Statements by organizations
Various prominent bodies have commented on global warming,
most notably the
Intergovernmental Panel on Climate Change (IPCC). National
and international scientific groups have issued statements both
detailing and summarizing the current state of scientific
knowledge on the earth's climate.
Intergovernmental Panel on Climate
In 2007, as part of its
Fourth Assessment Report, the IPCC concluded that human
actions are "very likely" the cause of global warming, meaning a
90% or greater probability.
"The world's leading climate scientists said global
warming has begun, is very likely caused by man, and will
be unstoppable for centuries, ... . The phrase very likely
translates to a more than 90 percent certainty that global
warming is caused by man's burning of fossil fuels. That was the
strongest conclusion to date, making it nearly impossible to say
natural forces are to blame."
"The report said that an increase in hurricane and
tropical cyclone strength since 1970 more likely than not
can be attributed to man-made global warming. The scientists
said global warming's connection varies with storms in different
parts of the world, but that the storms that strike the Americas
are global warming-influenced."
"On sea levels, the report projects rises of 7-23 inches
by the end of the century. That could be augmented by an
additional 4-8 inches if recent surprising polar ice sheet melt
Joint science academies’ statement
In 2005 the national science academies of the
G8 nations, plus Brazil, China and India, three of the
largest emitters of greenhouse gases in the developing world,
signed a statement on the global response to climate change. The
statement stresses that the scientific understanding of climate
change is now sufficiently clear to justify nations taking
, and explicitly endorsed the IPCC consensus.
US National Research Council, 2001
In 2001 the Committee on the Science of Climate Change of the
National Research Council published Climate Change Science:
An Analysis of Some Key Questions
. This report explicitly endorses the IPCC view of
attribution of recent climate change as representing the view of
the science community:
- The changes observed over the last several decades are
likely mostly due to human activities, but we cannot rule
out that some significant part of these changes is also a
reflection of natural variability. Human-induced warming and
associated sea level rises are expected to continue through
the 21st century... 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.
American Meteorological Society
The American Meteorological Society (AMS) statement adopted
by their council in 2003 said:
- There is now clear evidence that the mean annual
temperature at the Earth's surface, averaged over the entire
globe, has been increasing in the past 200 years. There is
also clear evidence that the abundance of greenhouse gases
in the atmosphere has increased over the same period. In the
past decade, significant progress has been made toward a
better understanding of the climate system and toward
improved projections of long-term climate change... Human
activities have become a major source of environmental
change. Of great urgency are the climate consequences of the
increasing atmospheric abundance of greenhouse gases...
Because greenhouse gases continue to increase, we are, in
effect, conducting a global climate experiment, neither
planned nor controlled, the results of which may present
unprecedented challenges to our wisdom and foresight as well
as have significant impacts on our natural and societal
Federal Climate Change Science
On May 2, 2006, the Federal Climate Change Science Program
commissioned by the Bush administration in 2002 released the
first of 21 assessments that concluded that there is clear
evidence of human influences on the climate system (due to
changes in greenhouse gases, aerosols, and stratospheric ozone)
. The study said that observed patterns of change
over the past 50 years cannot be explained by natural processes
alone, though it did not state what percentage of climate
change might be anthropogenic in nature.
Other scientific organizations have made position statements
on climate change.
American Geophysical Union position statement on greenhouse
gases and climate change
Climate Change Science: An Analysis of Some Key Questions,
National Academy of Sciences, Commission on Geosciences,
Environment and Resources, (Washington, DC: National Academy
Joint statement on the Science of Climate Change, issued
by the Australian Academy of Sciences, Royal Flemish Academy
of Belgium for Sciences and the Arts, Brazilian Academy of
Sciences, Royal Society of Canada, Caribbean Academy of
Sciences, Chinese Academy of Sciences, French Academy of
Sciences, German Academy of Natural Scientists Leopoldina,
Indian National Science Academy, Indonesian Academy of
Sciences, Royal Irish Academy, Accademia Nazionale dei
Lincei (Italy), Academy of Sciences Malaysia, Academy
Council of the Royal Society of New Zealand, Royal Swedish
Academy of Sciences, and Royal Society (UK).
A position paper of the Stratigraphy Commission of the
Geological Society of London.
Position Statement on Global Climate Change adopted by
Geological Society of America
Policy Statement on Climate Variability and Change by the
American Association of State Climatologists (AASC)
Australian Medical Association statement on climate change
American Chemical Society statement on Global Climate
Recent Surveys of scientists
Various surveys have been conducted to determine a scientific
consensus on global warming. Unfortunetly few have been
conducted within the last ten years. Greenspan believes that
scientific consensus has only been reached in the last ten
years, so we are conducting a survey of scientists and average
The current statistics on the public perception of climate
change are: 14% of US citizens never heard of climate change and
global warming; only 41% of US citizens believe that global
warming is a serious problem. That is a serious problem because
the solution to global warming must include the United States.
We are the leading emitter of greenhouse gases. It's no wonder
that politicians in this country are not motivated to ratify the
In December 2004, an article by geologist and historian of
science Naomi Oreskes summarized a study of the scientific
literature on climate change.
The essay concluded that there is a scientific consensus on the
reality of anthropogenic climate change. The author analyzed 928
abstracts of papers from refereed scientific journals between
1993 and 2003, listed with the keywords "global climate change".
The abstracts 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. 75% of the abstracts were
placed in the first three categories, thus either explicitly or
implicitly accepting the consensus view; 25% dealt with methods
or paleoclimate, thus taking no position on current
anthropogenic climate change; none of the abstracts disagreed
with the consensus position, which the author found to be
"remarkable". It was also pointed out, "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."
Bray and von Storch, 2003
was conducted in 2003 by Dr. Dennis Bray and German
climatologist Hans von Storch. Bray's submission to Science
on December 22, 2004 was rejected
 but the survey's results were reported through
. The survey has been criticized on the grounds
that it was performed on the web with no means to verify that
the respondents were climate scientists. The survey required
entry of a username and password, but this information was
circulated to a climate skeptics mailing list
 and elsewhere on the internet.
The survey received 530 responses from 27 different countries.
One of the questions asked was "To what extent do you agree
or disagree that climate change is mostly the result of
anthropogenic causes?", with a value of 1 indicating
strongly agree and a value of 7 indicating strongly disagree.
The results showed a mean of 3.62, with 50 responses (9.4%)
indicating "strongly agree" and 54 responses (9.7%) indicating
"strongly disagree". The same survey indicates a 72% to 20%
endorsement of the IPCC reports as accurate, and a 15% to 80%
rejection of the thesis that "there is enough uncertainty
about the phenomenon of global warming that there is no need for
immediate policy decisions".
Alleged U.S. governmental
interference in reporting
According to an Associated Press release of 30 January 2007
- "Climate scientists at seven government agencies say
they have been subjected to political pressure aimed at
downplaying the threat of global warming.
- "The groups presented a survey that shows two in five of
the 279 climate scientists who responded to a questionnaire
complained that some of their scientific papers had been
edited in a way that changed their meaning. Nearly half of
the 279 said in response to another question that at some
point they had been told to delete references to "global
warming" or "climate change" from a report."
'very likely' human-made", BBC News, BBC,
2007-02-01. Retrieved on 2007-02-01.
^ Naomi Oreskes
(December 3, 2004). "Beyond
the Ivory Tower: The Scientific Consensus on Climate Change".
Science 306 (5702): 1686.
also for an exchange of letters to Science)