing down the CO2 levels in the atmosphere10, which also helped the Antarctic Ice Sheet to form (Sher et al. 2015). As can be seen from figure 7, the ACC can today be said to be located at the center of the Earth’s Figure 7: The world’s ocean currents as seen with the oceanic currents. The strong winds between South Pole at the center. Since this configuration is Antarctica and the rest of the world somewhat only around 30 million years old (Sher et al 2015), and insulates it even as the rest of the world’s the oceans of such importance for the climate, it atmosphere warms. But the centrality and force of complicates efforts to compare our current era with the ACC means that Antarctica cannot escape the those before the ACC was established. Image Source: Wikimedia 2016 even more important accumulation of heat going on in the world oceans. Water travels around Antarctica in strong tumbling motion driven by the Earth’s rotation and the extreme differences in temperature between Antarctic summer and winter (Rintoul & Church 2002). For the most rapid part of the ACC, water completes one lap of 24000 km in only 8 years (Roberts 2000) (for comparison, it takes around 500 years for water to travel one complete circuit in the currents in figure 7 (NG 2016)). Figure 8 illustrates the uncertainty around just how much the seas will Figure 8: The extent and uncertainty to which global average sea levels have risen in the recent geologic past. Past sea levels under elevated rise if the climate system is allowed temperatures were at least 6 meters higher than presently. The era 3 to heat up and stay heated up in the million years ago are of special importance, as CO2 levels were similar way described by figure 5. to the present day. These levels are very likely incompatible with the glaciation of Greenland, and potentially with significant parts of During the two interglacial eras Antarctica. Source: Dutton et al. 2015 around 125,000 and 400,000 years

10 One possible explanation is that the Antarctic Circumpolar Current helped establish an excellent breeding ground for Phytoplankton, which uses CO2 to create its shells. Their importance for the global sequestration of carbon is in line with that of all land-based plant matter (Lindsey & Scott 2010). The efficiency of the shell-creation process is strongly associated with the PH level of the ocean, which in turn is directly related to the amount of CO2 in the atmosphere (Taylor et al 2011). One could speculate that as global CO2 levels decreased, the Phytoplankton became more efficient at sequestering carbon, causing the amount of CO2 deposited on the ocean floor in the form of sedimentary rock (partly made of Phytoplankton shells) to increase. This positive feedback may be at least partly responsible for the rapid decline over the last 10 million years to the very low CO2 levels of recent pre-industrial times. 25

ago (also seen in the bottom of figure 6), sea levels were elevated compared today, not because of greenhouse gases, but by the orientation of the Earth relative to the sun (known as the Milankovitch Cycles) (Dutton et al 2015). The most recent era similar to ours is found roughly 3 million years ago when CO2 ranged around 400ppm11 (also seen in the middle of figure 6). Pinning down the range for sea levels during the Pliocene has proven very difficult, with guesses ranging from 6 to over 40 meters over present sea level. The main issue, along with difficulties in identifying the exact age of old shore lines, is that the tectonic plates that cover the Earth tilt back and forth unpredictably (a bit like a raft at sea, with the plates “floating” on top of the thick molten lava of our planet’s mantle). This tilting motion is very slow, but over millions of years it translates into elevation changes that can be quite significant, up to 60 meters in certain places (ibid.). To sum up, it may not be so easy as to directly link glaciation and average world temperatures. The climate system has changed in fundamental ways since the before the most recent glaciation of the world. The very recent formation of Greenland indicates that it is unlikely to survive even a marginal increase in temperature. On the other hand, perhaps the isolated continent of Antarctica will prove to be more resilient against higher atmospheric temperatures than indicated by looking at the blue bands in of figure 6, where the world is mostly ice-free at temperatures only a few degrees over present values. Most significantly, our present pace of CO2 emissions has no precedent over the last 66 million years, being between 10 to 100 times faster than the Permian Thermal Maximum (PETM) marked out at the top left of figure 6 (Zeebe et al. 2016). This obviously makes comparisons with the very incremental changes of the past very difficult indeed.

11 Obviously this comparison ignores the many things that make the current era different, such as the emissions of non- CO2 greenhouse gases (which has no known pre-industrial analog) and other warming / cooling effects as detailed on page 20 - 22. 26

Global sea level rise in the 21st Century according to current scientific understanding “The IPCC working group did not mean to provide a risk assessment of future climate change and so it did not... For some quantities this is a more useful approach than it is for others. In the case of sea level, society might want to know what is science’s best guess for the future rise, but for any practical purposes of coastal protection it is the worst case that is relevant… In the latest assessment report of the IPCC we did not provide such an upper limit, but we allow the creative reader to construct it. The likely range [66% or better chance of prediction being right] of sea level rise in 2100 for the highest climate change scenario is 52 to 98 centimeters. However, the report notes that should sectors of the marine-based ice sheets of Antarctic collapse, sea level could rise by an additional several tenths of a meter during the 21st century. Thus, looking at the upper value of the likely range, you end up with an estimate for the upper limit between 1.2 meters and, say, 1.5 meters. That is the upper limit of global mean sea-level that coastal protection might need for the coming century.” Anders Levermann, lead author on the chapter for sea level rise for the IPCC’s Fifth Assessment Report. (Emphasis not in original) (Yale Environment 360 2013) The IPCC numbers of 52 to 98 cm discussed by Mr Levermann above (see also figure 9) of sea level rise this century are based on computer simulations and models of physical and chemical processes, and does not include semi-empirical models which tries to estimate currently unknown variables from the way we think melting glaciers has behaved in the past (NASA 2016b). Since semi-empirical models give sea level rise that is up to double of what the process based one does (ibid., EEA 2015), there is reason to suspect that the IPCC figures may be biased in a “scientifically conservative” direction (see page 14). It is not clear what type of models Levermann’s 1.5 meter “upper limit” scenario is built on (he does not tell us) but it may be a way of acknowledge semi-empirical modelling and / or modelling work done on the vulnerability for non- linear melt of the West Antarctic Ice Sheet (see page 30-32). In any case, it agrees with other worst case Figure 9: The 95% probability upper limit according to assessments. The US Army Corps of Engineers Jevrejeva et al. 2014 as compared to the most recent IPCC assessment (Source: Grinsted 2014) uses 1.5 meters as a ”high” scenario for planning civil works programmes, while it is 2 meters in the US National Climate Assessment and 1.9 meters in the United Kingdom Climate Impacts Programme (Jevrejeva et al. 2014). A survey of expert assessments of semi-empirical models and IPCC numbers pointed toward a 95% probability of the upper limit being 1.8 meters until 2100 (Jevrejeva et al. 2014) (figure 9). Com- bined with other assessments, there seem to be a fair amount of agreement among climate experts that current evidence restricts the upper limit of sea level rise this century to below 2 meters. But as participating author Aslak Grinsted notes in his commentary to the survey, this does not prove that even higher levels are impossible, but merely “indicates that other lines of evidence are needed to justify a larger sea level rise this century.” (Emphasis in original) (Grinsted 2014).

Localizing global average sea level rise It is tempting to imagine the ocean like a bathtub, where the average increase in sea level is equal to the local increase. This intuitive way of looking at sea level rise is however incorrect. For any given location, the actual rise in sea level as relative to the land will partly be influenced by the local temperature of the ocean (with hot water taking more space than the same amount of cold water) and the rate at which the land itself is moving up or down12.

Other factors include possible changes to Figure 10: Possible multiplier for actual local sea level rise were ocean streams such as the Gulf Stream (see the entire West Antarctic Ice Sheet to disappear. Takes into page 35) and the impact of an uneven account factors of gravity, change in the Earth’s spin, and distribution of melt from Greenland and topographical change from higher sea levels. A multiplier of Antarctica: below zero (red) shows areas where sea levels would see outright decline. Multipliers up to 1 (white to light blue) shows ”An ice sheet exerts a gravitational at- less than average sea level rise. Multipliers higher than 1 traction on the nearby ocean and thus (darker blue) shows higher than average sea level rise. Source: draws water toward it. If the ice sheet Mitrovica et al 2009 melts, this attraction will be reduced, and water will migrate away from the ice sheet. The net effect, despite the increase in the total volume of the oceans after a melting event, is that sea level will actually fall within ~2000 km of the collapsing ice sheet and progressively increase as one moves further from this region.” (Mitrovica et al 2009)

According to Mitrovica et al 2009, ice mass loss in the West Antarctic (see page 30) would be amplified by 10 to 20% in Western Europe as compared to average global sea level rise (Figure 10). Were the entire Greenland ice sheet to somehow melt Figure 11: The impact on global average sea level from melting ice on Greenland when tomorrow, (containing the earth’s spin and gravitational effects are included. The black dots signify sites used more than 7 meters of for measurement of sea level rise during the 19th Century. Due to their location, these have been found to be biased towards showing lower average global rise over this period global average sea Source: Thompson et al 2016. level rise), the sea level in Iceland would see outright decline relative to present sea levels (Figure 11) while far-away Hawaii would experience more than 2 meters of additional sea level rise (to a total of about 9 meters) (Lemonick 2010).

12 In Northern Sweden as much as 1 cm per year due to post-glacial rebound (SMHI 2009). Jakarta in Indonesia is sinking at an average of 7.5 cm per year, with extremes of 25 cm per year, mostly due to excessive ground water extraction (Heriyanto 2016). 28

Currently unknown science “For societies today… the biggest question may not be how high the sea ultimately rose during past warmings, but how quickly it happened. In particular, researchers would like to know answers to two questions: Did Antarctic ice melt in sudden surges and, if so, exactly what climate conditions unleashed such an event?” (Cornwall 2015) ”Can all tipping points be foreseen? Probably not. Some will have no precursors, or may be triggered by naturally occurring variability in the climate system. Some will be difficult to detect, clearly visible only after they have been crossed and an abrupt change becomes inevitable. Imagine an early European explorer in North America, paddling a canoe on the swift river. This river happens to be named Niagara, but the paddler does not know that.” (NRC 2013: viii) The previous two sections were dedicated to the current consensus around sea level rise. This section will be dedicated towards examining the types of very uncertain, potentially non-linear risks that the assessments quoted in previous sections have been unable to include. This inability is due to a few fundamental factors which have to with our current and future inability to fully anticipate the changing climate:

”First, because extreme climate phenomena represent rare events and modern climate records made by instruments are short, the modern record may capture only a few instances of these extreme events. Second, the statistical tools to which most climate researchers are accustomed are not applicable to this highly non-linear problem. Third, lack of quantitative understanding of the thresholds that trigger abrupt changes and causes of extreme climate events has limited our ability to provide process-based assessments of the risk of abrupt changes. Extreme events and the resul- tant abrupt changes are more likely unpredictable based on statistical models.” (Emphasis not in original) (NRC 2013: 80)

The above quote illustrates why the climate is so difficult to predict. The coming pages are great examples of very relevant information that is incredibly hard to include in a scientifically conservative report such as that done by the IPCC. If one were to try and use a traditional cost- benefit heuristic (e.g. impact x probability = risk (see page 10)) with information such as this, it would give a completely nonsensical answer, as neither factor can be stated with any type of precision. There are also structural reasons for the difficulty of dealing with this type of information. A seen in Chapter 1, scientific norms around conservatism and the demands of politics does not always make for a comfortable or uncomplicated partnership. Policy makers demand direction and continuity amid uncertainty, and scientific advisors need to try and satisfy this need, or risk being marginalized (page 16).

The West Antarctic

Figure 12: Current extent of the Antarctic Ice Sheet (black outline) superimposed upon a topographical map detailing height and depth relative to sea level. The top-to-bottom arrow [not in original] is approximate to the cross section shown in figure 13, first going through the outline of the Ronne Ice Shelf towards the outline of the Ross Ice Shelf. The West Antarctic is the archipelago part of Antarctica, while the East Antarctic is the main landmass. “West” and “East” refers to which hemisphere they are oriented towards. Source: Bindschadler 2006 Ice sheets resting upon bedrock below sea level in both West and East Antarctica are vulnerable to a runaway collapse process known as marine ice sheet instability. This instability is thought to be triggered mostly by melting at the ice sheet edges by warm ocean water. Although this process has been identified and tested in models, it has not yet been directly observed; and it is not known how fast this runaway collapse might occur or what parts of the Antarctic ice sheet will be involved. (NAS 2015a: 39) Estimates from IPCC range from 26 to Figure 13: Cross section of the Western Antarctic Ice Sheet. The 98 cm in this century [see page 27], but arrow in figure 12 runs from left (Ronne Ice Shelf) to right (Ross Ice recent modeling studies suggest that far Shelf). Source: ICCI 2015: 5 more rapid rates are possible and perhaps even likely… (ibid.: 41) 30

The West Antarctic is a section of Antarctica mostly based under water and thus very exposed to the warming oceans (see figure 11 and 12). This fact has been a source of concern for decades. There are other unstable locations in the Antarctic which represent equal or more average global sea level rise potential, but as glaciologist John Mercer warned in 1968, the West Antarctic is “a uniquely vulnerable and unstable body of ice” (NASA 2014). Today the scientific consensus is that at least parts of the West Antarctic have reached a point of no return, where melting will continue even if warming was somehow halted tomorrow (shown in figure 14 as “Today”) (ICCI 2015: 5) This is because once disturbed, some climate systems are subject Figure 14: The Hysteresis Loop. (After Mann & Kump 2015: 104) to “hysteresis”, meaning that they are prone to rapid collapse and take much colder conditions and many thousands of years of stable temperatures to recreate naturally. In the case of the West Antarctic, a new ice age would be needed (see figure 14) (Laden 2016). What is still very uncertain is the velocity and extent of this now likely unstoppable process. The two introductory quotes to this section were taken from A Strategic Vision for NSF Investments in Antarctic and Southern Ocean Research, which was prepared by the US National Research Council (NRC) to give direction to the US National Science Foundation (NSF) in its funding priorities. This peer-reviewed “Expert Consensus Report” is the result of a one year effort that consulted over 450 people in the Antarctic science community, as well as present scientific literature. (NRC 2015a: 1) It can therefore be considered well placed to comment on what science does not yet know, and give a snapshot of how glaciologists specialized on the Antarctic ice sheet view the range of uncertainty.

The following two passages illustrate this further. These were transcribed13 from the “webinar” (an online audio seminar followed by a Q&A session) which followed publication (Robert Dunbar and Robin Bell are two of the lead authors of the report):

00:14:00-00:15:05 Robert Dunbar: “…the ice core community identified some areas where they think there’s a very good chance of getting annually resolved ice core records from within the last interglacial. And we have known techniques now to examine how fast the ice was melting at that time. The marine geophysicists and sediment communities have developed ways to look at rapid change. The idea here is to bring these communities together in a way that they haven’t really been brought together in a coordinated fashion, along with modelers, to make rapid progress. Obviously it is

13 Inofficial trancription by the author. The full audio and presentation is available at https://nasevents.webex.com/mw3100/mywebex/default.do?siteurl=nasevents. The webinar was held 11 August 2015. 31

compelling science, and we feel it is very societally relevant because it addresses the question of sea level rise, that’s important for coastal infrastructure. Does it happen over a 100 years, 200 years or 2000 years? These are trillion dollar questions.” 00:47:45-00:48:45 Robin Bell: “All of us who work in Antarctica are often asked by our coastal managers or just people we meet when we travel; “How fast is the ice sheet going to disappear?” I feel this is the number one question, and I think that with the approach that we have set forward, which is really an integrative approach, that both looks at the past record, and the past processes… Basically, how fast did West Antarctica disappear during the last interglacial, as well as an improved understanding of what is driving the change now and our understanding of the ice sheet processes that can feed into predictive models. I do think that within the next decade we can make significant advances on answering that question: Is it going to be one meter, or two meters, and is it going to be within 50, 100, 200 or a 1000 years… Which really matters to coastal planners.” (NRC 2015b) (Emphasis not in original) The emphasis in the transcript above may be the most consequential paragraph in this thesis. Not only does it illustrate the immense uncertainties in timing and possible consequences of a rapid collapse of parts of West Antarctica, but also provides a time frame for reducing uncertainty into a format usable for policy makers and practitioners (see page 15). Even if the answer is not to our liking, the sooner we learn it, the more time there will be to deal with any fallout.

The Arctic sea ice, Greenland and the Gulf Stream The Arctic is warming twice as fast as the average location on the Earth. This rapid warming is melting the arctic sea ice much faster than the process based models of IPCC have predicted (figure 15), a failure caused by incomplete understanding of the underlying processes (Mann & Kump 2015: 97, IPCC 2007c). IPCC gives no worst case scenario for arctic sea ice, but states that some projections see the Arctic ocean being ice free in late summer by “the latter half of the century” (IPCC Figure 15: Range of IPCC predictions for Arctic sea ice extent 2007d). (black with range in grey) compared to actual extent (red). Source: Mann & Kump 2015: 97 The arctic sea ice is exposed to several types of positive feedbacks which causes the melt to proceed in a non-linear fashion. The Arctic is warming about twice as fast as the global average (NASA 2009), which melts more sea ice than would otherwise be the case. Less of the bright sea ice (which reflects up to 80% of the solar energy that hits it, while absorbing 20%) means that more of the darker ocean (which only reflects 10%, Figure 16: Age and relative extent of arctic sea ice from 1983 absorbing 90%) is exposed (NSIDC 2015b). to 2015 at the time of the September minimum extent. Source: The result is that the Arctic Ocean warms EPA 2015 more, making it harder for sea ice to regenerate the following winter. Following a sudden collapse in the age of sea ice after 2006 (figure 16), Arctic sea ice is now both thinner and less reflective than before, due differences in the properties between young and old sea ice. (Viñas 2014). This decrease in volume can be seen in figure 17, the two major drivers being the increase in young ice combined with the fact that the Arctic Ocean is retaining more heat, melting the sea ice from below. If the sea ice volume continues to Figure 17: Annual maximum (blue) and minimum (red) ice extent. Source: follow the linear trend line it has PSC 2016 followed since 1980, that would mean ice free summer conditions sometime in the 2020ies. In the worst case scenario, a non-linear short term trend from around 2000 point towards ice free conditions before 2020 (Ahmed 2013).

A mostly or completely ice free Arctic Ocean means a dramatic decrease in reflectivity during the sunny part of the year, which will mean accelerated warming of the Arctic Ocean. This would cause an acceleration towards the point where the Arctic Ocean potentially becomes ice-free all year round. It will also mean less difference in temperature between the Arctic and the rest of the planet, which will have an impact on northern hemisphere weather patterns, in particular the circumpolar jet stream (WU 2016). There is significant uncertainty about the longevity of late-summer Arctic sea ice coverage. Already floating in water, it does not by itself raise the global sea level. But not knowing when it will disappear significantly raises uncertainty as to the pace of future arctic warming, as well as when and what we should expect of weather patterns in the northern hemisphere14. This has implications for the contribution of Greenland to global sea level rise and adaptation for storms and storm surges. Greenland’s melt comes partly from the sun, but at least as potent as direct sunlight is the contact with warm water, which comes both from above in the shape of late summer rain falling on low elevations (Doyle et al. 2015) and from below in the shape of salt water penetrating into its interior (Rignot et al 2015). The exact geography of Greenland’s interior, with significant parts of the ice sheet being based on bedrock under sea level, is poorly understood. A study on the western side of Greenland has shown that sea water reaches further into Greenland than previously thought (ibid.).

14 As of November 2016 extraordinarily unseasonal temperature anomalies over the Arctic Sea has significantly delayed the formation of sea ice, leading to it being the lowest extent for the month on record, and equaling the lowest levels in volume set in 2012. This may lead to new overall record lows in both indicators during the 2017 melting season (PSC 2016).

“The Cold Spot” and Changing Weather Patterns “If the slowdown of the Atlantic overturning continues, the impacts might be substantial... A slowdown... adds to the regional sea-level rise affecting cities like New York and Boston. Finally, temperature changes in that region can also influence weather systems on both sides of the Atlantic, in North America as well as Europe. If the circulation weakens too much it can even break down completely, the Atlantic overturning has for long been considered a possible tipping element in the Earth System. This would mean a relatively rapid and hard-to-reverse change. The latest report by the IPCC estimates there to be an up to one-in-ten chance that this could happen as early as within Figure 18: Surface temperature change from 1910 to 2013 Source: Rahmstorf this century. However, expert et al. 2015 surveys indicate that many researchers assess the risk to be higher.” (PIK 2015) Figure 18 shows the average surface temperature change from 1910 to 2013, and a region of bright blue cold can be seen south of Greenland. While the rest of the world is record warm, this particular spot has over the last few years been at or near its coldest temperatures since modern records began. One explanation for this is that cold meltwater from Greenland, which is fresh, is layered above warm salt water. Fresh water is much lighter than salt water even when cold, and an accumulating pool of cool freshwater may be kept in place by meltwater coming from the north and the Gulf Stream coming from the south (Box 2016). Models of Greenland ice melt have not been able to reproduce this effect under today’s climate conditions (models predict them to appear much later in the century) which is why many scientists have been cautious to embrace the above theory (Sorg 2015). However, part of the data underlying those models have recently been proven to be wrong: ”"While we expected to find deeper fjords than previous maps showed, the differences are huge," said Eric Rignot of UCI and JPL, lead author of a paper on the research. "They are measured in hundreds of meters, even one kilometer in one place." The difference means that the glaciers actually reach deeper, warmer waters, making them more vulnerable to faster melting as the oceans warm. Co-author Ian Fenty of JPL noted that earlier maps were based on sparse measurements mostly collected several miles offshore. Mapmakers assumed that the ocean floor sloped upward as it got nearer the coast. That's a reasonable supposition, but it's proving to be incorrect around Green- land.” (NASA 2016c) This implies that the Greenland ice sheet is more vulnerable to ocean heat than previously thought, lending credence to the theory that meltwater is responsible for the cold spot south of Greenland. However, this does not automatically mean that it will persist, as understanding of it is still too incomplete:“It could disappear tomorrow or it could be here for 20 years,” (Jesse Farmer, paleoclimatologist at Columbia University (Sorg 2015)). 35

If it does persist, and even intensifies, it may come to affect the region around the Atlantic in two major ways: Firstly, as can be seen in figure 19, there are signs that it is slowing down the Gulf Stream, which transports heat and nutrients from the equator, along the North American East Coast, towards the North Sea. As the transport of water slows or even stops completely, temperate northern Europe becomes colder than it would otherwise be and the tropics and subtropics hotter (Atkinson 2016). Also, sea levels along the North American East Coast would rise, in the worst case up to a meter Figure 19: Strength of the Gulf Stream since 800 AD until today. (Ibid.). Uncertainty range in light blue. Rahmstorf et al 2015 The second way which the cold spot may affect us is by increasing the temperature differential between it and air above and around it. As the atmosphere warms, and increased melt from Greenland makes the marine freshwater spot stay cold, basic physics in the form of a phenomena called baroclinic instability dictate that stronger storms in the Atlantic will result (Box 2016). In the worst case scenario, a slowdown of the AMOC combines with a dramatic decline in Arctic sea ice seen on page 33. This would change weather patterns to an unknown extent. Exactly what impact this will have is unclear, but at the very least, the storms of the last centuries may turn out to be a poor guide to the future (Hansen et al. 2016).

Chapter 3: Overview and comparison Bremen, Bremerhaven and the North Sea Coast Kein Deich kein Land kein Leben15 (No dike, no land, no life) (BDarW 2010) Bremen and its sister city Bremerhaven (situated at the mouth of the river Weser) are 60 km apart. Tied together by history they together make up the Freie Hansestadt of Bremen, a Bundesland just like Bavaria (but a lot smaller). In theory, the status of Bundesland brings significant autonomy within the federation of Germany, but in practice Bremen’s size means that it cooperates extensively on many matters with Niedersachsen which surrounds it on all sides. Since 2005, Bremen is part of the metropolitan region of Bremen / Oldenburg (Figure 20), which together has almost 2.4 million inhabitants (NordWest2050) Figure 20: Metropolitan region of Bremen / Oldenburg. One of 11 similar metropolitan regions in Germany. Source: Nordwest 2050 In the areas around the German North Sea coast, dikes have existed in some form since around 1000 years (BDarW 2010). The gradual expansion of the dike system has over centuries transformed the coastline, making it to a large extent artificial. As can be seen in figure 21, only the area around Cuxhaven that would keep dry without dikes at high tide. Storm floods would reach even further inland (see also figure 24).

Figure 21: Areas under flooding and erosion risk at high tide if there were no coastal protection. Source: Hofstede 2007. The outlined area (not in original) corresponds to figure 20. The arrow (not in original) points towards the city of Cuxhaven, located near a ridge stretching all the way to the North Sea.

15 This observation is found at the start of the 2010 edition of the public information material from the dike maintenance association responsible for the North-East side of the river Weser in Bremen. 37

As can be seen in figure 22, for most of this time period, dikes were quite fragile. In combination with bad communications and a complete absence of weather forecasts, these would sometimes fail

Figure 22: Evolution of dike technology and extent over the last millennium. Source: Reise 2015 and collapse. One of the biggest disasters happened in Schleswig-Holstein, where the Nordstrand Flood of 1634 killed between 6 to 15 thousand people and drowned up to 50 thousand livestock (Mauelshagen 2007). It was far from the only such incident however. During the vast majority of this era, dike maintenance was a task for the people living along the coast. Anyone who didn’t live up their obligations lost their land, or in the case of dike failure (especially at night) their life (ibid.) This ever present potential for devastation, the changing landscape and the psychological stress of living behind primitive defenses may help to explain why the old port cities of Bremen and Hamburg are situated so far from the sea16. The area around Bremen has been populated for the last 12 thousand years, and a city of Bremen has existed since at least the 8th century (when the area was converted from the Norse faith and got its first bishop). In comparison, the deep-water ports of Bremerhaven and Wilhelmshaven were only founded in the 19th century (Britannica 2016). The struggle against the sea has thus been going on for countless generations, which has created a quite adversarial attitude towards the sea as something which has to be tamed and conquered. According to one informant that has had extensive contact with the people living just behind the

16 Other explanations include the very real threat of invasion from the sea. Being situated some distance from the coast helped provide protection and warning against raiding parties (KR email-exchange). 38

coastal dikes, most “live with their backs towards the sea” and do not really consider themselves to be coast dwellers at all, identifying with inland farming culture (KR Interview). Another informant contrasts this to the greater pragmatism found among the Dutch, where he finds greater acceptance that land taken from the sea may have to be given back Figure 23: Original cross-section of the river compared to historical and planned (KG Interview). expansions and deepenings of the river Weser in order to accommodate heavy shipping. Source: Reise 2015

Figure 24: Current coastal and riverine protection. Thick green line is shows dike extent. Dark areas show the region the dikes protect. Blue arrows shows existing storm surge barriers. (Source: GK 2007) Bremen’s largest industry is that of the port, which is run by the fully public Bremerports. According to a study commissioned by the port, it employs (directly or indirectly) around 1/5 of the workforce in Bremen, some 74.000 people (Bremenports 2016). While perhaps an exaggerated number, there is no doubt that the city has a strong dependence on the port, both for economy and identity. Demand from international trade for ever bigger and heavier vessels has meant that the river Weser has been transformed from being relatively shallow and prone to flooding to something distinctly man made. Figure 23 and 24 shows this remarkable transformation, which has not been without cost. The ecology of the surrounding landscape and the river itself has been changed dramatically, and the tidal amplitude (the difference between average low tide and average high tide) has gone up from 20 cm to 4 meters (MS Interview).

While previous expansions of the river have been largely uncontested, current plans are strongly opposed by the 36 dike maintenance organizations along the river. These are concerned for of the consequences the river deepening will have on their dikes, as well as potential infiltration of saline water. In addition, there is a lawsuit brought by the NGO “BUND”17 which has halted proceedings for Figure 25: Outline and organization of dike maintenance organizations (Deichband/- verband) from Bremerhaven to Brake. Source: GK 2007 the last 3 years (MS Interview, MS e-mail exchange). The organization of coastal defense Freie Hansestadt Bremen has three authorities that are responsible for the protection of the Land. These are the two Deichverband (dike maintenance associations) on the eastern and the western shores of the river Weser (figure 26), as well as Bremenports which is responsible for the protection of Bremerhaven. In Niedersachsen there are other authorities along the rivers, as well as the NLWKN, which is the authority Figure 26: Outline and organization of dike maintenance organizations (Deichband/- verband) along river Weser from Brake through Bremen. Source: GK 2007 responsible for the main coastal dikes outside of Bremerhaven (see figure 25) (KR Interview, MS Interview).

17 "Bund für Umwelt- und Naturschutz Deutschland" 40

There are around 650 km of channels and ditches on the eastern side (“am rechten Weserufer”) of the Weser within Bremen, and around 100 km of dikes. On the western side (“am linken Weserufer”) there are an additional 140 km of channels / ditches, and 64 km of dikes. These must be tended to all year round, each and every meter of the dikes inspected on foot every year (MS interview, MS e-mail exchange). The resources for building dikes is funded 2/3 by the federal government and 1/3 by the Bundesländer. This is a fixed ratio, so if a Bundesland does not come up with all the money, the federal money is reduced proportionally. Sometimes, the European Union also contributes money (KR Interview). Maintenance of the coastal dikes are funded in a similar fashion, while the upkeep of dikes along the river are run by civic organizations which may have been active for many hundreds of years. These are mainly funded by the real estate owners living in the area, which by law has to be members of a dike protection association (MS interview, MS e-mail exchange).

Sea Level Rise along the German North Sea Coast

Figure 27: While modern defenses are much more sophisticated than those of historical times, the society they have been built to protect is much bigger. This is an example of the Levee Effect (see page 8) where skill at defending creates vulnerability in the form of greater amounts of value / lives at risk. Image Source: Reise 2015 The German North Sea Coast is very flat, and is covered by a comparatively soft sedimentary geology created by the last ice age. It primarily consists of different types of clay, silt and sand (Jensen & Schwarzer 2013: 110). The same process which causes land to rise in Scandinavia (isostatic uplift from the ice shelves of the last ice age) is causing land in northern Germany to sink slightly (Reise 2015). This sinking is only about ½ mm per year (KR interview), or 5 cm per century, but there is also a contribution from historical extraction of peat for fuel and transformation of wetlands to farmlands (in practice a form of ground water extraction since drying out the soil causes it to shrink in volume). The combination of nature and human intervention can be seen in figure 27. Today, parts of Bremen and Niedersachsen sit up to 3 meters below sea level (KR interview). Storms and storm floods are of great concern in Bremen and Bremerhaven, potentially reaching 3 to 4 meters above high tide (KR email-exchange). Currently the coastal defenses are supposed to be dimensioned for a 1:4000 year storm (MS Interview). This value is based on data on storm surges since the 19th century, a fairly short period of data. Storm surges further back in time are thought to be overestimated and exaggerated (ibid.), but with so few extreme events in the period of measurement several of my informants (KR interview, UvB interview) thought that there is 41

significant uncertainty to these statistics. With the uncertainty which surrounds possible large scale ice melt in Western Antarctica this century (see page 30 - 32), there is a possibility that the German North Sea Coast will see additional impact due to the factors discussed on page 28. Last but certainly not least, there is considerable uncertainty of what future weather patterns in the North Atlantic will be like. It is not at all clear that the recent past will be a good guide to the future (see page 35), further questioning the assumptions with which present calculations are made. Since dikes are made of earth and clay, they are vulnerable to absorbing too much water during extended periods of heavy rain which weaken their structure. This would make them increasingly vulnerable to collapse during a subsequent storm surge (KR email-exchange). If such conditions become more common, dike construction mat have to be re-thought to deal with this issue.

Future plans The velocity of the water as it flows in and out of the river Weser puts significant erosion stress on the dike system which runs all along the river and into the city. With the latest megaships coming into operation a further deepening of the river is being planned (“Geplanter Ausbau” in figure 23). This deepening of the river is seen as a necessity for the port to stay competitive, but it is Figure 28: Internal structure and flexibility of future coastal dikes. These can be contested by the dike reinforced in three steps. Source: MELUR-SH 2013 associations and is currently stuck in the court system. This has had the consequence that the planning process is frozen (any change to the plans would necessitate a re-start of the entire judicial case), and prevents a compromise from being found (UvB Interview). With future sea level rise uncertain in both pace and ultimate magnitude, Bremen and Niedersachsen has elected to stay committed to the current path of raising the dikes. This plan stretches over the next 50 to 100 years, which is the structural lifespan of the type of dike that is being constructed. Figure 28 describes how the coastal dikes are meant to be constructed. Current plans call for 50 cm of extra height to compensate for sea level rise, along with the capacity to raise this with an additional meter. 42

Since the ground is soft, and coastal dikes sink with 17-25 cm per century even with a large “footprint” it is better to build gradually rather than all at once. Theoretically it would be possible to raise it for another 50 cm (to a total of 2 meters) before the dike becomes too heavy and the rate of sinking gets too severe (Nakott 2015). Despite the constraints the geology of the area puts upon constructions of this type, the consensus among my informants is that it is possible to build dikes of almost any height. But that statement has a few qualifying factors. The amount of material for each extra cm grows at a non- linear rate, as does the footprint which may start to displace and disrupt activities behind it. Dikes of increasing height also gets Figure 29: Example of possible future dike design. Source: Reise 2015 increasingly structurally complex on the inside, which adds to the expense of building them. One example of this can be seen in figure 29, where sand columns are constructed below ground to enable it to carry heavier loads. The expense of doing this over an entire coastline should of course not be underestimated. While the traditional perception in Germany is that coastal defense is an existential struggle with the sea, and there hasn’t really been much cost benefit analysis done on what should and should not be defended, there may be a change of heart if costs escalate too much (KR interview). One also have to account for psychological factors. The sheer size of dikes tends to become an ever present reminder of what happens if the dike were to fail (KR Interview, WO Interview). Will people want to live behind dikes of ever greater height, or would they rather retreat inland? There is also the issue of demography. The rural areas close to the coast are depopulating, making it questionable whether it makes sense to put increasing amounts of money to protect a decreasing amount of people and capital stock (WO Interview, JS Interview). How to change the dikes along the river Weser is a more complex question. A proposal to build a storm surge barrier at the mouth of the river Weser has been investigated and rejected. The reasons for this included the expense and complexity of such a heavy construction on soft soil (approximately €10 billion (MS Interview)), the disruption of shipping into Bremen during its construction, and the fact that it would raise the amplitude of the tide along the coast with a meter. It would also impact the amplitude of tides into the Elbe, impacting Hamburg. Finally, it would become obsolete as sea levels rise higher (UvB Interview). That being said, as can be seen in figure 24, many of the smaller rivers are already equipped with storm surge barriers, and the Bremerhaven harbor would not function without extensive use of locks seen in figure 25.

Possible Future Alternatives In Bremen, sea level rise is considered to be an existential issue. There is considerable debate, and considerable uncertainty, over what to do in the future, both within Bremenports, Bremen itself and between academics and practitioners. Several publications and projects have sought out alternatives to the status quo, such as NordWest 2050 (which was one of 7 regional projects sponsored by federal Germany in an effort known as KLIMZUG). Among my informants there was a consensus that there is a cultural divide between the academic sphere and the sphere of coastal defense practitioners.

This is partly to do with organizational culture as described in Chapter 2, with certain types of academics more open towards a risk perspective and making scenarios for alternative futures, while coastal defense agencies are more concerned with the present and do not care so much about staying current with the latest research (WO Interview, KG Interview)18. One idea which seems to have quite a few backers (but is still far from official policy) would be to convert a large area between Bremen and Bremerhaven into a tidal landscape. Here tides would be allowed to enter twice daily, which may allow for a deepening of the Weser without damaging the existing dike infrastructure. It could also reduce the impact of storm surges in the river (UvB Interview, WO Interview). This would allow for a compromise between the needs of Bremerports and of the dike associations along the Weser. It is also popular among ecologists, as it would restore a type of wetland habitat that has largely been lost during the transformation of the North Sea Coast over the last century. The losers would of course be the farmers which now occupy the land, but they may be the weakest party politically (KR Interview). Looking beyond the current coastal defense plan, which is supposed to stretch until 2100, this type of intervention might allow for a gradual retreat from the coast (WO Interview).

18 There is also the issue of different educational backgrounds, and different areas of expertise. Dike construction is not an issue for the universities, but is rather a type of empirical knowledge contained within the dike agencies and technical colleges (KR Interview). It requires a lot of trial and error, as large scale construction on soft soils has unpredictable consequences and cannot be fully planned in advance (Scott 1998: 327).

Gothenburg

Figure 30: Gothenburg in 1809. Source: Göteborg Stad 2016a. The outlined area (not in original) roughly corresponds to figure 31. Gothenburg is the second largest city in Sweden, and the municipality of Gothenburg is the second most populated with more than 500.000 people. It was founded in 1621 by Gustavus Adolphus / Gustav II Adolf19. For strategic reasons, the city became located in a wetland at the mouth of the Göta Älv river. This was actually the second attempt at building a port city on the Swedish west coast, with a previous attempt having been razed by Denmark which at that time controlled the land both to the north and to the south. Partly because building on top of this type of geology is very uncommon in Sweden, Dutch engineers were hired to prepare and plan the oldest parts of the city (Twedberg 2003) Figure 31: Älvstaden, the future expansion of Gothenburg being built over brownfield The extent to which areas located in former wetlands seen in figure 29. Göteborgs Stad 2016c Arrows (not in central Gothenburg has original) point out Kvillebäcken (long upper arrow) and Mölndalsån (short lower arrow). changed over the last 200 years can be clearly seen by comparing figures 30 and 31. In figure 30, note the two streams (Kvillebäcken coming from the north, Mölndalsån coming from the south20) leading into the basin

19 Coincidentally, Gustavus Adolphus intervention into the 30-year war led to Sweden occupying and then laying claim to Bremen in the years after the treaty of Westphalia in 1648. Bremen had however secured its status as a “Free City” already in 1646, and defended this against Sweden during two wars in 1653-54 and 1665-66 (Harrison 2013) 20 Kvillebäcken has a catchment area of 100km2, while Mölndalsån has a catchment area of 270km2 (Göteborg stad 2016b). Göta Älv has a catchment area of 50 229km2, or 1/10 of the surface of Sweden (Vattenportalen 2016) 45

(Göta Elf, today spelled as Göta Älv). Also note the navigable lanes, and the extent to which the city have grown into the wetlands. Similar to Bremen, the shipping industry is a major employer and source of identity. Gothenburg used to be home to several shipyards, which together with other Swedish shipyards represented 10% of the world’s production during the 1960ies. After the Suez Crisis, the market shifted towards heavier ships which Gothenburg could not produce. This, together with competition from Asia devastated the industry, which dwindled to almost nothing in the beginning of the 1980ies (Sandberg 2014). Parts of the brownfield areas that the inner city port left behind are very prone to flooding even under ordinary circumstances. This area is now in the process of being transformed by a project called Älvstaden (the Rivercity), a project that will stretch until 2030 and beyond, providing offices for 45.000 people and some 25.000 apartments (Göteborgs Stad 2016c).

The Organization of Sea Level Rise Adaptation Gothenburg has recently gone from one to two full-time positions for climate adaption planning, and Västra Götaland County has one person working full time on the issue (LW Interview). Sweden gives significant power and responsibilities to its municipalities, with county and state level providing support and oversight (OECD 2013: 97). Climate change adaptation in general is seen as a combination of crisis management and planning. Since responsibility for these areas falls heavily on the municipal level, adaptation has become a question for municipalities as well. There is also a strong principle of self-funding. This means that adaptation measures, like any infrastructure project, is to draw its main funding from those “that draw a benefit from them” (ÅS Interview). There is a possibility to seek funds from the agency for adaptation measures from the Swedish Civil Contingencies Agency (MSB), but this is still a minor source of funds (EC 2007: 4) Money for adaptation measures are primarily found within the municipal budget, and is thus normally allocated year by year. This means that it is hard to do bigger projects, and there are tight yearly deadlines for making project proposals (UM Interview). As with other areas, municipalities are audited in their adaptation planning work by the regional counties, which are meant to ensure that municipal planning follows state regulations and guidelines. (LW Interview) The state has given the Swedish Metrological Agency (SMHI) the responsibility to translate the findings of the IPCC, and add their own models to get locally relevant material. In addition, SMHI acts as a coordinator for the adaption work going on within the governmental departments (ÅS Interview). There are advantages and disadvantages to this approach. Among my informants there was a consensus that the current way Sweden tackles adaptation is not fit for purpose. One stated that both laws and organization must be “adapted” to climate change (UM Interview). Climate change, and thus by extension sea level rise, has been shoehorned into current laws and organizational principles. One danger is that the complexity, uncertainty and potentially very expensive consequences of climate change adaption overwhelms the capacity of individual municipalities to meaningfully respond (Goodsite et al 2012: 33).

Sea Level Rise on the Swedish West Coast The Swedish West Coast is generally steep and rocky, having formed around a billion years ago under intense pressure (Lathinen 2012). Softer materials has been scraped away by the successive ice ages. The ice which covered Scandinavia was up to 4 km thick (much like Greenland today) (Donner 1995), and the land is now slowly rebounding from the immense weight put on it. In Gothenburg, this rise is about 30 cm per century (compared to 0 cm in Scania (the most southern province of Sweden), 50 cm in Stockholm and 1 meter in northern Sweden)(SMHI 2009: 3). Since prehistory, the steady and very noticable “retreat” of the ocean has been a practical concern and a source of much puzzlement. Stockholm is situated where it is due to land rise cutting off the lake Mälaren from the Baltic Sea. Sea level rise is thus a completely novel problem, and something which until very recently was thought would become an issue only in the very distant future. Unlike the German North Sea Coast, tides are imperceptible in Gothenburg, and neither are storm surges any great problem. The two main water-related concerns for planners in the city are the issues of floods caused by rain and storm surges which raise water levels in the harbor and further up the stream by up to 2 meters over a duration of about 24 hours (UM Interview). Luckily, due to these two issues being caused by different weather conditions, they do not coincide (UM Interview). Rain is currently the bigger issue of the two, as the city becomes exposed to surges in water levels from the streams Kvillebäcken and Mölndalsån (see page 45), as well as the the river of Göta Älv (which is regulated by hydropower upstream, making it a lesser concern). Gothenburg is today experiencing non-tidal high water events. These vary in amplitude, but the city calculates with a worst case scenario of +1.95 meter rise, with an approximate 24 hour duration. The city calculates that this about 1% chance of happening in any given year (UM Interview) There is no great difference between Bremen and Gothenburg when it comes to how it may be impacted by global factors, since they are located only a short distance apart (see page 28). It is, however, much less vulnerable to a possible change in storms and weather patterns as discussed on page 35 - 36.

Future plans

Figure 32: Illustration of proposed high water barrier located outside of the western bridge. Another similar design is proposed for protecting Kungälv, north of the island Hisingen. Source: Göteborg 2016d Gothenburg has done an initial study on ways to deal with high water events under future sea levels. One study looked at the possibility of a storm surge barrier at the mouth of the river (figure 32) as well as the possibility for building walls and locks along the entire 17 km edge of the river (figure 33). A possible location in which the harbor would be protected as well was rejected as too costly and too disruptive for the shipping industry, while a location further towards the city had too little space for pumps (Göteborg Stad 2015: 42).

Figure 33: Schematic of barriers (in green) towards the river. Locks in black. Area colors indicate vulnerability to flooding. (Source: Göteborg Stad 2016c)

There have also been work done to study the potential for letting the water flood the city, including parts which would be floating. The latter solution was rejected due to cost and concerns about technical maturity (UM Interview). In the end, the city has opted for a combination of storm barriers and making the new part of the city resilient against flooding (ibid.). For example, the part of the future development Älvstaden known as “Frihamnen” (see figure 31) which will contain 9000 apartments will be designed to retain all critical functions even while flooded (Nordlander 2016). The combination of these two measures are meant to guard against both extreme rainfall and / or storm surges, while avoiding the problems and expense of building walls along the river. When the sea rises above what these designs can handle, there was agreement that something quite different would be needed, as the city would be below sea level, and with the Göta Älv river threatening the city from behind. (HBS Interview, UM Interview). What this might be is still unclear, possibly because it falls outside of Gothenburg’s current planning horizon and uncertainty estimates.

County Guidelines and City Plans In 2013-14 the Swedish Meterological and Hydrological Institute (SMHI) did a country-wide report seeking to help counties and municipalities localize the latest findings of the IPCC. They elected not to release any localized data on sea level rise. The county of Västra Götaland (where Gothenburg is located) and the City of Gothenburg responded to the draft of this material, demanding a chapter on sea level rise for the West Coast. This was accepted, and released in 2014 (Länsstyrelsen 2014). There are no national guidelines for sea level rise (Chalmers 2015), at least partly because the problem differs so greatly between different parts of the country. But this does not mean that there are no recommendations. The county stated that they were using a level of 1 meter + an extra 0.5 meters of global average sea level rise in their guidance to the municipalities of Västra Götaland until 2100. This number is then adjusted for the pace of land-rise at that particular location. According to SMHI, what IPCC has to say about the period after 2100 is too weak to us as a basis for a prognosis. Neither county nor SMHI considers themselves able to say anything about it (LW Interview, ÅS Interview). The unofficial guidelines up until 2100 that SMHI have communicated to the counties are in line with the IPCC lead author’s intentions, but since they require a “creative reader” (see page 27) they are not spelled out as clearly as they could be in the IPCC report. Gothenburg for its part has done an independent analysis. It has made models over extreme rains and flows and done a horizon scan (a survey for the range of expert opinion) over possible sea level rise scenarios until 2200 (UM Interview). This process relied on the numbers and probability ranges found in the latest IPCC report (discussed on page 27). This revealed that 2 meters of global average sea level rise until 2100 was considered as a worst case scenario (Fahlgren 2013), and that there were outlying predictions of up to 6 meters of sea level rise until 2200. In the end, both the worst case scenario for 2100 and the 6 meters until 2200 was rejected as too extreme to include in the planning process (UM Interview). The pace of adaptation is instead dimensioned towards the IPCC’s “likely” range of around 50 - 60 cm sea level rise this century (see figure 9 on page 27). The disparity between the county’s guidelines and the city’s own analysis (with the former looking at the upper part of the span while the city looked at the middle part of the span) led to a conflict over what analysis to use. The city considered the county guidelines to be too cautious, and to not be in accordance with the IPCC material as they understood it (UM Interview, FT Interview). Planning for 1.5 meters of local sea level rise would be very expensive for the harbor, and may 49

make the new piers hard or impossible to use. The county’s numbers seem to be applied for the construction of the Älvstaden development. Since this is supposed to be in use well into the next century and beyond, adding extra margin has less cost. Adapting to “too high” future sea levels in the city is one thing. It makes things more complicated, but will eventually be needed and costs does not rise too much since these are newly constructed areas. For the harbor the problem is much more complex, as building a pier “too high” means that shipping may be unable to use them, an issue that especially affects rolling cargo. The piers that Gothenburg Harbor use today and plan to build in the future (and which have a potential life length of 120 years (Göteborgs Hamn 2015)) cannot be more than approximately 50 cm too high or too low in comparison to the actual sea level (FT Interview). The end result is that Gothenburg Harbor aims for global sea level rise of between 60 cm to 80 cm until 2100 (JA Interview, FT Interview). The study looking at the storm surge barrier does not set out its assumptions in detail, but appears to be using SMHI’s numbers and extending them until at least 2150. Unlike the harbor the expected specifications are with a worst case scenario in mind, with water levels that are 1.5 meters over present (Göteborg Stad 2015: 39). Assuming that number includes about 40 cm of land rise (see page 47), this points towards their expected worst case scenario being up to 2 meters of global average sea level rise in roughly 140 years.21 The gates would be 16 meters high, stretch 5 meters above current sea level. Storm surges are thought to be capable of reaching 3 meters, with waves reaching an additional 1 meter (see figure 34). The report is written to make it appear that the barrier will have been built in 2050 (when, under the assumptions of the study it would need to be closed once ever ten years on average (ibid.)). But Gothenburg municipality expects to start construct it in the 2060ies at the earliest (UM Interview), which is in line with their expectation that the worst case scenario is very unlikely. What options there are after the storm surge barrier’s design specifications are Figure 34: The storm surge impact of a storm like the 2005 permanently exceeded is not discussed in “Gudrun”, today and in two scenarios for 2150. Source: the report, neither is the point when this is Göteborg Stad 2015: 55 occurs clearly defined.

21 Apart from isostatic uplift, there are of course other factors involved, as discussed on page 28. 50

Comparative Analysis Table 1: Key Comparative Gothenburg Bremen Parameters Coastal conditions Steep, geologically hard coast with Flat, geologically soft coast with around 30cm of isostatic uplift in around 5cm of isostatic sinking 100 years. No significant coastal in 100 years. Coastal dikes expe-

erosion. No significant tidal variat- rience an additional 17 to 25cm ion. of weight-induced sinking in 100 years. Significant coastal erosion. Up to 4 meters of tidal amplitude in central Bremen.

Expectations for Municipal planning dimensioned for Coastal defense planning di- future sea around 30cm of local sea level rise. mensioned for 2 meters until level rise Worst case planning analysis looking 2100. Analysis exists for conver-

at around 1 meter local rise to 2100, ting land to tidal landscapes to and 1.5 meters until 2150. reduce tidal amplitude in the Weser.

Division of Municipal planning and funding of Combined federal and regional responsibility for coastal defense and adaptation funding of coastal defense. planning and funding efforts. County and state in an ad- Regional responsibility for of coastal defense and visory role. Coastal defenses at the planning and construction. Ci- sea level rise adaptation planning stage. vil defense organizations main stakeholder responsible for maintenance and upkeep along ditches and rivers.

Bremen and Gothenburg are both of a similar size, are both port economies, are both situated in a very rich part of the world, and are both situated in countries with low corruption and with strong, competent civil services. Citizens in both countries have a comparatively high awareness of climate change and are very supportive of both adaptation and mitigation measures.

They are also similar in the way they have advanced into what used to be wetlands (in Gothenburg) and tidal zones (in Bremen). Similar strategies have been discussed in both contexts, and planners in Gothenburg think that the city will at some point have to adopt dikes or sea walls, with parts of the city below sea level (page 49). There are also quite a few differences. Bremen is located in an area battered by unpredictable storm surges and constant erosion from tides, while Gothenburg has no tides or storm surges to speak of, and erosion is a non-issue. The North Sea coast is flat and soft, and people living there has been locked in a struggle to capture land from the sea for centuries. A much younger city, Gothenburg has been rising upward, surrounded by a very hard and quite steep coast.

The historical experience in Bremen and Niedersachsen (as well as the proximity and influences from the Dutch, world leaders in coastal engineering (MS interview)) means that sea level rise and viewing the forces of the sea as a threat is nothing new. The sinking land, the increasingly violent storm surges and tides caused by the construction of a completely artificial coast, and semi- 51

permanence of the dikes means that Bremen has been forced to equip itself with a huge institutional infrastructure. Regular disasters have created a tradition of risk based planning and dike maintenance is dependent on a significant degree of citizenship engagement (page 38 - 41).

Even in the absence of climate induced sea level rise, storm surges and tides mean that the number of people directly and indirectly involved in coastal protection, dike maintenance and planning can be counted in the tens of thousands. The presence of world leading scientific institutions oriented towards studying sea level rise (the prime example being the Alfred Wegener Institute (AWI) in Bremerhaven) is quite helpful for introducing and understanding recent research. The federal German state has long been engaged in providing resources for coastal defense, and was early in pushing for long range studies of what is deemed a federal interest (MS interview). Last but not least, there is wide recognition and a growing acceptance among planners that sea level rise represents an existential threat to the present outline of the German North Sea coast (WO Interview).

In comparison to the above, there are quite a few things that can be said to be missing in Sweden and Gothenburg. Because of the perceived low vulnerability of Sweden to sea level rise and a system where resources and responsibility is a matter for municipalities (page 46), it has been natural for the state to mostly disassociate itself from adaptation planning and costs. Sweden has no equivalent of the AWI, and have until recently never had any reason to build up any institutional experience of dealing with sea level rise.

Gothenburg represents a special case in this regard, as its vulnerability to unpredictable high water events caused it to pay attention to the issue before the state did (UM Interview). But Gothenburg suffers from a lack of resources, even if to a lesser degree than most other Swedish coastal municipalities (page 46). After negotiations with the county, Gothenburg has decided to pursue a mixed strategy, with different types of infrastructure being adapted for different sea level rise scenarios and timespans (page 49 - 50).

Perhaps the starkest difference between the two cities can be found when comparing its ports. Bremenports has the ultimate responsibility for coastal defense of the city of Bremerhaven, and is a significant independent (if not always completely coherent (see page 39 - 40)) actor within the coastal adaptation debate. Because of their close proximity, they are in regular contact with AWI (both formally and informally (UvB Interview)) giving easier access to research that is both more recent and of greater sophistication than that produced by the IPCC process (KR Interview).

Göteborgs Hamn is for natural reasons much less active, being a much more streamlined organization. There is no mention of sea level rise in official documents of Göteborgs Hamn. Being owned by the municipality, it simply uses the numbers given to them by the city of Gothenburg (page 50, FM Interview).

Conclusion

“The Danes, the Dutch and the Germans are asked: What will you do when the sea rises? The Danes reply: we don’t care! We have other problems. The Dutch reply: We will build a second dike line, new drainage, new clever solutions. The Germans reply: Sea level is rising? We forbid it!” A joke on the attitudes of the nations of the North Sea coast, as told by Karsten Reise. (KR interview)

The many uncertainties around the future trajectory of sea level rise makes it hard to say anything definitive about the different strategies pursued in these two contexts. Unfortunately, the nature of this uncertainty appears to be that it is more a question about how much and how fast the sea will rise rather than how little or how slow (see Chapter 2). But, as already asked on page 16, how relevant are worst case scenarios for planners in reality? They have pressures, issues and wishes to deal with in the present, and perhaps the future can be dealt with when it arrives (page 12).

The basic difference in immediate vulnerability means that comparing the two contexts becomes quite problematic. Nevertheless, the greater familiarity with risk and risk assessments in Bremen means that it is much closer to the best practices outlined on page 9 - 10 than Gothenburg is. While there are problems, there are also established processes and a lively debate in place. When living next door to unpredictable forces that in the past has wiped out entire communities, there is little other choice. In comparison, risk assessment around climate change in both Gothenburg and Sweden suffers from lack of resources, structure and a lack of coordination (page 46). There is also a pervasive lack of attention to the issue, both in academia and more generally (UM Interview, ÅS Interview).

While even small amounts of sea level rise sustained over centuries spells trouble for the sinking North Sea Coast and threaten large populated areas of land with inundation, a slow sustained rise in global sea level would pose no major challenge to most of the Swedish coast. For this reason there have been little pressure toward risk oriented analysis, leading to a dominance of the perspectives of practitioners and scientists (who are influenced by the institutional biases as described on page 13 - 17).

Unfortunately, the result is an implicit, unwitting acceptance of risk. Sweden has a very long coast relative to its population, and its three biggest cities are all located close to the sea. Sweden is functionally an island, making it entirely dependent on coastal and port connections for the viability of the country. Gothenburg’s planned storm surge barrier would protect the parts of the city behind it up until 2 meters of local sea level rise. After this point Gothenburg appears to be committed to living below sea level, but it has yet to make a formal analysis of what this would actually mean, perhaps because it expects a pace of sea level rise that is significantly below the worst case scenario.

Building sea walls towards the sea may be less of an issue than the water entering the city from the north, south and east, from the river and the streams (see page 45). Current planning is oriented towards such a development occurring several centuries into the future, the implicit assumption being that it is not an issue that current planning need to take into account. It is hard not to attribute this to temporal discounting (page 12) and a tendency to see sea level rise as an issue that is linear and well understood.

There is a risk that the IPCC likelihood data will prove to be flawed and / or incomplete, in which case the useful life-length of current adaptation efforts would be shorter than currently assumed. The agency of SMHI (which is tasked to provide guidance on the issue) supports an optimistic reading of the data since its analysis is limited by the IPCC prognosis cutting off at 2100. It has yet 53

to do a formal prognosis beyond that date (page 46), but appears to give informal guidance which amounts to a worst case scenario of 2 meters global average sea level rise until 2150 (page 50).

Sweden has yet to formulate a strategy around sea level rise that is distinct from its other adaptation measures (page 46), and has yet to adopt a national strategy or make an analysis with a risk assessment perspective (Regeringskansliet 2016, André & Glaas 2013). Under the current institutional structure, were sea level rise to significantly outpace land rise, it is an open question what sort of collective strategy Sweden would elect to pursue, and what sort of help coastal communities could expect to receive from the state.

There is significantly more margin for error in Gothenburg and the Swedish West Coast than there is in Bremen or on the North Sea coast. Even the Swedish lack of institutional history may in theory be an advantage. Unlike Bremen or the North Sea Coast, neither Gothenburg nor Sweden is yet firmly locked into a strategy and still have the theoretical possibility to choose whether it wants to commit itself to building defenses and / or utilize other strategies.

It bears repeating that the vast uncertainties in the underlying science (as described in Chapter 2) makes it is impossible to falsify either Bremen’s or Gothenburg’s approaches. What can be said is that both contexts have issues with transparency towards the general public in their assumptions. In Bremen the planners are seemingly hesitant to adopt a long term plan that stretches beyond the next 50-100 years out of concern that the results would be too difficult to deal with politically.

In Sweden there seem to be a reluctance to include worst case scenarios in analysis or discussion. Too much of the underlying approach seem to be based on informal, undocumented deliberation between different stakeholders. This makes it hard to audit what sort of scientific considerations went into planning and scenarios, and sometimes give the impression that there is a lack of coherency between the outlook and assumptions of different stakeholders.

Both contexts seem to struggle with making sure that the analysis is based on cutting edge science. This is understandable to some degree since our understanding of Earth System Science moves a great deal faster than the institutional processes responsible for coastal defense and urban planning, which are highly averse to uncertainty and paralysis. But a central part of risk assessment procedure is that it should be iterative and cyclical (page 10). This certainly represents best practice in the normal case, and is absolutely essential for highly uncertain and non-linear risks such as climate change and sea level rise.

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Interview References

KR = Dr Karsten Reise (Formerly researcher at AWI, Sylt in coastal biology. Author of the book “Kurswechsel Küste. Was tun, wenn die Nordsee steigt?” Reise, Karsten 2015. Interviewed by phone the 6/4 2016, and by e-mail exchange 2/8 2016) MS = Dr Michael Schirmer (Since 2004 Deichhauptmann (Verbandsvorsteher) for the civic dike association Bremischen Deichverband am rechten Weserufer. Formerly researcher in coastal biology / chemistry at Bremen University. Interviewed in Bremen the 15/3 2016, and by e-mail exchange 15/8 2016) UvB = Herr Uwe von Bargen (Direktor für Umweltangelegenheiten at Bremenports, Bremerhaven. Involved in the NordWest2050 project. Interviewed by phone the 31/3 2016) JS = Herr Jan Scheve (PhD researcher at Bremen University. Interviewed in Bremen the 14/3 2016) WO = Dr Winfried Osthorst (Researcher in Social Science at Bremen University. Involved in the NordWest2050 project. Interviewed in Bremen the 13/3 2016) KG = Dr Klaus Grosfeld (Researcher in paleo-climate dynamics at AWI Bremerhaven. Interviewed in Bremerhaven the 16/3 2016)

FT = Fredrik Ternström (Senior Manager Port Development Gothenburg Port Authority) Interviewed by telephone the 5/4 2016) ÅS = Åsa Sjöström (Director at the National Knowledge Center for Climate Adaptation, SMHI. Interviewed by telephone the 25/4 2016) JA = Jan Andersson (Vice President Infrastructure, Gothenburg Port Authority E-mail exchange on the 3/3 2016) AO = Anders Omstedt (Professor in Oceanography at Gothenburg University. Interviewed by telephone the 4/7 2016) GE = Gunnar Elgered (Professor in Electrical Measurement Techniques at Chalmers University. Interviewed by telephone the 8/4 2016) HBS = Henrik Bodin-Sköld (Environmental Consultant, Sweco Environment AB. Interviewed in Gothenburg the 3/2 2016) LW = Lars Westholm (Climate Coordinator at the county of Västra Götaland. Interviewed by telephone the 10/2 2016) UM = Ulf Moback (Climate Expert at the Gothenburg City urban planning office. Interviewed in Gothenburg the 4/2 2016) SM = Staffan Moberg (Senior Legal Advisor at Insurance Sweden. Interviewed by telephone the 21/1 2016)