Loss Of Greenland Ice Cap May Now Be Unstoppable, Study Warns - Guardian

[hatrack]

My apologies - some overlap with the AP story posted immediately before with "U. of East Anglia" headline.

EDIT

If the Greenland ice sheet melted completely, for example, it would raise global sea levels by seven metres. According to the IPCC report, the melting should take about 1,000 years. But the study, by Tim Lenton of the University of East Anglia, showed the break-up could happen more quickly, in 300 years. Professor Lenton said: "We know that ice sheets in the last ice age collapsed faster than any current models can capture, so our models are known to be too sluggish."

His study identified eight tipping points that could be passed by the end of this century. They include the destruction of the Amazon rainforest, the melting of the west Antarctic ice sheet, and a collapse of the global ocean current known as the thermohaline circulation. If that circulation stopped, the Indian monsoons and the gulf stream could be shut down.

Prof Lenton said the IPCC way of working, including multiple reviews, caused it to issue more conservative reports than his team's studies. He added that the inevitable collapse of the Greenland ice sheet was closer than thought because of the latency in the Earth's climate system. "If you could stabilise the greenhouse gas levels to today's level, you'll still get some further warming ."

A global average temperature rise of just 1C would be enough to slip the Greenland ice over the edge. The IPCC's prediction for 2100 is a rise of 1.1C-6.4C.

EDIT/END

http://www.guardian.co.uk/environment/2007/aug/16/climatechange.greenland

[RaleighNCDUer]

1. I would bet that 300 years is wildly optimistic.

For some reason they seem unable to factor in the feedback loops which accelerate warming and melting at ever-increasing rates. And of course, the melting isn't happening only there, but in the actic tundra (releasing millions of tons of trapped methane into the atmosphere), in Antarctica (further raising the ocean levels), and high elevations (causing a loss of glaciers, and glacial runoff, affecting the lowland waterflow, and thus the evaporation rates over the lowlands, changing prevailing weather patterns).

I hope I'm not being optimistic by saying the end of this century.

[ramapo]

2. I wouldn't be shocked by 30 years

Seems impossible but when I think back 30 years....

[RaleighNCDUer]

3. I'd be shocked

but not surprised.

Kilmanjaro is supposed to lose its remaining entire icecap by the end of the decade, I remember reading. Hasn't been ice-free since before the last ice age.

What we are seeing is unprecedented.