Friday, February 17, 2006

'We don't have much time left' to stop global warming


This undated photo provided by the journal Science shows East Greenland icebergs. Large numbers of bergs are calved each year from the fast-flowing terminus of Kangerdlussuaq Glacier, East Greenland. Iceberg production is a major form of mass loss from ice sheets. (AP Photo/ho/J.A. Dowdeswell, Science) (J.a.dowdeswell - AP)

Global warming makes the front page of the Washington Post:

Glacier Melt Could Signal Faster Rise in Ocean Levels


Greenland's glaciers are melting into the sea twice as fast as previously believed, the result of a warming trend that renders obsolete predictions of how quickly Earth's oceans will rise over the next century, scientists said yesterday.

The new data come from satellite imagery and give fresh urgency to worries about the role of human activity in global warming. The Greenland data are mirrored by findings from Bolivia to the Himalayas, scientists said, noting that rising sea levels threaten widespread flooding and severe storm damage in low-lying areas worldwide.

The scientists said they do not yet understand the precise mechanism causing glaciers to flow and melt more rapidly, but they said the changes in Greenland were unambiguous -- and accelerating: In 1996, the amount of water produced by melting ice in Greenland was about 90 times the amount consumed by Los Angeles in a year. Last year, the melted ice amounted to 225 times the volume of water that city uses annually.

"We are witnessing enormous changes, and it will take some time before we understand how it happened, although it is clearly a result of warming around the glaciers," said Eric Rignot, a scientist at the California Institute of Technology's Jet Propulsion Laboratory.

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"Glaciers have retreated systematically and in an accelerated fashion in the last few decades," Casassa said. One glacier that provided Bolivia with its only ski slope five years ago has splintered into three and cannot be used for skiing, the scientist added.

Rapid melting of Himalayan glaciers also raises concerns for the large portion of humankind that gets its fresh water from glacier-fed rivers in South Asia, Aizen noted.

Most climate scientists believe a major cause for Earth's warming climate is increased emissions of greenhouse gases as a result of burning fossil fuels, largely in the United States and other wealthy, industrialized nations such as those of western Europe but increasingly in rapidly developing nations such as China and India as well. Carbon dioxide and several other gases trap the sun's heat and raise atmospheric temperature.

From the Independent (UK) we get the take of Jim Hansen, the director of the NASA Goddard Institute for Space Studies in New York; the scientist the Bush Administration attempted to muzzle.


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


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.

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[] 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.


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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.

2 comments:

Anonymous said...

The Stop Global Warming Virtual March is a non-partisan effort to bring all Americans together in one place to prove that global warming is here now... and, it is time for us to do something about it.

One person can can change the world. Over 275,000 people have already joined. Imagine what millions of marchers can do! Together we will be heard.
Join the March Now!

www.stopglobalwarming.org

It’s easy! There is every reason in the world to become a virtual marcher. Why? Because it affects our public health, our national security, our economy, our planet's future.

On Earth Day 2006, the March will arrive in Washington, DC and use the strength of our numbers to urge 1) Our government to join the rest of the world in addressing global warming, and 2) American business to start a new industrial revolution on clean energy products that reduce our dependence on oil and other global warming pollution.

Anonymous said...

The Stop Global Warming Virtual March is a non-partisan effort to bring all Americans together in one place to prove that global warming is here now... and, it is time for us to do something about it.

One person can can change the world. Over 275,000 people have already joined. Imagine what millions of marchers can do! Together we will be heard.
Join the March Now!

www.stopglobalwarming.org

It’s easy! There is every reason in the world to become a virtual marcher. Why? Because it affects our public health, our national security, our economy, our planet's future.

On Earth Day 2006, the March will arrive in Washington, DC and use the strength of our numbers to urge 1) Our government to join the rest of the world in addressing global warming, and 2) American business to start a new industrial revolution on clean energy products that reduce our dependence on oil and other global warming pollution.