More than 20 years ago, climate scientists began to raise alarms
over the possibility global temperatures were rising due to human
activities, such as deforestation and the burning of fossil fuels.
better understand this potential threat, the World Meteorological
Organization and the United Nations created the Intergovernmental Panel
on Climate Change (IPCC) in 1988 to provide a "comprehensive,
objective, scientific, technical and socioeconomic assessment of
human-caused climate change, its potential impacts and options for
adaptation and mitigation."
IPCC reports have predicted
average world temperatures will increase dramatically, leading to the
spread of tropical diseases, severe drought, the rapid melting of the
world's glaciers and ice caps, and rising sea levels. However, several
assessments of the IPCC's work have shown the techniques and methods
used to derive its climate predictions are fundamentally flawed.
a 2001 report, the IPCC published an image commonly referred to as the
"hockey stick." This graph showed relatively stable temperatures from
A.D. 1000 to 1900, with temperatures rising steeply from 1900 to 2000.
The IPCC and public figures, such as former Vice President Al Gore,
have used the hockey stick to support the conclusion that human energy
use over the last 100 years has caused unprecedented rise global
However, several studies cast doubt on the accuracy
of the hockey stick, and in 2006 Congress requested an independent
analysis of it. A panel of statisticians chaired by Edward J. Wegman,
of George Mason University, found significant problems with the methods
of statistical analysis used by the researchers and with the IPCC's
peer review process. For example, the researchers who created the
hockey stick used the wrong time scale to establish the mean
temperature to compare with recorded temperatures of the last century.
Because the mean temperature was low, the recent temperature rise
seemed unusual and dramatic. This error was not discovered in part
because statisticians were never consulted.
community of specialists in ancient climates from which the peer
reviewers were drawn was small and many of them had ties to the
original authors — 43 paleoclimatologists had previously coauthored
papers with the lead researcher who constructed the hockey stick.
problems led Mr. Wegman's team to conclude that the idea that the
planet is experiencing unprecedented global warming "cannot be
The IPCC published its Fourth Assessment Report
in 2007 predicting global warming will lead to widespread catastrophe
if not mitigated, yet failed to provide the most basic requirement for
effective climate policy: accurate temperature statistics. A number of
weaknesses in the measurements include the fact temperatures aren't
recorded from large areas of the Earth's surface and many weather
stations once in undeveloped areas are now surrounded by buildings,
parking lots and other heat-trapping structures resulting in an
Even using accurate temperature data, sound forecasting methods are
required to predict climate change. Over time, forecasting researchers
have compiled 140 principles that can be applied to a broad range of
disciplines, including science, sociology, economics and politics.
a recent NCPA study, Kesten Green and J. Scott Armstrong used these
principles to audit the climate forecasts in the Fourth Assessment
Report. Messrs. Green and Armstrong found the IPCC clearly violated 60
of the 127 principles relevant in assessing the IPCC predictions.
Indeed, it could only be clearly established that the IPCC followed 17
of the more than 127 forecasting principles critical to making sound
A good example of a principle clearly violated
is "Make sure forecasts are independent of politics." Politics shapes
the IPCC from beginning to end. Legislators, policymakers and/or
diplomatic appointees select (or approve) the scientists — at least the
lead scientists — who make up the IPCC. In addition, the summary and
the final draft of the IPCC's Fourth Assessment Report was written in
collaboration with political appointees and subject to their approval.
Mr. Green and Mr. Armstrong found no evidence the IPCC was even aware
of the vast literature on scientific forecasting methods, much less
applied the principles.
The IPCC and its defenders often
argue that critics who are not climate scientists are unqualified to
judge the validity of their work. However, climate predictions rely on
methods, data and evidence from other fields of expertise, including
statistical analysis and forecasting. Thus, the work of the IPCC is
open to analysis and criticism from other disciplines.
IPCC's policy recommendations are based on flawed statistical analyses
and procedures that violate general forecasting principles.
Policymakers should take this into account before enacting laws to
counter global warming — which economists point out would have severe