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關(guān)鍵詞: 氣候變化, 水, IPCC, 技術(shù)報告

Abstract: "limate Change and Water", the IPCC technical paper contribution to the IPCC Fourth Assessment Report (AR4) was launched on 8th April 2008. Based on three assessment reports of the IPCC AR4, this technical paper summarizes the newest peer-reviewed and comprehensive findings from international scientific communities on climate change and water for past, present and future. The robust key findings are: observed global warming over several decades has been linked to large-scale changes in the large-scale hydrological cycle. Climate models simulations for the 21st century are consistent in projecting precipitation increases at high latitudes and in parts of the tropics, and decreases while in some subtropical and lower mid-latitude regions. By the middle of the 21st century, annual average river runoff and water availability are projected to increase as a result of climate change at high latitudes and in some wet tropical areas, and decrease over some dry regions at mid-latitudes and in the dry tropics. Increased precipitation intensity and variability is projected to increase the risks of flooding and drought in many areas. Water supplies stored in glaciers and snow cover are projected to decline in the course of the century. Higher water temperatures, and changes in extremes, including floods and droughts are projected to affect water quality and exacerbate many forms of water pollution. Globally, the negative impacts of future climate change on freshwater systems are expected to outweigh the benefits. Changes in water quantity and quality due to climate change are expected to affect food availability, stability, access, and utilization. Climate change affects the function and operation of existing water infrastructure-including hydropower, structural flood defenses, drainage, and irrigation systems-as well as water management practices. Current water management practices may not be robust enough to cope with the impacts of climate change. Climate change challenges the traditional assumption that past hydrological experience provides a good guide to future conditions. Adaptation options designed to ensure water supply during average and drought conditions require integrated demand-side as well as supply-side strategies. Mitigation measures can reduce the magnitude of impacts of global warming on water resources, in turn reducing adaptation needs. Water resources management has clear impacts on many other policy areas.

Key words: climate change, water, IPCC, technical report