Search

As the world seeks to increase ambition rapidly to limit global warming to 1.5 °C, joint leadership from the world's largest greenhouse gas (GHG) emitters—the United States (U.S.) and China—will be critical to deliver significant emissions reductions from their own countries as well as to catalyze increased international action. After a period of uncertainty in international climate policy, these countries now both have current leadership that supports ambitious climate action. In this context, a feasible, high-impact, and potentially globally catalytic agreement by the U.S. and China to phase out coal would be a major contribution toward this global effort. We undertake a plant-by-plant assessment in the power sector to identify practical pathways for a 2030 coal phaseout in the U.S. and a 2045 coal phaseout in China in line with national priorities and the global 1.5 °C target. We demonstrate that such pathways would also lead to significant emissions reductions, lowering overall global energy-related CO2 emissions by about 9% in 2030 relative to 2020. A catalytic effect from the possibility of other country phaseout commitments is estimated to reduce global emissions by 5.1 Gt CO2 in 2030 and by 10.1 Gt CO2 in 2045. Subnational coal retirement pathways show heavier impacts for certain coal-intensive regions in both countries. Due to substantial variations of the existing coal fleets, the 1.5 °C-compatible pathways will result in an average retirement age of 47 years for the U.S. coal plants but only 22 years for Chinese coal plants.

Under the Paris Agreement, India has pledged that 40 percent of its electricity generating capacity will come from non-fossil-fuel sources by the year 2030; however, this pledge does not limit total coal-fired generating capacity. As of 2019, planned increases in coal-fired capacity totaled 95 gigawatts--46 percent of installed coal-fired capacity in 2018. In this paper, we estimate the carbon dioxide benefits and health co-benefits of not building these plants. We also estimate the mortality impacts of the 2018 stock of coal-fired power plants and use it to calculate the tax on electricity generation from coal that would internalize these damages.

Approaches that root national climate strategies in local actions will be essential for all countries as they develop new nationally determined contributions under the Paris Agreement. The potential impact of climate action from non-national actors in delivering higher global ambition is significant. Sub-national action in the United States provides a test for how such actions can accelerate emissions reductions. We aggregated U.S. state, city, and business commitments within an integrated assessment model to assess how a national climate strategy can be built upon non-state actions. We find that existing commitments alone could reduce emissions 25% below 2005 levels by 2030, and that enhancing actions by these actors could reduce emissions up to 37%. We show how these actions can provide a stepped-up basis for additional federal action to reduce emissions by 49%—consistent with 1.5 °C. Our analysis demonstrates sub-national actions can lead to substantial reductions and support increased national action., Climate action from local actors is vital in achieving nationally determined contributions under the Paris Agreement. Here the authors show that existing commitments from U.S. states, cities and business could reduce emissions 25% below 2005 levels by 2030, with expanded subnational action reducing emissions by 37% and federal action by up to 49%.

Wind energy can contribute to national climate, energy and economic goals by expanding clean energy and supporting economies through new manufacturing industries. However, the mechanisms for achieving these interlinked goals are not well understood. Here we analyse the wind energy manufacturing global value chain, using a dataset on 389 component supplier firms (2006–2016) that work with 13 original equipment manufacturers. We assess how technology complexity, that is, the knowledge intensity and difficulty of manufacturing components, shapes the location of suppliers. For countries without existing wind industries, we find evidence of the emergence of suppliers for only low-complexity components (for example, towers and generators). For countries with existing wind industries, we find that suppliers’ evolution, that is, changes in their international supply relationships, is less likely for high-complexity components (for example, blades and gearboxes). Our findings show the importance of understanding technologies along with firms and countries within global value chains for achieving policy goals. Clean energy technology manufacturing relies on global value chains, yet the patterns of these chains are poorly understood, obscuring the underlying drivers. Surana et al. analyse data on wind power global value chains to assess how technology complexity shapes the location of suppliers and evolves over time.

The Paris Agreement seeks to combine international efforts to keep global temperature increase to well‐below 2°C. Whilst current ambitions in many signatories are insufficient to achieve this goal, optimism prevailed in the second half of 2020. Not only did several major emitters announce net‐zero mitigation targets around mid‐century, but the new Biden Administration immediately announced the U.S.’s re‐entry into Paris and a net‐zero goal for 2050. U.S. federal re‐engagement in climate action could have a considerable impact on its national greenhouse gas emissions pathway, by significantly augmenting existing state‐level actions. Combined with U.S. re‐entry in the Paris Agreement, this could also serve as a stimulus to enhance ambitions in other countries. A critical question then becomes what such U.S. re‐engagement, through both national and international channels, would have on the global picture. This commentary explores precisely this question, by using an integrated assessment model to assess U.S. national emissions, global emissions, and end‐of‐century temperatures in five scenarios combining different climate ambition levels in both the U.S. and the rest of the world. Our analyses finds that ambitious climate leadership by the Biden Administration on top of enhanced climate commitments by other the major economies could potentially be the trigger for the world to fulfill the temperature goal of the Paris Agreement.

Non-state and subnational climate actors have become central to global climate change governance. Quantitatively assessing climate mitigation undertaken by these entities is critical to understand the credibility of this trend. In this Perspective, we make recommendations regarding five main areas of research and methodological development related to evaluating non-state and subnational climate actions: defining clear boundaries and terminology; use of common methodologies to aggregate and assess non-state and subnational contributions; systematically dealing with issues of overlap; estimating the likelihood of implementation; and addressing data gaps.

A global phaseout of unabated coal use is critical to meeting the Paris climate goals. This transition can potentially lead to large amounts of stranded assets, especially in regions with newer and growing coal fleets. Here we combine plant-level data with a global integrated assessment model to quantify changes in stranded asset risks across locations and over time. With new plant proposals, cancellations, and retirements over the past five years, global committed emissions in 2030 from existing and planned coal plants declined by 3.3 GtCO2 (25%). While these emissions are now roughly in line with near-term (2030) Nationally Determined Contributions (NDCs) to the Paris Agreement, they remain far off track from longer-term climate goals. Building all proposed coal plants in the pipeline leads to a 24% (503 GW) increase in capacity and a 55% ($520 billion) increase in stranded assets under 1.5°C. Stranded asset risks fall disproportionately on emerging Asian economies with newer and growing coal fleets.

The Paris Agreement of 2015 uses Nationally Determined Contributions (NDCs) to achieve its goal to limit climate change to well below 2°C. Article 6 allows countries to cooperatively implement NDCs provided they do not double-count mitigation. We estimate that economic efficiency gains from cooperative implementation of existing NDC goals using Article 6 could reduce the cost of achieving NDC goals in 2030 to all parties by [Formula: see text]$[Formula: see text], which if reinvested in additional emissions mitigation could add 9 billion tons CO2/year mitigation, beyond the 8 billion tons CO2/year currently pledged in 2030. We estimate that more than half of the 2030 gains could come from nature-based measures, but long-term potential for nature-based measures is more limited. How much or even if this economic potential can be realized is uncertain and will depend on both the rules and their implementation.

More than half of current coal power capacity is in China. A key strategy for meeting China’s 2060 carbon neutrality goal and the global 1.5 °C climate goal is to rapidly shift away from unabated coal use. Here we detail how to structure a high-ambition coal phaseout in China while balancing multiple national needs. We evaluate the 1037 currently operating coal plants based on comprehensive technical, economic and environmental criteria and develop a metric for prioritizing plants for early retirement. We find that 18% of plants consistently score poorly across all three criteria and are thus low-hanging fruits for rapid retirement. We develop plant-by-plant phaseout strategies for each province by combining our retirement algorithm with an integrated assessment model. With rapid retirement of the low-hanging fruits, other existing plants can operate with a 20- or 30-year minimum lifetime and gradually reduced utilization to achieve the 1.5 °C or well-below 2 °C climate goals, respectively, with complete phaseout by 2045 and 2055., A key strategy for meeting China’s 2060 carbon neutrality goal and the global 1.5 °C climate goal is to rapidly shift away from unabated coal use. Here, the authors detail how to structure a high-ambition, plant-by-plant coal phaseout in China while balancing multiple national needs.

We examine the health implications of electricity generation from the 2018 stock of coal-fired power plants in India, as well as the health impacts of the expansion in coal-fired generation capacity expected to occur by 2030. We estimate emissions of SO(2), NO(X), and particulate matter 2.5 μm (PM(2.5)) for each plant and use a chemical transport model to estimate the impact of power plant emissions on ambient PM(2.5). Concentration-response functions from the 2019 Global Burden of Disease (GBD) are used to project the impacts of changes in PM(2.5) on mortality. Current plus planned plants will contribute, on average, 13% of ambient PM(2.5) in India. This reflects large absolute contributions to PM(2.5) in central India and parts of the Indo-Gangetic plain (up to 20 μg/m(3)). In the south of India, coal-fired power plants account for 20–25% of ambient PM(2.5). We estimate 112,000 deaths are attributable annually to current plus planned coal-fired power plants. Not building planned plants would avoid at least 844,000 premature deaths over the life of these plants. Imposing a tax on electricity that reflects these local health benefits would incentivize the adoption of renewable energy.

Deep decarbonization paths to the 1.5 °C or 2 °C temperature stabilization futures require a rapid reduction in coal-fired power plants, but many countries are continuing to build new ones. Coal-fired plants are also a major contributor to air pollution related health impacts. Here, we couple an integrated human-earth system model (GCAM) with an air quality model (TM5-FASST) to examine regional health co-benefits from cancelling new coal-fired plants worldwide. Our analysis considers the evolution of pollutants control based on coal plants vintage and regional policies. We find that cancelling all new proposed projects would decrease air pollution related premature mortality between 101,388–213,205 deaths (2–5%) in 2030, and 213,414–373,054 (5–8%) in 2050, globally, but heavily concentrated in developing Asia. These health co-benefits are comparable in magnitude to the values obtained by implementing the Nationally Determined Contributions (NDCs). Furthermore, we estimate that strengthening the climate target from 2 °C to 1.5 °C would avoid 326,351 additional mortalities in 2030, of which 251,011 (75%) are attributable to the incremental coal plant shutdown. The authors acknowledge funding support from Bloomberg Philanthropies. This research is also supported by Basque Government through the BERC 2018-2021 and the Spanish Government through María de Maeztu excellence accreditation MDM-2017-0714. Jon Sampedro and Ignacio Cazcarro acknowledge financial support from the Ministry of the Economy and Competitiveness of Spain (RTI2018-099858-A-100 and RTI2018-093352-B-I00). Jon Sampedro acknowledge financial support from the Basque Government (PRE_2017_2_0139). The authors thank Patrick O’Rourke and Brinda Yarlagadda for their support with data processing. The authors declare no competing interests.

Disrupting the configural context, or relative organization and orientation of paired stimuli, between encoding and retrieval negatively impacts memory. Using univariate and multivariate fMRI analyses, we examined the effect of retaining and manipulating the configural context on neural mechanisms supporting associative retrieval. Behavioral results showed participants had significantly higher hit rates for recollecting pairs in a contextually congruent, versus incongruent, configuration. In addition, contextual congruency between memory phases was a critical determinant to characterizing both the magnitude and patterns of neural activation within visual and parietal cortices. Regions within visual cortices also exhibited higher correlations between patterns of activity at encoding and retrieval when configural context was congruent across memory phases than incongruent. Collectively, these findings shed light on how manipulating configural context between encoding and retrieval affects associative recognition, with changes in the configural context leading to reductions in information transfer and increases in task difficulty.

This paper examines the Global Climate Action Agenda (GCAA) and discusses options to improve sub- and non-state involvement in post-2020 climate governance. A framework that stimulates sub- and non-state action is a necessary complement to national governmental action, as the latter falls short of achieving low-carbon and climate-resilient development as envisaged in the Paris Agreement. Applying design principles for an ideal-type orchestration framework, we review literature and gather expert judgements to assess whether the GCAA has been collaborative, comprehensive, evaluative and catalytic. Results show that there has been greater collaboration and coordination among orchestrators, for instance, in the organization of events. However, mobilization efforts remain event-driven and too little effort is invested in understanding the progress of sub- and non-state action. Data collection has improved, although more sophisticated indicators are needed to evaluate climate and sustainable development impacts. Finally, the GCAA has recorded more action, but relatively little by actors in developing countries. As the world seeks to recover from the COVID-19 crisis, a post-2020 GCAA could make a vital contribution to climate action in challenging times by helping governments keep climate and enhance commitments; strengthening capacity for sub- and non-state action; enabling accountability; and helping to realize sustainable development.

This study analyzes the emergence of China’s wind power “miracle” – in which the country’s wind power installation grew from a low base to become world-leading in just 20 years – by exploring the initial motivations of central state-owned enterprises (CSOEs), which account for over 70% of China’s wind power market. Conventional theories frame CSOEs as pillars of state capitalism, singularly promoting the rapid growth of China's wind power installation to fulfill political obligations. This study challenges the prevailing assumption that CSOEs are monolithic political instruments by looking into their internal organization. Based on extensive, in-depth field investigations, this study finds that CSOE wind power investment decisions were not primarily motivated by top-down political imperatives. Instead, wind power business ventures were promoted by marginalized subsidiary companies within CSOEs as pragmatic business opportunities to “demarginalize” themselves and to survive and grow. This occurred despite the fact that CSOE headquarters generally regarded wind power as a non-mainstream energy source with low prospects for profitability. This internal impetus and the entrepreneurship of subsidiaries were responses to external institutional changes, namely market reforms in the power sector and among state-owned enterprises in the early 2000 s. It was the competitive environment fostered by these reforms that incentivized CSOE wind power business ventures. This research provides a new firm-level explanation for China’s wind power development. The policy implications may also be informative for the world’s other emerging renewable markets.

An important component of the Paris Agreement is the assessment of comparability across nationally determined contributions (NDCs). Indeed, game-theory literature on international environmental agreements highlights the need for comparable emission-mitigation efforts by countries to avoid free-riding 1 . At the same time, there are well-recognized links between mitigation and other national priorities, including but not limited to the 17 United Nations Sustainable Development Goals (SDGs)2–6, which raises the question of how such links might influence comparability assessments. Here, using a global integrated assessment model 7 , we demonstrate that geographical distributions of the influence of meeting the domestic mitigation component of the NDCs on a subset of the broader SDGs may not align with distributions of effort across NDCs obtained from conventional emissions-based or cost-based comparability metrics8–11. This implies that comparability assessments would be altered if interactions between mitigation and other SDGs were accounted for. Furthermore, we demonstrate that the extent to which these distributions differ depends on the degree to which mitigation activities directly affect broader SDGs domestically and indirectly affect international goals, and whether these effects are synergistic or antagonistic. Our analysis provides a foundation for assessing how comparability across NDCs could be better understood in the larger context of sustainability. To reduce emissions, countries have committed to nationally determined contributions (NDCs). However, countries are also committed to the UN Sustainable Development Goals (SDGs) and this study looks at the synergies between meeting NDCs and SDGs.

Transboundary pollution issues present significant challenges to local governments. Many places around the world have addressed these issues by initiating a regional approach for environmental management. While such strategies are often asserted to positively influence localities' environmental governance capacity, empirical evidence for these claims is thin. This study explores the association between regional integration plans and the involved localities' environmental management capacity using the valuable but understudied case of China's national-level city clusters. It constructs novel measures to assess 137 Chinese cities' actual performance in air pollution mitigation and applies structural equation modeling tools to analyze whether cities' capacity in environmental enforcement and compliance is different inside and outside of the major urban agglomerations. Results show that enforcement activities are done differently in these two studied groups, and differences in cities' enforcement-compliance capacity better explain the differences in the un-clustered cities' average air quality. Moreover, this study shows that the two studied groups face different capacity-building opportunities in environmental enforcement and compliance. These opportunities mainly exist in areas such as environmental impact assessment of new construction projects, supervisory monitoring of nationally monitored polluters, and spot-check on daily polluters. Our study is the first to empirically evaluate Chinese cities' capacity in environmental enforcement and compliance with reference to both the procedural outcomes and the environmental outcomes. Our results have important managerial implications for local environmental protection bureaus, major industrial polluters, and policy makers who are involved in the design and implementation of China's urban agglomeration development plans.

Afforestation and reforestation have the potential to provide effective climate mitigation through forest carbon sequestration. Strategic reforestation activities, which account for both carbon sequestration potential (CSP) and economic opportunity, can provide attractive options for policymakers who must manage competing social and environmental goals. In particular, forest carbon pricing can incentivize reforestation on private land, but this may require landholders to forego other profits. Here, we utilize an ambitious geospatial approach to quantify economic opportunities for reforestation in the state of Maryland (USA) based on high-resolution remoting sensing, ecosystem modeling, and economic analysis. Our results identify spatially-explicit areas of economic opportunity where the potential revenue from forest carbon outcompetes the expected profit of existing cropland at the hectare scale. Specifically, we find that under a baseline economic scenario of $20 per ton of carbon (5% rental rate) and decadal average crop profitability, a transition to forest on agricultural land would be more profitable than 23.2% of cropland in Maryland under a 20 year land-use commitment. Accounting for variations in carbon and crop pricing, 5.5%–55.4% of cropland would be immediately outcompeted by expected forest carbon revenue, with the potential for an additional 0.5%–10.6% of outcompeted cropland within 20 years. Under the baseline economic scenario, an annual allocation of $5.8 million towards a carbon rental program could protect 6.93 Tg C (3.4% of the state’s total remaining CSP) on reforested croplands. This moderate yearly cost is equal to 9.7% of Maryland’s average annual auction proceeds from participation in the Regional Greenhouse Gas Initiative (between 2014 and 2018), and 19.3% of the average annual subsidy payments for corn, soy, and wheat allocated over the same period. This methodological approach may be useful for state governments, not-for-profit organizations, or regional climate initiatives interested in identifying strategic areas for reforestation.

Examining past examples of rapid, transformational changes in energy technologies could help governments understand the factors associated with such transitions. We used an existing dataset to assess government strategies to connect new energy technologies with national narratives. Analyzing the diffusion stories told by experts, we demonstrate how governments connected the new technologies with their national narratives. The United States government supported the development of nuclear power after World War II with the national narrative that the United States was destined to improve creation, increasing the potential of raw materials exponentially for the nation’s good (“atoms for peace,” electricity “too cheap to meter”). In Brazil, the development of sugar cane ethanol was supported by the government’s invoking the national narrative of suffering leading to knowledge and redemption, coupled with the quest for improved societal well-being (technological development to produce ethanol and employment for farmers). In Sweden, biomass energy was tied to the national narrative of local control, as well as love of nature and tradition (the use of natural products). We found strong evidence that the pairing of technological transformations with national narratives facilitated the successful development and implementation of these major energy technologies in the three cases analyzed here.

A rapid transition away from unabated coal use is essential to fulfilling the Paris climate goals. However, many countries are actively building and operating coal power plants. Here we use plant-level data to specify alternative trajectories for coal technologies in an integrated assessment model. We then quantify cost-effective retirement pathways for global and country-level coal fleets to limit long-term temperature change. We present our results using a decision-relevant metric: the operational lifetime limit. Even if no new plants are built, the lifetimes of existing units are reduced to approximately 35 years in a well-below 2 °C scenario or 20 years in a 1.5 °C scenario. The risk of continued coal expansion, including the near-term growth permitted in some Nationally Determined Contributions (NDCs), is large. The lifetime limits for both 2 °C and 1.5 °C are reduced by 5 years if plants under construction come online and 10 years if all proposed projects are built., The plant-by-plant retirement needs are not well-understood yet to achieve the rapid transition away from coal use. Here the authors found that operational lifetimes of existing units must be reduced to approximately 35 years to keep warming well below 2 °C or 20 years for 1.5 °C, even if no new capacity comes online.

National-level policies to promote deployment of low-carbon technologies have been suggested and used as a means to reduce greenhouse gas emissions in the context of international climate change mitigation. The long-term benefits of such policies in the context of international climate change mitigation depend on their effects on near-term emissions abatement and resultant long-term technological change that will reduce abatement costs of achieving global mitigation goals. There is also an argument that these policies might foster early-mover advantages in international low-carbon technology markets. We first review the factors that could influence such benefits and use a global integrated assessment model to present an illustrative example to understand the potential magnitude of these benefits. We find that reductions in long-term abatement costs might not provide sufficient incentives to justify policies to promote the deployment of low-carbon technologies, in particular, the emerging, higher-risk, and currently expensive alternatives. We also find that early-mover advantages can potentially provide substantial benefits, but only if these advantages are both strong and persistent. Our results suggest a role for international cooperation in low-carbon technology deployment to address the existence of free-riding opportunities in the context of global climate change mitigation.

The Clean Development Mechanism (CDM) has been the major international offset mechanism within the broader world of carbon finance. It was designed with two goals in mind: to lead to significant emission reductions that will help reduce the cost of climate mitigation in countries with commitments as well as contribute to sustainable development in the host countries. However, there has been significant discussion about the degree to which these projects fulfilled their dual mission of emissions reductions and sustainable development, particularly with respect to fostering local community co-benefits as part of broader sustainable development outcomes. In this paper, we review literature on the co-benefits delivered by the CDM at the local or community level, based on a group of 84 peer-reviewed articles and other reports. While perspectives on co-benefits are diverse, most sources argue or acknowledge that even with more recent procedural improvements, the CDM has not consistently delivered significant co-benefits to local communities. It appears likely that the situation has improved somewhat in recent years as CDM procedures have been refined, and there may be more opportunities for enhancing procedures to favor such benefits. There is overall variability in delivering co-benefits depending on the technology type, design features and the country context.

Recent climate change negotiations indicate that near-term policies to address climate change are likely to vary across countries with countries employing a range of different policy options. One option frequently mooted at the national level is to promote, via policy, the deployment of low-carbon technologies. Promoting the deployment of low-carbon technologies can involve a near-term cost, if such technologies are more expensive overall, or require more upfront capital, than emitting alternatives. However, it lowers future costs of emissions abatement by reducing emissions in the near-term and potentially accelerating rates of improvement in targeted low-carbon technologies. We derive a globally cost-effective, near-term international technology investment strategy to achieve a long-term climate goal and show that it employs a diversified international technology investment portfolio across countries. We also explore the degree to which independent national technology deployment policies align with collaboratively determined regimes. We show that conditions exist under which there are substantial gains to international cooperation in the deployment of diverse low-carbon technologies and also circumstances in which domestic outcomes align with the global outcome.

In 2009, India set a voluntary target of reducing the emission intensity of GDP by 20–25% below 2005 levels by 2020, a commitment to be met while ensuring that poverty alleviation and economic growth are not compromised. This paper presents findings from an analysis of expert opinions on India's domestic climate policy, the opportunities and bottlenecks in transitioning to a low-carbon inclusive growth paradigm, with special emphasis on two key energy intensive sectors, transport and power. The findings reveal a consensus among experts that, while India has successfully initiated several programmes for ensuring development of its economy along low-carbon pathways, achieving a desirable level of emission reduction constitutes a challenge. Ensuring that a broader development agenda remains viable while constructively addressing emissions calls for changes in a number of complementary policy factors. Inadequacy of the current institutional structure, inadequate financial resources, inefficient subsidy system...

Assessments of emissions mitigation patterns have largely ignored differences in investment risk across technologies and regions. With a model accounting for such differences in the electricity generation sector, research now finds that mitigation costs are higher than with no risk variation, and highlights the importance of institutional reforms to lower investment risks.

Stabilizing the global climate will require large-scale global deployment of low-carbon technologies. Even in the presence of aggressive climate policies, however, the diffusion of such technologies may be limited by several institutional, behavioral, and social factors. In this paper, we review the literature on the sources of such diffusion constraints, and explore the potential implications of such constraints based on the GCAM integrated assessment model. Our analysis highlights that factors that limit technology deployment may have sizeable impacts on the feasibility and mitigation costs of achieving stringent stabilization targets. And such impacts are greatly amplified with major delays in serious climate policies. The results generally indicate that constraints on the expansions of CCS and renewables are more costly than those on nuclear or bioenergy, and jointly constraining these technologies leaves some scenarios infeasible.

Lovering et al. (2016) present data on the overnight costs of more than half of nuclear reactors built worldwide since the beginning of the nuclear age. The authors claim that this consolidated data set offers more accurate insights than previous country-level assessments. Unfortunately, the authors make analytical choices that mask nuclear power's real construction costs, cherry pick data, and include misleading data on early experimental and demonstration reactors. For those reasons, serious students of such issues should look elsewhere for guidance about understanding the true costs of nuclear power.

Achieving climate policy targets will require large-scale deployment of low-carbon energy technologies, including nuclear power. The small modular reactor (SMR) is viewed as a possible solution to the problems of energy security as well as climate change. In this paper, we use an integrated assessment model (IAM) to investigate the evolution of a global energy portfolio with SMRs under a stringent climate policy. Technology selection in the model is based on costs; we use results from previous expert elicitation studies of SMR costs. We find that the costs of achieving a 2 °C target are lower with SMRs than without. The costs are higher when large reactors do not compete for market share compared to a world in which they can compete freely. When both SMRs and large reactors compete for market share, reduction in mitigation cost is achieved only under advanced assumptions about SMR technology costs and future cost improvements. While the availability of SMRs could lower mitigation costs by a moderate amount, actual realization of these benefits would depend on the rapid up-scaling of SMRs in the near term. Such rapid deployment could be limited by several social, institutional and behavioral obstacles.

It is tempting to attribute variations in support for nuclear power to prominent accidents such as Three Mile Island in the United States or Fukushima in Japan. To illuminate how such attribution can be problematic, the authors discuss the historical context of the Three Mile Island accident in the United States. They point out that the US nuclear industry faced major challenges even before the 1979 accident: Forty percent of all US reactor cancellations between 1960 and 2010, they write, occurred before the accident in Pennsylvania. While safety concerns were undoubtedly a driver of public aversion to new nuclear construction in the United States, the nuclear industry already faced substantial economic and competitiveness obstacles, much like the nuclear industry worldwide before Fukushima.

After substantial global investments into biofuel production from 2005 to 2008, challenges to a sustainable and robust biofuel industry have become more apparent than many proponents have anticipated. Across country and development contexts, conflicts arose as plans to scale up production clashed with local preferences or national policies, and Southern Africa has been no exception. This article analyzes recent difficulties with biofuels projects in Tanzania before the background of the more successful experiences of Brazil and South Africa. We identify areas of incompatibility between local expectations, government policy, and investor incentives. An assessment of different biofuels business models shows that some—such as contract farming—may not be appropriate for Tanzania’s situation and that policies are necessary that can address the needs of both local and regional stakeholders and provide adequate incentives for investors to pursue sustainable biofuels production.

Policies to address climate change by reducing greenhouse gas emissions might be made more effective if we can better understand the pathways by which transformative technologies become significant components of energy systems. Indeed, the central question of mitigation revolves around the scope of policy to influence or accelerate the diffusion of low-carbon technology. While market forces clearly influence technology deployment, understanding the longer-term and large-scale changes in the energy system requires a broader understanding of the relative influence of institutional, behavioral, and social factors. This paper presents the results of an interview-based, comparative case approach to investigating systematically the relative importance of these non-economic factors influencing technological change across technology and country contexts. We identified two low-carbon energy sectors (bioenergy and nuclear power) that underwent significant changes over the past 50 years in the energy portfolio of three countries: Brazil, Sweden, and the United States. We identified nine categories of factors that might contribute to these large technological transformations, and then evaluated, via interviews with sector participants in each country, which factors were viewed as being determinative or highly influential in the trajectory of that technology in their country context. We also draw out policy implications and directions for future research.

Despite a history of problems, nuclear power is being discussed as a potentially useful and appropriate electricity source for both developed and developing countries. For example, expanding nuclear power's share of electricity portfolios could reduce, relative to a fossil-intensive baseline, greenhouse gas emissions that lead to climate change. Moreover, nuclear power has long been advocated as a route to energy security and indeed, for many of the nuclear nations, it could decrease dependence on oil imports under certain technological scenarios, such as an increased use of plug-in hybrid vehicles. The nuclear industry argues that a new generation of reactors, representing a refinement of existing technology, will enable this expansion. Because of these new motivations, some advocates have applied the term ‘nuclear renaissance’ to the possibility of a rapid expansion of nuclear power to satisfy a projected growing global electricity demand, while simultaneously reducing greenhouse gas emissions. This article outlines the primary challenges that this unique energy source presents for such a renaissance. Like other technologies, nuclear is situated in a social and political–economic matrix that influences its evolution. After reviewing the basic aspects of the technology, I discuss the history of the existing nuclear fleet, then address the prospects for advanced and next-generation nuclear technologies. I review the economics of nuclear power as it is currently deployed and the potential changes to these economics under potential future development. In examining future scenarios, I explore the effects of national and international policies on nuclear energy. WIREs Clim Change 2011 2 397–411 DOI: 10.1002/wcc.113 For further resources related to this article, please visit the WIREs website

At their core, societal decisions about climate policy—whether emissions reductions, adaptation to climate changes, or the implementation of geoengineering—hinge on collective judgments about the extent to which adverse effects to human welfare and ecosystem services will result from changes associated with anthropogenic release of greenhouse gases and the costs associated with the emissions reductions or adaptation activities. In this article, we discuss how risk is understood in the context of climate change, which presents particularly confounding, long-term, and pervasive threats to society and ecosystems. We review theoretical approaches to risk as applied to climate change and policy responses to climate change, focusing especially on the perspectives of individuals, governments, and firms with respect to traditional decision analysis frameworks. We also evaluate the peculiar role of uncertainty in climate debates and how it affects decision making; the origins and nature of the various uncertainties; and how uncertainty is represented, framed, and, at times, wielded by scientists, the Intergovernmental Panel on Climate Change (IPCC), the media, politicians, and others. We conclude by assessing the limitations of and appropriate venues for risk analysis in climate decision making.

The perspectives of developing-country firms are missing from the policy literature on carbon markets. This research addresses this gap by analysing participation in the Clean Development Mechanism (CDM) by sugar mills in Brazil. Specifically, the research documents how far the CDM has penetrated into Brazil's sugar sector; how sugar mill owners/managers perceive the benefits, risks and costs of CDM-related investments; and the processes by which Brazilian sugar mills entered the carbon market. The mill-level analysis of CDM participation reveals the market and non-market dynamics that drive patterns of sugar mill investment in carbon abatement. First, access to a trusted source of information was a key driver of initial CDM participation by sugar mills, alongside other market drivers such as revenue, cost and reputation concerns. Firms with pre-existing relationships with carbon industry experts were more willing to assume the risk of carbon market participation and were in a much better position to capt...

This article addresses forestry projects attempting to register with the Clean Development Mechanism (CDM). Advocates argue that forestry projects have significant potential for sequestering carbon, contributing to livelihood improvements, and promoting sustainable development in developing countries—especially African countries with predominately agrarian economies and relatively high GHG emissions from land-use change. Through a comparison of two carbon-forestry projects in central Tanzania, we investigated both the livelihood effects of these projects and the risk and benefit perceptions of project administrators and the government. Both projects have been unable to gain national government approval, and we find evidence of mixed benefits for local communities. Village communities participating in one program consistently identified environmental and social benefits of planting trees locally and judged them as more important than carbon payments. A key variable is ownership, as villagers that have forfeited their land to a plantation have little stake in the program, whereas villagers participating in a community-based program own their trees. Our results suggest that enhancing ties to local ownership can contribute to sustainable development while better enhancing the potential of the carbon market to work for the rural poor in developing countries.

The Clean Development Mechanism (CDM) has successfully demonstrated that market-based mechanisms can achieve some cost effective emissions reductions in developing countries. However the distribution of CDM projects has been extremely uneven across countries and regions, and a few technologies and sectors have dominated the early stages of CDM experience. This has caused some to question whether the CDM has fallen short of its potential in contributing to sustainable development. We review the broad patterns of CDM project approvals and evaluate 10 CDM projects according to their sustainability benefits. The difficulty of defining “sustainable development” and the process of defining criteria by individual non-Annex 1 governments has meant that sustainable development concerns have been marginalized in some countries. Given these observed limitations, we present possible CDM policy futures, focusing on the main proposals for a post-2012 climate regime. Five options for enhancing the sustainable development benefits in the CDM are discussed, including proactive approaches to favour eligibility of emission reduction projects which ensure such co-benefits.

Fructose and glucose (4 g/kg body-weight during 4 hours) were given intravenously to normal subjects and to patients with diabetes without insulin treatment. Liver and muscle glycogen content was determined before and after the infusion. In normal subjects glucose and fructose gave similar increases in muscle glycogen stores, while the liver glycogen increased 4 times more after fructose infusion as compared to glucose. In the diabetics only fructose gave a liver glycogen increase and neither fructose nor glucose affected the muscle glycogen content. The mechanism for the glycogen increase in the liver of diabetics after fructose infusion could be due to allosteric activation of glycogen synthetase D and/or to availability of fructokinase.

Shaping a pathway for global development in light of climate change and oil depletion need not imply radical disruption or widespread social harm.

Two intermittent high-intensity exercise protocols were performed before and after the administration of either creatine or a placebo, and performance characteristics and selected physiological responses were studied. Each exercise protocol consisted of 10 6-s bouts of high-intensity cycling at 2 exercise intensities (130 rev/min [EX130]: ∼820 W and 140 rev/min [EX140)]: ∼ 880 W) so that in EX130 the same amount of exercise was performed before and after the administration period, whereas an exercise intensity in EX140 was chosen to induce fatigue over the 10 exercise bouts. Sixteen healthy male subjects were randomly assigned to the 2 experimental groups. A double-blind design was used in this study. There were no significant changes in the placebo group for any of the measured parameters. Performance towards the end of each exercise bout in EX140 was enhanced following creatine supplementation, as shown by a smaller decline in work output from baseline along the 10 trials. Although more work was performed in EX140, after vs before the administration period, blood lactate accumulation decreased (mean and SEM), from 10.8 (0.5) to 9.1 (0.8) mmol·l−1 and plasma accumulation of hypoxanthine decreased from 21.1 (0.4) to 16.7 (0.8) μmol·l−1, but there was no change in oxygen uptake measured during 3 exercise and recovery periods [3.18 (0–1) vs 3.14 (0.1) l·min−1]. In EX130 blood lactate accumulation decreased, from 7.0 (0.5) to 5.1 (0.5) mmol·l−1, and oxygen uptake was also lower, decreasing from 2.84 (0.1) to 2.78 (0.1) l·min−1. A significant increase in body mass (11 kg: range 0.3 to 2.5 kg) was found in the creatine group. The mechanism responsible for the improved performance with creatine supplementation are postulated to be both a higher initial creatine phosphate content availability and an increased rate of creatine phosphate resynthesis during recovery periods. The lower blood lactate and hypoxanthine accumulation can also be explained by these mechanisms.