Nature of the Problem
Anna Rabinovich & Thomas Morton
Risk Analysis, forthcoming
Abstract:
In two experimental studies we investigated the effect of beliefs about the nature and purpose of science (classical vs. Kuhnian models of science) on responses to uncertainty in scientific messages about climate change risk. The results revealed a significant interaction between both measured (Study 1) and manipulated (Study 2) beliefs about science and the level of communicated uncertainty on willingness to act in line with the message. Specifically, messages that communicated high uncertainty were more persuasive for participants who shared an understanding of science as debate than for those who believed that science is a search for absolute truth. In addition, participants who had a concept of science as debate were more motivated by higher (rather than lower) uncertainty in climate change messages. The results suggest that achieving alignment between the general public's beliefs about science and the style of the scientific messages is crucial for successful risk communication in science. Accordingly, rather than uncertainty always undermining the effectiveness of science communication, uncertainty can enhance message effects when it fits the audience's understanding of what science is.
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The water footprint of humanity
Arjen Hoekstra & Mesfin Mekonnen
Proceedings of the National Academy of Sciences, forthcoming
Abstract:
This study quantifies and maps the water footprint (WF) of humanity at a high spatial resolution. It reports on consumptive use of rainwater (green WF) and ground and surface water (blue WF) and volumes of water polluted (gray WF). Water footprints are estimated per nation from both a production and consumption perspective. International virtual water flows are estimated based on trade in agricultural and industrial commodities. The global annual average WF in the period 1996-2005 was 9,087 Gm3/y (74% green, 11% blue, 15% gray). Agricultural production contributes 92%. About one-fifth of the global WF relates to production for export. The total volume of international virtual water flows related to trade in agricultural and industrial products was 2,320 Gm3/y (68% green, 13% blue, 19% gray). The WF of the global average consumer was 1,385 m3/y. The average consumer in the United States has a WF of 2,842 m3/y, whereas the average citizens in China and India have WFs of 1,071 and 1,089 m3/y, respectively. Consumption of cereal products gives the largest contribution to the WF of the average consumer (27%), followed by meat (22%) and milk products (7%). The volume and pattern of consumption and the WF per ton of product of the products consumed are the main factors determining the WF of a consumer. The study illustrates the global dimension of water consumption and pollution by showing that several countries heavily rely on foreign water resources and that many countries have significant impacts on water consumption and pollution elsewhere.
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Gabriel Chan et al.
NBER Working Paper, February 2012
Abstract:
The introduction of the U.S. SO2 allowance-trading program to address the threat of acid rain as part of the Clean Air Act Amendments of 1990 is a landmark event in the history of environmental regulation. The program was a great success by almost all measures. This paper, which draws upon a research workshop and a policy roundtable held at Harvard in May 2011, investigates critically the design, enactment, implementation, performance, and implications of this path-breaking application of economic thinking to environmental regulation. Ironically, cap and trade seems especially well suited to addressing the problem of climate change, in that emitted greenhouse gases are evenly distributed throughout the world's atmosphere. Recent hostility toward cap and trade in debates about U.S. climate legislation may reflect the broader political environment of the climate debate more than the substantive merits of market-based regulation.
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World natural gas endowment as a bridge towards zero carbon emissions
Roberto Aguilera & Roberto Aguilera
Technological Forecasting and Social Change, March 2012, Pages 579-586
Abstract:
We use a global energy market (GEM) model to show that natural gas has the potential to help stabilize global carbon emissions in a span of about 50-100 years and pave the way towards low and zero carbon energy. The GEM provides a close fit of the global energy mix between 1850 and 2005. It also matches historical carbon and CO2 emissions generated by the combustion of fossil fuels. The model is used then to forecast the future energy mix, as well as the carbon and CO2 emissions, up to the year 2150. Historical data show relative decarbonization and an increase in the amount of hydrogen burned as a percent of fossil fuel use between 1850 and 1970. The GEM indicates that with a larger contribution of natural gas to the future energy market, the burned hydrogen percentage will increase. This decarbonization will help to advance economic and environmental sustainability.
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Recent contributions of glaciers and ice caps to sea level rise
Thomas Jacob et al.
Nature, forthcoming
Abstract:
Glaciers and ice caps (GICs) are important contributors to present-day global mean sea level rise. Most previous global mass balance estimates for GICs rely on extrapolation of sparse mass balance measurements representing only a small fraction of the GIC area, leaving their overall contribution to sea level rise unclear. Here we show that GICs, excluding the Greenland and Antarctic peripheral GICs, lost mass at a rate of 148 ± 30 Gt yr-1 from January 2003 to December 2010, contributing 0.41 ± 0.08 mm yr-1 to sea level rise. Our results are based on a global, simultaneous inversion of monthly GRACE-derived satellite gravity fields, from which we calculate the mass change over all ice-covered regions greater in area than 100 km2. The GIC rate for 2003-2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period. The high mountains of Asia, in particular, show a mass loss of only 4 ± 20 Gt yr-1 for 2003-2010, compared with 47-55 Gt yr-1 in previously published estimates. For completeness, we also estimate that the Greenland and Antarctic ice sheets, including their peripheral GICs, contributed 1.06 ± 0.19 mm yr-1 to sea level rise over the same time period. The total contribution to sea level rise from all ice-covered regions is thus 1.48 ± 0.26 mm -1, which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources.
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The publics' concern for global warming: A cross-national study of 47 countries
Berit Kvaløy, Henning Finseraas & Ola Listhaug
Journal of Peace Research, January 2012, Pages 11-22
Abstract:
This article relies on data from the 2005-09 World Values Survey to examine individual and cross-national variation in perception of the seriousness of global warming. The data show that a large majority of the public in all countries are concerned about the problem of global warming and that this assessment is part of a broader concern for global environmental issues. The widespread concern implies that global warming has the potential to generate mass political participation and demand for political action. Motivated by a value-based approach to the study of public opinion, the article shows that perception of the seriousness of the problem is positively correlated with high education, post-materialism, and a leftist position on the left-right scale. In addition, religious beliefs are important, suggesting that there is some diversity in the value basis for the issue and that it is not only linked to the ‘new-politics' perspective. Variation across nations in wealth and CO2 emissions is not significantly related to the publics' assessments of the problem, and, somewhat counterintuitively, people from countries relatively more exposed to climate-related natural disasters are less concerned about global warming. We suggest possible explanations for the latter finding and discuss our results in relation to the broader literature on environmental change, insecurity, and the potential for conflict.
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Climate change, rainfall, and social conflict in Africa
Cullen Hendrix & Idean Salehyan
Journal of Peace Research, January 2012, Pages 35-50
Abstract:
Much of the debate over the security implications of climate change revolves around whether changing weather patterns will lead to future conflict. This article addresses whether deviations from normal rainfall patterns affect the propensity for individuals and groups to engage in disruptive activities such as demonstrations, riots, strikes, communal conflict, and anti-government violence. In contrast to much of the environmental security literature, it uses a much broader definition of conflict that includes, but is not limited to, organized rebellion. Using a new database of over 6,000 instances of social conflict over 20 years - the Social Conflict in Africa Database (SCAD) - it examines the effect of deviations from normal rainfall patterns on various types of conflict. The results indicate that rainfall variability has a significant effect on both large-scale and smaller-scale instances of political conflict. Rainfall correlates with civil war and insurgency, although wetter years are more likely to suffer from violent events. Extreme deviations in rainfall - particularly dry and wet years - are associated positively with all types of political conflict, though the relationship is strongest with respect to violent events, which are more responsive to abundant than scarce rainfall. By looking at a broader spectrum of social conflict, rather than limiting the analysis to civil war, we demonstrate a robust relationship between environmental shocks and unrest.
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Come rain or shine: An analysis of conflict and climate variability in East Africa
Clionadh Raleigh & Dominic Kniveton
Journal of Peace Research, January 2012, Pages 51-64
Abstract:
Previous research on environment and security has contested the existence, nature and significance of a climate driver of conflict. In this study, we have focused on small-scale conflict over East Africa where the link between resource availability and conflict is assumed to be more immediate and direct. Using the parameter of rainfall variability to explore the marginal influence of the climate on conflict, the article shows that in locations that experience rebel or communal conflict events, the frequency of these events increases in periods of extreme rainfall variation, irrespective of the sign of the rainfall change. Further, these results lend support to both a ‘zero-sum' narrative, where conflicting groups use force and violence to compete for ever-scarcer resources, and an ‘abundance' narrative, where resources spur rent-seeking/wealth-seeking and recruitment of people to participate in violence. Within the context of current uncertainty regarding the future direction of rainfall change over much of Africa, these results imply that small-scale conflict is likely to be exacerbated with increases in rainfall variability if the mean climate remains largely unchanged; preferentially higher rates of rebel conflict will be exhibited in anomalously dry conditions, while higher rates of communal conflict are expected in increasingly anomalous wet conditions.
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Civil war, climate change, and development: A scenario study for sub-Saharan Africa
Conor Devitt & Richard SJ Tol
Journal of Peace Research, January 2012, Pages 129-145
Abstract:
This article presents a model of development, civil war and climate change. There are multiple interactions. Economic growth reduces the probability of civil war and the vulnerability to climate change. Climate change increases the probability of civil war. The impacts of climate change, civil war and civil war in the neighbouring countries reduce economic growth. The model has two potential poverty traps - one is climate-change-induced and one is civil-war-induced - and the two poverty traps may reinforce one another. The model is calibrated to sub-Saharan Africa and a double Monte Carlo analysis is conducted in order to account for both parameter uncertainty and stochasticity. Although the IPCC Special Report on Emission Scenarios (SRES) is used as the baseline, thus assuming rapid economic growth in Africa and convergence of African living standards to the rest of the world, the impacts of civil war and climate change (ignored in SRES) are sufficiently strong to keep a number of countries in Africa in deep poverty with a high probability.
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Climate-related natural disasters, economic growth, and armed civil conflict
Drago Bergholt & Päivi Lujala
Journal of Peace Research, January 2012, Pages 147-162
Abstract:
Global warming is expected to make the climate warmer, wetter, and wilder. It is predicted that such climate change will increase the severity and frequency of climate-related disasters like flash floods, surges, cyclones, and severe storms. This article uses econometric methods to study the consequences of climate-induced natural disasters on economic growth, and how these disasters are linked to the onset of armed civil conflict either directly or via their impact on economic growth. The results show that climate-related natural disasters have a negative effect on growth and that the impact is considerable. The analysis of conflict onset shows that climate-related natural disasters do not increase the risk of armed conflict. This is also true when we instrument the change in GDP growth by climatic disasters. The result is robust to inclusion of country and time fixed effects, different estimation techniques, and various operationalization of the disasters measure, as well as for conflict incidence and war onset. These findings have two major implications: if climate change increases the frequency or makes weather-related natural disasters more severe, it is an economic concern for countries susceptible to these types of hazards. However, our results suggest - based on historical data - that more frequent and severe climate-related disasters will not lead to more armed conflicts through their effects on GDP growth.
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Don't blame the weather! Climate-related natural disasters and civil conflict
Rune Slettebak
Journal of Peace Research, January 2012, Pages 163-176
Abstract:
The issue of climate change and security has received much attention in recent years. Still, the results from research on this topic are mixed and the academic community appears to be far from a consensus on how climate change is likely to affect stability and conflict risk in affected countries. This study focuses on how climate-related natural disasters such as storms, floods, and droughts have affected the risk of civil war in the past. The frequency of such disasters has risen sharply over the last decades, and the increase is expected to continue due to both climate change and demographic changes. Using multivariate methods, this study employs a global sample covering 1950 to the present in order to test whether adding climate-related natural disasters to a well-specified model on civil conflict can increase its explanatory power. The results indicate that this is the case, but that the relation is opposite to common perceptions: Countries that are affected by climate-related natural disasters face a lower risk of civil war. One worrying facet of the claims that environmental factors cause conflict is that they may contribute to directing attention away from more important conflict-promoting factors, such as poor governance and poverty. There is a serious risk of misguided policy to prevent civil conflict if the assumption that disasters have a significant effect on war is allowed to overshadow more important causes.
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Pathways of human development and carbon emissions embodied in trade
Julia Steinberger et al.
Nature Climate Change, February 2012, Pages 81-85
Abstract:
It has long been assumed that human development depends on economic growth, that national economic expansion in turn requires greater energy use and, therefore, increased greenhouse-gas emissions. These interdependences are the topic of current research. Scarcely explored, however, is the impact of international trade: although some nations develop socio-economically and import high-embodied-carbon products, it is likely that carbon-exporting countries gain significantly fewer benefits. Here, we use new consumption-based measures of national carbon emissions1 to explore how the relationship between human development and carbon changes when we adjust national emission rates for trade. Without such adjustment of emissions, some nations seem to be getting far better development ‘bang' for the carbon ‘buck' than others, who are showing scant gains for disproportionate shares of global emissions. Adjusting for the transfer of emissions through trade explains many of these outliers, but shows that further socio-economic benefits are accruing to carbon-importing rather than carbon-exporting countries. We also find that high life expectancies are compatible with low carbon emissions but high incomes are not. Finally, we see that, despite strong international trends, there is no deterministic industrial development trajectory: there is great diversity in pathways, and national histories do not necessarily follow the global trends.
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Quantifying the hurricane risk to offshore wind turbines
Stephen Rose et al.
Proceedings of the National Academy of Sciences, forthcoming
Abstract:
The U.S. Department of Energy has estimated that if the United States is to generate 20% of its electricity from wind, over 50 GW will be required from shallow offshore turbines. Hurricanes are a potential risk to these turbines. Turbine tower buckling has been observed in typhoons, but no offshore wind turbines have yet been built in the United States. We present a probabilistic model to estimate the number of turbines that would be destroyed by hurricanes in an offshore wind farm. We apply this model to estimate the risk to offshore wind farms in four representative locations in the Atlantic and Gulf Coastal waters of the United States. In the most vulnerable areas now being actively considered by developers, nearly half the turbines in a farm are likely to be destroyed in a 20-y period. Reasonable mitigation measures - increasing the design reference wind load, ensuring that the nacelle can be turned into rapidly changing winds, and building most wind plants in the areas with lower risk - can greatly enhance the probability that offshore wind can help to meet the United States' electricity needs.
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Maksim Yemelyanau, Aliaksandr Amialchuk & Mir Ali
Journal of Labor Research, March 2012, Pages 1-20
Abstract:
The Chernobyl nuclear accident of 1986 had deleterious health consequences for the population of Belarus, especially for those who were children at the time of the disaster. Using the 2003-2008 waves of the Belarusian Household Survey of Income and Expenditure (BHSIE), we estimate the effect of radiation exposure on the health, education, and labor market outcomes among cohorts and areas affected by the accident, utilizing the nuclear accident as a natural experiment. We find that young individuals who came from the most contaminated areas had worse health, were less likely to hold university degrees, were less likely to be employed, and had lower wages compared to those who were older at the time of the accident and who came from less contaminated areas.
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Global Climate Change, the Economy, and the Resurgence of Tropical Disease
Douglas Gollin & Christian Zimmermann
Mathematical Population Studies, Winter 2012, Pages 51-62
Abstract:
How will global climate change affect the prevalence of tropical diseases? In general, warmer temperatures will expand the areas in which these diseases are endemic. However, if households can take actions to protect themselves from disease - such as purchasing bednets or insecticidal sprays - then economic factors may greatly mitigate the effects of climate change. These actions are costly, however, and particularly in poor countries, many households face borrowing constraints. A model of disease transmission combining the household's objectives and constraints shows that a temperature increase of 3°C will induce modest changes in disease prevalence and output. These effects can be mitigated by improvements in the efficacy of disease prevention.
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The Consequences of Industrialization: Evidence from Water Pollution and Digestive Cancers in China
Avraham Ebenstein
Review of Economics and Statistics, February 2012, Pages 186-201
Abstract:
China's rapid industrialization has led to a severe deterioration in water quality in the country's lakes and rivers. By exploiting variation in pollution across China's river basins, I estimate that a deterioration of water quality by a single grade (on a six-grade scale) increases the digestive cancer death rate by 9.7%. The analysis rules out other potential explanations such as smoking rates, dietary patterns, and air pollution. I estimate that doubling China's levy rates for wastewater dumping would save roughly 17,000 lives per year but require an additional $500 million in annual spending on wastewater treatment.
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The sociology of ecologically unequal exchange and carbon dioxide emissions, 1960-2005
Andrew Jorgenson
Social Science Research, March 2012, Pages 242-252
Abstract:
The author engages the sociological theory of ecologically unequal exchange to assess the extent to which levels of per capita anthropogenic carbon dioxide emissions are a function of the "vertical flow" of exports to high-income nations. Results of cross-national fixed effects panel model estimates indicate that levels of such emissions are positively associated with the vertical flow of exports, and the relationship is much more pronounced for lower-income countries than for high-income countries. Additional findings suggest that the observed relationship for lower-income nations has grown in magnitude through time, indicating that structural associations between high-income and lower-income countries have become increasingly ecologically unequal, at least in the context of greenhouse gas emissions. These results hold, net of various important controls.
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Crop yields in a geoengineered climate
J. Pongratz et al.
Nature Climate Change, February 2012, Pages 101-105
Abstract:
Crop models predict that recent and future climate change may have adverse effects on crop yields. Intentional deflection of sunlight away from the Earth could diminish the amount of climate change in a high-CO2 world. However, it has been suggested that this diminution would come at the cost of threatening the food and water supply for billions of people. Here, we carry out high-CO2, geoengineering and control simulations using two climate models to predict the effects on global crop yields. We find that in our models solar-radiation geoengineering in a high-CO2 climate generally causes crop yields to increase, largely because temperature stresses are diminished while the benefits of CO2 fertilization are retained. Nevertheless, possible yield losses on the local scale as well as known and unknown side effects and risks associated with geoengineering indicate that the most certain way to reduce climate risks to global food security is to reduce emissions of greenhouse gases.
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Framing Climate Change: A study of US and Swedish press coverage of global warming
Adam Shehata & David Nicolas Hopmann
Journalism Studies, forthcoming
Abstract:
This comparative study investigates news coverage of climate change in the United States and Sweden. The main research question concerns the extent to which news coverage of climate change is influenced by domestic political elite discussion or the scientific consensus surrounding the issue. While there has been a widespread consensus in Sweden that climate change is (partly) caused by human activity and that there is an unquestionable need to take countermeasures, there has been substantial debate about the causes and the necessity of political action in the United States. Based on an extensive content analysis of 1785 articles over a 10-year period, as well as an intensive analysis of news coverage of the Kyoto and Bali summits, results show that media coverage is strikingly similar in these two countries, indicating a weak influence of national political elites on how climate change is framed in news coverage.
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"Evolution Canyon," a potential microscale monitor of global warming across life
Eviatar Nevo
Proceedings of the National Academy of Sciences, forthcoming
Abstract:
Climatic change and stress is a major driving force of evolution. The effects of climate change on living organisms have been shown primarily on regional and global scales. Here I propose the "Evolution Canyon" (EC) microscale model as a potential life monitor of global warming in Israel and the rest of the world. The EC model reveals evolution in action at a microscale involving biodiversity divergence, adaptation, and incipient sympatric speciation across life from viruses and bacteria through fungi, plants, and animals. The EC consists of two abutting slopes separated, on average, by 200 m. The tropical, xeric, savannoid, "African" south-facing slope (AS = SFS) abuts the forested "European" north-facing slope (ES = NFS). The AS receives 200-800% higher solar radiation than the ES. The ES represents the south European forested maquis. The AS and ES exhibit drought and shade stress, respectively. Major adaptations on the AS are because of solar radiation, heat, and drought, whereas those on the ES relate to light stress and photosynthesis. Preliminary evidence suggests the extinction of some European species on the ES and AS. In Drosophila, a 10-fold higher migration was recorded in 2003 from the AS to ES. I advance some predictions that could be followed in diverse species in EC. The EC microclimatic model is optimal to track global warming at a microscale across life from viruses and bacteria to mammals in Israel, and in additional ECs across the planet.
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Tongwen Zhang et al.
International Journal of Climatology, forthcoming
Abstract:
In this paper, ring-width chronologies of pine trees (Pinus sylvestris var. mongolica) from one sampling site in the northern Greater Higgnan Mountains, China, were constructed. The results of growth-climate responses show that mean temperature is the limiting factor affecting radial growth of pine trees in the study area. Consequently, mean temperature from May to October from 1717 to 2008 has been reconstructed using the standard chronology. For the calibrated period (1957-2008), the explained variance of the reconstruction is 57%. The characteristics of the reconstruction expose that mean temperature has increased since the 1970s, and the decade 2000s and 1990s are also ranked as the warm decades on record. However, this period from 1970s to now is not exceptional within the past 300 years. By applying an 11-year moving average to the reconstruction, three warm periods and three cold periods are evident. The warm and cold periods of the reconstructed mean temperature correspond well with other reconstructions. Power spectral and wavelet analysis demonstrated the existence of significant ∼70- and ∼100-year cycles of variability. Furthermore, the reconstruction and North Atlantic Oscillation Index showed a significant positive correlation (r = 0.34, n = 136, p < 0.0001).