The role of money and the financial sector in energy-economy models used for assessing climate and energy policy

This article outlines a critical gap in the assessment methodology used to estimate the macroeconomic costs and benefits of climate and energy policy, which could lead to misleading information being used for policy-making. We show that the Computable General Equilibrium (CGE) models that are typically used for assessing climate policy use assumptions about the financial system that sit at odds with the observed reality. These assumptions lead to ‘crowding out’ of capital and, because of the way the models are constructed, negative economic impacts (in terms of gross domestic product (GDP) and welfare) from climate policy in virtually all cases.

In contrast, macro-econometric models, which follow non-equilibrium economic theory and adopt a more empirical approach, apply a treatment of the financial system that is more consistent with reality. Although these models also have major limitations, they show that green investment need not crowd out investment in other parts of the economy – and may therefore offer an economic stimulus. Our conclusion is that improvements in both modelling approaches should be sought with some urgency – both to provide a better assessment of potential climate and energy policy and to improve understanding of the dynamics of the global financial system more generally.

POLICY RELEVANCE

This article discusses the treatment of the financial system in the macroeconomic models that are used in assessments of climate and energy policy. It shows major limitations in approach that could result in misleading information being provided to policy-makers.     

Adaptation to climate change in Bangladesh

Climate change is expected to disproportionately affect agriculture in Bangladesh; however, there is limited information on smallholder farmers’ overall vulnerability and adaptation needs. This article estimates the impact of climatic shocks on the household agricultural income and, subsequently, on farmers’ adaptation strategies. Relying on data from a survey conducted in several communities in Bangladesh in 2011 and based on an IV probit approach, the results show that a 1 percentage point (pp) climate-induced decline in agricultural income pushes Bangladeshi households to adapt by almost 3 pp. Moreover, Bangladeshi farmers undertake a variety of adaptation options. However, several barriers to adaptation were identified, noticeably access to electricity and wealth. In this respect, policies can be implemented in order to assist the Bangladeshi farming community to adapt to climate change.

Policy relevance

This study contributes to the literature of adaptation to climate change by providing evidence of existing risk-coping strategies and by showing how a household’s ability to adapt to weather-related risk can be limited. This study helps to inform the design of policy in the context of increasing climatic stress on the smallholder farmers in Bangladesh.     

Benefit cost analysis,resilience and climate change

Applying a resilience theory framework, land transport funding in New Zealand is used to show how benefit cost analysis can reinforce a preference for maintaining existing economic and social systems when, instead, consideration of more socially disruptive options may be required. In this context, resilience is seen as the ability to maintain transport systems rather than the ability to reduce the probability of climate change. The latter role of resilience attempts to identify thresholds and regime shifts, and so critiques decision-making processes, while the former privileges social stability, thereby reducing the range of potentially useful emission mitigation options to be considered.

Policy relevance

Transitioning to a lower-carbon future requires policy formulation that challenges business-as-usual assumptions. Benefit cost analysis can be applied in ways that create barriers to such transitioning. The New Zealand case study identifies the conditions under which this can be the case. That benefit cost analysis could undermine the potential of resilience theory and application to identify low-carbon emission pathways is of concern to policy makers globally.     

Convergence of per capita carbon dioxide emissions: implications and meta-analysis

There is a rich empirical literature testing whether per capita carbon dioxide emissions tend to converge over time and across countries. This article provides a meta-analysis of the results from this research, and discusses how carbon emissions convergence may be understood in, for instance, the presence of international knowledge spillovers and policy convergence. The results display evidence of either divergence or persistent gaps at the global level, but convergence of per capita carbon dioxide emissions between richer industrialized countries. However, the results appear sensitive to the choice of data sample and choice of convergence concept, e.g. stochastic convergence versus β-convergence. Moreover, peer-reviewed studies have a higher likelihood of reporting convergence in carbon dioxide emissions compared to non-refereed work.

POLICY RELEVANCE

The empirical basis for an egalitarian rule of equal emissions per capita in the design of global climate agreements is not solid; this supports the need to move beyond single allocation rules, and increase knowledge about the impacts of combined scenarios. However, even in the context of the 2015 Paris Agreement with its emphasis on voluntary contributions and ‘national circumstances’, different equity-based principles could serve as useful points of reference for how the remaining carbon budget should be allocated.     

The tools of climate adaptation policy: analysing instruments and instrument selection

Governments have a key role to play in the process of climate adaptation, through the development and implementation of public policy. Governments have access to a diverse array of instruments that can be employed to adapt their operations and influence the behaviour of individuals, organizations, and other governments. However, the choice of policy instrument is political, because it affects the distribution of benefits and costs, and entrenches institutional procedures and resources that are difficult to redeploy. This article identifies four key governing resources that governments employ in the service of adaptation and analyses these resources using criteria drawn from the policy studies literature. For each category, specific policy instruments are described, and examples are provided to illustrate how they have been used in particular jurisdictions. The article also discusses instrument selection, focusing on trade-offs among the instrument attributes, processes for setting the stage for instrument choice, jurisdictional constraints on instrument selection, and ways to avoid negative vertical and horizontal policy interplay.

Policy relevance

Adaptation is a nascent field of public policy, and courses of action to reduce vulnerability and build adaptive capacity are in their infancy. This article contributes to policy development and analysis by identifying the range of policy instruments available to governments and analysing concrete ways in which they are employed to implement adaptation policy objectives. Taking stock of these adaptation tools and comparing their behavioural assumptions and attributes helps to illuminate potential policy options, and to evaluate their technical viability, political acceptability, and economic feasibility. Providing examples of how these instruments have been implemented successfully in other jurisdictions offers ideas and lessons for public officials.     

Improving technology transfer through national systems of innovation: climate relevant innovation-system builders (CRIBs)

The Technology Executive Committee (TEC) of the United Nations Framework Convention on Climate Change (UNFCCC) recently convened a workshop seeking to understand how strengthening national systems of innovation (NSIs) might help to foster the transfer of climate technologies to developing countries. This article reviews insights from the literatures on Innovation Studies and Socio-Technical Transitions to demonstrate why this focus on fostering innovation systems has potential to be more transformative as an international policy mechanism for climate technology transfer than anything the UNFCCC has considered to date. Based on insights from empirical research, the article also articulates how the existing architecture of the UNFCCC Technology Mechanism could be usefully extended by supporting the establishment of CRIBs (climate relevant innovation-system builders) in developing countries – key institutions focused on nurturing the climate-relevant innovation systems and building technological capabilities that form the bedrock of transformative, climate-compatible technological change and development.

Policy relevance

This article makes a direct contribution to current work by the TEC of the UNFCCC on enhancing enabling environments for and addressing barriers to technology development and transfer (specifically, it will contribute to Activity 4.3 of the TEC's 2014–15 rolling workplan ‘Further work on enablers and barriers, taking into account the outcomes of the workshop on NSIs’). The article articulates both the conceptual basis that justifies a focus on NSIs in relation to climate technology transfer and makes concrete recommendations as to how this can be implemented under the Convention as a Party-driven extension to the existing architecture of the Technology Mechanism.     

Linkage of greenhouse gas emissions trading systems: learning from experience

The last ten years have seen the growth of linkages between many of the world's cap-and-trade systems for GHGs, both directly between systems, and indirectly via connections to credit systems such as the Clean Development Mechanism. If nations have tried to act in their own self-interest, this proliferation of linkages implies that for many nations, the expected benefits of linkage outweighed expected costs. In this article, we draw on the past decade of experience with carbon markets to examine why systems have demonstrated this revealed preference for linking. Linkage is a multi-faceted policy decision that can be used by political jurisdictions to achieve a variety of objectives, and we find qualitative evidence that many economic, political, and strategic factors – ranging from geographic proximity to integrity of emissions reductions – influence the decision to link. We also identify some potentially important effects of linkage, such as loss of control over domestic carbon policies, which do not appear to have deterred real-world decisions to link.

Policy relevance

These findings have implications for the future role that decentralized linkages may play in international climate policy architecture. The Kyoto Protocol has entered what is probably its final commitment period, covering only a small fraction of global GHG emissions. Under the Durban Platform for Enhanced Action, negotiators may now gravitate toward a hybrid system, combining top-down elements for establishing targets with bottom-up elements of pledge-and-review tied to national policies and actions. The incentives for linking these national policies are likely to continue to produce direct connections among regional, national, and sub-national cap-and-trade systems. The growing network of decentralized, direct linkages among these systems may turn out to be a key part of a future hybrid climate policy architecture.     

Characteristics of forest carbon credit transactions in the voluntary carbon market

The voluntary carbon market allows participants to go beyond regulatory carbon offsetting. Recent developments have improved the transparency and credibility of voluntary carbon trading, and forest carbon credit transactions constitute more than half of trade volume. Its workings, however, have not been sufficiently explored in the literature. This study analyses the characteristics of forest carbon credit transactions in the voluntary carbon market using frequency analysis and logistic regression analysis. The results reveal that the co-benefits of forest carbon projects are an important factor influencing carbon credit transactions. From the higher transaction ratio of credits from CCB Standards-labelled projects and projects using co-benefit-oriented standards, it can be inferred that credits with potential for co-benefits (e.g. fostered corporate social responsibility, social cohesion of local communities and voluntary leadership, and positive environmental impacts) are preferred to those focusing exclusively on emission reduction in the voluntary carbon market. The findings of this study suggest that developing co-benefits is important for strengthening the market competitiveness of forest carbon credits in the voluntary carbon market. Additionally, unlike the compliance carbon market, in the voluntary carbon market stringent carbon standards do not always guarantee credit transaction performance.

POLICY RELEVANCE

After UNFCCC COP-21, the global society agreed to acknowledge various forms of international carbon crediting mechanisms, and noted the significance of greenhouse gas emissions reduction for sustainable development and environmental integrity through the Paris Agreement. Moreover, the agreement encouraged both REDD+ activities in developing countries and supports from developed countries. Additionally, co-benefits of forest carbon projects are important for credit transaction in the global voluntary carbon market. Under the new climate regime, co-benefits of forest carbon projects are expected to gain attention in the carbon market. To promote the social, economic, and environmental co-benefits of forest carbon projects, the introduction of an objective co-benefit assessment and certification system should be reviewed at the national level.     

Assessing the EU ETS with a bottom-up,multi-sector model

The European Emissions Trading System (EU ETS) is the central pillar of the EU response against climate change. This trading mechanism is considered, from the theoretical point of view, as the most cost-effective method to reduce GHG. However, previous studies show that the agents who participate in these markets may behave in a way that may lead to inefficient CO₂ prices, creating doubts about the static and dynamic efficiency of the system. This article analyses these possible anomalies by first trying to model the ETS in a more realistic way, addressing some of the limitations of previous models, and second, by comparing the results with real market transactions. For this, a bottom-up, multi-sector model has been built, which represents the EU ETS in an integrated, cross-sectoral way, paying particular attention to the interactions among the most emissions intensive industries. The results show the benefits of this modelling approach and how it better reflects real market conditions. Some preliminary conclusions regarding the behaviour of the agents in the ETS market are also presented.

POLICY RELEVANCE

Low allowance prices in the EU ETS have put into question the dynamic efficiency of the EU ETS system, prompting various ideas for structural reform. However, determining the right reform also requires estimating correctly how agents will respond to it. This article proposes a tool to realistically simulate the EU ETS under the assumption of rational agents, and compare it to real market outcomes, in order to understand better the behaviour of agents in this carbon market, and therefore how to design better policies.     

Assessing the ambition of post-2020 climate targets: a comprehensive framework

One of the most fundamental questions surrounding the new Paris Agreement is whether countries’ proposals to reduce GHG emissions after 2020 are equally ambitious, considering differences in circumstances between countries. We review a variety of approaches to assess the ambition of the GHG emission reduction proposals by countries. The approaches are applied illustratively to the mitigation part of the post-2020 climate proposals (nationally determined contributions, or NDCs) by China, the EU, and the US. The analysis reveals several clear trends, even though the results differ per individual assessment approach. We recommend that such a comprehensive ambition assessment framework, employing a large variety of approaches, is used in the future to capture a wide spectrum of perspectives on ambition.

POLICY RELEVANCE

Assessing the ambition of the national climate proposals is particularly important as the Paris Agreement asks for regular reviews of national contributions, keeping in mind that countries raise their ambition over time. Such an assessment will be an important part of the regular global stocktake that will take place every five years, starting with a ‘light’ version in 2018. However, comprehensive methods to assess the proposals are lacking. This article provides such a comprehensive assessment framework.     

Could Cohesion Policy push EU climate efforts?

The main purpose of this article is to evaluate the extent to which the Cohesion Policy of the EU contributes to its climate change mitigation effort. While climate change mitigation and the EU Cohesion Policy have been both thoroughly studied theoretically, the novelty of the present article lies in an analysis of their mutual relationship. Also, a unique feature of this research is an analysis of the contribution of the Cohesion Policy to climate change mitigation over a period of 20 years, including a comparison of the three last programming periods (2000–2006, 2007–2013 and 2014–2020). The results of this research suggest that, while the beginning of the new millennium saw the Cohesion Policy neglecting the issue of climate change mitigation, the current programming period (2014–2020) placed it among its key priorities. This conclusion is supported by a comprehensive set of data on five selected indicators. This article also displays the results against the perspective of the overall climate change mitigation objectives of the EU.

POLICY RELEVANCE

The present article shows how a policy, which used to be considered rather distant from climate change, progressively adopted climate change mitigation as one of its principal objectives. As such, it provides a practical guidance on the integration of climate change mitigation in other policy areas, which may be applied not only in a supranational organisation but also on a national, regional or local level.     

The Korean emissions trading scheme: business perspectives on the early years of operations

Korea’s domestic emissions trading scheme commenced in January 2015. It targeted mainly industrial and power sectors, and compelled companies to transform how they manage energy efficiency and mitigate GHGs. This study sets out to explore how Korean companies evaluated their allocation position and engaged in emissions trading in the first compliance period, and to identify their views on trading barriers and policy expectations at the start of emissions trading. Questionnaire surveys and on-site interviews targeting Korean companies under the Korean emissions trading scheme were conducted at the start of operations (February to March 2015) and after the first compliance year (May 2016), respectively. Actual operation results are observed and compared with the survey findings. This study extrapolates implications for policy and presents suggestions for the government and the target companies in terms of how to improve the current emissions trading scheme in order to further stimulate emissions trading.

POLICY RELEVANCE

This study attempts to bridge the gap between companies and government policy in operating the domestic emission trading scheme in Korea. Empirical results, based on analysis of company-level data, reveal how businesses perceive K-ETS and how this relates to the operating results, which saw only limited trading of surplus emissions taking place in the early phase. Key barriers to active trading identified in the study include supply–demand imbalance, policy uncertainty and lack of preparedness of companies over carbon pricing. These barriers could be addressed by improved transparency of allowance allocation methods, possibly restricting carry-over of surplus allowances, ending policy uncertainty and providing more information to companies that can support companies’ policy understanding of the carbon pricing based on the market mechanism. Targeted companies should proactively participate in emissions trading in the early phase, in order to learn from it and prepare for the future introduction of auctioning.     

Power,coalitions and institutional change in South African climate policy

This paper examines power relations, coalitions and conflicts that drive and hinder institutional change in South African climate policy. The analysis finds that the most contested climate policies are those that create distributional conflicts where powerful, non-poor actors will potentially experience real losses to their fossil fuel-based operations. This finding opposes the assumption of competing objectives between emissions and poverty reduction. Yet, actors use discourse that relates to potentially competing objectives between emissions reductions, jobs, poverty reduction and economic welfare.

The analysis relates to the broader questions on how to address public policy problems that affect the two objectives of mitigating climate change and simultaneously boosting socio-economic development. South Africa is a middle-income country that represents the challenge of accommodating simultaneous efforts for emissions and poverty reduction.

Institutional change has been constrained especially in the process towards establishing climate budgets and a carbon tax. The opposing coalitions have succeeded in delaying the implementation of these processes, as a result of unequal power relations. Institutional change in South African climate policy can be predominantly characterized as layering with elements of policy innovation. New policies build on existing regulations in all three cases of climate policy examined: the climate change response white paper, the carbon tax and the renewable energy programme. Unbalanced power relations between coalitions of support in government and civil society and opposition mainly from the affected industry result in very fragile institutional change.

Key policy insights

• The South African government has managed to drive institutional change in climate policy significantly over the past 7 years.

• Powerful coalitions of coal-related industries and their lobbies have constrained institutional change and managed to delay the implementation of carbon pricing measures.

• A successfully managed renewable energy programme has started to transform a coal- and nuclear-powered electricity sector towards integrating sustainable energy technologies. The programme is vulnerable to intergovernmental opposition and requires management at the highest political levels.

• Potential conflict with poverty reduction measures is not a major concern that actively hinders institutional change towards climate objectives. Predominantly non-poor actors frequently use poverty-related discourse to elevate their interests to issues of public concern.

     

Compliance of the Parties to the Kyoto Protocol in the first commitment period

This article provides an ex post analysis of the compliance of the Parties to the Kyoto Protocol during the first commitment period (2008–2012) based on the final data for national GHG emissions and exchanges in carbon units that became available at the end of 2015. On the domestic level, among the 36 countries that fully participated in the Kyoto Protocol, only nine countries emitted higher levels of GHGs than committed and therefore had to resort to flexibility mechanisms. On the international level – i.e. after the use of flexibility mechanisms – all Annex B Parties are in compliance. Countries implemented different compliance strategies: purchasing carbon units abroad, stimulating the domestic use of carbon credits by the private sector and incentivizing domestic emission reductions through climate policies.

Overall, the countries party to the Protocol surpassed their aggregate commitment by an average 2.4 GtCO₂e yr^–1. Of the possible explanations for this overachievement, ‘hot-air’ was estimated at 2.2 GtCO₂e yr^–1, while accounting rules for land use, land-use change and forestry (LULUCF) further removed 0.4 GtCO₂e yr^–1 from the net result excluding LULUCF. The hypothetical participation of the US and Canada would have reduced this overachievement by a net 1 GtCO₂e yr^–1. None of these factors – some of which may be deemed illegitimate – would therefore on its own have led to global non-compliance, even without use of the 0.3 GtCO₂e of annual emissions reductions generated by the Clean Development Mechanism. The impact of domestic policies and ‘carbon leakage’ – neither of which is quantitatively assessed here – should not be neglected either.

Policy relevance

Given the ongoing evolution of the international climate regime and the adoption of the Paris Agreement in December 2015, we believe that there is a need to evaluate the results of the first commitment period of the Kyoto Protocol. To our knowledge there has been no overarching quantitative ex post assessment of the Kyoto Protocol based on the final emissions data for 2008–2012, which became available in late 2015. This article attempts to fill this gap, focusing on the domestic and international compliance of the Parties to the Kyoto Protocol in the first commitment period.     

Climate policy strength compared: China,the US,the EU,India, Russia,and Japan

The few systematic international comparisons of climate policy strength made so far have serious weaknesses, particularly those that assign arbitrary weightings to different policy instrument types in order to calculate an aggregate score for policy strength. This article avoids these problems by ranking the six biggest emitters by far – China, the US, the EU, India, Russia, and Japan – on a set of six key policy instruments that are individually potent and together representative of climate policy as a whole: carbon taxes, emissions trading, feed-in tariffs, renewable energy quotas, fossil fuel power plant bans, and vehicle emissions standards. The results cast strong doubt on any idea that there is a clear hierarchy on climate policy with Europe at the top: the EU does lead on a number of policies but so does Japan. China, the US, and India each lead on one area. Russia is inactive on all fronts. At the same time climate policy everywhere remains weak compared to what it could be.

Policy relevance

This study enables climate policy strength, defined as the extent to which the statutory provisions of climate policies are likely to restrict GHG emissions if implemented as intended, to be assessed and compared more realistically across space and time. As such its availability for the six biggest emitters, which together account for over 70% of global CO₂ emissions, should facilitate international negotiations (1) by giving participants a better idea of where major emitters stand relative to each other as far as climate policy stringency is concerned, and (2) by identifying areas of weakness that need action.     

Could fiscal policies induce green innovation in developing countries? The case of Brazilian manufacturing sectors

Brazil is the first major developing country to pledge for absolute reductions in greenhouse gas emissions. This article explores the extent to which fiscal policies could contribute to this reduction and to greening the Brazilian economy. It was found that the use of green fiscal policies is at an early stage in Brazil, but a growing number of measures have been adopted in recent years led by subnational-level policies. An econometric analysis of 24 Brazilian manufacturing sectors for the years 2001–2008 shows that some fiscal instruments, such as low-cost (subsidized) finance for innovation and fiscal incentives for sustainable practices, have been effective in inducing green innovation. However, less than 14% of more than 100 thousand companies included in the study have adopted greener technologies. Even though Brazilian green fiscal policies have been rather uncoordinated and ad hoc, their significant impact on the uptake of green technologies indicates these can play an important role in a transition to a green economy.

POLICY RELEVANCE

Faced with the challenge of reducing its greenhouse gas emissions in absolute terms, Brazil now needs to put in place policies to help deliver the country’s pledge. This article analyses which fiscal policies should be adopted and how these policies could form part of a low carbon policy framework in the country. Among our policy-relevant findings is that subnational green fiscal policies are relatively less complex to introduce and encourage uptake of green technologies. Thus, they could be an entry point to a wider green fiscal policy strategy. We also found that fiscal incentives for green innovation projects can present more than proportional impact on the uptake of green technologies owing to positive feedbacks, increasing returns to scale and spill-overs. These are attractive features of green innovations to developing countries in addition to environmental benefits, as they favour the accumulation of indigenous technological capabilities that are critical for long-term technological and economic development. These lessons learned from green fiscal policies in Brazil are applicable to other developing countries.     

Effective and geographically balanced? An output-based assessment of non-state climate actions

At COP21 in Paris, governments reiterated the importance of ‘non-Party’ contributions, placing big bets that the efforts of cities, regions, investors, companies, and other social groups will help keep average global warming limited to well under 2°C. However, there is little systematic knowledge concerning the performance of non-state and subnational efforts. We established a database of 52 climate actions launched at the 2014 UN Climate Summit in New York to assess output performance – that is, the production of relevant outputs – to understand whether they are likely to deliver social and environmental impacts. Moreover, we assess to which extent climate actions are implemented across developed and developing countries. We find that climate actions are starting to deliver, and output performance after one year is higher than one might expect from previous experiences with similar actions. However, differences exist between action areas: resilience actions have yet to produce specific outputs, whereas energy and industry actions perform above average. Furthermore, imbalances between developing and developed countries persist. While many actions target low-income and lower-middle-income economies, the implementation gap in these countries remains greater. More efforts are necessary to mobilize and implement actions that benefit the world’s most vulnerable people.

Policy relevance

Climate actions by non-state and subnational actors are an important complement to the multilateral climate regime and the associated contributions made by national governments. Although such actions hold much potential, we still know very little about how they could deliver in practice. This article addresses this knowledge gap, by showing how 52 climate actions announced at the UN Climate Summit in 2014 have performed thus far. Based on our analysis, we argue that the post-Paris action agenda for non-state and subnational climate action should (1) find more effective ways to incentivize private sector actors to engage in transnational climate governance through actions that seek to reduce greenhouse gas emissions and promote climate resilience in a tangible manner; (2) identify factors underlying effectiveness, to take appropriate measures to support underperforming climate actions; and (3) address the large implementation gap of climate actions in developing countries.     

Challenges in developing effective policy for soil carbon sequestration: perspectives on additionality,leakage, and permanence

If carbon sequestration is to be a cost-effective substitute for reducing emissions then it must occur under a framework that ensures that the sequestration is additional to what would otherwise have occurred, the carbon is stored permanently, and any leakage is properly accounted for. We discuss significant challenges in meeting these requirements, including some not previously recognized. Although we focus on sequestration in soil, many of the issues covered are applicable to all types of sequestration. The common-practice method for determining additionality achieves its intention of reducing transaction costs in the short term but not in the medium to long term. Its design results in the least costly, additional abatement-measures being excluded from policy support and fails to address how, in the case of sequestration, revisions to the additionality of sequestering practices should apply not just to the future, but in theory, also retrospectively. Permanence is sometimes approximated as 100 years of sequestration. Re-release of sequestered carbon after this will not only reverse the sequestration, but may raise atmospheric carbon to higher levels than they would have been if the sequestration had never occurred. Leakage associated with sequestration practices can accumulate over time to exceed the total level of sequestration; nonetheless, adoption of such practices can be attractive to landholders, even when they are required to pay for this leakage at contemporary prices.

Policy relevance

Globally, much has been written and claimed about the ability to offset emissions with sequestration. The Australian Government plans to use sequestration to source much of the abatement required to reach its emissions targets. Designing effective policy for sequestration will be challenging politically, and will involve substantial transaction costs. Compromises in policy design intended to make sequestration attractive and reduce transaction costs can render it highly inefficient as a policy.     

Temperature Extremes from Canadian Regional Climate Model (CRCM) Climate Change Projections

Future climate projections of extreme events can help forewarn society of high-impact events and allow the development of better adaptation strategies. In this study a non-stationary model for Generalized Extreme Value (GEV) distributions is used to analyze the trend in extreme temperatures in the context of a changing climate and compare it with the trend in average temperatures.

The analysis is performed using the climate projections of the Canadian Regional Climate Model (CRCM), under an IPCC SRES A2 greenhouse gas emissions scenario, over North America. Annual extremes in daily minimum and maximum temperatures are analyzed. Significant positive trends for the location parameter of the GEV distribution are found, indicating an expected increase in extreme temperature values. The scale parameter of the GEV distribution, on the other hand, reveals a decrease in the variability of temperature extremes in some continental regions. Trends in the annual minimum and maximum temperatures are compared with trends in average winter and summer temperatures, respectively. In some regions, extreme temperatures exhibit a significantly larger increase than the seasonal average temperatures.

The CRCM projections are compared with those of its driving model and framed in the context of the Coupled Model Intercomparison Project, phase 3 (CMIP3) Global Climate Model projections. This enables us to establish the CRCM position within the CMIP3 climate projection uncertainty range. The CRCM is validated against the HadEX2 dataset in order to assess the CRCM representation of temperature extremes in the present climate. The validation is also framed in the context of CMIP3 validation results. The CRCM cold extremes validate better and are closer to the driving model and CMIP3 projections than the hot extremes.