So hot
Big Data Sensors of Organic Advocacy: The Case of Leonardo DiCaprio and Climate Change
Eric Leas et al.
PLoS ONE, August 2016
Abstract:
The strategies that experts have used to share information about social causes have historically been top-down, meaning the most influential messages are believed to come from planned events and campaigns. However, more people are independently engaging with social causes today than ever before, in part because online platforms allow them to instantaneously seek, create, and share information. In some cases this “organic advocacy” may rival or even eclipse top-down strategies. Big data analytics make it possible to rapidly detect public engagement with social causes by analyzing the same platforms from which organic advocacy spreads. To demonstrate this claim we evaluated how Leonardo DiCaprio’s 2016 Oscar acceptance speech citing climate change motivated global English language news (Bloomberg Terminal news archives), social media (Twitter postings) and information seeking (Google searches) about climate change. Despite an insignificant increase in traditional news coverage (54%; 95%CI: -144 to 247), tweets including the terms “climate change” or “global warming” reached record highs, increasing 636% (95%CI: 573–699) with more than 250,000 tweets the day DiCaprio spoke. In practical terms the “DiCaprio effect” surpassed the daily average effect of the 2015 Conference of the Parties (COP) and the Earth Day effect by a factor of 3.2 and 5.3, respectively. At the same time, Google searches for “climate change” or “global warming” increased 261% (95%CI, 186–335) and 210% (95%CI 149–272) the day DiCaprio spoke and remained higher for 4 more days, representing 104,190 and 216,490 searches. This increase was 3.8 and 4.3 times larger than the increases observed during COP’s daily average or on Earth Day. Searches were closely linked to content from Dicaprio’s speech (e.g., “hottest year”), as unmentioned content did not have search increases (e.g., “electric car”). Because these data are freely available in real time our analytical strategy provides substantial lead time for experts to detect and participate in organic advocacy while an issue is salient. Our study demonstrates new opportunities to detect and aid agents of change and advances our understanding of communication in the 21st century media landscape.
---------------------
The abandoned ice sheet base at Camp Century, Greenland, in a warming climate
William Colgan et al.
Geophysical Research Letters, forthcoming
Abstract:
In 1959 the U.S. Army Corps of Engineers built Camp Century beneath the surface of the northwestern Greenland Ice Sheet. There they studied the feasibility of deploying ballistic missiles within the ice sheet. The base and its wastes were abandoned with minimal decommissioning in 1967, under the assumption they would be preserved for eternity by perpetually accumulating snowfall. Here we show that a transition in ice sheet surface mass balance at Camp Century from net accumulation to net ablation is plausible within the next 75 years, under a business-as-usual anthropogenic emissions scenario (Representative Concentration Pathway 8.5). Net ablation would guarantee the eventual remobilization of physical, chemical, biological, and radiological wastes abandoned at the site. While Camp Century and four other contemporaneous ice sheet bases were legally established under a Danish-U.S. treaty, the potential remobilization of their abandoned wastes, previously regarded as sequestered, represents an entirely new pathway of political dispute resulting from climate change.
---------------------
A Forward Looking Ricardian Approach: Do Land Markets Capitalize Climate Change Forecasts?
Christopher Severen, Christopher Costello & Olivier Deschenes
NBER Working Paper, July 2016
Abstract:
The hedonic pricing method is one of the fundamental approaches used to estimate the economic value of attributes that affect the market price of an asset. In environmental economics, such methods are routinely used to derive the economic valuation of environmental attributes such as air pollution and water quality. For example, the Ricardian approach is based on a hedonic regression of land values on historical climate variables. Forecasts of future climate can then be employed to estimate the future costs of climate change. This extensively-applied approach contains an important implicit assumption that current land markets ignore current climate forecasts. While this assumption was defensible decades ago (when this literature first emerged), it is reasonable to hypothesize that information on climate change is so pervasive today that markets may already price in expectations of future climate change. We show how to account for this with a straightforward empirical correction (called the Forward-Looking Ricardian Approach) that can be implemented with readily available data. We apply this empirically to agricultural land markets in the United States and find evidence that these markets already are accounting for climate change forecasts. Failing to account for this would lead a researcher to understate climate change damages by 36% to 66%.
---------------------
Political affiliation affects adaptation to climate risks: Evidence from New York City
W.J. Wouter Botzen et al.
Climatic Change, forthcoming
Abstract:
Research reveals that liberals and conservatives in the United States diverge about their beliefs regarding climate change. We show empirically that political affiliation also matters with respect to climate related risks such as flooding from hurricanes. Our study is based on a survey conducted 6 months after Superstorm Sandy in 2012 of over 1,000 residents in flood-prone areas in New York City. Democrats’ perception of their probability of suffering flood damage is significantly higher than Republicans’ and they are also more likely to invest in individual flood protection measures. However, 50% more Democrats than Republicans in our sample expect to receive federal disaster relief after a major flood. These results highlight the importance of taking into account value-based considerations in designing disaster risk management policies.
---------------------
Partisan differences in the relationship between newspaper coverage and concern over global warming
Xiaoquan Zhao, Justin Rolfe-Redding & John Kotcher
Public Understanding of Science, July 2016, Pages 543-559
Abstract:
The effects of news media on public opinion about global warming have been a topic of much interest in both academic and popular discourse. Empirical evidence in this regard, however, is still limited and somewhat mixed. This study used data from the 2006 General Social Survey in combination with a content analysis of newspaper coverage of the same time period to examine the relationship between general news climate and public concern about global warming. Results showed a pattern of political polarization, with increased coverage associated with growing divergence between Democrats and Republicans. Further analysis also showed evidence of reactivity in partisan response to coverage from different news outlets. These findings point to a particular form of politically motivated, biased processing of news information.
---------------------
Chang-Yuan Lee et al.
PLoS ONE, July 2016
Abstract:
In the last few decades, awareness of environmental issues has increased significantly. Little has changed, however, in human activities contributing to environmental damage. Why is it so difficult for us to change our behavior in a domain that is clearly so important to the future of humanity? Here we propose and test the possibility that self-signaling, the way we view ourselves based on our past behaviors, is one of the factors contributing to the difficulty of taking environmental action. In three experiments, we show that previous self-interested thoughts or behaviors serve as important signals that hinder the likelihood of acting in line with an individual’s reported concern for the environment. This study not only helps explain the gap between environmental awareness and action, but also suggests alternative strategies for policymakers and environmental agencies to promote proenvironmental behavior.
---------------------
How Positive Framing May Fuel Opposition to Low-Carbon Technologies: The Boomerang Model
Gerdien de Vries
Journal of Language and Social Psychology, forthcoming
Abstract:
Low-carbon technologies are necessary to combat global warming. However, they are often opposed by members of the general public, causing costly delays and cancellations. In this article, I argue that language may be a relevant cause of such opposition. I introduce a theoretical model describing a boomerang effect in which positively framed communication about low-carbon technologies may actually lead to opposition in the long run. An example of positive framing is emphasising the climate benefits of a technology while neglecting to mention associated safety risks. I predict that, over time, people begin to perceive positive framing as an attempt to manipulate them into supporting a technology. In turn, this perceived manipulation may make them feel that their freedom to make their own decision to support or oppose the technology is under threat. To counter this behavioural threat, people may begin to oppose low-carbon technologies. My boomerang model further describes how certain characteristics of the source of information as well as of the recipient may influence both the direct and indirect effects of positive framing. I then discuss the model’s implications for effective communication and indicate directions for future research.
---------------------
Attributing human mortality during extreme heat waves to anthropogenic climate change
Daniel Mitchell et al.
Environmental Research Letters, July 2016
Abstract:
It has been argued that climate change is the biggest global health threat of the 21st century. The extreme high temperatures of the summer of 2003 were associated with up to seventy thousand excess deaths across Europe. Previous studies have attributed the meteorological event to the human influence on climate, or examined the role of heat waves on human health. Here, for the first time, we explicitly quantify the role of human activity on climate and heat-related mortality in an event attribution framework, analysing both the Europe-wide temperature response in 2003, and localised responses over London and Paris. Using publicly-donated computing, we perform many thousands of climate simulations of a high-resolution regional climate model. This allows generation of a comprehensive statistical description of the 2003 event and the role of human influence within it, using the results as input to a health impact assessment model of human mortality. We find large-scale dynamical modes of atmospheric variability remain largely unchanged under anthropogenic climate change, and hence the direct thermodynamical response is mainly responsible for the increased mortality. In summer 2003, anthropogenic climate change increased the risk of heat-related mortality in Central Paris by ~70% and by ~20% in London, which experienced lower extreme heat. Out of the estimated ~315 and ~735 summer deaths attributed to the heatwave event in Greater London and Central Paris, respectively, 64 (±3) deaths were attributable to anthropogenic climate change in London, and 506 (±51) in Paris. Such an ability to robustly attribute specific damages to anthropogenic drivers of increased extreme heat can inform societal responses to, and responsibilities for, climate change.
---------------------
Demographic controls of future global fire risk
W. Knorr, A. Arneth & L. Jiang
Nature Climate Change, August 2016, Pages 781–785
Abstract:
Wildfires are an important component of terrestrial ecosystem ecology but also a major natural hazard to societies, and their frequency and spatial distribution must be better understood. At a given location, risk from wildfire is associated with the annual fraction of burned area, which is expected to increase in response to climate warming. Until recently, however, only a few global studies of future fire have considered the effects of other important global environmental change factors such as atmospheric CO2 levels and human activities, and how these influence fires in different regions. Here, we contrast the impact of climate change and increasing atmospheric CO2 content on burned area with that of demographic dynamics, using ensembles of climate simulations combined with historical and projected population changes under different socio-economic development pathways for 1901–2100. Historically, humans notably suppressed wildfires. For future scenarios, global burned area will continue to decline under a moderate emissions scenario, except for low population growth and fast urbanization, but start to increase again from around mid-century under high greenhouse gas emissions. Contrary to common perception, we find that human exposure to wildfires increases in the future mainly owing to projected population growth in areas with frequent wildfires, rather than by a general increase in burned area.
---------------------
Climate consequences of low-carbon fuels: The United States Renewable Fuel Standard
Jason Hill, Liaila Tajibaeva & Stephen Polasky
Energy Policy, October 2016, Pages 351–353
Abstract:
A common strategy for reducing greenhouse gas (GHG) emissions from energy use is to increase the supply of low-carbon alternatives. However, increasing supply tends to lower energy prices, which encourages additional fuel consumption. This “fuel market rebound effect” can undermine climate change mitigation strategies, even to the point where efforts to reduce GHG emissions by increasing the supply of low-carbon fuels may actually result in increased GHG emissions. Here, we explore how policies that encourage the production of low-carbon fuels may result in increased GHG emissions because the resulting increase in energy use overwhelms the benefits of reduced carbon intensity. We describe how climate change mitigation strategies should follow a simple rule: a low-carbon fuel with a carbon intensity of X% that of a fossil fuel must displace at least X% of that fossil fuel to reduce overall GHG emissions. We apply this rule to the United States Renewable Fuel Standard (RFS2). We show that absent consideration of the fuel market rebound effect, RFS2 appears to reduce GHG emissions, but once the fuel market rebound effect is factored in, RFS2 actually increases GHG emissions when all fuel GHG intensity targets are met.
---------------------
Global sea-level rise: Weighing country responsibility and risk
Dean Hardy & Bryan Nuse
Climatic Change, August 2016, Pages 333-345
Abstract:
Accelerated sea-level rise will be one of the most significant effects of global warming. Global mean sea level has risen more than 0.2 m since 1880 and continues rising at above 4 mm yr.−1. Here we allocate responsibility to countries for global sea-level rise commitment (SLRC) over the period 1850 to 2100 and weigh that against their exposure to inundation from sea-level rise. We bridge two lines of climate-related research by combining assessment of countries’ greenhouse gas emissions with predictions of the multi-millennial sea level response to global warming. Under the Intergovernmental Panel on Climate Change’s business-as-usual scenario our findings show that the five most responsible countries for global SLRC are also the most exposed to absolute land loss. This is mostly due to their own emissions, which we call intrinsic risk. We also assess extrinsic risk, defined as a country’s land exposed to inundation due to all other countries’ emissions. We show that for 6 m of global SLRC, the two non-island countries with the highest extrinsic risk are predicted to lose 27 % and 15 % of their own land, yet contributed less than 1.1 % each to the emissions driving SLRC. We anticipate that our findings will directly inform policy discussions in international climate negotiations by identifying the relative degree of country responsibility and risk associated with sea-level rise.
---------------------
Future Decreases in Freezing Days Across North America
Michael Rawlins et al.
Journal of Climate, forthcoming
Abstract:
We used air temperatures from a suite of regional climate models participating in the North American Climate Change Assessment Program (NARCCAP) together with two atmospheric reanalysis data sets to investigate changes in freezing days (defined as days with daily average temperature below freezing) likely to occur between 30 year baseline (1971–2000) and mid-century (2041–2070) periods across most of North America. Changes in NARCCAP ensemble mean winter temperature show a strong gradient with latitude, with warming of over 4°C near Hudson Bay. The decline in freezing days ranges from less than 10 days across north-central Canada to nearly 90 days in the warmest areas of the continent that currently undergo seasonally freezing conditions. The area experiencing freezing days contracts by 0.9–1.0 million km2 (5.7%–6.4% of the total area). Areas with mean annual temperature between 2–6°C and a relatively low rate of change in climatological daily temperatures (< 0.2°C day−1) near the time of spring thaw will encounter the greatest decreases in freezing days. Advances in the timing of spring thaw will exceed the delay in fall freeze across much of the US, with the reverse pattern likely over most of Canada.
---------------------
Effects of a Warming Climate on Daily Snowfall Events in the Northern Hemisphere
James Danco et al.
Journal of Climate, forthcoming
Abstract:
Using simulations performed with 24 coupled atmosphere-ocean global climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5), projections of Northern Hemisphere daily snowfall events under the RCP8.5 emissions scenario are analyzed for the periods of 2021-2050 and 2071-2100 and compared to the historical period of 1971-2000. The overall frequency of daily snowfall events is simulated to decrease across much of the Northern Hemisphere, except at the highest latitudes such as northern Canada, northern Siberia, and Greenland. Seasonal redistributions of daily snowfall event frequency and average daily snowfall are also projected to occur in some regions. For example, large portions of the Northern Hemisphere, including much of Canada, Tibet, northern Scandinavia, northern Siberia, and Greenland, are projected to experience increases in average daily snowfall and event frequency in midwinter. But in warmer months, the regions with increased snowfall become fewer in number and are limited to northern Canada, northern Siberia, and Greenland. These simulations also show changes in the frequency distribution of daily snowfall event intensity, including an increase in heavier snowfall events even in some regions where the overall snowfall decreases. The projected changes in daily snowfall event frequency exhibit some dependence on the temperature biases of the individual models in certain regions and times of the year, with colder models typically toward the positive end of the distribution of event frequency changes and warmer models toward the negative end, particularly in regions near the transition zone between increasing and decreasing snowfall.
---------------------
Bridging the Gap: Do Fast Reacting Fossil Technologies Facilitate Renewable Energy Diffusion?
Elena Verdolini, Francesco Vona & David Popp
NBER Working Paper, July 2016
Abstract:
The diffusion of renewable energy in the power system implies high supply variability. Lacking economically viable storage options, renewable energy integration has so far been possible thanks to the presence of fast-reacting mid-merit fossil-based technologies, which act as back-up capacity. This paper discusses the role of fossil-based power generation technologies in supporting renewable energy investments. We study the deployment of these two technologies conditional on all other drivers in 26 OECD countries between 1990 and 2013. We show that a 1% percent increase in the share of fast-reacting fossil generation capacity is associated with a 0.88% percent increase in renewable in the long run. These results are robust to various modifications in our empirical strategy, and most notably to the use of system-GMM techniques to account for the interdependence of renewable and fast-reacting fossil investment decisions. Our analysis points to the substantial indirect costs of renewable energy integration and highlights the complementarity of investments in different generation technologies for a successful decarbonization process.
---------------------
A retrospective analysis of benefits and impacts of U.S. renewable portfolio standards
Galen Barbose et al.
Energy Policy, September 2016, Pages 645–660
Abstract:
As states consider revising or developing renewable portfolio standards (RPS), they are evaluating policy costs, benefits, and other impacts. We present the first U. S. national-level assessment of state RPS program benefits and impacts, focusing on new renewable electricity resources used to meet RPS compliance obligations in 2013. In our central-case scenario, reductions in life-cycle greenhouse gas emissions from displaced fossil fuel-generated electricity resulted in $2.2 billion of global benefits. Health and environmental benefits from reductions in criteria air pollutants (sulfur dioxide, nitrogen oxides, and particulate matter 2.5) were even greater, estimated at $5.2 billion in the central case. Further benefits accrued in the form of reductions in water withdrawals and consumption for power generation. Finally, although best considered resource transfers rather than net societal benefits, new renewable electricity generation used for RPS compliance in 2013 also supported nearly 200,000 U. S.-based gross jobs and reduced wholesale electricity prices and natural gas prices, saving consumers a combined $1.3–$4.9 billion. In total, the estimated benefits and impacts well-exceed previous estimates of RPS compliance costs.
---------------------
Crop Yield Changes Induced by Emissions of Individual Climate-Altering Pollutants
Drew Shindell
Earth's Future, forthcoming
Abstract:
Climate change damages agriculture, causing deteriorating food security and increased malnutrition. Many studies have examined the role of distinct physical processes, but impacts have not been previously attributed to individual pollutants. Using a simple model incorporating process-level results from detailed models, here I show that although carbon dioxide (CO2) is the largest driver of climate change, other drivers dominate agricultural yield changes. I calculate that anthropogenic emissions to date have decreased global agricultural yields by 9.5 ± 3.0%, with roughly 93% stemming from non-CO2 emissions, including methane (-5.2 ± 1.7%) and halocarbons (-1.4 ± 0.4%). The differing impacts stem from atmospheric composition responses: CO2 fertilizes crops, offsetting much of the loss induced by warming; halocarbons do not fertilize; methane leads to minimal fertilization but increases surface ozone which augments warming-induced losses. By the end of the century, strong CO2 mitigation improves agricultural yields by ~3 ± 5%. In contrast, strong methane and hydrofluorocarbon mitigation improve yields by ~16 ± 5% and ~5 ± 4%, respectively. These are the first quantitative analyses to include climate, CO2 and ozone simultaneously, and hence additional studies would be valuable. Nonetheless, as policy makers have leverage over pollutant emissions rather than isolated processes, the perspective presented here may be more useful for decision making than that in the prior work upon which this study builds. The results suggest that policies should target a broad portfolio of pollutant emissions in order to optimize mitigation of societal damages.
---------------------
Past and Projected Changes in Western North Pacific Tropical Cyclone Exposure
James Kossin, Kerry Emanuel & Suzana Camargo
Journal of Climate, August 2016, Pages 5725–5739
Abstract:
The average latitude where tropical cyclones (TCs) reach their peak intensity has been observed to be shifting poleward in some regions over the past 30 years, apparently in concert with the independently observed expansion of the tropical belt. This poleward migration is particularly well observed and robust in the western North Pacific Ocean (WNP). Such a migration is expected to cause systematic changes, both increases and decreases, in regional hazard exposure and risk, particularly if it persists through the present century. Here, it is shown that the past poleward migration in the WNP has coincided with decreased TC exposure in the region of the Philippine and South China Seas, including the Marianas, the Philippines, Vietnam, and southern China, and increased exposure in the region of the East China Sea, including Japan and its Ryukyu Islands, the Korea Peninsula, and parts of eastern China. Additionally, it is shown that projections of WNP TCs simulated by, and downscaled from, an ensemble of numerical models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) demonstrate a continuing poleward migration into the present century following the emissions projections of the representative concentration pathway 8.5 (RCP8.5). The projected migration causes a shift in regional TC exposure that is very similar in pattern and relative amplitude to the past observed shift. In terms of regional differences in vulnerability and resilience based on past TC exposure, the potential ramifications of these future changes are significant. Questions of attribution for the changes are discussed in terms of tropical belt expansion and Pacific decadal sea surface temperature variability.
---------------------
Lothar Schlüter et al.
Science Advances, July 2016
Abstract:
Marine phytoplankton may adapt to ocean change, such as acidification or warming, because of their large population sizes and short generation times. Long-term adaptation to novel environments is a dynamic process, and phenotypic change can take place thousands of generations after exposure to novel conditions. We conducted a long-term evolution experiment (4 years = 2100 generations), starting with a single clone of the abundant and widespread coccolithophore Emiliania huxleyi exposed to three different CO2 levels simulating ocean acidification (OA). Growth rates as a proxy for Darwinian fitness increased only moderately under both levels of OA [+3.4% and +4.8%, respectively, at 1100 and 2200 μatm partial pressure of CO2 (PCO2)] relative to control treatments (ambient CO2, 400 μatm). Long-term adaptation to OA was complex, and initial phenotypic responses of ecologically important traits were later reverted. The biogeochemically important trait of calcification, in particular, that had initially been restored within the first year of evolution was later reduced to levels lower than the performance of nonadapted populations under OA. Calcification was not constitutively lost but returned to control treatment levels when high CO2–adapted isolates were transferred back to present-day control CO2 conditions. Selection under elevated CO2 exacerbated a general decrease of cell sizes under long-term laboratory evolution. Our results show that phytoplankton may evolve complex phenotypic plasticity that can affect biogeochemically important traits, such as calcification. Adaptive evolution may play out over longer time scales (>1 year) in an unforeseen way under future ocean conditions that cannot be predicted from initial adaptation responses.
---------------------
Global climate change driven by soot at the K-Pg boundary as the cause of the mass extinction
Kunio Kaiho et al.
Scientific Reports, July 2016
Abstract:
The mass extinction of life 66 million years ago at the Cretaceous/Paleogene boundary, marked by the extinctions of dinosaurs and shallow marine organisms, is important because it led to the macroevolution of mammals and appearance of humans. The current hypothesis for the extinction is that an asteroid impact in present-day Mexico formed condensed aerosols in the stratosphere, which caused the cessation of photosynthesis and global near-freezing conditions. Here, we show that the stratospheric aerosols did not induce darkness that resulted in milder cooling than previously thought. We propose a new hypothesis that latitude-dependent climate changes caused by massive stratospheric soot explain the known mortality and survival on land and in oceans at the Cretaceous/Paleogene boundary. The stratospheric soot was ejected from the oil-rich area by the asteroid impact and was spread globally. The soot aerosols caused sufficiently colder climates at mid–high latitudes and drought with milder cooling at low latitudes on land, in addition to causing limited cessation of photosynthesis in global oceans within a few months to two years after the impact, followed by surface-water cooling in global oceans in a few years. The rapid climate change induced terrestrial extinctions followed by marine extinctions over several years.