Public Attitudes, Perceptions, and Concern about Global Warming: Evidence from a New Survey
According to a February, 18, 2007, press release describing a survey on public perceptions of global warming, a majority of Americans agreed with most scientists that the Earth is getting warmer, but were divided over the seriousness of the problem, predicated on a belief that scientists themselves disagreed about global warming. What, if any, was the role of the news media in fueling that perception? Is that perception still prevalent? And where does the public stand today regarding amelioration strategies? Do people support the policy solutions that are most favored by the Presidential candidates? Is there a relation between what people know about global warming and how concerned they are about it? Is there a divide between Republicans and Democrats on these matters? If so, how might one explain these differences in perceptions about global warming?Program SummaryWith both major Presidential candidates endorsing cap and trade programs to reduce greenhouse gas emissions and Congress increasingly devoting effort to climate change legislation, the American public's views of these matters will become more important in the coming months. Yet survey evidence suggests that cap-and-trade is one of the public's least favorite ways to reduce emissions. Our speaker today, Professor Jon Krosnick, has conducted a new national survey to explore the reasons for this reluctance. Different respondents were randomly assigned to receive different descriptions of cap-and-trade, to see whether some framings increased the policy's appeal. The results identify communication strategies that were and were not successful and thereby point to reasons for the public's reluctance. The survey also experimentally tested the hypothesis that "balanced" news media coverage of climate change has caused the majority of Americans to believe that there is no consensus among scientific experts about the existence of climate change. The survey's evidence highlights unintended consequences of "optimal" journalism and the power of the press.BiographyFor 25 years, Dr. Jon A. Krosnick has conducted research exploring how the American public's political attitudes are formed, change, and shape thinking and action. He is co-principal investigator of the American National Election Study, the nation's preeminent academic project exploring voter decision-making and political campaign effects. A world-renowned expert on questionnaire design and survey research methodology, he has conducted survey studies of Americans' attitudes on environmental issues in collaboration with ABC News, the Washington Post, Time magazine, and New Scientist magazine. Dr. Krosnick has authored six books and more than 120 peer-reviewed scientific articles. His books include the Handbook of Questionnaire Design (forthcoming), Attitude Strength, Thinking about Politics, and Introduction to Survey Research, Polling, and Data Analysis. Dr. Krosnick teaches courses on survey methodology around the world at universities, for corporations, and for government agencies, testifies regularly as an expert witness in courts in the U.S. and abroad, and has served as an on-air election-night television commentator and exit poll data analyst.Dr. Krosnick earned an A.B. degree in Psychology (Magna Cum Laude) from Harvard University in 1980; an M.A. degree in Social Psychology (with Honors) from the University of Michigan in 1983, and a Ph.D. in Social Psychology from University of Michigan in 1986.
23 Jul 2008
Climate & Health Effects of Carbon Dioxide, Black Carbon & other Air-borne Particles (16 May 2008)
Contribution of Black Carbon and Atmospheric Brown Clouds to Climate Warming: Impacts and OpportunitiesBlack carbon (BC) in soot is the dominant absorber of visible solar radiation in the atmosphere. Anthropogenic sources of black carbon, although distributed globally, are most concentrated in the tropics where solar irradiance is highest. Black carbon is often transported over long distances, mixing with other aerosols along the way. The aerosol mix can form transcontinental plumes of atmospheric brown clouds (ABCs), with vertical extents of 1.8 to 3.1 miles. Because of the combination of high absorption, a regional distribution roughly aligned with solar irradiance, and the capacity to form widespread atmospheric brown clouds in a mixture with other aerosols, emissions of black carbon are the second strongest contribution to current global warming, after carbon dioxide emissions. In the Himalayan region, solar heating from black carbon at high elevations may be just as important as carbon dioxide (CO2) in the melting of snowpacks and glaciers. The interception of solar radiation by atmospheric brown clouds leads to dimming at the Earth’s surface with important implications for the hydrological cycle, and the deposition of black carbon darkens snow and ice surfaces, which can contribute to melting, in particular of Arctic sea ice. Presently, populations on the order of 3 billion people are living under the influence of regional ABC hotspots.Black carbon (BC) is an important part of the combustion product commonly referred to as soot. BC in indoor environments is largely due to cooking with biofuels such as wood, dung and crop residue. Outdoors, it is due to fossil fuel combustion (diesel and coal), open biomass burning (associated with deforestation and crop residue burning), and cooking with biofuels.Soot aerosols absorb and scatter solar radiation. BC refers to the absorbing components of soot. Dust, which also absorbs solar radiation, is not included in the definition of BC. Globally, the annual emissions of BC are (for the year 1996) roughly 8.8 tons per year, with about 20% from biofuels, 40% from fossil fuels and 40% from open biomass burning. The uncertainty in the published estimates for BC emissions is a factor of two to five on regional scales and at least ±50% on global scales. High BC emissions occur in both the northern and the Southern Hemisphere, resulting largely from fossil fuel combustion and open burning, respectively.Atmospheric brown clouds are composed of numerous submicrometer aerosols, including BC, but also sulphates, nitrates, fly ash and others. BC is also internally mixed with other aerosol species such as sulphates, nitrates, organics, dust and sea salt. BC is removed from the atmosphere by rain and snowfall. Removal by precipitation, as well as direct deposition to the surface, limits the atmospheric lifetime of BC to about one (±1) week. Causal Link between Carbon Dioxide and Air Pollution MortalityRecent research suggests that carbon dioxide, through its increase in temperatures and water vapor, increases U.S. air pollution deaths. This effect is greatest in locations where air pollution is already high. The causes of the increased death rate are increased respiratory illness, cardiovascular diseases, and complications from asthma due to increases in ozone and particulate matter. Ozone increases with more carbon dioxide because, in urban areas, higher temperatures and water vapor independently increase ozone through enhanced chemical reactions. These effects are not so important in rural areas. However, in rural areas, higher temperatures increase organic gas emissions from vegetation, increasing ozone slightly. Particles increase with more carbon dioxide because carbon dioxide increases air temperatures more than ground temperatures, reducing vertical and horizontal dispersion of pollutants.
17 May 2008
Solar Radiation, Cosmic Rays and Greenhouse Gases: What's Driving Global Warming? (23 March 2008)
Separating Solar and Anthropogenic (Greenhouse Gas-Related) Climate ImpactsDuring the past three decades a suite of space-based instruments has monitored the Sun’s brightness as well as the Earth’s surface and atmospheric temperatures. These datasets enable the separation of climate’s responses to solar activity from other sources of climate variability (anthropogenic greenhouse gases, El Niño Southern Oscillation, volcanic aerosols). The empirical evidence indicates that the solar irradiance 11-year cycle increase of 0.1% produces a global surface temperature increase of about 0.1 K with larger increases at higher altitudes. Historical solar brightness changes are estimated by modeling the contemporary irradiance changes in terms of their solar magnetic sources (dark sunspots and bright faculae) in conjunction with simulated long-term evolution of solar magnetism. In this way, the solar irradiance increase since the seventeenth century Maunder Minimum is estimated to be slightly larger than the increase in recent solar activity cycles, and smaller than early estimates that were based on variations in Sun-like stars and cosmogenic isotopes. Ongoing studies are beginning to decipher the empirical Sun- climate connections as a combination of responses to direct solar heating of the surface and lower atmosphere, and indirect heating via solar UV irradiance impacts on the ozone layer and middle atmosphere, with subsequent communication to the surface and climate. The associated physical pathways appear to involve the modulation of existing dynamical and circulation atmosphere-ocean couplings, including the El Nino Southern Oscillation (El Nino/La Nina cycles) and the Quasi-Biennial Oscillation.The Sun's Role in Past, Current and Future Climate ChangeCorrelations of instrumental or reconstructed climate time series with indices of solar activity are often being used to suggest that the climate system is tightly coupled to the sun. Yet correlations have to be used with caution because they are not necessarily synonymous with cause-and-effect relationships. Therefore, it is critical to understand the physical mechanisms that are responsible for the signals. Independent tests can then be applied to validate or reject a hypothesized link. Spatial structures that are related to the processes that translate the solar influence into a climatic response can serve as such a test. A particularly powerful example is obtained by looking at the vertical extent of the solar signal in the atmosphere.BiographiesDr. Judith Lean is Senior Scientist for Sun-Earth System Research in the Space Science Division of the Naval Research Laboratory in Washington, DC. She has served on a variety of NASA, NSF, NOAA and NRC advisory committees, including as Chair of the National Research Council (NRC) Working Group on Solar Influences on Global Change and, most recently, the NRC Committee on a Strategy to Mitigate the Impact of Sensor De-scopes and De-manifests on the NPOESS and GOES-R Spacecraft. A member of the AGU, IAGA, AAS/SPD and AMS, she was inducted as a Fellow of the American Geophysical Union in 2002 and a member of US National Academy of Sciences in 2003. Dr. Caspar Ammann is a research scientist, in the Climate and Global Dynamics Division of the National Center for Atmospheric Research in Boulder, Colorado. He has a M.S. degree in Geography and Geology from the University of Bern, Switzerland and a Ph.D. in Geosciences from the University of Massachusetts. His primary research is focused on the climate of past centuries and millennia, and how the current changes compare to this natural background. He has reconstructed past climates as well as volcanic forcing from proxy (e.g., ice cores, corals etc..) records and then simulated climate variability and response to forcings in state-of-the-art coupled Atmosphere-Ocean-General Circulation Models.
29 May 2008
The Science of Communications: What We Know We Didn't Know but Convinced Ourselves Otherwise (23 Jan 2008)
Joint Panel Discussion 8, The Science of Communications: What We Know We Didn't Know but Convinced Ourselves Otherwise (Joint between the Seventh Communications Workshop and the Third Symposium on Policy and Socio-Economic Research).Panelists: Chris Mooney, Seed Magazine, Washington, DC; Arthur Lupia, Univ. of Michigan, Ann Arbor, MI; Baruch Fischhoff, Carnegie Mellon Univ., Pittsburgh, PA; Molly Bentley, BBC World News.Moderator: Anthony Socci, AMS Policy Program, Washington, DC.
11 May 2008
Most Popular Podcasts
Adapting to Climate Change (with Q & A): What Happens to Our Transportation Infrastructure? (7 April 2008)
Adapting to Climate Change – Impacts on Our Transportation InfrastructureThe U.S. transportation system was built for the typical weather and climate experienced locally. Moderate changes in the mean climate have little impact on transportation. However, changes in weather and climate extremes can have considerable impact on transportation. Transportation relevant measures of extremes have been changing over the past several decades and are projected to continue to change in the future. Some of the changes are likely to have a positive impact on transportation and some negative.As the climate warms, cold temperature extremes are projected to continue to decrease. Milder winter conditions would likely improve the safety record for rail, air and ships. Warm extremes, on the other hand, are projected to increase. This change would likely increase the number of roadbed and railroad track bucklings and adversely impact maintenance work. As the cold season decreases and the warm season increases, northern transportation dependent upon ice roads and permanently frozen soil would be adversely affected while the projected commercial opening of the Northwest Passage would result in clear benefits to marine transportation.The warming would also produce a side benefit of shifting more of the precipitation from snow to rain. But not all precipitation changes are likely to be beneficial. Heavy precipitation events are projected to increase, which can cause local flooding. At the same time, summer drying in the interior of the continent is likely to contribute to low water levels in inland waterways. Strong mid-latitude storms are likely to become more frequent and hurricane rainfall and wind speeds are also likely increase in response to human-induced warming. Coastal transportation infrastructure is vulnerable to the combined effects of storm surge and global sea-level rise.Transportation planning operates on several different time scales. Road planners typically look out 25 years. Railroad planners consider 50 years. And bridges and underpasses are generally designed with 100 years in mind. In all cases, planning that takes likely changes into consideration will be important.
8 Apr 2008