http://www.gtp89.dial.pipex.com/chpt.htm“The impacts of climate change on freshwater systems and
their management are mainly due to the observed and
projected increases in temperature, evaporation, sea level
and precipitation variability (very high confidence).
More than one-sixth of the world’s population live in glacier- or
snowmelt-fed river basins and will be affected by a decrease in
water volume stored in glaciers and snowpack, an increase in
the ratio of winter to annual flows, and possibly a reduction in
low flows caused by decreased glacier extent or melt-season
snow water storage [3.4.1, 3.4.3]. Sea-level rise will extend
areas of salinisation of groundwater and estuaries, resulting in
a decrease in freshwater availability for humans and ecosystems
in coastal areas [3.2, 3.4.2]. Increased precipitation intensity
and variability is projected to increase the risk of floods and
droughts in many areas [3.3.1]. Up to 20% of the world’s
population live in river basins that are likely to be affected by
increased flood hazard by the 2080s in the course of global
warming”