Climate change: The science and the risks

1. Climate change: The science and the risks Prof Guy F Midgley National Biodiversity Institute University KwaZulu Natal LTAS project lead, IPCC lead author NATIONAL CLIMATE CHANGE RESPONSE ADAPTATION IMPLEMENTATION

2. Phenomenal increase in wealth and human well-being, esp. wealthiest Urbanisation, often coastal Green revolution, and deforestation Globalisation, trade, information Democratisation, environmentalism Population ~9 billion peak Highest CO2 level in 5 million years,projected higher than 20 million years by end of century Associated pollution Ocean acidification “Greening”, esp. arid and semi-arid ecosystems Highest temps in > 2000 years Warmer oceans Rising sea level, melting ice and permafrost Increasing rainfall intensity Increasing high temperature and rainfall extremes Changes in ecology

3. 1850 1870 1890 1910 1930 1950 1970 1990 2010 Anthropogenic C Emissions: Fossil Fuel 2006 Fossil Fuel: 8.4 Pg C [2006-Total Anthrop. Emissions:8.4+1.5 = 9.9 Pg] • 1990 - 1999: 1.3% y-1 • 2000 - 2006: 3.3% y-1 Raupach et al. 2007, PNAS; Canadell et al 2007, PNAS

4. Greenhouse effect observed from space Harries, 2001

6. Arctic sea ice www.mtholyoke.edu

8. Permafrost

9. Local impacts of permafrost melt

10. Sea level rise

11. More CO2More heatMore evaporationMore water vapour Trenberth et al 2004 Climate Dynamics

12. More evaporation, more rain Held & Soden 2006; J Climate

13. http://www.earth-policy.org/indicators/C54 Drought trends 1950-2010 Sheffield et al 2012 naturev491

15. Trend in Sea Surface Temp 1982-2005 Rouault 2007

16. South African land based measurements show warming (1960 to 2003) Adapted from Kruger and Shongwe (2004)

17. Limpopo, annual rainfall trends Total rainfall # raindays

18. 1955 Eastern Cape Courtesy Timm Hoffman (U Cape Town)

19. 2010 Eastern Cape. Courtesy Timm Hoffman ( U Cape Town)

20. Acacia sieberiana LGM 180 ppm Pre-industrial 260 ppm Ambient 375 ppm Above-ambient 450 ppm

21. Arid regions where vegetation cover has increased ~10% since 1980’s Donahue et al in press

22. Linking mitigation to impacts/adaptation

24. Mitigation impact on temperature change

25. IGSM Scenarios (Sokolov etal., 2009, andWebster etal., 2009)

26. Zones used • Changes average for the period 2045-2050

27. Mitigation impact on rainfall change, ~2050

28. Mitigation impact on temperature change~2050

29. Integrated Analytical Framework Global change (temperature, rainfall, fossil fuel prices) Rivers (runoff, streamflow) Sea level rise (land loss, salination) Flooding (frequency, severity) Infrastructure (roads, ports, houses) Energy (hydropower) Agriculture (food, exports) Local economy (growth, jobs, welfare, inequality)

30. Mozambique Effects of Global/LocalMitigationPolicy Change intotal value-added (GDP) 60 UnconstrainedEmissions L1Stablization(withUEprices) L1Stabilization(withL1Sprices) 50 40 Density 30 20 10 0 -10% -5% 0% Averagedeviationfrombaseline,2046-2050 -15% 5%

31. Main risksfor South Africa? • Observations • increasing mean and maximum temperatures (high confidence) • fewer rain days, no change in total rainfall (medium confidence) • increasing wildfire risk (high confidence) • plant cover increasing due to CO2 fertilization (medium confidence) • costs of extreme events 2000-2009 at least ~R1 billion per annum (high confidence), trends not known • Future risks and opportunities • Extreme climate events – low-lying, flood plain, coastal settlements • Water – drought and flood risk, allocations • Land cover change – vegetation thickening • Human health and discomfort – labour, aged, infants, informal housing, vector-borne diseases • Agriculture and food supply – intensive (livestock, grains, vegetables and fruit), extensive, small scale subsistence • Transport infrastructure – vulnerability, increased specification • Opportunities – using ecosystems/biodiversity to reduce risks

32. Can ecosystems be managed for climate change adaptation?Can this be incentivised? ~1940 ~1960 ~2000 Wetland intact Wetland degrading Wetland degraded +109589