1. IPCC Working Group I Summary For Policymakers: The Physical Science Basis Assembled by Brenda Ekwurzel March 2, 2007 www.ucsusa.org Slides for Communicating IPCC

2. IPCC Scenarios

3. The IPCC based its projections on six emission scenarios, running each one through sophisticated climate simulation programs. Governance Development Local Global EnvironmentalEconomic A1B1 B2A2 Adapted from Arnell et al. (2004). Global Environmental Change, 14:3-20 A1B A1FI A1T

4. The IPCC based its projections on six emission scenarios, running each one through sophisticated climate simulation programs. Governance Development Local Global EnvironmentalEconomic A1B1 B2A2 Adapted from Arnell et al. (2004). Global Environmental Change, 14:3-20 A1B A1FI A1T

5. Population at 2100 Governance Development Local Global EnvironmentalEconomic A1B1 B2A2 Adapted from Arnell et al. (2004). Global Environmental Change, 14:3-20

6. Gross Domestic Product Growth at 2100 Governance Development Local Global EnvironmentalEconomic A1B1 B2A2 Adapted from Arnell et al. (2004). Global Environmental Change, 14:3-20

7. Energy Use at 2100 Governance Development Local Global EnvironmentalEconomic A1B1 B2A2 Adapted from Arnell et al. (2004). Global Environmental Change, 14:3-20

8. Governance Development Local Global EnvironmentalEconomic B1 B2A2 Adapted from Arnell et al. (2004). Global Environmental Change, 14:3-20 A1B A1FI A1T Technological Change at 2100 Country A Country B Country C

9. NOTE: Be careful of comparisons between lowest and highest projections between 2001 (TAR) and 2007 (AR4) IPCC. The IPCC’s prior assessment in 2001 used many more emission scenarios, so the entire range of projections of temperature changes, sea-level rise, etc. in that report are not directly comparable with those in the new assessment.

10. For example with sea-level rise, the midpoint of the scenarios used in both assessments differed by only 10% between the prior assessment and the current one.