Transcript Slide 1
Climate Change and the Water Cycle Richard Harding Centre for Ecology and Hydrology Drivers of Global Change: • Increasing population • Increasing water consumption • Land cover/use change • Increasing greenhouse gases Stern Review (2006) 3000 Assessment Consumption, km 3/year 2500 2000 Agriculture Forecast Industry 1500 Municipal needs Reservoir 1000 Total 500 0 1900 1920 1940 1960 1980 2000 2020 2040 Water Consumption - after Shiklomanov 2000 Areas of physical and economic water scarcity (IWMI, 2006) To predict the future we need the climate models We represent the earth by a grid of squares, typically of length 150 km or smaller. The atmosphere and oceans are divided into vertical slices of varying depths. FIGURE SPM-6. Relative changes in precipitation (in percent) for the period 2090–2099, relative to1980–1999. Values are multi-model averages based on the SRES A1B scenario for December to February (left) and June to August (right). White areas are where less than 66% of the models agree in the sign of the change and stippled areas are where more than 90% of the models agree in the sign of the change. IPCC 2007 Land precipitation is changing significantly over broad areas Increases Decreases Smoothed annual anomalies for precipitation (%) over land from 1900 to 2005; other regions are dominated by variability. Climate change scenarios – the changing seasons • UK winter Wetter: Up 10% by 2020s, up to 30% by 2080s • UK summer Drier: 20% by 2020s, up to 50% by 2080s Climate change scenarios – changing extremes 90 0 2 00 20 0 186 4-year event 12-year event 30-year event Climate change scenarios – impact on flows Percentage change in flows for the 20year return period Glacier melt in the Himalayas 1978 1989 2000 1996 10km SAGARMATHA: Snow and Glacier Aspects of Water Resources Management in the Himalaya 60 40 % change 20 0 Uttarkashi 0 1 2 3 4 5 6 7 Haridwar Kanpur Allahbad -20 -40 -60 %change in decadal mean flow for Ganges from regional climate model output (RCM2) -80 Decade http://www.nwl.ac.uk/ih/www/research/SAGARMATHA/ The WATCH Integrated Project: 25 European partners: hydrology, climate and resource scientists 13m euros of effort Feedbacks in the climate hydrological system Past, present and future population, LUCC and water demand Extremes and scales of hydrological events WB5 WB2 WB4 20th Century Global water cycle WB1 21st Century Global water cycle WB3 International programme research, workshops, training, dissemination Assessing the vulnerability of water resources WB6 Management, training and dissemination WB7 WATCH Thank You