Global Warming

[descartes]

Can anyone give me statistics on increase in sea levels due to Global Warming? We are continually been shown of the depletion of Artic ice(I understand about floating ice not increasing sea level), but land based ice, glasiers shearing off and tundra leaking etc. It does seem to me that sea levels should be increasing at a measureable rate..........but yet this info is not there that I can find. We are told that London will be under 35 ft of water in some future year.......but surely this should be gradual. I am not interested in surges. Thanks

[ibis]

IPCC figures - metres rise over the next century:

B1 scenario 0.18 – 0.38
A1T scenario 0.20 – 0.45
B2 scenario 0.20 – 0.43
A1B scenario 0.21 – 0.48
A2 scenario 0.23 – 0.51
A1FI scenario 0.26 – 0.59

These are "model-based range excluding future rapid dynamical changes in ice flow" - which is to say that they are the conservative estimates of sea-level rise based on no Antarctic and no Greenland ice-sheet melting, and no noticeable increase of ice flow into the oceans.

Greenland: "Contraction of the Greenland ice sheet is projected to continue to contribute to sea level rise after 2100. Current models suggest ice mass losses increase with temperature more rapidly than gains due to precipitation and that the surface mass balance becomes negative at a global average warming (relative to pre-industrial values) in excess of 1.9 to 4.6°C. If a negative surface mass balance were sustained for millennia, that would lead to virtually complete elimination of the Greenland ice sheet and a resulting contribution to sea level rise of about 7 m."

Source.

[Lennon]

Can anyone give me statistics on increase in sea levels due to Global Warming? We are continually been shown of the depletion of Artic ice(I understand about floating ice not increasing sea level), but land based ice, glasiers shearing off and tundra leaking etc. It does seem to me that sea levels should be increasing at a measureable rate..........but yet this info is not there that I can find. We are told that London will be under 35 ft of water in some future year.......but surely this should be gradual. I am not interested in surges. Thanks

This is a link to a previous discussion on rising sea levels arising from climate change:

http://www.politics.ie/viewtopic.php?t=26031

The predicted sea level rises calculated by the IPCC do not take into account the possibility of a sudden catastrophic rise resulting from the disintegration of the Greenland or Western Antarctic ice sheets. Experts do not know how quickly this will happen…….

[Defeated Romanticist]

But isn't the Antarctic getting bigger, and doesn't that, not the Arctic hold most of the worlds ice?

[ibis]

But isn't the Antarctic getting bigger, and doesn't that, not the Arctic hold most of the worlds ice?

Currently decreasing...

[Defeated Romanticist]

But isn't the Antarctic getting bigger, and doesn't that, not the Arctic hold most of the worlds ice?

Currently decreasing...

Really?

My scientist are better than your scientists

[Lennon]

But isn't the Antarctic getting bigger, and doesn't that, not the Arctic hold most of the worlds ice?

The Larsen B ice shelf collapsed in 2002, probably the first time that this ice shelf has collapsed during the Holocene (Domack et al 2005). Much of the WAIS lies at, or below, sea level and hence has the potential to collapse rapidly. Ice sheets have become unstable in the past; in the late Pleistocene, deglaciation of ice sheets lead to large-scale calving events, with consequent rapid increases in sea level.

There are a range of views on the stability of the ice sheets, from Huybrechts et al (2004) who suggest that their net contribution to sea level change over the 21st century is not significantly different from zero to those who argue that the ice sheets are displaying signs of instability.

There are clear and worrying trends in the behaviour of component parts of the Greenland and Antarctic Ice Sheet, with the WAIS in particular showing anomalous behaviour. Meaningful predictions of the likelihood of rapid, catastrophic ice discharge, ice sheet collapse or lake outbursts in the near future are impossible. However, an increase in instability, with a resultant impact on sea level within our lifetime, is a credible risk. Insurers and other commercial institutions sensitive to these risks are keeping a close watch on future developments and are prepared to revise their strategies regularly.

[ibis]

[quote=Defeated Romanticist]

But isn't the Antarctic getting bigger, and doesn't that, not the Arctic hold most of the worlds ice?

Currently decreasing...

Really?

My scientist are better than your scientists[/quote:1bjsf2qr]

Touché! However, the two reports are not contradictory:

Your scientists:

"The vast East Antarctic Ice Sheet — a 2-mile-thick wasteland larger than Australia, drier than the Sahara and as cold as a Martian spring — increased in mass every year from 1992 to 2003 because of additional annual snowfall, an analysis of satellite radar measurements showed.

"It is an effect that has been predicted as a likely result of climate change," said David Vaughan, an independent expert on the ice sheets at the British Antarctic Survey in Cambridge, England. "

My scientists:

"University of Colorado at Boulder researchers have used data from a pair of NASA satellites orbiting Earth in tandem to determine that the Antarctic ice sheet, which harbors 90 percent of Earth's ice, has lost significant mass in recent years.

"This is the first study to indicate the total mass balance of the Antarctic ice sheet is in significant decline," said Isabella Velicogna of CU-Boulder's Cooperative Institute for Research in Environmental Sciences, chief author of the new study that appears in the March 2 online issue of Science Express.

The team used measurements taken with the Gravity Recovery and Climate Experiment, or GRACE, to conclude the Antarctic ice sheet is losing up to 36 cubic miles of ice, or 152 cubic kilometers, annually. By comparison, the city of Los Angeles uses about 1 cubic mile of fresh water annually.

The most recent Intergovernmental Panel on Climate Change assessment, completed in 2001, predicted the Antarctic ice sheet would gain mass in the 21st century due to increased precipitation in a warming climate. But the new study signals a reduction in the continent's total ice mass, with the bulk of loss occurring in the West Antarctic ice sheet, said Velicogna."

So the East Antarctic ice sheet is growing, but the West Antarctic ice sheet is shrinking, and the shrinkage is larger than the gain, so the net is loss...

[descartes]

Assuming we are in a warming period, it follows that there will be an increase in sea level. Not taking into account any dam release of melt water this warming should roughly show a corresponding rise in sea level. We hear all the time of pre-dicted rises of 7m etc in the next 50 years(which is hard for the average man to grasp) but there is no talk of actual rise. Should we not be seeing yearly rises recorded locally? This sort of information would be invaluable to influence public opinion.

[John_C]

What's the difference between East Antarctic and West Antarctic? Is it not all north and south down there?