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Marijn Sauer 2124122
Thesis BSc Earth and Economics
Supervisor: Cees Withagen
03-07-
[ADAPTATION VS. MITIGATION]
The undesirable impacts of climate change are more shown every day. The question arises what is the best approach: adaptation, mitigation or a combination. This literature research investigates (1) the pros and cons on mitigation and adaptation, and (2) if it is even possible to use one or the other, or else if a combination is always necessary. After this, (3) the results of the RICE-2011 model will be explained and (4) a reflection on the situation of Europe is made.Main results include that adaptation and mitigation could be better approached separately as they mismatch in time and governing scale, describing uncertainty, and because they are interacting. However, a combination is necessary as a total emission reduction still leads to global warming and only adaptation will lead to an inhabitable planet. The RICE-2011 model calculates a global social cost of carbon of $42.68 per metric ton carbon, and a European one of $4.11. However the result should be interpreted as a guideline, as the outcome is heavily dependent on uncertain parameters. It should be wise for Europe to invest in approaches that not only deal with the undesirable impacts of climate change, but rather creates economic opportunities and enhances the robustness of society.
Table of content
- 1 Introduction and method p.
- 2 Theoretical framework p.
- Adaptation versus mitigation p. Results
- 3.1 Introduction p.
- 3.2 Explanation of terms p.
- 3.3 Overall pros and cons p.
- 3.3.1 Advantages adaptation p.
- 3.3.2 Disadvantages adaptation p.
- 3.3.3 Advantages mitigation p.
- 3.3.4 Disadvantages mitigation p.
- 3 .3 Comparison difficulties p.
- 3.4 Separation or combination? p.
- Mitigation, or no mitigation p.
- 4.1 No mitigation – Fossil fuel consumption p.
- 4.2 Only mitigation p.
- 4.2.1 Needed amount of adaptation p.
- The RICE- 2011 model p.
- EU response to climate change p.
- 7 Discussion P.
- Conclusion p.
- References p.
- Appendix A: Policy responses p.
- Appendix B: Adaptation difficulties p.
- Appendix C: Trade-off adaptation, mitigation, do nothing p.
- Appendix D: Fossil fuel, year of depletion p.
- Appendix E: Fossil fuel reserves, consumption, and year of depletion p.
- Appendix F: Carbon-climate response p.
- Appendix G: CO 2 scenarios p.
- Appendix H: Optimal adaptation with no mitigation p.
- Appendix I: The RICE-2011 welfare function and SSC function p.
Through literature research the second chapter investigates if it is even possible to use only mitigation, only adaptation, or that a combination is always necessary. To conclude if mitigation is necessary, or if only adaptation is an option, data from the Carbon Dioxide Information Analysis Centre (CDIAC) and British Petroleum (BP) are used. Own calculations are made with data on fossil fuel consumption from the British Petroleum 2014 report to determine when current discovered fossil fuel reserves are fully depleted. Although important, population growth, economic growth, and technological improvements are not included in these calculations due to great uncertainty. In the same sub-chapter, the geological consequences of burning all fossil fuels are set forth. Henceforth, the chapter continues with literature research to conduct an answer if only mitigation is an option. In this part more attention is paid to adaptation with the 2◦C scenario. This scenario was chosen because of the already inevitable temperature rise, even if strict mitigation efforts were made.
The last chapter, chapter 3, is dedicated to the RICE-2011 model coined by William Nordhaus. This model calculates the social cost of carbon, which represents the economic damages associated with an increase of one metric ton of carbon in the atmosphere. In a complete and perfect market, the result of the social cost of carbon should be equal to the carbon tax. A perfect carbon tax is a cost- effective governmental instrument to mitigate. And when the optimal amount of mitigation is known, the amount of adaptation necessary could be investigated afterwards. The RICE model has been chosen as an integrated assessment model (Hereafter IAM) , because it is one of the three main integrated assessment models used by the United States Environmental Protection Agency, and because it derives the world into regions, such as the EU. After the RICE- 2011 results are set put with literature research, a conclusion is drawn on the best approach to deal with the undesirable impacts of climate change for the EU.
2. Theoretical framework
Anthropogenic climate change
For the development of this theory the Intergovernmental Panel on Climate Change (IPCC) plays an important role. It is the leading international body for the assessment of climate change since 1988 and has ever since gathered scientific, technical and socio-economic data and information concerning causes and effects of climate change (IPCC). Since the previous century there is growing consensus that substantial climate change is caused by GHG emerged from human activity (Johns et al, 2003). In the fifth assessment (AR5) in 2014 of the IPCC, scientists are more than 95% certain that a major part of global warming is caused by anthropogenic activities. The theory is reinforced by analyses of the ecological consequences of human activity, based either upon simplified climate models, expert opinions, or predictions from general circulation models and statistical tests. Furthermore, projected increasing temperatures differ quite strongly due to a number of matters. For example: uncertainty about the balance of greenhouse warming, sulphate aerosol cooling, and the effect on the ocean. Despite evidence provided by climatologists and other scientists, there still is lack of long term knowledge of the most recent human actions, and therefore certainty about the consequences of anthropogenic pollution up until now remains fragile (Myles et al, 2000). Thus, intensification of quantification of long term effects is needed. Overall, a positive causal relation is scientifically observed between the actions of human and climate change. Important insight for this research is that even though there still is uncertainty about the precise drivers, pressures, states, impacts and responses to climate change, IPCC has agreed upon the fact that adaptation and mitigation measures are essential for protection of future societies (Chmielewski, 2002).
Game theory
Game theory is the science of strategy, and was pioneered by Princeton mathematician John van Neumann. The discussion of game theory started in 1928, when first mentioned in “Theory of Parlor Games” (Dixit and Nalebuff, 2008). This theory attempts to determine mathematically and logically the actions that “players” should take to secure the best outcomes for themselves in a wide array of “games” (Dixit and Nalebuff, 2008). It is the study of multi-person decision problems, frequently arising in economics. For example, each firm must consider what the other will do (Gibbons, 1992).
Criticism on the game theory was that it is truly a model, and like all models must be looked upon as such (Morgenstern, 1964). Sometimes decisions are bounded to laws for instance, and that the mathematical outcomes are based upon a ‘normal’ world, not a world in chaos (Morgenstern, 1964). Also, the theory assumes that everyone makes decisions rational.
This is important in this research because when choosing mitigation or adaptation, men need to consider the action of other “players”. For example, if Europe chooses to mitigate, however all other
Green paradox
The Green paradox theory is coined by the German economist Hans-Werner Sinn in 2008. He was convinced that instead of mulling over for the thousandth time about which technical measures can be applied to reduce CO 2 emissions, we should turn to the core question of how to induce the resource owners to leave more carbon underground, as that is the sole possible way to solve the climate problem. (Sinn, 2009) Because according to Sinn, fighting climate change through fossil fuel demand-reducing policies that are intended to flatten the time profile are paradoxical. The impact of such policies only steepens the extraction path of fossil fuels rather than flatten it. (van der Ploeg and Withagen, 2010). Although the measurements to reduce consumption exert an increasingly stronger downward pressure upon the world’s fossil fuel market price and dampen the rate of increase in such prices, the supply side is not taken into account. However, several researches have been conducted on the likeliness of the occurrence of the Paradox. Grafton, Kompas & van Long (2010) concluded that the Green Paradox can be caused from a policy of biofuel subsidies, but is not a general result. This depends on demand and supply elasticities, technological change in fossil fuel extraction and how extraction costs respond to changes in remaining reserves. Also a research in 2011 and 2013 concluded that this theory is limited to specific conditions (Edenhofer & Kalkuhl. 2011; Hoel, 2013). For instance, if policy is aimed at the supply-side, no Green Paradox will occur (Hoel, 2013). An important insight for this research is that mitigation of climate change does not necessarily lead to a lower global amount of emissions, but rather to a replacement of polluter. Also a demand-side approach, as suggested as solutions to the Jevons’ paradox, could result in a Green paradox.
DICE and RICE model
One of the earliest dynamic economic models of climate change was the Dynamic Integrated model of Climate and the Economy, or DICE model. This model was developed from a line of previous energy models and one of the first models that was integrated to an end-to-end mode (Nordhaus and Boyer, 1999). This means that the parameters economics, the carbon cycle, climate science, and the impact are modelled by eliminating as many middle layers or steps as possible to optimize performance and efficiency. Thus, the model, as all models do, simplified the reality for conducting results on how to slow greenhouse warming (Nordhaus and Boyer, 2000). The RICE model is a regional version of the DICE model, were the world is separated into 12 regions. The basic structure of the DICE and RICE models has survived mostly all scientific criticism (Nordhaus and Boyer, 2000). However, these models rely on very debatable and uncertain parameters, and should therefore be contemplated before using without further consideration (Pindyck, 2013).
3. Adaptation versus mitigation
3.1 Introduction
Climate change is one of the hardest and most complex problems policy has ever needed to deal with, harder than any other issue with high importance. Its form and size is far from certain, as well as the impacts and remedies. And however climate change is already happening, it is rather felt in the future than confrontational in the present. As will be further investigated in this chapter, effective mitigation lies beyond the national borders, and will require international cooperation. (Garnaut, 2008) For a long time mitigation was the main policy approach, and it was politically incorrect to speak about adaptation, as this was felt as accepting defeat in the battle against the emissions resulting in climate change (Burton, 1994). This has changed since scientists repeatedly pointed out that climate change cannot be altogether avoided even if trying very hard, and because not everybody is going to try equally as hard to reduce GHG emissions (Tol, 2005). In this chapter both terms, adaptation and mitigation, are set forth with the geological, economic and political (dis)advantages. The last sub-chapters explain if adaptation and mitigation are best used together or separately, with all the difficulties in comparison.
3.2 Explanation of terms
The undesirable negative effects of climate change can be tackled by two main approaches; adaptation and mitigation (Appendix A).
Adaptation involves efforts to limit human’s vulnerability to climate change impacts through various measures, while not necessarily dealing with the underlying cause of those impacts (Mann, Alley & Pugh, 2014). The main goal of adaptation is to increase the adaptive capacity, which is the ability of a system to adjust to climate change. This includes the variability and extremes of the climate, to decrease potential damages, and to deal with the consequences. As not all consequences are negative, adaptation can also take advantage of opportunities that come from climate change. (IPCC, 2001) Some examples of adaptation costs are for instance the estimated costs for developing drought resistant crops or climate change resilient building. The costs for developing genetic modified traits range between $1 million up to $136 million (McDougall, 2011; Goodman, 2002). The costs of constructing more resilient buildings against climate change in the Organisation for Economic Co-operation and Development (hereafter OECD) countries, such as storms and floods, could range from $15 to $150 billion each year (higher costs are expected with further increase in temperature) (Stern, 2006). A case study of adaptation in the Netherlands has shown that adaptation could mitigate most of the damage caused by river flooding at moderate costs. The estimated economic costs resulting from flood damage decreased from 39.9 billion to 1.1 billion with relatively small adaptation costs around 1.5 billion (EEA, 2007). Adaptation is a private good which mainly benefits the societal welfare of the nation (Kane & Shogren, 2000), and can be autonomous or policy driven (IPCC, 2001). Autonomous adaptation occurs gradually and is not necessarily a response to climate change alone. It is constrained by economic, social, technological, institutional, and political conditions (IPCC, 2001). Policy driven
climate variability and is probably also more robust to other socio-economic change (Tol, 2005). Such robust adaptation should always yield benefits as a ‘no regret’ strategy, regardless if and how climate change would occur. For instance: protecting water sources. The outcome of precipitation models differ widely from one another, so an investment in water safety should also range. In this case, a robust adaptation strategy could be installing water tanks to assure water security and to avoid water contamination and salinization.
So adaptation can make the society more robust and flexible, which is also preferable against other changes, many of which are more rapid than global warming. One does not want to use drought resistant crops because of climate change, but rather because there already exists a drought problem in many places in the world. Climate change is only another reason to invest in further developing. (Tol, 2005)
3.3.2 Disadvantages of adaptation
The implementation of adaptation options also presents constraints that are financial, technical and political (IPCC, 2001). There are limits to the ability to adapt to fundamental and rapid climate change, in the sense that the human and economic costs could become very large, for example building dikes along the entire coast to deal with the consequences of sea level rise. Also due to limits, there are impacts that will be unavoidable ( Appendix B ). For example, the constraints on building or extending flood defences would include pressure for land, conservation needs, and amenity value of coastal areas (IPCC, 2001). To build foreword on the previous example, a flood defence could also have negative effects on the tourism industry because they change landscape, ecosystem health and beach leisure attractions. These costs are difficult to estimate as guidelines for monetization are not always available (Hallegatte, 2009).
Adaptation is particularly difficult when the precise nature and incidence of effects are uncertain (Stern, 2006). Ideally, climate models would be able to produce climate statistics for the future, from today to when a building or when infrastructure will need to be replaced, so future investments can be optimized (Hallegatte, 2009). However, problems arise with this. First, there is a scale of misfit between what can be provided by climate models and what is needed by decision-makers. Decision- makers want clear and reliable results that they can use to determine the best investments. Nevertheless a model is a simplified replica of reality, and should therefore be seen as a guideline, a range of opportunities, rather than a clear solution. More reliable results could be generated by downscaling techniques (e.g. using regional models with limited domains or statistical relationships calibrated on the present climate), but the problem of climate change uncertainty still arises. (Hallegatte, 2009) Improved knowledge could mean narrower projection ranges, however uncertainty will still exist in future emission paths. And ill-designed implemented adaptation strategies could make the situation even worse than without any adaptation. (Hallegatte, 2009) This maladaptation, such as promoting development in risky locations, can occur due to decisions based on short-term consideration, neglect of known climatic variability, imperfect foresight, insufficient information, and over-reliance on insurance mechanisms (IPCC, 2010).
Only investing in adaptation and not in mitigation will raise problems that are humane, economic and social (Adger et al., 2006). Adaptation options generally occur in socioeconomic sectors and systems in which revenue of capital investment and operating costs is shorter so that costs are quickly recouped, and less often where long-term investment is required (IPCC, 2001). An example is the purchase of more efficient irrigation equipment by individual farmers in prospect of increased evapotranspiration in a warmer climate. In terms of international solidarity, the rich countries, who contributed by far the most in climate change, will have to channel development assistance to less developed countries to meet the new demands arising out of climatic disasters (Adger et al., 2006). However, applying principles of fairness and equity is not a given, because nations will probably want to maximize their own welfare based on selfishness.
3.3.3 Advantages of mitigation
Reducing carbon emissions does not necessarily mean that it makes poorer, especially in comparison to adaptation measures. Taking action to tackle climate change can create economic opportunities and higher living standards by energy-efficient and resource-efficient production and consumption (King, 2004). And even when mitigation investments are primarily (short-term) negative, they are still less expensive than most adaptation measures. An extensive review by the IPCC suggest that stabilizing atmospheric carbon dioxide at 550 ppm would lead to an average gross domestic product ( hereafter GDP) loss for developed countries by 2050 of only around 1%. This figure should be more than offset by the reduction from the risks, for example, flooding associated by climate change. If just one flood broke through the Thames Barrier today, it would cost about £30 billion in damage to London, roughly 2% of the current U.K. GDP. (King, 2004) So in comparison with adaptation, mitigation can be more cost efficient as in many cases the costs of mitigation are lower than to deal with the undesirable impacts afterwards CO 2 is emitted. Also some co-benefits arise from mitigation. Near-term health benefits for example, from reduced air pollution that may offset a substantial fraction of mitigation costs (IPCC, 2007b). Mitigation can also be positive for energy security, balance of trade improvement, provision of modern energy services to rural areas, sustainable agriculture and employment (IPCC, 2007b).
Current GHG emissions are largely the result of past emissions from rich countries, such as the countries in the EU. They are the source of the problem, yet the impacts on developing countries will be of great severity (Stern, 2006). In human terms, developing countries are likely to be worst affected. They will be hit not only by increased variability but also by more adverse overall environment as temperatures rise. They will have to deal with this despite low incomes, often small margins for adjustment and little resources. (Stern, 2006) As mentioned before, mitigation is a public good, so developing countries also profit from the action taken by more developed countries. As fewer resources are in place to adapt and climate change hits the hardest in developing countries, the question rises if only adaptation in developed countries is ethical. So from a global perspective, the benefits of mitigation are higher in comparison with adaptation (which is a private good).
However, waiting for technology progress as a sustainable solution can backfire or rebound, causing higher production and consumption (Alcott, 2004). When efficiency increases, prices will decrease and therefore the technology will be cheaper and more easily available for the ones who were not capable before. As stated before, this can be overcome by governmental instruments as a carbon tax or cap and trade (Siegel, 2011). However with the use of these kinds of instruments, it is likely to provoke a Green Paradox (Box 2).
As stated as one of the pros on mitigation, the following can also turn in a con; developing countries that are better off with mitigation because of the nature of mitigation as public good also seem to get worse of it. Mitigation, which presumably strives to reduce climate change impacts, in fact increases them (Tol and Dowlatabadi, 2001). A reduction in economic growth in the OECD, caused by emission abatement, could have negative effects on the economic growth at the bottom of the value chain. Because when it protects its own employees, it is often done at the expense of its suppliers. At the bottom of the value chain there are exporters of primary products, including most African countries. A lower economic growth would imply that there is less money to spend on health care, something currently more pressing on the welfare of these countries than climate change. (Tol, 2005; Tol and Dowlatabadi, 2001)
The last reason why mitigation is not always a preferable approach is because it may also add to risks. Example given by van Vuuren et al. (2011) is bio-energy. However bio-energy can reduce CO 2 emissions by substituting fossil fuel based energy, when implemented wrong it can further biodiversity loss and reduce the food security (van Vuuren et al., 2011).
BOX 2: The Green Paradox According to Sinn (2009), fighting climate change through fossil fuel demand-reducing policies that are intended to flatten the time profile are paradoxical. The impact of such policies only steepens the extraction path of fossil fuels rather than flatten it (van der Ploeg and Withagen, 2010), because resource owners are likely to bring forward their extraction plans securing their resources as financial capital when valuation diminishes over time.
BOX 1: The IPAT equation. The equation states that environmental impact (I) equals, or is a function of, population (P), affluence (A), and technology (T). Apparent from the equation is that population growth and consumption growth worsens environmental problem, and that technological improvements on the other hand reduces this pressure (Alexander, 2014). In other words: decision makers can focus on advancement in technology, as this will score out the effects of a growing more consuming population.
3.4 Comparison difficulties
A combined assessment of adaptation and mitigation can be useful for a number of reasons: (1) the expected climate impacts and the costs of adaptation are key values of the mitigation strategy chosen, (2) it considers the limitations that come with adaption to climate change, (3) there is some interaction between adaptation and mitigation strategies, (4) and what should be taken into account are the feedbacks that could come from the impacts of climate change (van Vuuren et al., 2010).
However, methodological differences obstruct such joint assessment of mitigation and adaptation strategies, especially the strategies that describe autonomous adaptation processes because it is mostly an individual process that cannot be measured with ease (Patt et al., 2010). Besides, even when the costs and benefits of mitigation, adaptation and leftover damages can be traded-off against each other (Appendix C) is suggested, conceptual and analytical problems make it difficult for such an approach (van Vuuren, 2010).
First of all, the disciplines involved in mitigation and adaptation research describe uncertainty different from one another. As mitigation research mostly uses quantitative methods and concentrates on mean estimates, adaptation research mostly uses qualitative descriptions of uncertainty and concentrates on the risk of dangerous events even those which have a low chance of occurrence (van Vuuren et al, 2011). These different perceptions of uncertainty may make a collective assessment of different strategies difficult (Swart et al., 2009).
Second, there is a mismatch of spatial scale. While mitigation action is most of the times taken at a national or local scale, the benefits are global. As a result and already mentioned as disadvantage of mitigation, a key factor in the success and cost of climate policy extends to international negotiations and cooperation (Tol, 2005; Barker et al., 2009; van Vuuren et al., 2009). In comparison, adaptation is primarily a concern of local managers of natural resources, households and companies, within a regional economy and society (Tol, 2005). The costs and benefits occur on several scales from local to international (van Vuuren et al., 2010). For these kinds of reasons, assessment of mitigation tends to concentrate on the global level, while adaptation research is mostly focused at the local scale.
Also, there is a mismatch of timescale. Strict mitigation scenarios require strong, early reduction of emissions. However, the climatic impacts will in the first decades hardly vary from those in scenarios without climate change policy due to large inertia within the climate system (van Vuuren et al., 2010). In contrast some co-benefits are to be seen in shorter term, for example reduced air pollution. This while adaptation measures are likely to yield private and social benefits over the near-term (e.g. air conditioning). Some exceptions exist in long-term planning like flood protection (van Vuuren et al., 2010). This gives trouble comparing the two in costs and benefits. While a cost-benefit analyses (Hereafter CBA) on mitigation focuses on short term action for possible harmful long-term developments, a CBA on adaptation looks at short term actions for short- to medium term developments. This implies that these CBA’s should be made at different timescales, and therefore are very different from each other and not comparable (Tol, 2005).
Although adaptation and mitigation are not easily combined, and should therefore be approached separately, the fact cannot be ignored that we need both. Even with the most stringent mitigation paths, unavoidable economic-cost should be minimized with adaptation measures. A governmental institution should focus more on mitigation, because of its transboundary character. Besides such institutions can internalize externalities with the use of governmental instruments, such as taxes. Adaptation will need less governmental interference as autonomous adaptation occurs spontaneously and locally. Hereby, the government is only necessary to invest in public goods, for example flood defence and enhancing or guaranteeing water security. Reaching an optimum will be difficult to achieve and should not be pursued, because of climate uncertainties, both in short and long term, and due to monetizing problems.
4. Mitigation or no mitigation
This chapter will use literature research to determine if it is even possible to use the one or the other, or if a combination is always necessary. First the fossil fuel consumption will be investigated with an inference on how long it will take for reserves to be fully depleted. After, the physic geological effects of burning all fossil fuels are set forth. Second, the consequences of only mitigation are explained and the amount of adaptation needed when continuing on this mitigation path is studied.
4.1 No mitigation – fossil fuel consumption
The concentration of atmospheric CO 2 has unambiguously increased since 1751. One of the prime contributors to this increase has been the combustion of fossil fuels. (Andres et al., 1998) Fossil fuels are hydrocarbons, and have three major forms: coal, oil and natural gas.
Since 1751 approximately 365 billion metric tonnes of carbon have been released worldwide to the atmosphere from the consumption of fossil fuels and cement production. Half of these fossil-fuel related CO 2 emissions have occurred since the mid-1980s. (CDIAC, 2015) The 2010 global fossil-fuel carbon emission estimate, 9167 million metric tons of carbon, represents an all-time high and a 4.9% increase over 2009 emissions. The increase marks a quick recovery from the 2008-2009 global financial crisis which had obvious economic and energy use consequences, particularly in North America and Europe. (CDIAC, 2015) Despite a further decrease of energy intensity, world energy consumption is expected to more than double in the 2000-2050 period and increases by another 25% in the 2050-2100 period. Even with the mitigation goals to increase green energy, over the whole century, energy supply is expected to remain dominated by fossil fuels. While oil and natural gas production peak and decline during the century, the use of coal is expected to increase during the whole period. (van Vuuren et al., 2010)
The question arises if we can continue on this path, or that mitigation is always necessary. First because of fossil fuels being a finite source, the question is whether when instead of if we need to make a transition to another energy source. And second because of the undesirable impact of carbon based CO 2 emission by fossil fuel burning.
At this moment we consume over 11 billion tonnes of oil in fossil fuels across the globe each year. According to the Central Intelligence Agency ( Hereafter CIA ) (2015) crude oil reserves are vanishing at the rate of 4 billion tonnes a year, and if this continues without implementing increase in population or aspirations, the known oil deposits will be gone by 2052. Even though coal and gas can substitute oil, using gas to fill the gap will only give an estimated 8 more years, till 2060. Adding the coal reserves, those are often claimed as enough coal to last hundreds of years, will only give enough energy to 2088 when also substituted for the other finished fossil fuels (Appendix D). (Ecotricity,
- By 2088 all reserves known to man this day are most certainly used, however new reserves will probably be found between now and 2088. This does not mean it will gives use infinite time, just more time to find an alternative solution to fossil fuels. (Ecotricity, 2015)
4.2 Only mitigation
If we stop emitting carbon dioxide today (total mitigation), global warming would not immediately stop. The existing of a delay in temperature increase makes sure that the climate catches up with all the carbon already emitted. Solomon et al. (2008) tested what would happen if CO 2 emissions immediately ceased after concentrations peaked at various values, starting at 450 ppm. They concluded that CO 2 levels diminish so slowly that they remained substantially above pre-industrials levels 1,000 years into the future. Global temperatures also stayed up, and declined only from their peak by the year 3000. This means that once carbon dioxide is emitted into the air, it affects the climate for thousands of years (Clark, 2012). The slow recovery has several reasons. First of all, there are geological processes that remove carbon dioxide from the atmosphere, performing as a natural sink (Solomon et al., 2008). Between 65 – 80 % of CO 2 released into the air dissolves into the ocean over a period of 20 up to 200 years. The rest is removed by slower processes that take up to several hundreds of thousands of years, including chemical weathering and rock formation. (Clark et al., 2012) So roughly 20% of the emitted gas will stay in the air for at least a millennium which leads to a warmer planet even after emissions are cut off (Solomon et al., 2008). The second reason why there is a slow recovery of atmospheric CO 2 is because of the inertia of the oceans. As the large mass of ocean on the globe is delaying the rate of climate warming today because most of it is lagging behind the increase in surface temperatures. Once emissions have stopped, this will delay the earth’s cooling (Solomon et al., 2008).
In 2009, the Copenhagen Accord was signed by the world leaders, agreeing to limit the increase in global average surface temperature to less than 2 degrees Celsius above the pre-industrial level (Sanford et al., 2014). This illustrates the most ambitious mitigation pathway to let CO 2 levels not exceed the 240 ppm mark (Anderson and Bows, 2010; Monastersky, 2009). However Hansen et al. (2008) offered a number of reasons for arguing that even the level 450 ppm is too high to avoid major impact of climate change, such as crossing the threshold of losing Antarctica’s ice. These CO 2 levels range between 350 to 500 ppm, were it is best to keep at the bottom of the range. (Monastersky, 2009). This implies a temperature rise of maximum of 1. degrees Celsius, which is consistent with the IPCC RCP 2.6 scenario (Peters et al., 2012). However, as illustrated in Appendix G, this output of the RCP2.6 scenario is already unfeasible as the world is not abating CO 2 emissions that ambitiously (Mora et al., 2013).
So, as also mentioned before, substantial climate change is already inevitable, since mitigation will have only minor effect on stocks of GHG in the coming decennia’s (Stern, 2006). In the context that humankind already is challenged today to provide, and for future generations to achieve a more sustainable and equitable standard of living (IPCC, 2010), adaptation has become essential, especially in the countries most affected.
4.2.1 Needed amount of adaptation with no mitigation
Although the impacts of temperature rise are uncertain, and therefore adaptation costs are also uncertain to calculate, more is known every day about the geological consequences. For example, according to Solomon et al. (2008), sea level is expected to rise upon a range of 0.2-0. meter per ◦C increase. And although given particular years would show some exceptions, the long- term irreversible warming and main rainfall changes are suggested to have important consequences for many regions (Solomon et al., 2008). Decreases in dry-season precipitation in northern Africa, southern Europe, and western Australia are expected to be near 20% for 2 °C warming (Solomon et al., 2008).
As some damage costs cannot be prevented by adaptation because sometimes this cannot be done at reasonable costs, or is simply not possible, climate costs exist of costs of mitigation, cost of adaptation and costs of damages (EEA, 2007). Ciscar et al. (2010) estimates that if the climate change of the 2080s were to occur today, the annual loss in household welfare in the EU resulting from the four market impacts agriculture, river floods, coastal areas, and tourism, would range between 0.2-1%. If the welfare loss is assumed to be constant over time, climate change may halve the EU’s annual welfare growth (Ciscar et al., 2010).
However, most costs can be avoided by adaptation. These costs to minimize damage due to climate change are estimated on $4 to $100 billion a year over the next 20 years (EEA, 2007). Also estimations of costs and benefits are made with the AD-DICE and AD-WITCH models with the optimal amount of adaptation in a no mitigation scenario. Although, investing in adaptation is not necessarily immediately beneficial, it is a vital approach in order to minimize damage costs (Agrawala et al., 2010). The costs are estimated at respectively 0.28 and 0.19% of world GDP, and the benefits between 0.28% with the AD-DICE model and respectively 0.38% with the AD-WITCH model. Thus, this results a net benefit between 0.2 to 0.23% of world GDP (Appendix H). (Agrawala et al., 2010)
