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Thursday, October 25, 2012

Emitting and projecting

 

The polarizing impact of science literacy and numeracy on perceived climate change risks

Dan Kahan et al.
Nature Climate Change, October 2012, Pages 732-735

Abstract:
Seeming public apathy over climate change is often attributed to a deficit in comprehension. The public knows too little science, it is claimed, to understand the evidence or avoid being misled. Widespread limits on technical reasoning aggravate the problem by forcing citizens to use unreliable cognitive heuristics to assess risk. We conducted a study to test this account and found no support for it. Members of the public with the highest degrees of science literacy and technical reasoning capacity were not the most concerned about climate change. Rather, they were the ones among whom cultural polarization was greatest. This result suggests that public divisions over climate change stem not from the public's incomprehension of science but from a distinctive conflict of interest: between the personal interest individuals have in forming beliefs in line with those held by others with whom they share close ties and the collective one they all share in making use of the best available science to promote common welfare.

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Late Pleistocene climate change and the global expansion of anatomically modern humans

Anders Eriksson et al.
Proceedings of the National Academy of Sciences, 2 October 2012, Pages 16089-16094

Abstract:
The extent to which past climate change has dictated the pattern and timing of the out-of-Africa expansion by anatomically modern humans is currently unclear [Stewart JR, Stringer CB (2012) Science 335:1317-1321]. In particular, the incompleteness of the fossil record makes it difficult to quantify the effect of climate. Here, we take a different approach to this problem; rather than relying on the appearance of fossils or archaeological evidence to determine arrival times in different parts of the world, we use patterns of genetic variation in modern human populations to determine the plausibility of past demographic parameters. We develop a spatially explicit model of the expansion of anatomically modern humans and use climate reconstructions over the past 120 ky based on the Hadley Centre global climate model HadCM3 to quantify the possible effects of climate on human demography. The combinations of demographic parameters compatible with the current genetic makeup of worldwide populations indicate a clear effect of climate on past population densities. Our estimates of this effect, based on population genetics, capture the observed relationship between current climate and population density in modern hunter-gatherers worldwide, providing supporting evidence for the realism of our approach. Furthermore, although we did not use any archaeological and anthropological data to inform the model, the arrival times in different continents predicted by our model are also broadly consistent with the fossil and archaeological records. Our framework provides the most accurate spatiotemporal reconstruction of human demographic history available at present and will allow for a greater integration of genetic and archaeological evidence.

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The Climate-Change Dilemma: Examining the Association Between Parental Status and Political Party Support

Taciano Milfont et al.
Journal of Applied Social Psychology, October 2012, Pages 2386-2410

Abstract:
Determining when, and for whom, positive attitudes toward climate-change actions translate into actual behavior is critically important in promoting pro-environmental behavior. An important way climate change can be tackled is through changes to social policy at the governmental level, which, in turn, depends on individual voting behavior in democratic nations. The present study examined this issue with regard to political party support in New Zealand, and demonstrated - using a large general population sample of voters - that support for climate-change actions predict differential support for center-left and center-right political parties only for people who have children. Parental status moderated the link between support for climate-change actions and voting intentions. Practical and theoretical implications of the findings are discussed.

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Climate negotiations under scientific uncertainty

Scott Barrett & Astrid Dannenberg
Proceedings of the National Academy of Sciences, 23 October 2012, Pages 17372-17376

Abstract:
How does uncertainty about "dangerous" climate change affect the prospects for international cooperation? Climate negotiations usually are depicted as a prisoners' dilemma game; collectively, countries are better off reducing their emissions, but self-interest impels them to keep on emitting. We provide experimental evidence, grounded in an analytical framework, showing that the fear of crossing a dangerous threshold can turn climate negotiations into a coordination game, making collective action to avoid a dangerous threshold virtually assured. These results are robust to uncertainty about the impact of crossing a threshold, but uncertainty about the location of the threshold turns the game back into a prisoners' dilemma, causing cooperation to collapse. Our research explains the paradox of why countries would agree to a collective goal, aimed at reducing the risk of catastrophe, but act as if they were blind to this risk.

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Renaissance or Requiem: Is Nuclear Energy Cost Effective in a Post-Fukushima World?

Peter Schwarz & Joseph Cochran
Contemporary Economic Policy, forthcoming

Abstract:
In the aftermath of Fukushima, decisions to slow or stop the future use of nuclear power have not been based on rational economic analysis. We find that there are cost-effective technologies that would greatly mitigate future natural disasters. Even if the U.S. nuclear industry adopted new safety technologies and paid the full cost of insurance and borrowing, it is more efficient to continue to use existing nuclear plants than to replace them with new fossil fuel plants. However, new nuclear plant costs can exceed fossil fuel alternatives if the price of carbon emissions is below $118/ton.

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The rapid disintegration of projections: The West Antarctic Ice Sheet and the Intergovernmental Panel on Climate Change

Jessica O'Reilly, Naomi Oreskes & Michael Oppenheimer
Social Studies of Science, October 2012, Pages 709-731

Abstract:
How and why did the scientific consensus about sea level rise due to the disintegration of the West Antarctic Ice Sheet (WAIS), expressed in the third Intergovernmental Panel on Climate Change (IPCC) assessment, disintegrate on the road to the fourth? Using ethnographic interviews and analysis of IPCC documents, we trace the abrupt disintegration of the WAIS consensus. First, we provide a brief historical overview of scientific assessments of the WAIS. Second, we provide a detailed case study of the decision not to provide a WAIS prediction in the Fourth Assessment Report. Third, we discuss the implications of this outcome for the general issue of scientists and policymakers working in assessment organizations to make projections. IPCC authors were less certain about potential WAIS futures than in previous assessment reports in part because of new information, but also because of the outcome of cultural processes within the IPCC, including how people were selected for and worked together within their writing groups. It became too difficult for IPCC assessors to project the range of possible futures for WAIS due to shifts in scientific knowledge as well as in the institutions that facilitated the interpretations of this knowledge.

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Climate variability and conflict risk in East Africa, 1990-2009

John O'Loughlin et al.
Proceedings of the National Academy of Sciences, forthcoming

Abstract:
Recent studies concerning the possible relationship between climate trends and the risks of violent conflict have yielded contradictory results, partly because of choices of conflict measures and modeling design. In this study, we examine climate-conflict relationships using a geographically disaggregated approach. We consider the effects of climate change to be both local and national in character, and we use a conflict database that contains 16,359 individual geolocated violent events for East Africa from 1990 to 2009. Unlike previous studies that relied exclusively on political and economic controls, we analyze the many geographical factors that have been shown to be important in understanding the distribution and causes of violence while also considering yearly and country fixed effects. For our main climate indicators at gridded 1° resolution (∼100 km), wetter deviations from the precipitation norms decrease the risk of violence, whereas drier and normal periods show no effects. The relationship between temperature and conflict shows that much warmer than normal temperatures raise the risk of violence, whereas average and cooler temperatures have no effect. These precipitation and temperature effects are statistically significant but have modest influence in terms of predictive power in a model with political, economic, and physical geographic predictors. Large variations in the climate-conflict relationships are evident between the nine countries of the study region and across time periods.

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Climate triggers: Rainfall anomalies, vulnerability and communal conflict in Sub-Saharan Africa

Hanne Fjelde & Nina von Uexkull
Political Geography, forthcoming

Abstract:
The mounting evidence for climate change has put the security implications of increased climate variability high on the agenda of policymakers. However, several years of research have produced no consensus regarding whether climate variability increases the risk of armed conflict. Many have suggested that instead of outright civil war, climate variability is likely to heighten the risk of communal conflict. In particular, erratic rainfall, which reduces the availability of water and arable land, could create incentives for violent attacks against other communities to secure access to scarce resources. Yet, whether groups resort to violence in the face of environmentally induced hardship is likely to depend on the availability of alternative coping mechanisms, for example through market transfers or state accommodation. This suggests that the effect of rainfall anomalies on communal conflict will be stronger in the presence of economic and political marginalization. We evaluate these arguments statistically, utilizing a disaggregated dataset combining rainfall data with geo-referenced events data on the occurrence of communal conflict in Sub-Saharan Africa between 1990 and 2008. Our results suggest that large negative deviations in rainfall from the historical norm are associated with a higher risk of communal conflict. There is some evidence that the effect of rainfall shortages on the risk of communal conflict is amplified in regions inhabited by politically excluded ethno-political groups.

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Future heat vulnerability in California, Part I: Projecting future weather types and heat events

Scott Sheridan et al.
Climatic Change, November 2012, Pages 291-309

Abstract:
Excessive heat significantly impacts the health of Californians during irregular but intense heat events. Through the 21st century, a significant increase in impact is likely, as the state experiences a changing climate as well as an aging population. To assess this impact, future heat-related mortality estimates were derived for nine metropolitan areas in the state for the remainder of the century. Here in Part I, changes in oppressive weather days and consecutive-day events are projected for future years by a synoptic climatological method. First, historical surface weather types are related to circulation patterns at 500mb and 700mb, and temperature patterns at 850mb. GCM output is then utilized to classify future circulation patterns via discriminant function analysis, and multinomial logistic regression is used to derive future surface weather type at each of six stations in California. Five different climate model-scenarios are examined. Results show a significant increase in heat events over the 21st century, with oppressive weather types potentially more than doubling in frequency, and with heat events of 2 weeks or longer becoming up to ten times more common at coastal locations.

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Financial Costs of Meeting Global Biodiversity Conservation Targets: Current Spending and Unmet Needs

Donal McCarthy et al.
Science, forthcoming

Abstract:
World governments have committed to halting human-induced extinctions and safeguarding important sites for biodiversity by 2020, but the financial costs of meeting these targets are largely unknown. We estimate the cost of reducing the extinction risk of all globally threatened bird species (by ≥1 IUCN Red List category) to be US$0.875-1.23 billion annually over the next decade, of which 12% is currently funded. Incorporating threatened non-avian species increases this total to US$3.41-$4.76 billion annually. We estimate that protecting and effectively managing all terrestrial sites of global avian conservation significance (11,731 Important Bird Areas) would cost US$65.1 billion annually. Adding sites for other taxa increases this to US$76.1 billion annually. Meeting these targets will require conservation funding to increase by at least an order of magnitude.

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Shrinking of fishes exacerbates impacts of global ocean changes on marine ecosystems

William Cheung et al.,
Nature Climate Change, forthcoming

Abstract:
Changes in temperature, oxygen content and other ocean biogeochemical properties directly affect the ecophysiology of marine water-breathing organisms. Previous studies suggest that the most prominent biological responses are changes in distribution, phenology and productivity. Both theory and empirical observations also support the hypothesis that warming and reduced oxygen will reduce body size of marine fishes. However, the extent to which such changes would exacerbate the impacts of climate and ocean changes on global marine ecosystems remains unexplored. Here, we employ a model to examine the integrated biological responses of over 600 species of marine fishes due to changes in distribution, abundance and body size. The model has an explicit representation of ecophysiology, dispersal, distribution, and population dynamics. We show that assemblage-averaged maximum body weight is expected to shrink by 14-24% globally from 2000 to 2050 under a high-emission scenario. About half of this shrinkage is due to change in distribution and abundance, the remainder to changes in physiology. The tropical and intermediate latitudinal areas will be heavily impacted, with an average reduction of more than 20%. Our results provide a new dimension to understanding the integrated impacts of climate change on marine ecosystems.

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The Political Economy of Deforestation in the Tropics

Robin Burgess et al.
Quarterly Journal of Economics, forthcoming

Abstract:
Tropical deforestation accounts for almost one-fifth of greenhouse gas emissions and threatens the world's most diverse ecosystems. Much of this deforestation is driven by illegal logging. We use novel satellite data that tracks annual deforestation across eight years of Indonesian institutional change to examine how local officials' incentives affect deforestation. Increases in the number of political jurisdictions lead to increased deforestation and lower timber prices, consistent with Cournot competition between jurisdictions. Illegal logging and local oil and gas rents are short run substitutes, but this effect disappears over time with political turnover. The results illustrate how local officials' incentives affect deforestation, and show how standard economic theories can explain illegal behavior.

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How much is United States greenhouse gas emissions certainty worth?

Marla Sanchez, Scott Matthews & Paul Fischbeck
Energy Policy, forthcoming

Abstract:
The United States (US) Environmental Protection Agency's (EPA) Greenhouse Gas (GHG) Mandatory Reporting Program (GHGRP) is designed to collect accurate and timely facility-level emissions data that might be used by policy makers to support sound climate policy decisions in the future. After reviewing the US Inventory and the expected improvements under GHGRP, we find that the benefits of GHGRP are minimal and quite possibly zero while the cost of implementation is relatively high, that the stated goal of reducing emissions uncertainty is not met by the program in its current form, and that the additional emissions data to be collected is likely not needed given the ongoing non-committal environment of US GHG regulation. Our review also highlights the need for EPA to make its US Inventory GHG models accessible to the public, which would enable a more thorough review of its assumptions and methods by the broader scientific community.

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The Equity and Efficiency of Two-Part Tariffs in U.S. Natural Gas Markets

Severin Borenstein & Lucas Davis
Journal of Law and Economics, February 2012, Pages 75-128

Abstract:
Residential natural gas customers in the United States face volumetric charges that average about 30 percent more than the marginal cost of gas. This inefficient departure from marginal cost pricing allows gas utilities to cover their fixed infrastructure and operating costs. Proposals for recovering these costs instead through fixed monthly fees are often opposed because of a widespread belief that current rate schedules have desirable distributional consequences. Using nationally representative household-level data, we show that the correlation between household income and natural gas consumption is indeed positive but surprisingly weak, so current rate schedules are only mildly progressive. In part, we argue that this is because poor households tend to have larger families and less energy-efficient homes. We calculate bill impacts under a variety of scenarios and show that even a modest energy assistance program would more than offset the distributional impact of tariff rebalancing for most low-income households.

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Fast Carbon Footprinting for Large Product Portfolios

Christoph Meinrenken et al.
Journal of Industrial Ecology, October 2012, Pages 669-679

Abstract:
Publicly Available Specification 2050-2011 (PAS 2050), the Green House Gas Product Protocol (GHGPP) standard and forthcoming guideline 14067 from the International Organization for Standardization (ISO) have helped to propel carbon footprinting from a subdiscipline of life cycle assessment (LCA) to the mainstream. However, application of carbon footprinting to large portfolios of many distinct products and services is immensely resource intensive. Even if achieved, it often fails to inform company-wide carbon reduction strategies because footprint data are disjointed or don't cover the whole portfolio. We introduce a novel approach to generate standard-compliant product carbon footprints (CFs) for companies with large portfolios at a fraction of previously required time and expertise. The approach was developed and validated on an LCA dataset covering 1,137 individual products from a global packaged consumer goods company. Three novel techniques work in concert in a single approach that enables practitioners to calculate thousands of footprints virtually simultaneously: (i) a uniform data structure enables footprinting all products and services by looping the same algorithm; (ii) concurrent uncertainty analysis guides practitioners to gradually improve the accuracy of only those data that materially impact the results; and (iii) a predictive model generates estimated emission factors (EFs) for materials, thereby eliminating the manual mapping of a product or service's inventory to EF databases. These autogenerated EFs enable non-LCA experts to calculate approximate CFs and alleviate resource constraints for companies embarking on large-scale product carbon footprinting. We discuss implementation roadmaps for companies, including further road-testing required to evaluate the effectiveness of the approach for other product portfolios, limitations, and future improvements of the fast footprinting methodology.

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Carbon lock-in, rebound effects and China at the limits of statism

Rasmus Karlsson
Energy Policy, forthcoming

Abstract:
From the beginning, the statist frame of the Kyoto Protocol has invited a focus on national carbon budgets and piecemeal mitigation within rich countries. Despite the Clean Development Mechanism and other efforts to diffuse low carbon technologies to developing countries, China has over the last decades continued to construct hundreds of new thermal coal power plants leading not only to skyrocketing emissions in the present but also to long-term carbon lock-in. In light of this, China is likely to continue to put strong upward pressure on global emissions for many decades to come. Ignoring the seriousness of this situation, many rich countries have persisted to seek marginal improvements to intermittent low-energy sources such as wind power rather than taking the lead in developing breakthrough baseload technologies such as nuclear fusion. This paper argues that only such high-energy technologies, if made significantly cheaper than any fossil alternatives, will be capable of breaking the current carbon lock-in process in China and other developing countries.

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Natural and anthropogenic variations in methane sources during the past two millennia

C.J. Sapart et al.
Nature, 4 October 2012, Pages 85-88

Abstract:
Methane is an important greenhouse gas that is emitted from multiple natural and anthropogenic sources. Atmospheric methane concentrations have varied on a number of timescales in the past, but what has caused these variations is not always well understood. The different sources and sinks of methane have specific isotopic signatures, and the isotopic composition of methane can therefore help to identify the environmental drivers of variations in atmospheric methane concentrations. Here we present high-resolution carbon isotope data (δ13C content) for methane from two ice cores from Greenland for the past two millennia. We find that the δ13C content underwent pronounced centennial-scale variations between 100 BC and AD 1600. With the help of two-box model calculations, we show that the centennial-scale variations in isotope ratios can be attributed to changes in pyrogenic and biogenic sources. We find correlations between these source changes and both natural climate variability - such as the Medieval Climate Anomaly and the Little Ice Age - and changes in human population and land use, such as the decline of the Roman empire and the Han dynasty, and the population expansion during the medieval period.

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Millennial total sea-level commitments projected with the Earth system model of intermediate complexity LOVECLIM

H. Goelzer et al.
Environmental Research Letters, October-December 2012

Abstract:
Sea-level is expected to rise for a long time to come, even after stabilization of human-induced climatic warming. Here we use simulations with the Earth system model of intermediate complexity LOVECLIM to project sea-level changes over the third millennium forced with atmospheric greenhouse gas concentrations that stabilize by either 2000 or 2100 AD. The model includes 3D thermomechanical models of the Greenland and Antarctic ice sheets coupled to an atmosphere and an ocean model, a global glacier melt algorithm to account for the response of mountain glaciers and ice caps, and a procedure for assessing oceanic thermal expansion from oceanic heat uptake. Four climate change scenarios are considered to determine sea-level commitments. These assume a 21st century increase in greenhouse gases according to SRES scenarios B1, A1B and A2 with a stabilization of the atmospheric composition after the year 2100. One additional scenario assumes 1000 years of constant atmospheric composition from the year 2000 onwards. For our preferred model version, we find an already committed total sea-level rise of 1.1 m by 3000 AD. In experiments with greenhouse gas concentration stabilization at 2100 AD, the total sea-level rise ranges between 2.1 m (B1), 4.1 m (A1B) and 6.8 m (A2). In all scenarios, more than half of this amount arises from the Greenland ice sheet, thermal expansion is the second largest contributor, and the contribution of glaciers and ice caps is small as it is limited by the available ice volume of maximally 25 cm of sea-level equivalent. Additionally, we analysed the sensitivity of the sea-level contributions from an ensemble of nine different model versions that cover a large range of climate sensitivity realized by model parameter variations of the atmosphere-ocean model. Selected temperature indices are found to be good predictors for sea-level contributions from the different components of land ice and oceanic thermal expansion after 1000 years.

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Cost-effectiveness of plug-in hybrid electric vehicle battery capacity and charging infrastructure investment for reducing US gasoline consumption

Scott Peterson & Jeremy Michalek
Energy Policy, forthcoming

Abstract:
Federal electric vehicle (EV) policies in the United States currently include vehicle purchase subsidies linked to EV battery capacity and subsidies for installing charging stations. We assess the cost-effectiveness of increased battery capacity vs. nondomestic charging infrastructure installation for plug-in hybrid electric vehicles as alternate methods to reduce gasoline consumption for cars, trucks, and SUVs in the US. We find across a wide range of scenarios that the least-cost solution is for more drivers to switch to low-capacity plug-in hybrid electric vehicles (short electric range with gasoline backup for long trips) or gasoline-powered hybrid electric vehicles. If more gasoline savings are needed per vehicle, nondomestic charging infrastructure installation is substantially more expensive than increased battery capacity per gallon saved, and both approaches have higher costs than US oil premium estimates. Cost effectiveness of all subsidies are lower under a binding fuel economy standard. Comparison of results to the structure of current federal subsidies shows that policy is not aligned with fuel savings potential, and we discuss issues and alternatives.

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Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderate CO2 Concentrations on Human Decision-Making Performance

Usha Satish et al.
Environmental Health Perspectives, forthcoming

Background: Associations of higher indoor carbon dioxide (CO2) concentrations with impaired work performance, increased health symptoms, and poorer perceived air quality have been attributed to correlation of indoor CO2 with concentrations of other indoor air pollutants also influenced by rates of outdoor-air ventilation.

Objectives: We assessed direct effects of CO2, within the range of indoor concentrations, on decision making.

Methods: Twenty two participants were exposed to CO2 at 600, 1,000, and 2,500 ppm in an office-like chamber, in six groups. Each group was exposed to these conditions in three 2.5-hour sessions, all on one day, with exposure order balanced across groups. At 600 ppm, CO2 came from outdoor air and participants' respiration. Higher concentrations were achieved by injecting ultrapure CO2. Ventilation rate and temperature were constant. Under each condition, participants completed questionnaires on health symptoms and perceived air quality, and a computer-based test of decision-making performance. Participants, and the person administering the decision-making test, were blinded to CO2 level. Data were analyzed with analysis of variance models.

Results: Relative to 600 ppm, at 1,000 ppm CO2, moderate and statistically significant decrements occurred in six of nine scales of decision-making performance. At 2,500 ppm, large and statistically significant reductions occurred in seven scales of decision-making performance (raw score ratios 0.06-0.56), but performance on the focused activity scale increased.

Conclusions: Direct adverse effects of CO2 on human performance may be economically important and may limit energy-saving reductions in outdoor air ventilation per person in buildings. Confirmation of these findings is needed.

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Spatial and Temporal Heterogeneity of Marginal Emissions: Implications for Electric Cars and Other Electricity-Shifting Policies

Joshua Graff Zivin, Matthew Kotchen & Erin Mansur
NBER Working Paper, October 2012

Abstract:
In this paper, we develop a methodology for estimating marginal emissions of electricity demand that vary by location and time of day across the United States. The approach takes account of the generation mix within interconnected electricity markets and shifting load profiles throughout the day. Using data available for 2007 through 2009, with a focus on carbon dioxide (CO2), we find substantial variation among locations and times of day. Marginal emission rates are more than three times as large in the upper Midwest compared to the western United States, and within regions, rates for some hours of the day are more than twice those for others. We apply our results to an evaluation of plug-in electric vehicles (PEVs). The CO2 emissions per mile from driving PEVs are less than those from driving a hybrid car in the western United States and Texas. In the upper Midwest, however, charging during the recommended hours at night implies that PEVs generate more emissions per mile than the average car currently on the road. Underlying many of our results is a fundamental tension between electricity load management and environmental goals: the hours when electricity is the least expensive to produce tend to be the hours with the greatest emissions. In addition to PEVs, we show how our estimates are useful for evaluating the heterogeneous effects of other policies and initiatives, such as distributed solar, energy efficiency, and real-time pricing.

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Recent changes to the Gulf Stream causing widespread gas hydrate destabilization

Benjamin Phrampus & Matthew Hornbach
Nature, 25 October 2012, Pages 527-530

Abstract:
The Gulf Stream is an ocean current that modulates climate in the Northern Hemisphere by transporting warm waters from the Gulf of Mexico into the North Atlantic and Arctic oceans. A changing Gulf Stream has the potential to thaw and convert hundreds of gigatonnes of frozen methane hydrate trapped below the sea floor into methane gas, increasing the risk of slope failure and methane release. How the Gulf Stream changes with time and what effect these changes have on methane hydrate stability is unclear. Here, using seismic data combined with thermal models, we show that recent changes in intermediate-depth ocean temperature associated with the Gulf Stream are rapidly destabilizing methane hydrate along a broad swathe of the North American margin. The area of active hydrate destabilization covers at least 10,000 square kilometres of the United States eastern margin, and occurs in a region prone to kilometre-scale slope failures. Previous hypothetical studies postulated that an increase of five degrees Celsius in intermediate-depth ocean temperatures could release enough methane to explain extreme global warming events like the Palaeocene-Eocene thermal maximum (PETM) and trigger widespread ocean acidification. Our analysis suggests that changes in Gulf Stream flow or temperature within the past 5,000 years or so are warming the western North Atlantic margin by up to eight degrees Celsius and are now triggering the destabilization of 2.5 gigatonnes of methane hydrate (about 0.2 per cent of that required to cause the PETM). This destabilization extends along hundreds of kilometres of the margin and may continue for centuries. It is unlikely that the western North Atlantic margin is the only area experiencing changing ocean currents; our estimate of 2.5 gigatonnes of destabilizing methane hydrate may therefore represent only a fraction of the methane hydrate currently destabilizing globally. The transport from ocean to atmosphere of any methane released - and thus its impact on climate - remains uncertain.

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Intensification of Northern Hemisphere subtropical highs in a warming climate

Wenhong Li et al.
Nature Geoscience, forthcoming

Abstract:
Semi-permanent high-pressure systems over the subtropical oceans, known as subtropical highs, influence atmospheric circulation, as well as global climate. For instance, subtropical highs largely determine the location of the world's subtropical deserts, the zones of Mediterranean climate and the tracks of tropical cyclones. The intensity of two such high-pressure systems, present over the Northern Hemisphere oceans during the summer, has changed in recent years. However, whether such changes are related to climate warming remains unclear. Here, we use climate model simulations from the Intergovernmental Panel on Climate Change Fourth Assessment Report, reanalysis data from the 40-year European Centre for Medium-Range Weather Forecasts, and an idealized general circulation model, to assess future changes in the intensity of summertime subtropical highs over the Northern Hemisphere oceans. The simulations suggest that these summertime highs will intensify in the twenty-first century as a result of an increase in atmospheric greenhouse-gas concentrations. We further show that the intensification of subtropical highs is predominantly caused by an increase in thermal contrast between the land and ocean. We suggest that summertime near-surface subtropical highs could play an increasingly important role in regional climate and hydrological extremes in the future.

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Reviving manufacturing with a federal cogeneration policy

Marilyn Brown, Matt Cox & Paul Baer
Energy Policy, forthcoming

Abstract:
Improving the energy economics of manufacturing is essential to revitalizing the industrial base of advanced economies. This paper evaluates ex-ante a federal policy option aimed at promoting industrial cogeneration - the production of heat and electricity in a single energy-efficient process. Detailed analysis using the National Energy Modeling System (NEMS) and spreadsheet calculations suggest that industrial cogeneration could meet 18% of U.S. electricity requirements by 2035, compared with its current 8.9% market share. Substituting less efficient utility-scale power plants with cogeneration systems would produce numerous economic and environmental benefits, but would also create an assortment of losers and winners. Multiple perspectives to benefit/cost analysis are therefore valuable. Our results indicate that the federal cogeneration policy would be highly favorable to manufacturers and the public sector, cutting energy bills, generating billions of dollars in electricity sales, making producers more competitive, and reducing pollution. Most traditional utilities, on the other hand, would lose revenues unless their rate recovery procedures are adjusted to prevent the loss of profits due to customer owned generation and the erosion of utility sales. From a public policy perspective, deadweight losses would be introduced by market-distorting federal incentives (ranging annually from $30 to $150 million), but these losses are much smaller than the estimated net social benefits of the federal cogeneration policy.

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Residential Photovoltaic Energy Systems in California: The Effect on Home Sales Prices

Ben Hoen et al.
Contemporary Economic Policy, forthcoming

Abstract:
Relatively little research exists estimating the marginal impacts of photovoltaic (PV) energy systems on home sale prices. Using a large data set of California homes that sold from 2000 through mid-2009, we find strong evidence, despite a variety of robustness checks, that existing homes with PV systems sold for a premium over comparable homes without PV systems, implying a near full return on investment. Premiums for new homes are found to be considerably lower than those for existing homes, implying, potentially, a trade-off between price and sales velocity. The results have significant implications for homeowners, builders, appraisers, lenders, and policymakers.

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Cross Country Fairness Considerations and Country Implications of Alternative Approaches to a Global Emission Reduction Regime

Huifang Tian, Xiaojun Shi & John Whalley
NBER Working Paper, October 2012

Abstract:
The UNFCCC process of negotiating multilateral carbon emissions reductions thus far has focused on approximately equiproportional cuts in annual carbon emissions by country along the lines of the Kyoto Protocol agreement. But now, with the objective of involving large developing countries such as China and India in a post 2012 regime, broader considerations imply alternative approaches to emissions reduction arrangements by countries be considered. Here we consider the implications of alternative cross country fairness considerations entering the global negotiation process using a numerical simulation model which captures the potential impacts of alternative emission reductions across major economies which in turn reflect different fairness arguments. We put other fairness considerations, such as intergenerational equity, on one side. We use a global equilibrium emissions and trade model with transfers which are calibrated to a 2005-2050 BAU scenario and treats damage from climate change as utility damage. It thus captures the benefit side of emissions reduction agreements as well as the implications of such considerations for financial transfers agreed as a part of the process. Our analyses consider four alternative justices formulations. One is equal per capita allocation of absorptive capacity of the atmosphere given a temperature change target for global emissions. Yet another is where cuts by countries yield equal benefits per capita to other countries. A third is where there are equal costs per capita to countries making cuts. Finally, we also consider financial transfers to developing countries to compensate them for the costs of meeting emission restraints. The impacts of alternative emissions reductions differ sharply from the equi-proportional cuts of annual emissions implied by a continuation of the Kyoto process. These impacts emphasize the large and ill defined bargaining set for a post Kyoto Process involving large developing countries in a significant way.

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A non-linear model for estimating the cost of achieving emission reduction targets: The case of the U.S., China and India

Lei Zhu, Xiao-Bing Zhang & Ying Fan
Journal of Systems Science and Systems Engineering, September 2012, Pages 297-315

Abstract:
With the world talking about climate change, the United States (U.S.), China and India have announced their carbon emission reduction targets. For these three countries to achieve their targets, significant questions arise, such as what will be the annual emission reduction efforts to achieve those targets, how much it would cost and what would be the economic effects. This paper puts the carbon intensity reduction targets of China and India together with the absolute emission reduction target of the U.S. into the same non-linear model to quantitatively study the optimal emission control strategies and associated total cost for achieving those targets by the year 2020, and estimate and compare the minimized total costs of the three countries to reach their targets. Our results show that the total cost for the U.S. to achieve its emission reduction target is greater than those of China and India in terms of absolute amount. However, in terms of proportion of total cost to GDP, China and India's ratios are significantly greater than that of the U.S., indicating that for the developing countries such as China and India, the achievement of emission reduction targets needs relatively greater effort.

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Unilateral Climate Policy Design: Efficiency and Equity Implications of Alternative Instruments to Reduce Carbon Leakage

Christoph Böhringer, Jared Carbone & Thomas Rutherford
Energy Economics, forthcoming

Abstract:
Global cost-effectiveness of unilateral emission abatement can be seriously hampered by carbon leakage. We assess three widely discussed proposals for leakage reduction: carbon-motivated border tax adjustments, industry exemptions from carbon regulation, and output-based allocation of emission allowances. We find that none of these measures amounts to a "magic bullet" when both efficiency and equity criteria matter. Compared to unilateral emission pricing alone, border carbon adjustments are most effective in leakage reduction and promotion of global cost-effectiveness but can markedly exacerbate regional inequality; exemptions and output-based allocation tend to avoid distributional pitfalls but are less effective in leakage reduction and global cost savings; exemptions may even decreae global cost-effectiveness of unilateral emission abatement.

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Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools

Karen Seto, Burak Güneralp & Lucy Hutyra
Proceedings of the National Academy of Sciences, 2 October 2012, Pages 16083-16088

Abstract:
Urban land-cover change threatens biodiversity and affects ecosystem productivity through loss of habitat, biomass, and carbon storage. However, despite projections that world urban populations will increase to nearly 5 billion by 2030, little is known about future locations, magnitudes, and rates of urban expansion. Here we develop spatially explicit probabilistic forecasts of global urban land-cover change and explore the direct impacts on biodiversity hotspots and tropical carbon biomass. If current trends in population density continue and all areas with high probabilities of urban expansion undergo change, then by 2030, urban land cover will increase by 1.2 million km2, nearly tripling the global urban land area circa 2000. This increase would result in considerable loss of habitats in key biodiversity hotspots, with the highest rates of forecasted urban growth to take place in regions that were relatively undisturbed by urban development in 2000: the Eastern Afromontane, the Guinean Forests of West Africa, and the Western Ghats and Sri Lanka hotspots. Within the pan-tropics, loss in vegetation biomass from areas with high probability of urban expansion is estimated to be 1.38 PgC (0.05 PgC yr-1), equal to ∼5% of emissions from tropical deforestation and land-use change. Although urbanization is often considered a local issue, the aggregate global impacts of projected urban expansion will require significant policy changes to affect future growth trajectories to minimize global biodiversity and vegetation carbon losses.

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Quantification of Fossil Fuel CO2 Emissions on the Building/Street Scale for a Large U.S. City

Kevin Gurney et al.
Environmental Science & Technology, forthcoming

Abstract:
In order to advance the scientific understanding of carbon exchange with the land surface, build an effective carbon monitoring system, and contribute to quantitatively based U.S. climate change policy interests, fine spatial and temporal quantification of fossil fuel CO2 emissions, the primary greenhouse gas, is essential. Called the "Hestia Project", this research effort is the first to use bottom-up methods to quantify all fossil fuel CO2 emissions down to the scale of individual buildings, road segments, and industrial/electricity production facilities on an hourly basis for an entire urban landscape. Here, we describe the methods used to quantify the on-site fossil fuel CO2 emissions across the city of Indianapolis, IN. This effort combines a series of data sets and simulation tools such as a building energy simulation model, traffic data, power production reporting, and local air pollution reporting. The system is general enough to be applied to any large U.S. city and holds tremendous potential as a key component of a carbon-monitoring system in addition to enabling efficient greenhouse gas mitigation and planning. We compare the natural gas component of our fossil fuel CO2 emissions estimate to consumption data provided by the local gas utility. At the zip code level, we achieve a bias-adjusted Pearson r correlation value of 0.92 (p < 0.001).

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Reducing Greenhouse Gas Emissions Through Operations and Supply Chain Management

Erica Plambeck
Energy Economics, forthcoming

Abstract:
The experiences of the largest corporation in the world and those of a start-up company show how companies can profitably reduce greenhouse gas emissions in their supply chains. The operations management literature suggests additional opportunities to profitably reduce emissions in existing supply chains, and provides guidance for expanding the capacity of new "zero emission" supply chains. The potential for companies to profitably reduce emissions is substantial but (without effective climate policy) likely insufficient to avert dangerous climate change.

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Privatizing Climate Change Policy: Is there a Public Benefit?

Daniel Matisoff
Environmental and Resource Economics, November 2012, Pages 409-433

Abstract:
The Chicago Climate Exchange (CCX) and the Carbon Disclosure Project (CDP) are two private voluntary initiatives aimed at reducing carbon emissions and improving carbon management by firms. I sample power plants from firms participating in each of these programs, and match these to plants belonging to non-participating firms, to control for differences between participating and non-participating plants. Using a difference-in-differences model to control for unobservable differences between participants and non-participants, and to control for the trajectory of emissions prior to program participation, I find that the CCX is associated with a decrease in total carbon dioxide emissions for participating plants when non-publicly traded firms are included in the sample. Effects are produced largely by decreases in output. CCX participation is associated with increases in carbon dioxide intensity. The CDP is not associated with a decrease of carbon dioxide emissions or electricity generation, and program participation is associated with an increase in carbon dioxide intensity. I explore these results within the context of voluntary environmental programs to address carbon emissions.

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Should a vehicle fuel economy standard be combined with an economy-wide greenhouse gas emissions constraint? Implications for energy and climate policy in the United States

Valerie Karplus et al.
Energy Economics, forthcoming

Abstract:
The United States has adopted fuel economy standards that require increases in the on-road efficiency of new passenger vehicles, with the goal of reducing petroleum use and (more recently) greenhouse gas (GHG) emissions. Understanding the cost and effectiveness of fuel economy standards, alone and in combination with economy-wide policies that constrain GHG emissions, is essential to inform coordinated design of future climate and energy policy. In this work we use a computable general equilibrium model, the MIT Emissions Prediction and Policy Analysis (EPPA) model, to investigate the effect of combining a fuel economy standard with an economy-wide GHG emissions constraint in the United States. First, a fuel economy standard is shown to be at least five to fourteen times less cost effective than a price instrument (fuel tax) when targeting an identical reduction in cumulative gasoline use. Second, when combined with a cap-and-trade (CAT) policy, a binding fuel economy standard increases the cost of meeting the GHG emissions constraint by forcing expensive reductions in passenger vehicle gasoline use, displacing more cost-effective abatement opportunities. Third, the impact of adding a fuel economy standard to the CAT policy depends on the availability and cost of abatement opportunities in transport - if advanced biofuels provide a cost-competitive, low carbon alternative to gasoline, the fuel economy standard does not bind and the use of low carbon fuels in passenger vehicles makes a significantly larger contribution to GHG emissions abatement relative to the case when biofuels are not available. This analysis underscores the potentially large costs of a fuel economy standard relative to alternative policies aimed at reducing petroleum use and GHG emissions. It further emphasizes the need to consider sensitivity to vehicle/fuel technology availability and costs as well as economy-wide responses when forecasting the energy, environmental, and economic outcomes of policy combinations.

By KEVIN LEWIS | 09:00:00 AM