Transcript Communicating Climate Change Science (Intergovernmental Panel on Climate Change) Tim Killeen Director, National Center for Atmospheric Research President, American Geophysical Union AGI Geoscience Leadership Forum 30 April 2007

Communicating Climate
Change Science
(Intergovernmental Panel on
Climate Change)
Tim Killeen
Director, National Center for Atmospheric Research
President, American Geophysical Union
AGI Geoscience Leadership Forum
30 April 2007
National Center for
Atmospheric Research
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National Science Foundation funded
Center, >1,000 Scientists and
engineers, 48 year history
Earth System Sciences:
Computational and Observational
Science and facilities for Weather,
Climate, Chemistry, Space Weather,
Society-Environment Interactions
American Geophysical Union
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World’s largest Geophysics Society (>49,900 members,
20% students, 130 countries)
Interdisciplinary science for the atmospheric and ocean
sciences; solid-Earth sciences; hydrologic sciences; and
space science
AGU Mission
AGU Council, 2005
EOS, Vol. 86, No. 23, 219, 2005
• AGU is a worldwide scientific community that advances,
through unselfish cooperation in research, the understanding
of Earth and space for the benefit of humanity.
• AGU is advancing the Earth and space sciences by catalyzing
and supporting the efforts of individual scientists within and
outside the membership. We are organizing and disseminating
information for the scientific community. As a learned society
we meet our obligation to serve the public good by fostering
quality in the Earth and space sciences and bringing the results
of research to the public. These efforts are yielding greater
numbers and diversity of well-educated students and young
professionals in the Earth and space sciences, and are
increasing the public's understanding and appreciation of the
value of science and support for it.
The Two Cultures
What scientists say:
• 90% of scientists think few members of the press
understand the nature of science and technology
• 66% said most press members have no idea how to
interpret scientific results
• 69% said most reporters have no understanding of
scientific method
• More than 50% have had a bad experience
What journalists say:
• 85% of reporters think scientists are somewhat or
not at all accessible
• 62% think scientists are so intellectual or immersed
in their jargon that they cannot communicate
Results from survey, used in NCAR media training, 2007
NCAR
Scientists
Involved
in IPCC
Working
Group I
AGU’s Climate
Statements
1998 (reaffirmed in 2002)
AGU believes that the present level of scientific
uncertainty does not justify inaction in the mitigation
of human-induced climate change and/or the
adaptation to it.
2003:
The global climate is changing and human activities
are contributing to that change.
2007:
Planned
The Challenge of Simulating the
Global Earth System
Atmosphere
Hydrosphere
Cryosphere
Biosphere
The Earth System
From Andi Andreae
CCSM Working Groups
Atmosphere
Model
Crosscutting
Climate Change
PaleoClimate
Biogeochemistry
Climate Variability
Software Engineering
Land
Model
Model-centric
Ocean
Model
Polar
Climate
Need for High Resolution
QuickTime™ and a
Photo decompressor
are needed to see this picture.
Science Driven Demand for
Supercomputing
Modern Climate Model Simulations
NCAR’s Bluesky Supercomputer: Characteristics of NCAR Model:
• 1600 Processors
• Peak speed: 8.3 Teraflops
• ~1 quadrillion operations/simulated year
• UN IPCC ~10,800 years simulated
• Rate of simulation: 3.5 sim. years/day
• Output: 10 GB/simulated year
• Data volume for IPCC: ~110 TB
(~200,000 Data CDs)
• Development effort: ~1 person-century
Community Climate System Model
and the IPCC
Intergovernmental Panel on
Climate Change (IPCC)
Fourth Assessment Report
 NCAR Community Climate
System Model (CCSM-3).
 Open Source
 8-member ensembles
 11,000 model years
simulated
 “T85” - high resolution
IPCC 2007 Summary for Policymakers:
Higher confidence in projected patterns of warming and regional-scale
features, continuing currently observed trends:
– warming greatest over land and at most high northern latitudes (least
over Southern Ocean and parts of NA ocean)
– snow cover will contract
– widespread increases in thaw depth over most permafrost regions
– sea ice will shrink in both Arctic and Antarctic, in some projections late
summer sea ice disappears in the Arctic by latter part of 21st century
– very likely that hot extremes, heat waves, and heavy precipitation
events will continue to become more frequent
– likely that typhoons and hurricanes will become more intense
– extra-tropical storm tracks will move poleward
– precipitation at high latitude very likely to increase, while decreases are
likely in most subtropical land regions
– Very likely that meridional overturning circulation of the Atlantic Ocean
will slow down during the 21st century. Average reduction by 2100 is
25% (0-50%). Very abrupt transition is very unlikely in 21st century.
Anthropogenic warming and sea level rise will continue for centuries due
to the timescales associated with climate processes and feedbacks,
even if greenhouse gas concentrations were stabilized
So, how best to
communicate?
(some results)
Tony Blair
“What is now plain is that the emission of greenhouse
gases…is causing global warming at a rate that began as
significant, and is simply unsustainable in the long-term. And
by long-term I do not mean centuries ahead, I mean within the
lifetime of my children certainly; and possibly within my own.
And by unsustainable I do not mean a phenomenon causing
problems of adjustment. I mean a challenge so far-reaching in
its impact and irreversible in its destructive power, that it alters
radically human existence.”
A lifetime of climate change…
NASA
Global mean temperatures are rising faster with time
Warmest 12 years:
1998,2005,2003,2002,2004,2006,
2001,1997,1995,1999,1990,2000
Period
25
50
100
150
Rate
0.1770.052
0.1280.026
0.0740.018
0.0450.012
Years /decade
Time Scales in the Climate System
Probabilistic Outcomes
1.8
PROBABILISTIC PROJECTIONS OF GLOBAL
WARMING
1990-2030
PROBABILITY DENSITY ((oC)-1)
1.6
1.4
1.2
1
0.8
1990-2070
0.6
0.4
1990-2100
0.2
0
TAR RANGE
0
1
2
3
4
5
6
GLOBAL-MEAN TEMPERATURE CHANGE FROM 1990 ( oC)
Wigley
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Simulated late 20th century ice conditions
Ann avg
1980-1999
ice
thickness
IPCC AR4
Dash=March
extent
White=Obs
Extent
Abrupt Ice Retreat Could Produce
Ice-Free Arctic Summers by 2040
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Recent retreat of Arctic sea
ice is likely to accelerate so
rapidly that Arctic Ocean
devoid of ice during
summertime as early as 2040
Study by Marika Holland and
teams from University of
Washington, and McGill
University
Several reasons for the abrupt
Ice loss in a gradually
warming world.
“Positive Feedback”
As the ice retreats, the ocean
transports more heat to the
Arctic and the open water
absorbs more sunlight,
further accelerating the rate of
warming and leading to the
loss of more ice
Ice Retreat Animation
QuickTime™
QuickTime™ and
and a
a
BMP
decompressor
BMP decompressor
are
are needed
needed to
to see
see this
this picture.
picture.
Projections of Degradation of
Near-Surface Permafrost
Lawrence and Slater, 2005
Future changes in frost days from the
climate model show greatest decreases in
the western and southwestern U.S., similar
to late 20th century
Changes in snowpacks/ timing of
runoff have occurred & will continue
Observed streamflow timing
changes (Center of mass)
Trends are projected to continue
through the 21st Century…
with increased winter flood risks
& lower summer low-flows in
many rivers.
Observed: 1948-2002
Large circles indicate sites with trends
that differ significantly from zero at a
90% confidence level;
(Courtesy of Michael Dettinger USGS,
based on Stewart et al. 2005.)
Ozone Recovery in the 21st Century
Global Average Total Ozone Column
Ozone (Dobson Units)
A1B
NCC
1980
2030
2050
National Security and the
Threat of Climate Change
CNA Corporation, 2007:
• National security consequences of climate change should be
fully integrated into national security and national defense
strategies
• US should commit to a stronger national and international role
to help stabilize climate changes at levels that will avoid
significant disruption to global security and stability
• U.S. should commit to global partnerships that help less
developed nations build the capacity and resiliency to better
manage climate impacts
• DoD should enhance its operational capability… through
energy efficiency
• DoD should conduct an assessment of the impact on U.S.
military installations world-wide of rising sea levels, extreme
weather events, and other possible climate change impacts
over the next 30 to 40 years.
National Security and the
Threat of Climate Change
CNA Corporation, 2007:
• “There is no known natural forcing that can account for the
severity of the recent warming. For example, while claims are
made that the variation in the intensity of the Sun is
responsible, the solar radiation’s effect on the climate is
estimated to be less than 5% as strong as that of humaninduced greenhouse gases.”
• Precipitation patterns have changed
• Extreme weather events are more frequent and Ice and snow
cover is disappearing
• Oceans are warming
• Sea levels are rising
• Ocean salinity has changed
Total number of bachelor's degrees
granted by discipline, 1985 to 2000
100000
90000
80000
70000
Legend
Psychology
Engineering
Biolog Sci
Comp Sci
Math
Chemistry
Geosci
Physics
60000
50000
40000
30000
20000
10000
0
1985
1990
1995
YEAR
2000
Lessons Learned
Large efforts to develop comprehensive scientific viewpoints can be
extremely significant in influencing public debate
The key question “what do we do about climate change?” is much less
well addressed than the scientific case for climate change itself.
Issues of timescales, rates, “greenhouse effect”, and uncertainty all
need careful treatment.
The propensity of the media to describe arguments continues to lead to
public confusion.
Responsibly informing societal decision makers with the best available
science is tough for individuals trained as scientists.
Bottom line: “The IPCC Fourth Assessment Report is currently the most
comprehensive assessment of the scientific literature on climate change, and
effectively and accurately communicates to policymakers and the public the
state of human knowledge on this topic.”