Communicating Climate Change Science (Intergovernmental Panel on Climate Change)

1. 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

2. National Center for Atmospheric Research • 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 • 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

3. AGU Mission AGU Council, 2005EOS, 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.

4. 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

5. NCAR ScientistsInvolved in IPCCWorking Group I

6. 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

7. The Challenge of Simulating the Global Earth System Hydrosphere Cryosphere Biosphere Atmosphere

8. The Earth System From Andi Andreae

10. CCSM Working Groups Model-centric Atmosphere Model Land Model Ocean Model Polar Climate Crosscutting Climate Change PaleoClimate Biogeochemistry Climate Variability Software Engineering

11. Need for High Resolution

12. Science Driven Demand for Supercomputing

13. Modern Climate Model Simulations • NCAR’s Bluesky Supercomputer: • 1600 Processors • Peak speed: 8.3 Teraflops • Characteristics of NCAR Model: • ~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

14. Community Climate System Model and the IPCC

15. 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

16. 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

17. So, how best to communicate?(some results)

18. 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.”

19. A lifetime of climate change… NASA

20. Warmest 12 years: 1998,2005,2003,2002,2004,2006, 2001,1997,1995,1999,1990,2000 25 0.1770.052 50 0.1280.026 100 0.0740.018 150 0.0450.012 Global mean temperatures are rising faster with time Period Rate Years /decade

21. Time Scales in the Climate System

22. Probabilistic Outcomes Wigley

23. Simulated late 20th century ice conditions Ann avg 1980-1999 ice thickness IPCC AR4 Dash=March extent White=Obs Extent

24. Abrupt Ice Retreat Could Produce Ice-Free Arctic Summers by 2040 • 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

25. Projections of Degradation of Near-Surface Permafrost Lawrence and Slater, 2005

26. Future changes in frost days from the climate model show greatest decreases in the western and southwestern U.S., similar to late 20th century

27. 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.)

28. A1B NCC 1980 2030 2050 Ozone Recovery in the 21st Century Global Average Total Ozone Column Ozone (Dobson Units)

29. 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.

30. 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 human-induced 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

32. 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.”