Gaged NASA Scientist says ice caps melting FAST !

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Thu, 16 Feb 2006 20:01:44 -0500

Gaged NASA Scientist says ice caps melting FAST !

 

 

Gaged NASA Scientist says ice caps melting FAST !

 

Address:http://news.independent.co.uk/environment/article345926.ece

 

 

 

 

 

Climate change: On the edge

Greenland ice cap breaking up at twice the rate it was five years ago,

says scientist Bush tried to gag

By Jim Hansen

Published: 17 February 2006

 

 

 

 

A satellite study of the Greenland ice cap shows that it is melting

far faster than scientists had feared - twice as much ice is going

into the sea as it was five years ago. The implications for rising sea

levels - and climate change - could be dramatic.

 

Yet, a few weeks ago, when I - a Nasa climate scientist - tried to

talk to the media about these issues following a lecture I had given

calling for prompt reductions in the emission of greenhouse gases, the

Nasa public affairs team - staffed by political appointees from the

Bush administration - tried to stop me doing so. I was not happy with

that, and I ignored the restrictions. The first line of Nasa's mission

is to understand and protect the planet.

 

This new satellite data is a remarkable advance. We are seeing for the

first time the detailed behaviour of the ice streams that are draining

the Greenland ice sheet. They show that Greenland seems to be losing

at least 200 cubic kilometres of ice a year. It is different from even

two years ago, when people still said the ice sheet was in balance.

 

Hundreds of cubic kilometres sounds like a lot of ice. But this is

just the beginning. Once a sheet starts to disintegrate, it can reach

a tipping point beyond which break-up is explosively rapid. The issue

is how close we are getting to that tipping point. The summer of 2005

broke all records for melting in Greenland. So we may be on the edge.

 

Our understanding of what is going on is very new. Today's forecasts

of sea-level rise use climate models of the ice sheets that say they

can only disintegrate over a thousand years or more. But we can now

see that the models are almost worthless. They treat the ice sheets

like a single block of ice that will slowly melt. But what is

happening is much more dynamic.

 

Once the ice starts to melt at the surface, it forms lakes that empty

down crevasses to the bottom of the ice. You get rivers of water

underneath the ice. And the ice slides towards the ocean.

 

Our Nasa scientists have measured this in Greenland. And once these

ice streams start moving, their influence stretches right to the

interior of the ice sheet. Building an ice sheet takes a long time,

because it is limited by snowfall. But destroying it can be

explosively rapid.

 

contunued.....