Water
Global warming will lead to an intensification of the global water or hydrological cycle through increases in surface temperature and rates of evaporation, and in some regions, increases in precipitation . Changes in the total amount of precipitation and its frequency and intensity directly affect the magnitude and timing of run-off and the intensity of floods and droughts. Such changes will have significant impacts on regional water resources. It is not certain how individual water catchment areas will respond to changing evaporation rates and precipitation. It is likely however, that currently dry regions will be more sensitive to changes in climate. Relatively small changes in temperature and precipitation could cause relatively large changes in run-off. Arid and semi-arid regions will therefore be particularly sensitive to reduced rainfall and to increased evaporation. An increase in the duration of dry spells will not necessarily lead to an increased likelihood of low river fl...