1. The latest science on the climate change challenge David Karoly, Univ of Melbourne TC Larry, 2006 From Bureau of Meteorology

2. Summary Recent observed changes of several climate variables and recent CO 2 emissions have been at or above the upper range of IPCC estimates “Australia has a larger interest in a strong mitigation outcome than other developed countries; small variations in climate are more damaging to us than to other developed countries” (Garnaut, 2008) Stabilisation of greenhouse gas concentrations at 450 ppm CO 2 -eq will require removal of greenhouse gases from the atmosphere, either through natural processes or anthropogenic sequestration (not further emissions) Delays in reducing CO 2 emissions commit the world to greater magnitude, largely irreversible climate change for at least a millenium

3. Recent variations Top to bottom: observed CO 2 concentrations, global mean surface temperature, and sea level change, compared to IPCC (2001) projections, from 1990 (Rahmstorf et al., 2007). From Stroeve et al, GRL, 2007 Observations to 2005

4. Sea ice in Sept 2007 From Stroeve et al, GRL, 2007 Sept 2005

5. Observed and projected Australian rainfall Best estimate projected rainfall change for 2070 (from “Climate change in Australia”) Observed trend in annual rainfall 1970-2007

6. Global CO 2 emissions from fuel consumption Comparison of IPCC emission scenarios and new growth path From Raupach et al. 2007, PNAS SRES (2000) growth rates in % y -1 for 2000- 2010: A1B: 2.42 A1FI: 2.71 A1T: 1.63 A2: 2.13 B1: 1.79 B2: 1.61 2006 2005 Observed 2000-2006 3.3%/yr

7. Projected climate change hotspots in Australia (from IPCC AR4 WGII, chapt 11)

8. Stabilisation scenarios 455 ppm CO 2 -eq in 2005, 379 ppm CO 2 conc I: CO 2 -eq stabilisation at 445-490 ppm, emissions peak in 2000-2015, global CO 2 emissions -85% to -50% in 2050, warming of 2.0 to 2.4  C above pi II: CO 2 -eq stabilisation at 490-535 ppm, emissions peak in 2000-2020, global CO 2 emissions -60% to -30% in 2050, warming of 2.4 to 2.8  C above pi Assuming equal per capita emissions, 50% global emission reduction in 2050 means ~90% emission reduction for Australia IPCC SyR Fig SPM.11

9. Probability distribution of committed global warming (relative to preindustrial) for greenhouse gases in the atmosphere in 2005 From Ramanathan and Feng, PNAS, 2008

10. From www.nicholsoncartoons.com.au

11. Solomon et al., PNAS, 2009: “ climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop”

12. Summary Recent observed changes of several climate variables and recent CO 2 emissions have been at or above the upper range of IPCC estimates “Australia has a larger interest in a strong mitigation outcome than other developed countries; small variations in climate are more damaging to us than to other developed countries” (Garnaut, 2008) Stabilisation of greenhouse gas concentrations at 450 ppm CO 2 -eq will require removal of greenhouse gases from the atmosphere, either through natural processes or anthropogenic sequestration (not further emissions) Delays in reducing CO 2 emissions commit the world to greater magnitude, largely irreversible climate change for at least a millenium