From The Guardian…
A critical meltdown of ice sheets and severe sea level rise could be
inevitable because of global warming, the world’s scientists are
preparing to warn their governments. New studies of Greenland and
Antarctica have forced a UN expert panel to conclude there is a 50%
chance that widespread ice sheet loss “may no longer be avoided”
because of greenhouse gases in the atmosphere.Such melting would
raise sea levels by four to six metres, the scientists say. It would
cause “major changes in coastline and inundation of low-lying areas”
and require “costly and challenging” efforts to move millions of people
and infrastructure from vulnerable areas. The previous official line,
issued in 2001, was that the chance of such an event was “not well
known, but probably very low”.The melting process could take centuries, but increased warming caused
by a failure to cut emissions would accelerate the ice sheets’ demise,
and give nations less time to adapt to the consequences. Areas such as
the Maldives would be swamped and low-lying countries such as the
Netherlands and Bangladesh, as well as coastal cities including London,
New York and Tokyo, would face critical flooding.The warning appears in a report from the Intergovernmental Panel on
Climate Change, which assesses the likely impacts of global warming and
will be published in April. A final draft of the report’s
summary-for-policymakers chapter, obtained by the Guardian, says: “Very
large sea level rises that would result from widespread deglaciation of
Greenland and West Antarctic ice sheets imply major changes in
coastlines and inundation of low-lying areas, with greatest effects in
river deltas.