In a consensus letter to U.S. policymakers, a partnership of 31 leading nonpartisan scientific societies today reaffirmed the reality of human-caused climate change, noting that greenhouse gas emissions "must be substantially reduced" to minimize negative impacts on the global economy, natural resources, and human health.
"Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research concludes that the greenhouse gases emitted by human activities are the primary driver," the collaborative said in its 28 June letter to Members of Congress. "This conclusion is based on multiple independent lines of evidence and the vast body of peer-reviewed science."
Climate-change impacts in the United States have already included increased threats of extreme weather events, sea-level rise, water scarcity, heat waves, wildfires, and disturbances to ecosystems and animals, the intersociety group reported. "The severity of climate change impacts is increasing and is expected to increase substantially in the coming decades," the letter added. It cited the scientific consensus of the vast majority of individual climate scientists and virtually every leading scientific organization in the world, including the U.S. Global Change Research Program, the U.S. National Academies, the Intergovernmental Panel on Climate Change, the American Association for the Advancement of Science (AAAS), the American Chemical Society, the American Geophysical Union, the American Meteorological Society, the American Statistical Association, the Ecological Society of America, and the Geological Society of America.
"To reduce the risk of the most severe impacts of climate change, greenhouse gas emissions must be substantially reduced," the group said, adding that adaptation is also necessary to "address unavoidable consequences for human health and safety, food security, water availability, and national security, among others."
The 28 June letter, representing a broad range of scientific disciplines, reaffirmed the key climate-change messages in a 2009 letter signed by 18 leading scientific organizations. The letter is being released again, by a larger consortium of 31 scientific organizations, to reassert the scientific consensus on climate change, and to provide objective, authoritative information to policymakers who must work toward solutions.
"Climate change is real and happening now, and the United States urgently needs to reduce greenhouse gas emissions," said AAAS Chief Executive Officer Rush Holt, executive publisher of the Science family of journals. "We must not delay, ignore the evidence, or be fearful of the challenge. America has provided global leadership to successfully confront many environmental problems, from acid rain to the ozone hole, and we can do it again. We owe no less to future generations."
The 28 June letter was signed by leaders of the following organizations:
American Association for the Advancement of Science
American Chemical Society
American Geophysical Union
American Institute of Biological Sciences
American Meteorological Society
American Public Health Association
American Society of Agronomy
American Society of Ichthyologists and Herpetologists
American Society of Naturalists
American Society of Plant Biologists
American Statistical Association
Association for the Sciences of Limnology and Oceanography
Association for Tropical Biology and Conservation
Association of Ecosystem Research Centers
BioQUEST Curriculum Consortium
Botanical Society of America
Consortium for Ocean Leadership
Crop Science Society of America
Ecological Society of America
Entomological Society of America
Geological Society of America
National Association of Marine Laboratories
Natural Science Collections Alliance
Organization of Biological Field Stations
Society for Industrial and Applied Mathematics
Society for Mathematical Biology
Society for the Study of Amphibians and Reptiles
Society of Nematologists
Society of Systematic Biologists
Soil Science Society of America
University Corporation for Atmospheric Research
Leaders of participating organizations offered the following comments:
"Climate change has far-reaching implications to everyone on our planet, as it is tied closely with national security, economics, human health, and food security. There is consensus in the scientific community - climate is changing. Now we need policymakers to act, to invest in research to understand the effects of climate change and opportunities to mitigate its drivers, and to adapt to its impacts."
-- RADM Jonathan W. White, USN (Ret.), president and CEO, Consortium for Ocean Leadership
"Climate change poses significant challenges to natural and managed ecosystems. Now is the time for scientists and policy-makers to work together to address the issue of climate change in order to protect agricultural productivity, global food security and environmental resources."
-- Harold van Es, president, Soil Science Society of America
"The environmental, social, and economic challenges posed by climate change are among the most important issues of our time. Comprehensive solutions grounded in understanding of ecological systems - our lands, waters, oceans, and atmosphere -- and society are urgently needed. A sustainable future remains possible if we work together and act now."
-- Monica G. Turner, president, Ecological Society of America
"This letter, signed by a diverse set of scientific organizations, conveys the solid scientific consensus view that anthropogenic climate change is occurring. How climate change will manifest for specific geographic regions within the next decade and beyond is a topic of intense research. Statisticians are experts in making decisions when specifics aren't clear and stand ready to work with decision-makers."
-- Jessica Utts, president, American Statistical Association
"Geological studies have demonstrated that climate has changed repeatedly in the past and that future climate change is inevitable. Understanding the complex processes involved in climate change is necessary for adaptation and mitigation."
-- Jonathan G. Price, Ph.D., CPG, President, Geological Society of America
"The reality of climate change is already upon us, and is affecting not only our lives but that of all life on earth. We must do all that we can to mitigate these effects using scientific knowledge and mobilizing society for action. It is the responsibility of our politicians to move us forward in these actions."
--Dr. Robin L. Chazdon, executive director of the Association for Tropical Biology and Conservation,
"The phenomenon of human-mediated climate change is not a matter of opinion, but of careful evaluation of data from a vast spectrum of scientific disciplines. What remains unclear is the degree to which climate change will cause environmental, social, and economic havoc. Estimates range from severe to catastrophic. We owe it to our children and to our children's children to take bold action now so that our descendants do not pay the price for our generation's greed."
-- Anne D. Yoder, president, Society of Systematic Biologists
"Climate change is one of the most profound challenges facing our society. Consensus on this matter is evident in the diversity of organizations that have signed this letter. Science can be a powerful tool in our efforts to mitigate and adapt to the impacts of climate change, and we stand ready to work with policymakers as they deliberate various options for action."
-- Christine McEntee, executive director/CEO of the American Geophysical Union
"Climate influences where plants and animals live. Rapid climate change will force species to find new habitat in hospitable conditions, but many species will not be able to and will go extinct. This isn't good. It disrupts our ecosystems, which are the source for our food, and clean air and water."
-- Robert Gropp, Ph.D., interim co-executive director, American Institute of Biological Sciences
A PDF of the consensus letter is available at http://www.