Scientists identify ecological systems most at risk from climate change

Study: Climate Set To 'Tip'
This Century. By Pallab Ghosh,
BBC, February 5, 2008. "Many of Earth's
climate systems will undergo a series of sudden shifts this century as a result
of human-induced climate change, a study [PDF, 8 pp] suggests.
A number of these shifts could occur this century, say the report's authors...
an international team [whose work is published] in the Proceedings of the
National Academy of Sciences. 'Our findings suggest that a variety of tipping
elements could reach their critical point within this century'... said Professor
Tim Lenton from the University of East Anglia, the lead researcher. "The
greatest threats are tipping of the Arctic sea-ice and the Greenland ice sheet,
and at least five other elements could surprise us by exhibiting a nearby
tipping point'... The researchers have listed and ranked nine ecological systems
that they say could be lost this century... melting of Arctic sea-ice (about 10
years), decay of the Greenland ice sheet (about 300 years), collapse of the West
Antarctic ice sheet (about 300 years), collapse of the Atlantic thermohaline
circulation (about 100 years), increase in the El Nino Southern Oscillation
(about 100 years), collapse of the Indian summer monsoon (about 1 year),
greening of the Sahara/Sahel and disruption of the West African monsoon (about
10 years), dieback of the Amazon rainforest (about 50 years), dieback of the
Boreal Forest (about 50 years)."