New Report Calls for Attention to Abrupt Impacts From Climate Change,
Emphasizes Need for Early Warning System
"Research has helped us begin to distinguish more imminent threats from
those that are less likely to happen this century," said James W.C.
White, professor of geological sciences at the University of Colorado,
Boulder, and chair of the committee that wrote the report.
"Evaluating climate changes and impacts in terms of their potential
magnitude and the likelihood they will occur will help policymakers and
communities make informed decisions about how to prepare for or adapt to
them."
Abrupt
climate changes and impacts already under way are of immediate concern,
the report says. These include the disappearance of late-summer
Arctic sea ice and increases in extinction rates of marine and
terrestrial species.
Other
scenarios, such as the destabilization of the west Antarctic ice sheet,
have potentially major consequences, but the probability of these
changes occurring within the next century is not well-understood,
highlighting the need for more research.
In some
cases, scientific understanding has progressed enough to determine
whether certain high-impact climate changes are likely to happen within
the next century. The report notes that a shutdown in the Atlantic
Ocean circulation patterns or a rapid release of methane from
high-latitude permafrost or undersea ice are now known to be unlikely
this century, although these potential abrupt changes are still
worrisome over longer time horizons.
But
even changes in the physical climate system that happen gradually over
many decades or centuries can cause abrupt ecological or socio-economic
change once a "tipping point" is reached, the report adds. For
example, relatively slow global sea-level rise could directly affect
local infrastructure such as roads, airports, pipelines, or subway
systems if a sea wall or levee is breached. And slight increases
in ocean acidity or surface temperatures could cross thresholds beyond
which many species cannot survive, leading to rapid and irreversible
changes in ecosystems that contribute to further extinction events.
Further
scientific research and enhanced monitoring of the climate, ecosystems,
and social systems may be able to provide information that a tipping
point is imminent, allowing time for adaptation or possibly mitigation,
or that a tipping point has recently occurred, the report says.
"Right
now we don’t know what many of these thresholds are," White said.
"But with better information, we will be able to anticipate some major
changes before they occur and help reduce the potential consequences."
The report identifies several research needs, such as identifying
keystone species whose population decline due to an abrupt change would
have cascading effects on ecosystems and ultimately on human provisions
such as food supply.
If
society hopes to anticipate tipping points in natural and human systems,
an early warning system for abrupt changes needs to be developed, the
report says. An effective system would need to include careful and
vigilant monitoring, taking advantage of existing land and satellite
systems and modifying them if necessary, or designing and implementing
new systems when feasible. It would also need to be flexible and
adaptive, regularly conducting and alternating between data collection,
model testing and improvement, and model predictions that suggest future
data needs.
The
study was sponsored by the National Oceanic and Atmospheric
Administration, National Science Foundation, U.S. intelligence
community, and the National Academies. The National Academy of
Sciences, National Academy of Engineering, Institute of Medicine, and
National Research Council make up the National Academies. They are
private, independent nonprofit institutions that provide science,
technology, and health policy advice under a congressional charter
granted to NAS in 1863. The Research Council is the principal
operating agency of the National Academy of Sciences and the National
Academy of Engineering. For more information, visit
http://national-academies.org.
A committee roster follows.
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NATIONAL RESEARCH COUNCIL
Division on Earth and Life Studies
Board
on Atmospheric Sciences and Climate
Committee on Understanding and Monitoring Abrupt Climate Change and Its
Impacts
James W.C. White
(chair)
Professor of Geological Sciences
Department of Geological Sciences
University of Colorado
Boulder
Richard B. Alley*
Evan
Pugh Professor of Geosciences
Department of Geosciences and the Earth and Environmental Systems
Institute
Pennsylvania State University
University Park
David Archer
Professor
Department of Geophysical Sciences
University of Chicago
Chicago
Anthony D. Barnosky
Professor
Department of Integrative Biology
University of California
Berkeley
Jonathan Foley
Director
Institute on the Environment, and
Professor and McKnight Presidential Chair
Department of Ecology, Evolution, and Behavior
University of Minnesota
Saint
Paul
Rong Fu
Professor
Jackson School of Geosciences
University of Texas
Austin
Marika Holland
Ice Specialist
Oceanography Section
Climate and Global Dynamics
National Center for Atmospheric Research
Boulder, Colo.
Susan Lozier
Professor
Nicholas School of the Environment
Duke University
Durham, N.C.
Johanna Schmitt*
Distinguished Professor
Department of Evolution and Ecology
University of California
Davis
Laurence C. Smith
Professor
Department of Geography
University of California
Los Angeles
George Sugihara
Professor and Chair
Scripps
Institution of Oceanography
University of California, San Diego
La
Jolla
David Thompson
Professor
Department of Atmospheric Science
Colorado State University
Fort Collins
Andrew J. Weaver
Lansdowne Professor
School of Earth and Ocean Sciences
University of Victoria
British Columbia
Steven C. Wofsy*
Abbott Lawrence Rotch Professor of Atmospheric and Environmental
Sciences
School of Engineering and Applied Science and
Department of Earth and Planetary Sciences
Harvard University
Cambridge, Mass.
STAFF
Edward
Dunlea
Study
Director
The National Academies
Copyright © 113. National Academy of Sciences. All rights reserved.
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