National Climate Assessment Draft Report (more...)
25x'25 Alliance Reports on Agriculture and Forestry in a Changing Climate (more...)
Reports of the US Climate Change Science Program (CCSP)
America's Climate Choices, US National Academies of Science (more...)
Climate Projections FAQ, US Department of Agriculture (more...)
Climate Engineering Fact Sheet, NOAA Research Council (more...)
The Easter Freeze of April 2007: A Climatological Perspective and Assessment of Impacts and Services (PDF 23.5MB)
Water, People, and the Future: Water Availability for Agriculture in the United States (PDF 8.6MB)
Position Statements on Climate Change by Scientific Societies
American Chemical Society (ACS) Position
Careful and comprehensive scientific assessments have clearly demonstrated that the
Earth's climate system is changing rapidly in response to growing atmospheric burdens
of greenhouse gases and absorbing aerosol particles (IPCC, 2007). There is very little
room for doubt that observed climate trends are due to human activities. The threats are
serious and action is urgently needed to mitigate the risks of climate change. The reality
of global warming, its current serious and potentially disastrous impacts on Earth
system properties, and the key role emissions from human activities play in driving
these phenomena have been recognized by earlier versions of this ACS policy statement
(ACS, 2004), by other major scientific societies, including the American Geophysical
Union (AGU, 2003), the American Meteorological Society (AMS, 2007) and the American
Association for the Advancement of Science (AAAS, 2007), and by the U. S. National
Academies and ten other leading national academies of science (NA, 2005). This
statement reviews key global climate change impacts and recommends actions
required to mitigate or adapt to currently anticipated consequences. More...
American Meteorological Society
The American Meteorological Society (AMS) http://www.ametsoc.org Council adopted a
new statement on climate change in August 2012.
The statement reads, in part,
"There is unequivocal evidence that Earth’s lower atmosphere, ocean, and land surface
are warming; sea level is rising; and snow cover, mountain glaciers, and Arctic sea ice
are shrinking. The dominant cause of the warming since the 1950s is human activities.
This scientific finding is based on a large and persuasive body of research. The
observed warming will be irreversible for many years into the future, and even larger
temperature increases will occur as greenhouse gases continue to accumulate in the
atmosphere. Avoiding this future warming will require a large and rapid reduction in
global greenhouse gas emissions. The ongoing warming will increase risks and
stresses to human societies, economies, ecosystems, and wildlife through the 21st
century and beyond, making it imperative that society respond to a changing climate. To
inform decisions on adaptation and mitigation, it is critical that we improve our
understanding of the global climate system and our ability to project future climate
through continued and improved monitoring and research. This is especially true for
smaller (seasonal and regional) scales and weather and climate extremes, and for
important hydroclimatic variables such as precipitation and water availability."
"Technological, economic, and policy choices in the near future will determine the extent
of future impacts of climate change. Science-based decisions are seldom made
in a context of absolute certainty. National and international policy discussions should
include consideration of the best ways to both adapt to and mitigate climate change.
Mitigation will reduce the amount of future climate change and the risk of impacts that
are potentially large and dangerous. At the same time, some continued climate change is
inevitable, and policy responses should include adaptation to climate change.
Prudence dictates extreme care in accounting for our relationship with the only planet
known to be capable of sustaining human life.."
Read the complete statement as follows:
Climate Change: An Information Statement of the American Meteorological Society
AGU revises position on climate change
Public release date: January 25, 2008
Contact: Peter Weiss
American Geophysical Union
WASHINGTON - A statement released on January 24 by the world’s largest scientific
society of Earth and space scientists - the American Geophysical Union, or AGU -
updates the organization’s position on climate change: the evidence for it,
potential consequences from it, and how to respond to it.
The statement is the first revision since 2003 of the climate-change position of the AGU,
which has a membership of 50,000 researchers, teachers, and students in 137
countries. The society adopted the statement at a meeting of AGU’s leadership body, the
AGU Council, in San Francisco, California, on 14 December 2007. AGU position
statements expire in four years, unless extended by the Council.
Following is the text of the revised statement (also available online at
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.
Global average surface temperatures increased on average by about 0.6°C over the
period 1956 - 2006. As of 2006, eleven of the previous twelve years were warmer than
any others since 1850. The observed rapid retreat of Arctic sea ice is expected to
continue and lead to the disappearance of summertime ice within this century. Evidence
from most oceans and all continents except Antarctica shows warming attributable to
human activities. Recent changes in many physical and biological systems are linked
with this regional climate change. A sustained research effort, involving many AGU
members and summarized in the 2007 assessments of the Intergovernmental Panel on
Climate Change, continues to improve our scientific understanding of the climate.
During recent millennia of relatively stable climate, civilization became established and
populations have grown rapidly. In the next 50 years, even the lower limit of impending
climate change - an additional global mean warming of 1°C above the last decade -
is far beyond the range of climate variability experienced during the past thousand years
and poses global problems in planning for and adapting to it. Warming greater than 2°C
above 19th century levels is projected to be disruptive, reducing global agricultural
productivity, causing widespread loss of biodiversity, and - if sustained over centuries -
melting much of the Greenland ice sheet with ensuing rise in sea level of several
meters. If this 2°C warming is to be avoided, then our net annual emissions of CO2
must be reduced by more than 50 percent within this century. With such projections,
there are many sources of scientific uncertainty, but none are known that could make the
impact of climate change inconsequential. Given the uncertainty in climate projections,
there can be surprises that may cause more dramatic disruptions than anticipated from
the most probable model projections.
With climate change, as with ozone depletion, the human footprint on Earth is apparent.
The cause of disruptive climate change, unlike ozone depletion, is tied to energy use
and runs through modern society. Solutions will necessarily involve all aspects of
society. Mitigation strategies and adaptation responses will call for collaborations
across science, technology, industry, and government. Members of the AGU, as part of
the scientific community, collectively have special responsibilities: to pursue research
needed to understand it; to educate the public on the causes, risks, and hazards; and to
communicate clearly and objectively with those who can implement policies to shape
Adopted by AGU Council, December, 2003
Revised and Reaffirmed, December, 2007