Scientific consensus on AGW is overwhelming

Discussion in 'Politics & Religion' started by futurecurrents, Mar 4, 2013.

  1. Scientific societies and scientists have released statements and studies showing the growing consensus on climate change science. A common objection to taking action to reduce our heat-trapping emissions has been uncertainty within the scientific community on whether or not global warming is happening and if it is caused by humans. However, there is now an overwhelming scientific consensus that global warming is indeed happening and humans are contributing to it. Below are links to documents and statements attesting to this consensus.

    Scientific Societies

    Statement on climate change from 18 scientific associations

    "Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver." (October, 2009)

    American Meteorological Society: Climate Change: An Information Statement of the American Meteorological Society

    "It is clear from extensive scientific evidence that the dominant cause of the rapid change in climate of the past half century is human-induced increases in the amount of atmospheric greenhouse gases." (August 2012)

    American Physical Society: Statement on Climate Change

    "The evidence is incontrovertible: Global warming is occurring. If no mitigating actions are taken, significant disruptions in the Earth’s physical and ecological systems, social systems, security and human health are likely to occur. We must reduce emissions of greenhouse gases beginning now." (November 2007)

    American Geophysical Union: Human Impacts on Climate

    "The Earth's climate is now clearly out of balance and is warming. Many components of the climate system—including the temperatures of the atmosphere, land and ocean, the extent of sea ice and mountain glaciers, the sea level, the distribution of precipitation, and the length of seasons—are now changing at rates and in patterns that are not natural and are best explained by the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th century." (Adopted December 2003, Revised and Reaffirmed December 2007)

    American Association for the Advancement of Science: AAAS Board Statement on Climate Change

    "The scientific evidence is clear: global climate change caused by human activities is occurring now, and it is a growing threat to society." (December 2006)

    Geological Society of America: Global Climate Change

    "The Geological Society of America (GSA) supports the scientific conclusions that Earth’s climate is changing; the climate changes are due in part to human activities; and the probable consequences of the climate changes will be significant and blind to geopolitical boundaries." (October 2006)

    American Chemical Society: Statement on Global Climate Change

    "There is now general agreement among scientific experts that the recent warming trend is real (and particularly strong within the past 20 years), that most of the observed warming is likely due to increased atmospheric greenhouse gas concentrations, and that climate change could have serious adverse effects by the end of this century." (July 2004)

    National Science Academies

    U.S. National Academy of Sciences: Understanding and Responding to Climate Change (pdf)

    "The scientific understanding of climate change is now sufficiently clear to justify taking steps to reduce the amount of greenhouse gases in the atmosphere." (2005)

    International academies: Joint science academies’ statement: Global response to climate change (pdf)

    "Climate change is real. There will always be uncertainty in understanding a system as complex as the world’s climate. However there is now strong evidence that significant global warming is occurring." (2005, 11 national academies of science)

    International academies: The Science of Climate Change

    "Despite increasing consensus on the science underpinning predictions of global climate change, doubts have been expressed recently about the need to mitigate the risks posed by global climate change. We do not consider such doubts justified." (2001, 16 national academies of science)


    National Research Council of the National Academies, America’s Climate Choices

    "Most of the recent warming can be attributed to fossil fuel burning and other human activities that release carbon dioxide and other heat-trapping greenhouse gases into the atmosphere." America's Climate Choices, Advancing the Science of Climate Change, 2010

    U.S. Climate Change Research Program, Global Climate Change Impacts in the United States (2009)

    "Global warming is unequivocal and primarily human-induced. Global temperature has increased over the past 50 years. This observed increase is due primarily to human-induced emissions of heat-trapping gases."

    Examining the Scientific Consensus on Climate Change, Peter T. Doran and Maggie Kendall Zimmerman

    "It seems that the debate on the authenticity of global warming and the role played by human activity is largely nonexistent among those who understand the nuances and scientific basis of long-term climate processes."

    Doran surveyed 10,257 Earth scientists. Thirty percent responded to the survey which asked: 1. When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant? and 2. Do you think human activity is a significant contributing factor in changing mean global temperatures?

    Beyond the Ivory Tower: The Scientific Consensus on Climate Change, Naomi Oreskes

    "Oreskes analyzed 928 abstracts published in refereed scientific journals between 1993 and 2003 and listed in the ISI database with the keywords 'climate change.'... Of all the papers, 75 percent either explicitly or implicitly accepted the consensus view that global warming is happening and humans are contributing to it; 25 percent dealt with methods or ancient climates, taking no position on current anthropogenic [human-caused] climate change. Remarkably, none of the papers disagreed with the consensus position."

    Intergovernmental Panel on Climate Change

    Climate Change 2007: The Physical Science Basis, IPCC, 2007. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

    “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level”

    “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”

    IPCC defines "very likely" as greater than 90% probability of occurrence.

    Sign-on Statements

    The Importance of Science in Addressing Climate Change: Scientists’ letter to the U.S. Congress. Statement signed by 18 scientists.
    "We want to assure you that the science is strong and that there is nothing abstract about the risks facing our Nation." (2011)

    Climate Change and the Integrity of Science
    Signed by 255 members of the National Academy of Sciences. "... For a problem as potentially catastrophic as climate change, taking no action poses a dangerous risk for our planet. ... The planet is warming due to increased concentrations of heat-trapping gases in our atmosphere. ...Most of the increase in the concentration of these gases over the last century is due to human activities, especially the burning of fossil fuels and deforestation." (2010)

    U.S. Scientists and Economists' Call for Swift and Deep Cuts in Greenhouse Gas Emissions

    "We call on our nation's leaders to swiftly establish and implement policies to bring about deep reductions in heat-trapping emissions. The strength of the science on climate change compels us to warn the nation about the growing risk of irreversible consequences as global average temperatures continue to increase over pre-industrial levels (i.e. prior to 1860). As temperatures rise further, the scope and severity of global warming impacts will continue to accelerate." (2008)
  2. The most respected scientific bodies have stated unequivocally that global warming is occurring, and people are causing it by burning fossil fuels and cutting down forests.

    This conclusion is shared by the national science academies of developed and developing countries (read the statement [PDF]), plus many other organizations, including the Intergovernmental Panel on Climate Change, which was established by the United Nations and the World Meteorological Organization to provide the world with "a clear scientific view" on climate change.

    The only real debate is about how fast warming will occur, and how much damage will be done, as a result of human activities that produce heat-trapping CO2 and other greenhouse-gas emissions.
  3. "IPCC is not alone in its conclusions. In recent years, all major scientific bodies in the United States whose members' expertise bears directly on the matter have issued similar statements. For example, the National Academy of Sciences report, Climate Change Science: An Analysis of Some Key Questions, begins: “Greenhouse gases are accumulating in Earth's atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise” [p. 1 in (5)]. The report explicitly asks whether the IPCC assessment is a fair summary of professional scientific thinking, and answers yes: “The IPCC's conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue” [p. 3 in (5)].

    Others agree. The American Meteorological Society (6), the American Geophysical Union (7), and the American Association for the Advancement of Science (AAAS) all have issued statements in recent years concluding that the evidence for human modification of climate is compelling (8).

    The drafting of such reports and statements involves many opportunities for comment, criticism, and revision, and it is not likely that they would diverge greatly from the opinions of the societies' members. Nevertheless, they might downplay legitimate dissenting opinions. That hypothesis was tested by analyzing 928 abstracts, published in refereed scientific journals between 1993 and 2003, and listed in the ISI database with the keywords “climate change” (9).

    The 928 papers were divided into six categories: explicit endorsement of the consensus position, evaluation of impacts, mitigation proposals, methods, paleoclimate analysis, and rejection of the consensus position. Of all the papers, 75% fell into the first three categories, either explicitly or implicitly accepting the consensus view; 25% dealt with methods or paleoclimate, taking no position on current anthropogenic climate change. Remarkably, none of the papers disagreed with the consensus position.

    Admittedly, authors evaluating impacts, developing methods, or studying paleoclimatic change might believe that current climate change is natural. However, none of these papers argued that point.

    This analysis shows that scientists publishing in the peer-reviewed literature agree with IPCC, the National Academy of Sciences, and the public statements of their professional societies. Politicians, economists, journalists, and others may have the impression of confusion, disagreement, or discord among climate scientists, but that impression is incorrect."
  4. 18 leading scientific organizations send letter to Senators affirming the climate is changing, “human activities are the primary driver,” impacts are projected to worsen “substantially” and “If we are to avoid the most severe impacts of climate change, emissions of greenhouse gases must be dramatically reduced.”

    American Association for the Advancement of Science
    American Chemical Society
    American Geophysical Union
    American Institute of Biological Sciences
    American Meteorological Society
    American Society of Agronomy
    American Society of Plant Biologists
    American Statistical Association
    Association of Ecosystem Research Centers
    Botanical Society of America
    Crop Science Society of America
    Ecological Society of America
    Natural Science Collections
    Alliance Organization of Biological Field Stations
    Society for Industrial and Applied Mathematics
    Society of Systematic Biologists
    Soil Science Society of America
    University Corporation for Atmospheric Research
  5. Numerous survey studies have been done, and the results are overwhelmingly in favor of scientific consensus that the earth is warming and human activity is the cause. Surveys done by reputable organizations find that around 97% of climate scientists agree with the statements above. The following are results from a few of these surveys, plus a resolution from a very distinguished group of scientists.

    Expert Credibility in Climate Change (NAS)

    This study compiled a list of 1,372 climate scientists, and then looked at those who are "actively publishing" in the science of climate. They categorized the scientists as either "convinced" or "unconvinced" by the evidence. The results were that 97% of actively publishing climate scientists are convinced by the evidence of anthropogenic climate change. They also found that those scientists that were unconvinced had significantly fewer publications (in any science) than those that were convinced. This suggests that the (vocal) "unconvinced" group actually has done a lot less research. (Read this study in full.)

    Examining the Scientific Consensus on Climate Change (AGU)

    This study was done in order to address the broader question of public opinion versus scientific opinion. It asked two questions, one about whether temperature is increasing, and one about whether or not human activity is contributing to any change. Here are the results:

    Question #1: When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?

    About 90% of all the scientists and 97% of the climate scientists said temperatures had risen.
    Question #2: Do you think human activity is a significant contributing factor in changing mean global temperatures?

    About 82% of all the scientists and 97% climate scientists agreed that human activity is a significant contributing factor.
    The anonymous poll sought the opinion of the most complete list of earth scientists they could find, contacting more than 10,200 experts at universities and government labs around the world listed in the 2007 edition of the American Geological Institute's Directory of Geoscience Departments. The 2-minute, two-question poll had 3146 responses (30.7% of those polled). Approximately 90% of the scientists who responded were from the U.S., and about 90% held a Ph.D. degree. Of these scientists, 5% were climate scientists who published more than 50% of all their peer-reviewed publications in the past five years on the subject of climate change. The authors noted that the survey included participants with well-documented dissenting opinions on global warming theory. More results from this study, including responses from the general public, are shown below in Figure 1. (Read this study in full.)
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  7. You're a loon
  8. Ricter


    But not so much as the GW deniers.
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    Well, there are still some folks here who apparently don't know about the overwhelming consensus so I thought I would (try) to educate them.
    #10     Mar 5, 2013