1. Valuing Our Life Support Systems Savoy Place, 29 April 2009 IMPACTS ON THE ENVIRONMENT: CLIMATE CHANGE Robert M May Zoology Department Oxford OX1 3PS, UK

3. Humanity’s Impacts Over the past century and a half: the human population has increased x 7 the global average energy use per person has increased x 7 That is, overall energy use has increased roughly fifty-fold

4. Fig. 2: ECOLOGICAL FOOTPRINT AND BIOCAPACITY BY REGION, 2003 (After Ref. 5)

5. STATEMENT BY SCIENCE ACADEMIES OF THE G8, plus CHINA, INDIA, BRAZIL Calls on G8 countries to “identify cost- effective steps that can be taken now to contribute to substantial and long-term reduction in net global greenhouse gas emission [and] recognise that delayed action will increase the risk of adverse environmental effects and will likely incur a greater cost”

6. Building a Low-Carbon Economy – The UK's Contribution to Tackling Climate Change www.theccc.org.uk

7. 1. The 2050 target (i)Required global emissions reduction (ii)Appropriate UK contribution (iii)Technologies for meeting required reductions

8. (i) Required global emissions reduction Required global emissions reduction of 50% 20-24 GtCO 2 e emissions in 2050 8-10 GtCO 2 e in 2100 Required global emissions reduction of 50% 20-24 GtCO 2 e emissions in 2050 8-10 GtCO 2 e in 2100 What’s changed? Advances in science Actual emissions higher than forecast What’s changed? Advances in science Actual emissions higher than forecast Assessment of damage Decision rule keep temperature change close to 2°C and probability of 4°C increase at very low level (less than 1%) Assessment of damage Decision rule keep temperature change close to 2°C and probability of 4°C increase at very low level (less than 1%) Global trajectories considered Early or later peak (2015 vs. 2030) 3%/4% annual emissions reduction Global trajectories considered Early or later peak (2015 vs. 2030) 3%/4% annual emissions reduction

9. (ii) Appropriate UK contribution 50% global reduction Burden share Alternative methodologies (contract and converge, intensity convergence, triptych etc.) Equal per capita emissions: ̶ 20-24 GtCO 2 e total at global level in 2050 ̶ Implies 2.1-2.6 tCO 2 e per capita Burden share Alternative methodologies (contract and converge, intensity convergence, triptych etc.) Equal per capita emissions: ̶ 20-24 GtCO 2 e total at global level in 2050 ̶ Implies 2.1-2.6 tCO 2 e per capita All GHGs Aviation and shipping included 2.1-2.6 CO 2 e per capita gives a UK reduction of at least 80% in 2050

11. Conclusion 80% cut in GHG emission by 2050 relative to 1990: all GHGs, aviation and shipping included Unilateral 34% cut in GHGs by 2020 relative to 1990 (21% relative to 2005) 42% cut in GHGs by 2020 relative to 1990 (31% relative to 2005) after global deal is achieved 34% cut predominantly through domestic emissions reduction 42% through domestic emissions reduction and credit purchase 2020 cost less than 1% of GDP 80% cut in GHG emission by 2050 relative to 1990: all GHGs, aviation and shipping included Unilateral 34% cut in GHGs by 2020 relative to 1990 (21% relative to 2005) 42% cut in GHGs by 2020 relative to 1990 (31% relative to 2005) after global deal is achieved 34% cut predominantly through domestic emissions reduction 42% through domestic emissions reduction and credit purchase 2020 cost less than 1% of GDP

12. Climate Change - a Multiplier for Instability Recent Conflicts Demography Crop decline Hunger Coastal risk Waterscarcity