date: Thu, 14 Feb 2002 20:17:07 -0500
from: John Arnfield <johnaatXYZxyzGRAPHY.OHIO-STATE.EDU>
subject: AASC Policy Statement on Climate Variability and Change
CLIMLIST Mailing Number 02-02-26
Origin: "David E. Stooksbury" <stooksatXYZxyzr.uga.edu>
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Policy Statement on Climate Variability and Change
by the American Association of State Climatologists (AASC)[*]
This statement provides the perspective of the AASC on issues of climate
variability and change. Since the AASC members work directly with users
of climate information at the local, state and regional levels, it is
uniquely able to put global climate issues into the local perspective
needed by the users of climate information.
Our conclusions are as follows:
1. Past climate is a useful guide to the future ^� Assessing past climate
conditions provides a very effective analysis tool to assess societal
and environmental vulnerability to future climate, regardless of the
extent the future climate is altered by human activity. Our current and
future vulnerability, however, will be different than in the past, even
if climate were not to change, because society and the environment
change as well. Decision makers need assessments of how climate
vulnerability has changed.
2. Climate prediction is complex with many uncertainties ^� The AASC
recognizes climate prediction is an extremely difficult undertaking.
For time scales of a decade or more, understanding the empirical
accuracy of such predictions ^� called ^�verification^� ^� is simply
impossible, since we have to wait a decade or longer to assess the
accuracy of the forecasts.
Climate prediction is difficult because it involves complex, nonlinear
interactions among all components of the earth^�s environmental system.
These components include the oceans, land, lakes, and continental ice
sheets, and involve physical, biological, and chemical processes. The
complicated feedbacks and forcings within the climate system are the
reasons for the difficulty in accurately predicting the future climate.
The AASC recognizes that human activities have an influence on the
climate system. Such activities, however, are not limited to greenhouse
gas forcing and include changing land use and sulfate emissions, which
further complicates the issue of climate prediction. Furthermore,
climate predictions have not demonstrated skill in projecting future
variability and changes in such important climate conditions as growing
season, drought, flood-producing rainfall, heat waves, tropical cyclones
and winter storms. These are the type of events that have a more
significant impact on society than annual average global temperature
3.Policy responses to climate variability and change should be flexible
and sensible ^� The difficulty of prediction and the impossibility of
verification of predictions decades into the future are important
factors that allow for competing views of the long-term climate future.
Therefore, the AASC recommends that policies related to long-term
climate not be based on particular predictions, but instead should focus
on policy alternatives that make sense for a wide range of plausible
climatic conditions regardless of future climate. Climate is always
changing on a variety of time scales and being prepared for the
consequences of this variability is a wise policy.
4. In their interactions with users of climate information, AASC members
recognize that the nation^�s climate policies must involve much more than
discussions of alternative energy policies ^� Climate has a profound
effect on sectors such as energy supply and demand, agriculture,
insurance, water supply and quality, ecosystem management and the
impacts of natural disasters. Whatever policies are promulgated with
respect to energy, it is imperative that policy makers recognize that
climate ^� its variability and change ^� has a broad impact on society.
The policy responses too should also be broad.
Thus, to address the issues of climate variability and change,
modernizing and maintaining high quality long-term climate data must be
a high priority in order to permit careful monitoring. With the rapid
dissemination of these data, State Climate Offices, as well as the
Regional Climate Center Offices, and the National Climatic Data
Center can better monitor emerging climate threats to critical national
resources, such as our water supply, agriculture, and energy needs. The
climate data must include all-important components of the climate system
(e.g., temperature, precipitation, humidity, vegetation health and soil
moisture). We also recommend that the nation strengthen its local,
state, and regional climate services infrastructure in order to develop
greater support capabilities for those decision makers who have to
respond to climate variability and change.
Finally, ongoing political debate about global energy policy should not
stand in the way of common sense action to reduce societal and
environmental vulnerabilities to climate variability and change.
Considerable potential exists to improve policies related to climate;
the AASC is working to turn that potential into reality.
Approved by AASC in November, 2001
[*] The American Association of State Climatologists (AASC) is the
professional organization of State Climatologists of the United States.
Each State Climatologist is appointed in his/her respective state to
provide expertise on issues associated with climate. The State
Climatologists collaborate with the six Regional Climate Centers and the
Department of Commerce^�s National Climatic Data Center (NCDC) located in
Asheville, North Carolina.