Findings

Tough climate

Kevin Lewis

September 12, 2012

Are the Economy and the Environment Decoupling? A Comparative International Study, 1960-2005

Andrew Jorgenson & Brett Clark
American Journal of Sociology, July 2012, Pages 1-44

Abstract:
Ecological modernization theory posits that even though economic development harms the environment, the magnitude of the harmful link decreases over the course of development. In contrast, the treadmill of production theory argues that the strong relationship between environmental harms and economic development will remain constant or possibly increase through time. To evaluate these competing propositions, interactions between economic development and time are used in cross-national panel analyses of three measures of carbon dioxide emissions. The results vary across the three outcomes as well as between developed and less developed countries, providing mixed support for both theoretical perspectives. The authors conclude by discussing how both theories could benefit from engaging contemporary research concerning changes within the transnational organization of production and the structure of international trade and how these global shifts influence environment/economic development relationships.

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The gigatonne gap in China's carbon dioxide inventories

Dabo Guan et al.
Nature Climate Change, September 2012, Pages 672-675

Abstract:
Reliable national statistics are fundamental for climate change science as well as for global negotiations about future emission targets and the allocation of responsibilities. China, the world's top CO2 emitter, has frequently been questioned about its data transparency and accuracy of energy and emission statistics. China implemented a top-down statistical system where energy statistics are compiled under the aegis of the National Bureau of Statistics (NBS) at the central government level, which oversees and coordinates the corresponding statistical departments at provincial and county levels. The NBS publishes annually both national and provincial energy statistics. We compile the CO2 emission inventories for China and its 30 provinces for the period 1997-2010. However, CO2 emissions calculated on the basis of the two publicly available official energy data sets differ by 1.4 gigatonnes for 2010. The figure is equivalent to Japan's annual CO2 emissions, the world's fourth largest emitter, with 5% of the global total. Differences in reported coal consumption in coal washing and manufacturing are the main contributors to the discrepancy in official energy statistics. This paper presents an initial step to share and validate data and discuss methodologies in full transparency towards better energy and emission data for China.

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Wind versus coal: Comparing the local economic impacts of energy resource development in Appalachia

Alan Collins, Evan Hansen & Michael Hendryx
Energy Policy, forthcoming

Abstract:
Two energy development scenarios were compared for the Coal River Mountain in Raleigh County, West Virginia: (1) mountaintop mining (MTM) of coal, and (2) wind energy plus underground mining of coal. Economic impact computations over the life of each energy development scenario were made on a county basis for output of goods and services, the number of jobs created, and local earnings. Externality costs were assigned monetary values for coal mining and subtracted from earnings. Premature mortality within the general population due to additional coal mining accounted for 96% of these external cost computations. The results showed that economic output over the life of each scenario was twice as high for MTM mining as wind energy plus underground coal mining. Over the short term, employment and earnings were higher for MTM mining, but towards the end of the scenario, cumulative employment and earnings became higher under scenario (2). When local externality costs were subtracted from local earnings, MTM coal production had an overall negative net social impact on the citizens of Raleigh County. The external costs of MTM coal production provide an explanation of the existence of a "resource curse" and the conflicting results of output versus income provide insights into why coal-producing counties are underdeveloped.

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Uncertainty, scepticism and attitudes towards climate change: Biased assimilation and attitude polarization

Adam Corner, Lorraine Whitmarsh & Dimitrios Xenias
Climatic Change, October 2012, Pages 463-478

Abstract:
‘Scepticism' in public attitudes towards climate change is seen as a significant barrier to public engagement. In an experimental study, we measured participants' scepticism about climate change before and after reading two newspaper editorials that made opposing claims about the reality and seriousness of climate change (designed to generate uncertainty). A well-established social psychological finding is that people with opposing attitudes often assimilate evidence in a way that is biased towards their existing attitudinal position, which may lead to attitude polarisation. We found that people who were less sceptical about climate change evaluated the convincingness and reliability of the editorials in a markedly different way to people who were more sceptical about climate change, demonstrating biased assimilation of the information. In both groups, attitudes towards climate change became significantly more sceptical after reading the editorials, but we observed no evidence of attitude polarization - that is, the attitudes of these two groups did not diverge. The results are the first application of the well-established assimilation and polarisation paradigm to attitudes about climate change, with important implications for anticipating how uncertainty - in the form of conflicting information - may impact on public engagement with climate change.

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Vulnerability of US and European electricity supply to climate change

Michelle van Vliet et al.
Nature Climate Change, September 2012, Pages 676-681

Abstract:
In the United States and Europe, at present 91% and 78% of the total electricity is produced by thermoelectric (nuclear and fossil-fuelled) power plants, which directly depend on the availability and temperature of water resources for cooling. During recent warm, dry summers several thermoelectric power plants in Europe and the southeastern United States were forced to reduce production owing to cooling-water scarcity. Here we show that thermoelectric power in Europe and the United States is vulnerable to climate change owing to the combined impacts of lower summer river flows and higher river water temperatures. Using a physically based hydrological and water temperature modelling framework in combination with an electricity production model, we show a summer average decrease in capacity of power plants of 6.3-19% in Europe and 4.4-16% in the United States depending on cooling system type and climate scenario for 2031-2060. In addition, probabilities of extreme (>90%) reductions in thermoelectric power production will on average increase by a factor of three. Considering the increase in future electricity demand, there is a strong need for improved climate adaptation strategies in the thermoelectric power sector to assure future energy security.

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Cost analysis of stratospheric albedo modification delivery systems

Justin McClellan, David Keith & Jay Apt
Environmental Research Letters, July-September 2012

Abstract:
We perform engineering cost analyses of systems capable of delivering 1-5 million metric tonnes (Mt) of albedo modification material to altitudes of 18-30 km. The goal is to compare a range of delivery systems evaluated on a consistent cost basis. Cost estimates are developed with statistical cost estimating relationships based on historical costs of aerospace development programs and operations concepts using labor rates appropriate to the operations. We evaluate existing aircraft cost of acquisition and operations, perform in-depth new aircraft and airship design studies and cost analyses, and survey rockets, guns, and suspended gas and slurry pipes, comparing their costs to those of aircraft and airships. Annual costs for delivery systems based on new aircraft designs are estimated to be $1-3B to deliver 1 Mt to 20-30 km or $2-8B to deliver 5 Mt to the same altitude range. Costs for hybrid airships may be competitive, but their large surface area complicates operations in high altitude wind shear, and development costs are more uncertain than those for airplanes. Pipes suspended by floating platforms provide low recurring costs to pump a liquid or gas to altitudes as high as ~ 20 km, but the research, development, testing and evaluation costs of these systems are high and carry a large uncertainty; the pipe system's high operating pressures and tensile strength requirements bring the feasibility of this system into question. The costs for rockets and guns are significantly higher than those for other systems. We conclude that (a) the basic technological capability to deliver material to the stratosphere at million tonne per year rates exists today, (b) based on prior literature, a few million tonnes per year would be sufficient to alter radiative forcing by an amount roughly equivalent to the growth of anticipated greenhouse gas forcing over the next half century, and that (c) several different methods could possibly deliver this quantity for less than $8B per year. We do not address here the science of aerosols in the stratosphere, nor issues of risk, effectiveness or governance that will add to the costs of solar geoengineering.

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Biodiversity tracks temperature over time

Peter Mayhew et al.
Proceedings of the National Academy of Sciences, forthcoming

Abstract:
The geographic distribution of life on Earth supports a general pattern of increase in biodiversity with increasing temperature. However, some previous analyses of the 540-million-year Phanerozoic fossil record found a contrary relationship, with paleodiversity declining when the planet warms. These contradictory findings are hard to reconcile theoretically. We analyze marine invertebrate biodiversity patterns for the Phanerozoic Eon while controlling for sampling effort. This control appears to reverse the temporal association between temperature and biodiversity, such that taxonomic richness increases, not decreases, with temperature. Increasing temperatures also predict extinction and origination rates, alongside other abiotic and biotic predictor variables. These results undermine previous reports of a negative biodiversity-temperature relationship through time, which we attribute to paleontological sampling biases. Our findings suggest a convergence of global scale macroevolutionary and macroecological patterns for the biodiversity-temperature relationship.

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Communication of climate projections in US media amid politicization of model science

Karen Akerlof et al.
Nature Climate Change, September 2012, Pages 648-654

Abstract:
Computer models generate projections of future climatic conditions that lie at the crux of climate change science and policy, and are increasingly used by decision-makers. Yet their complexity and politicization can hinder the communication of their science, uses and limitations. Little information on climate models has appeared in US newspapers over more than a decade. Indeed, we show it is declining relative to climate change. When models do appear, it is often within sceptic discourses. Using a media index from 2007, we find that model projections were frequently portrayed as likely to be inaccurate. Political opinion outlets provided more explanation than many news sources.

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Temperature, Human Health, and Adaptation: A Review of the Empirical Literature

Olivier Deschenes
NBER Working Paper, August 2012

Abstract:
This paper presents a survey of the empirical literature studying the relationship between health outcomes, temperature, and adaptation to temperature extremes. The objective of the paper is to highlight the many remaining gaps in the empirical literature and to provide guidelines for improving the current Integrated Assessment Model (IAM) literature that seeks to incorporate human health and adaptation in its framework. I begin by presenting the conceptual and methodological issues associated with the measurement of the effect of temperature extremes on health, and the role of adaptation in possibly muting these effects. The main conclusion that emerges from the literature is that despite the wide variety of data sets and settings most studies find that temperature extremes lead to significant reductions in health, generally measured with excess mortality. Regarding the role of adaptation in mitigating the effects of extreme temperature on health, the available knowledge is limited, in part due to the lack of real-world data on measures of adaptation behaviors. Finally, the paper discusses the implications of the currently available evidence for assessments of potential human health impacts of global climate change.

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Failing to learn from experience about catastrophes: The case of hurricane preparedness

Robert Meyer
Journal of Risk and Uncertainty, August 2012, Pages 25-50

Abstract:
This paper explores the question of whether there are inherent limits to our ability to learn from experience about the value of protection against low-probability, high-consequence, events. Findings are reported from two controlled experiments in which participants have a monetary incentive to learn from experience making investments to protect against hurricane risks. A central finding is that investments display a short-term forgetting effect consistent with the use of reinforcement learning rules, where a significant driver of investments in a given period is whether storm losses were incurred in the precious period. Given the relative rarity of such losses, this reinforcement process produces a mean investment level below that which would be optimal for most storm threats. Investments are also found to be insensitive to the censoring effect of protection itself, implying that the size of experienced losses - rather than losses that are avoided - is the primary driver of investment decisions.

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Do people "personally experience" global warming, and if so how, and does it matter?

Karen Akerlof et al.
Global Environmental Change, forthcoming

Abstract:
For most people, the direct and personally observable signals of climate change should be difficult to detect amid the variability of everyday weather. Yet, previous research has shown that some people believe they have personally experienced global warming. Through four related studies, our paper sheds light on what signals of global warming some people believe they are detecting, why, and whether or not it matters. These studies were conducted using population survey and climatic data from a single county in Michigan. Study 1 found that 27% of the county's adult residents felt that they had personally experienced global warming. Study 2 - based on content analysis of people's open-ended responses - found that the most frequently described personal experiences of global warming were changes in seasons (36%), weather (25%), lake levels (24%), animals and plants (20%), and snowfall (19%). Study 3 - based on NOAA climatic data - found that most, but not all, of these detected signals are borne out in the climatic record. Study 4 - using the survey data - found that personal experience of global warming matters in that it predicts perceptions of local risk of global warming, controlling for demographics, political affiliation, and cultural beliefs about national policy outcomes. We conclude that perceived personal experience of global warming appears to heighten people's perception of the risks, likely through some combination of direct experience, vicarious experience (e.g., news media stories), and social construction.

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Projections of Future Extreme Weather Losses Under Changes in Climate and Exposure

Laurens Bouwer
Risk Analysis, forthcoming

Abstract:
Many attempts are made to assess future changes in extreme weather events due to anthropogenic climate change, but few studies have estimated the potential change in economic losses from such events. Projecting losses is more complex as it requires insight into the change in the weather hazard but also into exposure and vulnerability of assets. This article discusses the issues involved as well as a framework for projecting future losses, and provides an overview of some state-of-the-art projections. Estimates of changes in losses from cyclones and floods are given, and particular attention is paid to the different approaches and assumptions. All projections show increases in extreme weather losses due to climate change. Flood losses are generally projected to increase more rapidly than losses from tropical and extra-tropical cyclones. However, for the period until the year 2040, the contribution from increasing exposure and value of capital at risk to future losses is likely to be equal or larger than the contribution from anthropogenic climate change. Given the fact that the occurrence of loss events also varies over time due to natural climate variability, the signal from anthropogenic climate change is likely to be lost among the other causes for changes in risk, at least during the period until 2040. More efforts are needed to arrive at a comprehensive approach that includes quantification of changes in hazard, exposure, and vulnerability, as well as adaptation effects.

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Are Green Hopes too Rosy? Employment and Welfare Impacts of Renewable Energy Promotion

Christoph Böhringer, Andreas Keller & Edwin van der Werf
Energy Economics, forthcoming

Abstract:
In view of pressing unemployment problems, policy makers across all parties jump on the prospects of renewable energy promotion as a job creation engine which can boost economic well-being. Our shows that initial labour market rigidities in theory provide some scope for such a double dividend. However, the practical outcome of renewable energy promotion might be sobering. Our computable general equilibrium analysis of subsidized electricity production from renewable energy sources (RES-E) in Germany suggests that the prospects for employment and welfare gains are quite limited and hinge crucially on the level of the subsidy rate and the financing mechanism. If RES-E subsidies are financed by labour taxes, welfare and employment effects are strictly negative for a broad range of subsidy rates. The use of an electricity tax to fund RES-E subsidies generates minor benefits for small subsidy rates but these benefits quickly turn into significant losses as the subsidy rate exceeds some threshold value.

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Climate-society feedbacks and the avoidance of dangerous climate change

A.J. Jarvis, D.T. Leedal & C.N. Hewitt
Nature Climate Change, September 2012, Pages 668-671

Abstract:
The growth in anthropogenic CO2 emissions experienced since the onset of the Industrial Revolution is the most important disturbance operating on the Earth's climate system. To avoid dangerous climate change, future greenhouse-gas emissions will have to deviate from business-as-usual trajectories. This implies that feedback links need to exist between climate change and societal actions. Here, we show that, consciously or otherwise, these feedbacks can be represented by linking global mean temperature change to the growth dynamics of CO2 emissions. We show that the global growth of new renewable sources of energy post-1990 represents a climate-society feedback of ~0.25% yr-1 per degree increase in global mean temperature. We also show that to fulfill the outcomes negotiated in Durban in 2011, society will have to become ~ 50 times more responsive to global mean temperature change than it has been since 1990. If global energy use continues to grow as it has done historically then this would result in amplification of the long-term endogenous rate of decarbonization from -0.6% yr-1 to ~-13% yr-1. It is apparent that modest levels of feedback sensitivity pay large dividends in avoiding climate change but that the marginal return on this effort diminishes rapidly as the required feedback strength increases.

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A Health Impact Assessment of California's Proposed Cap-and-Trade Regulations

Maxwell Richardson, Paul English & Linda Rudolph
American Journal of Public Health, September 2012, Pages e52-e58

Objectives: To identify unintended health effects of California's controversial cap-and-trade regulations and establish health-promoting policy recommendations, we performed a health impact assessment.

Methods: We used literature reviews, public data, and local health surveys to qualitatively assess potential health risks and benefits related to changes in employment and income, energy costs, effects of emission offset projects, and cobenefits from the allocation of program revenue. We examined case studies from various communities to find existing social, economic, and environmental health conditions.

Results: We found that policy implementation will minimally impact job creation (< 0.1% change) and that health effects from job sector shifts are unlikely. Fuel prices may increase (0%-11%), and minor negative health effects could accrue for some low-income households.

Conclusions: Offset projects would likely benefit environmental health, but more research is needed. Allocating some program revenue for climate change adaptation and mitigation would have substantial health benefits. Health impact assessment is a useful tool for health agencies to engage in policy discussions that typically fall outside public health. Our results can inform emission reduction strategies and cap-and-trade policy at the federal level.

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Is climate change an ethical issue? Examining young adults' beliefs about climate and morality

Ezra Markowitz
Climatic Change, October 2012, Pages 479-495

Abstract:
Moral philosophers argue that climate change poses an ‘ethical problem' for humanity and thus that humans have moral obligations to respond. Little empirical research has explored whether non-philosophers agree with these conclusions. This is unfortunate, because non-experts' moral intuitions (or lack thereof) about climate change likely hold important implications for willingness to engage cognitively, emotionally and behaviorally with the issue. After reviewing the moral philosophical position on climate change, I present results of two studies conducted with a total of 922 U.S. undergraduate students that explored beliefs about the ‘ethics of climate change.' Forty-five percent of the students sampled stated unequivocally that climate change represents a moral or ethical issue; a full quarter of students said it was not an ethical issue and roughly 30% were unsure. Participants' beliefs regarding the causes of climate change were predictive of intentions to perform pro-environmental actions, and this relationship was fully mediated by ascriptions of personal moral obligation to respond. Implications and directions for future research are discussed.

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Thermodynamic analysis of low-temperature carbon dioxide and sulfur dioxide capture from coal-burning power plants

Charles Swanson et al.
Physical Review E, July 2012

Abstract:
We discuss the possibility of capturing carbon dioxide from the flue gas of a coal-fired electrical power plant by cryogenically desublimating the carbon dioxide and then preparing it for transport in a pipeline to a sequestration site. Various other means have been proposed to accomplish the same goal. The problem discussed here is to estimate the "energy penalty" or "parasitic energy loss,' defined as the fraction of electrical output that will be needed to provide the refrigeration and that will then not be deliverable. We compute the energy loss (7.9-9.2% at 1 atm) based on perfect Carnot efficiency and estimate the achievable parasitic energy loss (22-26% at 1 atm) by incorporating the published coefficient of performance values for appropriately sized refrigeration or liquefaction cycles at the relevant temperatures. The analyses at 1 atm represent a starting point for future analyses using elevated pressures.

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Geophysical limits to global wind power

Kate Marvel, Ben Kravitz & Ken Caldeira
Nature Climate Change, forthcoming

Abstract:
There is enough power in Earth's winds to be a primary source of near-zero-emission electric power as the global economy continues to grow through the twenty-first century. Historically, wind turbines are placed on Earth's surface, but high-altitude winds are usually steadier and faster than near-surface winds, resulting in higher average power densities1. Here, we use a climate model to estimate the amount of power that can be extracted from both surface and high-altitude winds, considering only geophysical limits. We find wind turbines placed on Earth's surface could extract kinetic energy at a rate of at least 400 TW, whereas high-altitude wind power could extract more than 1,800 TW. At these high rates of extraction, there are pronounced climatic consequences. However, we find that at the level of present global primary power demand (~ 18 TW; ref. 2), uniformly distributed wind turbines are unlikely to substantially affect the Earth's climate. It is likely that wind power growth will be limited by economic or environmental factors, not global geophysical limits.

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Saturation wind power potential and its implications for wind energy

Mark Jacobson & Cristina Archer
Proceedings of the National Academy of Sciences, forthcoming

Abstract:
Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world's all-purpose power from wind in a 2030 clean-energy economy.

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Wind Turbine Acoustic Investigation: Infrasound and Low-Frequency Noise - A Case Study

Stephen Ambrose, Robert Rand & Carmen Krogh
Bulletin of Science, Technology & Society, April 2012, Pages 128-141

Abstract:
Wind turbines produce sound that is capable of disturbing local residents and is reported to cause annoyance, sleep disturbance, and other health-related impacts. An acoustical study was conducted to investigate the presence of infrasonic and low-frequency noise emissions from wind turbines located in Falmouth, Massachusetts, USA. During the study, the investigating acousticians experienced adverse health effects consistent with those reported by some Falmouth residents. The authors conclude that wind turbine acoustic energy was found to be greater than or uniquely distinguishable from the ambient background levels and capable of exceeding human detection thresholds. The authors emphasize the need for epidemiological and laboratory research by health professionals and acousticians concerned with public health and well-being to develop effective and precautionary setback distances for industrial wind turbines that protect residents from wind turbine sound.

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Climate change and impacts in the Eastern Mediterranean and the Middle East

J. Lelieveld et al.
Climatic Change, October 2012, Pages 667-687

Abstract:
The Eastern Mediterranean and the Middle East (EMME) are likely to be greatly affected by climate change, associated with increases in the frequency and intensity of droughts and hot weather conditions. Since the region is diverse and extreme climate conditions already common, the impacts will be disproportional. We have analyzed long-term meteorological datasets along with regional climate model projections for the 21st century, based on the intermediate IPCC SRES scenario A1B. This suggests a continual, gradual and relatively strong warming of about 3.5-7°C between the 1961-1990 reference period and the period 2070-2099. Daytime maximum temperatures appear to increase most rapidly in the northern part of the region, i.e. the Balkan Peninsula and Turkey. Hot summer conditions that rarely occurred in the reference period may become the norm by the middle and the end of the 21st century. Projected precipitation changes are quite variable. Annual precipitation is expected to decrease in the southern Europe - Turkey region and the Levant, whereas in the Arabian Gulf area it may increase. In the former region rainfall is actually expected to increase in winter, while decreasing in spring and summer, with a substantial increase of the number of days without rainfall. Anticipated regional impacts of climate change include heat stress, associated with poor air quality in the urban environment, and increasing scarcity of fresh water in the Levant.

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Food security and climate change: On the potential to adapt global crop production by active selection to rising atmospheric carbon dioxide

Lewis Ziska et al.
Proceedings of the Royal Society: Biological Sciences, 22 October 2012, Pages 4097-4105

Abstract:
Agricultural production is under increasing pressure by global anthropogenic changes, including rising population, diversion of cereals to biofuels, increased protein demands and climatic extremes. Because of the immediate and dynamic nature of these changes, adaptation measures are urgently needed to ensure both the stability and continued increase of the global food supply. Although potential adaption options often consider regional or sectoral variations of existing risk management (e.g. earlier planting dates, choice of crop), there may be a global-centric strategy for increasing productivity. In spite of the recognition that atmospheric carbon dioxide (CO2) is an essential plant resource that has increased globally by approximately 25 per cent since 1959, efforts to increase the biological conversion of atmospheric CO2 to stimulate seed yield through crop selection is not generally recognized as an effective adaptation measure. In this review, we challenge that viewpoint through an assessment of existing studies on CO2 and intraspecific variability to illustrate the potential biological basis for differential plant response among crop lines and demonstrate that while technical hurdles remain, active selection and breeding for CO2 responsiveness among cereal varieties may provide one of the simplest and direct strategies for increasing global yields and maintaining food security with anthropogenic change.

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Estimating Global "Blue Carbon" Emissions from Conversion and Degradation of Vegetated Coastal Ecosystems

Linwood Pendleton et al.
PLoS ONE, September 2012

Abstract:
Recent attention has focused on the high rates of annual carbon sequestration in vegetated coastal ecosystems - marshes, mangroves, and seagrasses - that may be lost with habitat destruction (‘conversion'). Relatively unappreciated, however, is that conversion of these coastal ecosystems also impacts very large pools of previously-sequestered carbon. Residing mostly in sediments, this ‘blue carbon' can be released to the atmosphere when these ecosystems are converted or degraded. Here we provide the first global estimates of this impact and evaluate its economic implications. Combining the best available data on global area, land-use conversion rates, and near-surface carbon stocks in each of the three ecosystems, using an uncertainty-propagation approach, we estimate that 0.15-1.02 Pg (billion tons) of carbon dioxide are being released annually, several times higher than previous estimates that account only for lost sequestration. These emissions are equivalent to 3-19% of those from deforestation globally, and result in economic damages of $US 6-42 billion annually. The largest sources of uncertainty in these estimates stems from limited certitude in global area and rates of land-use conversion, but research is also needed on the fates of ecosystem carbon upon conversion. Currently, carbon emissions from the conversion of vegetated coastal ecosystems are not included in emissions accounting or carbon market protocols, but this analysis suggests they may be disproportionally important to both. Although the relevant science supporting these initial estimates will need to be refined in coming years, it is clear that policies encouraging the sustainable management of coastal ecosystems could significantly reduce carbon emissions from the land-use sector, in addition to sustaining the well-recognized ecosystem services of coastal habitats.

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Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia

J.E. Vonk et al.
Nature, 6 September 2012, Pages 137-140

Abstract:
The future trajectory of greenhouse gas concentrations depends on interactions between climate and the biogeosphere. Thawing of Arctic permafrost could release significant amounts of carbon into the atmosphere in this century. Ancient Ice Complex deposits outcropping along the ~7,000-kilometre-long coastline of the East Siberian Arctic Shelf (ESAS), and associated shallow subsea permafrost, are two large pools of permafrost carbon, yet their vulnerabilities towards thawing and decomposition are largely unknown. Recent Arctic warming is stronger than has been predicted by several degrees, and is particularly pronounced over the coastal ESAS region. There is thus a pressing need to improve our understanding of the links between permafrost carbon and climate in this relatively inaccessible region. Here we show that extensive release of carbon from these Ice Complex deposits dominates (57 ± 2 per cent) the sedimentary carbon budget of the ESAS, the world's largest continental shelf, overwhelming the marine and topsoil terrestrial components. Inverse modelling of the dual-carbon isotope composition of organic carbon accumulating in ESAS surface sediments, using Monte Carlo simulations to account for uncertainties, suggests that 44 ± 10 teragrams of old carbon is activated annually from Ice Complex permafrost, an order of magnitude more than has been suggested by previous studies. We estimate that about two-thirds (66 ± 16 per cent) of this old carbon escapes to the atmosphere as carbon dioxide, with the remainder being re-buried in shelf sediments. Thermal collapse and erosion of these carbon-rich Pleistocene coastline and seafloor deposits may accelerate with Arctic amplification of climate warming.

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Weakening of hurricanes via marine cloud brightening (MCB)

John Latham et al.
Atmospheric Science Letters, forthcoming

Abstract:
This paper examines the potential to cool ocean surface waters in regions of hurricane genesis and early development. This would be achieved by seeding, with copious quantities of seawater cloud condensation nuclei (CCN), low-level maritime stratocumulus clouds covering these regions or those at the source of incoming currents. Higher cloud droplet density would increase these clouds' reflectivity to incoming sunlight, and possibly their longevity. This approach is therefore a more localized application of the marine cloud brightening (MCB) geoengineering technique promoting global cooling. By utilizing a climate ocean/atmosphere coupled model, HadGEM1, we demonstrate that - subject to the satisfactory resolution of defined but unresolved issues - judicious seeding of maritime stratocumulus clouds might significantly reduce sea surface temperatures (SSTs) in regions where hurricanes develop. Thus artificial seeding may reduce hurricane intensity; but how well the magnitude of this effect could be controlled is yet to be determined. We also address the important question as to how MCB seeding may influence precipitation. GCM modelling indicates that the influence of seeding on undesirable rainfall reductions depends on its location and magnitude. Much more work on this topic is required.

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The influence of hurricane risk on tourist destination choice in the Caribbean

Johanna Forster et al.
Climatic Change, October 2012, Pages 745-768

Abstract:
Climate change could have major implications for the global tourism industry if changing environmental conditions alter the attractiveness of holiday destinations. Countries with economies dependent on tourism and with tourism industries reliant on vulnerable natural resources are likely to be particularly at risk. We investigate the implications that climate-induced variations in Atlantic hurricane activity may have for the tourism-dependent Caribbean island of Anguilla. Three hundred tourists completed standardised questionnaires and participated in a choice experiment to determine the influence hurricane risk has on their risk perceptions and decisions regarding holiday preferences. The hurricane season had been considered by 40 % of respondents when making their holiday choice, and the beaches, climate and tranquility of the island were more important than coral reef-based recreational activities in determining holiday destination choice. Choice models demonstrated that respondents were significantly less likely to choose holiday options where hurricane risk is perceived to increase, and significantly more likely to choose options that offered financial compensation for increased risk. However, these choices and decisions varied among demographic groups, with older visitors, Americans, and people who prioritize beach-based activities tending to be most concerned about hurricanes. These groups comprise a significant component of the island's current clientele, suggesting that perceived increases in hurricane risk may have important implications for the tourism economy of Anguilla and similar destinations. Improved protection of key environmental features (e.g. beaches) may be necessary to enhance resilience to potential future climate impacts.

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World War II contrails: A case study of aviation-induced cloudiness

A.C. Ryan et al.
International Journal of Climatology, September 2012, Pages 1745-1753

Abstract:
Dense and persistent condensation trails or contrails were produced by daytime US Army Air Force (USAAF) bombing raids, flown from England to Europe during World War II (WW2). These raids occurred in years when civilian air travel was rare, giving a predominantly contrail-free background sky, in a period when there were more meteorological observations taken across England than at any time before or since. The aircraft involved in the raids entered formation at contrail-forming altitudes (generally over 16 000 ft, approximately 5 km) over a relatively small part of southeast England before flying on to their target. This formation strategy provides us a unique opportunity to carry out multiple observation-based comparisons of adjacent, same day, well-defined overflown and non-over-flown regions. We compile evidence from archived meteorological data, such as Met Office daily weather reports and individual station meteorological registers, together with historical aviation information from USAAF and Royal Air Force (RAF) tactical mission reports. We highlight a number of potential dates for study and demonstrate, for one of these days, a marked difference in the amount of high cloud cover, and a statistically significant (0.8 °C) difference in the 07:00-13:00 UTC temperature range when comparing data from highly overflown stations to those upwind of the flight path on the same day. Although one event cannot provide firm conclusions regarding the effect of contrails on climate, this study demonstrates that the wealth of observational data associated with WW2 bombing missions allows detailed investigation of meteorological perturbations because of aviation-induced cloudiness.


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