Climate change now VERY serious

THE INDEPENDENT
17 February 206

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


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.

How fast can this go? Right now, I think our best measure is what
happened in the past. We know that, for instance, 14,000 years ago sea
levels rose by 20m in 400 years - that is five metres in a century.
This was towards the end of the last ice age, so there was more ice
around. But, on the other hand, temperatures were not warming as fast
as today.

How far can it go? The last time the world was three degrees warmer
than today - which is what we expect later this century - sea levels
were 25m higher. So that is what we can look forward to if we don't act
soon. None of the current climate and ice models predict this. But I
prefer the evidence from the Earth's history and my own eyes. I think
sea-level rise is going to be the big issue soon, more even than
warming itself.

It's hard to say what the world will be like if this happens. It would
be another planet. You could imagine great armadas of icebergs breaking
off Greenland and melting as they float south. And, of course, huge
areas being flooded.

How long have we got? We have to stabilise emissions of carbon dioxide
within a decade, or temperatures will warm by more than one degree.
That will be warmer than it has been for half a million years, and many
things could become unstoppable. If we are to stop that, we cannot wait
for new technologies like capturing emissions from burning coal. We
have to act with what we have. This decade, that means focusing on
energy efficiency and renewable sources of energy that do not burn
carbon. We don't have much time left.

--------------------------
Jim Hansen, the director of the Nasa Goddard Institute for Space
Studies in New York, is President George Bush's top climate modeller.

none wrote:

THE INDEPENDENT
17 February 206

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


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.

How fast can this go? Right now, I think our best measure is what
happened in the past. We know that, for instance, 14,000 years ago sea
levels rose by 20m in 400 years - that is five metres in a century.
This was towards the end of the last ice age, so there was more ice
around. But, on the other hand, temperatures were not warming as fast
as today.

How far can it go? The last time the world was three degrees warmer
than today - which is what we expect later this century - sea levels
were 25m higher. So that is what we can look forward to if we don't act
soon. None of the current climate and ice models predict this. But I
prefer the evidence from the Earth's history and my own eyes. I think
sea-level rise is going to be the big issue soon, more even than
warming itself.

It's hard to say what the world will be like if this happens. It would
be another planet. You could imagine great armadas of icebergs breaking
off Greenland and melting as they float south. And, of course, huge
areas being flooded.

How long have we got? We have to stabilise emissions of carbon dioxide
within a decade, or temperatures will warm by more than one degree.
That will be warmer than it has been for half a million years, and many
things could become unstoppable. If we are to stop that, we cannot wait
for new technologies like capturing emissions from burning coal. We
have to act with what we have. This decade, that means focusing on
energy efficiency and renewable sources of energy that do not burn
carbon. We don't have much time left.

--------------------------
Jim Hansen, the director of the Nasa Goddard Institute for Space
Studies in New York, is President George Bush's top climate modeller.



is the planet static or dynamic? Thats all you need to know.

"Tchiowa" wrote in message
oups.com...

none wrote:
THE INDEPENDENT
17 February 206

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


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.

snip

Funny but the most recent studies show quite the opposite. Ice sheets
melting near the edges but actually getting thicker in the middle.

http://www.esa.int/esaEO/SEMILF638FE_planet_0.html

4 November 2005
Researchers have utilised more than a decade's worth of data from radar
altimeters on ESA's ERS satellites to produce the most detailed picture
yet of thickness changes in the Greenland Ice Sheet.

A Norwegian-led team used the ERS data to measure elevation changes in
the Greenland Ice Sheet from 1992 to 2003, finding recent growth in the
interior sections estimated at around six centimetres per year during
the study period. The research is due to be published by Science
Magazine in November, having been published in the online Science
Express on 20 October.

O **** !
it's bulging ?!!

er.. is that good or bad?