Assessing the Physical Science of Climate Change: Key Findings of IPCC Working Group 1 (2007) Presented by Elisabeth A. Holland Lead Author Boulder, June 8, 2007. WG 1: Summary for Policy Makers Authors.
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Assessing the Physical Science of Climate Change: Key Findings of IPCC Working Group 1 (2007)Presented by Elisabeth A. HollandLead AuthorBoulder, June 8, 2007
Drafting Authors: Richard Alley, Terje Berntsen, Nathaniel L. Bindoff, Zhenlin Chen, Amnat Chidthaisong, Pierre Friedlingstein, Jonathan Gregory, Gabriele Hegerl, Martin Heimann, Bruce Hewitson, Brian Hoskins, Fortunat Joos, Jean Jouzel, Vladimir Kattsov, Ulrike Lohmann, Martin Manning, Taroh Matsuno, Mario Molina, Neville Nicholls, Jonathan Overpeck, Dahe Qin, Graciela Raga, Venkatachalam Ramaswamy, Jiawen Ren, Matilde Rusticucci, Susan Solomon, Richard Somerville, Thomas F. Stocker, Peter Stott, Ronald J. Stouffer, Penny Whetton, Richard A. Wood, David Wratt
Draft Contributing Authors: Julie Arblaster,Guy Brasseur, Jens Hesselbjerg Christensen, Kenneth Denman, David W. Fahey, Piers Forster, Eystein Jansen, Philip D. Jones, Reto Knutti, Hervv Le Treut, Peter Lemke, Gerald Meehl, Philip Mote, David Randall, Daithi A. Stone, Kevin E. Trenberth, Jugen Willebrand, Francis Zwiers
3) Key findings of the WG1 AR4, with a few additional explanatory points by SS
Globally averaged, the planet is about 0.75°C warmer than it was in 1860, based upon dozens of high-quality long records using thermometers worldwide. Calibration and sampling issues have been meticulously dealt with, and they need to be: it’s a slow effect over very broad scales.
Do we have reason to believe this is due to human activity? Or is it natural?
WG1 - Climate Change: century ago.
WG2 - Climate Change: Impacts and Adaptation
Socio-economics, policy options, discount rates, emission scenarios,…..
Flowering dates, corals, coastal zone erosion,….
Interactions guided by respective scopes, available literature, and practicalities of the timeline and workload. IPCC assesses research but it doesn’t do research.
WG1 SPM now available at ipcc-wg1.ucar.edu
• Dramatic rise in the industrial era
• Largest growth rate of CO2 seen over the last ten years (1995-2005) than in any decade at least since direct measurements began (1960).
Rising sea level
Reductions in NH snow coverDirect Observations of Recent Climate Change
Sea level is rising in 20 AR4th century
Land precipitation is changing significantly over broad areas
Smoothed annual anomalies for precipitation (%) over land from 1900 to 2005; other regions are dominated by variability.
CO2 equivalent: 600 ->1550
The future depends on human choices about emissions. Best estimates and likely ranges given now in IPCC for the first time.
600 ppmv CO2 equiv (B1) Best estimate is +1.8°C by 2100; likely 1.8-2.9°C further warming;
1550 ppmv (A1FI) Best 4°C [likely 2.4-6.4°C]
Expected for all forcings
Natural forcing onlyUnderstanding and Attributing Climate Change
Anthropogenic warming is likely discernible on all inhabited continents
Coordinating Lead Authors: Kenneth L. Denman (Canada), Guy Brasseur (USA, Germany)
Lead Authors (13) : Amnat Chidthaisong (Thailand), Philippe Ciais (France), Peter Cox (UK), Robert E. Dickinson (USA), Didier Hauglustaine (France), Christoph Heinze (Norway, Germany), Elisabeth Holland (USA), Daniel Jacob (USA, France), Ulrike Lohmann (Switzerland), Srikanthan Ramachandran (India), Pedro Leite da Silva Dias (Brasil), Steven C. Wofsy (USA), Xiaoye Zhang (China)
Contributing Authors (64) : David Archer (USA), Vivek Arora (Canada), John Austin (USA), David Baker (USA), Joe Berry (USA), Richard A. Betts (UK), Gordon Bonan (USA), Philippe Bousquet (France), Josep Canadell (Australia), James Christian, Deborah A. Clark (USA), Martin Dameris (Germany), Frank Dentener (EU), David Easterling (USA), Veronika Eyring (Germany), Johann Feichter (Germany), Pierre Friedlingstein (France, Belgium), Inez Fung (USA), Sandro Fuzzi (Italy), Sunling Gong (Canada), Nicolas Gruber (USA, Switzerland), Alex Guenther (USA), Kevin Gurney (USA), Ann Henderson-Sellers (Australia), Joanna House (UK), Andy Jones (UK), Christopher Jones (UK), Bernd K較cher (Germany), Michio Kawamiya (Japan), Keith Lassey (New Zealand), Caroline Leck (Sweden), Julia Lee-Taylor (USA,UK), Corinne Le Quere (Germany, France, Canada), Gordon McFiggans (UK), Yadvinder Malhi (UK), Kenneth Masarie (USA), Surabi Menon (USA), John B. Miller (USA), Philippe Peylin (France), Andrew Pitman (Australia), Johannes Quaas (Germany), Michael Raupach (Australia), Peter Rayner (Australia), Gregor Rehder (Germany), Ulf Riebesell (Germany), Christian Rodenbeck (Germany), Leon Rotstayn (Australia), Nigel Roulet (Canada), Christopher Sabine (USA), Martin G. Schultz (Germany), Michael Schulz (France, Germany), Stephen E. Schwartz (USA), Will Steffen (Australia), David Stevenson (UK), Yuhong Tian (USA, China), Kevin E. Trenberth (USA), Twan Van Noije, Oliver Wild (Japan, UK), Tingjun Zhang (USA, China), Liming Zhou (USA, China)
Review Editors: Kansri Boonpragob (Thailand), Martin Heimann (Germany, Switzerland), Mario Molina (USA, Mexico)
Conclusions and Biogeochemistry
•The concentration of carbon dioxide is now 379 ppm and methane is over 1774 ppb, both very likely much higher than any time in at least 650,000 years (during which carbon dioxide remained between 180 and 300 ppm and methane between 320 and 790 ppb). •The recent rate of change is dramatic and unprecedented; increases in carbon dioxide never exceeded 30 ppm in 1,000 years -- yet now carbon dioxide has risen by 30 ppm in just the last 17 years.•It is very likely that the increase in the combined radiative forcing from carbon dioxide, methane and nitrous oxide has been at least six times faster between1960 to 1999 than over any 40 year period during the two millennia prior to the year 1800. •On average, present-day tropospheric ozone has increased 38% since pre-industrial times, and the increase results from atmospheric reactions of short-lived pollutants emitted by human activity.
Individuals and groups make choices to take risks. and Biogeochemistry
Decisions about global issues of risk are very complex, and involve much more than science alone in my opinion. The role of science is information, not policy.