Ice Age lesson predicts a faster rise in sea level

Aug 31, 2008

If the lessons being learned by scientists about the demise of the last great North American ice sheet are correct, estimates of global sea level rise from a melting Greenland ice sheet may be seriously underestimated.

Writing this week (Aug. 31) in the journal Nature Geoscience, a team of researchers led by University of Wisconsin-Madison geologist Anders Carlson reports that sea level rise from greenhouse-induced warming of the Greenland ice sheet could be double or triple current estimates over the next century.

"We're not talking about something catastrophic, but we could see a much bigger response in terms of sea level from the Greenland ice sheet over the next 100 years than what is currently predicted," says Carlson, a UW-Madison professor of geology and geophysics. Carlson worked with an international team of researchers, including Allegra LeGrande from the NASA Center for Climate Systems at Columbia University, and colleagues at the Woods Hole Oceanographic Institution, the California Institute of Technology, University of British Columbia and University of New Hampshire.

Scientists have yet to agree on how much melting of the Greenland ice sheet — a terrestrial ice mass encompassing 1.7 million square kilometers — will contribute to changes in sea level. One reason, Carlson explains, is that in recorded history there is no precedent for the influence of climate change on a massive ice sheet.

"We've never seen an ice sheet disappear before, but here we have a record," says Carlson of the new study that combined a powerful computer model with marine and terrestrial records to provide a snapshot of how fast ice sheets can melt and raise sea level in a warmer world.

Carlson and his group were able to draw on the lessons of the disappearance of the Laurentide ice sheet, the last great ice mass to cover much of the northern hemisphere. The Laurentide ice sheet, which encompassed large parts of what are now Canada and the United States, began to melt about 10,000 years ago in response to increased solar radiation in the northern hemisphere due to a cyclic change in the orientation of the Earth's axis. It experienced two rapid pulses of melting — one 9,000 years ago and another 7,600 years ago — that caused global sea level to rise by more than half an inch per year.

Those pulses of melting, according to the new study, occurred when summer air temperatures were similar to what are predicted for Greenland by the end of this century, a finding the suggests estimates of global sea level rise due to a warming world climate may be seriously underestimated.

The most recent estimates of sea level rise due to melting of the Greenland ice sheet by the Intergovernmental Panel on Climate Change (IPCC) suggest a maximum sea level rise during the next 100 years of about 1 to 4 inches. That estimate, Carlson and his colleagues note, is based on limited data, mostly from the last decade, and contrasts sharply with results from computer models of future climate, casting doubt on current estimates of change in sea level due to melting ice sheets.

According to the new study, rising sea levels up to a third of an inch per year or 1 to 2 feet over the course of a century are possible.

Even slight rises in global sea level are problematic as a significant percentage of the world's human population — hundreds of millions of people — lives in areas that can be affected by rising seas.

"For planning purposes, we should see the IPCC projections as conservative," Carlson says. "We think this is a very low estimate of what the Greenland ice sheet will contribute to sea level."

The authors of the new Nature Geoscience report were able to document the retreat of the Laurentide ice sheet and its contributions to changes in sea level by measuring how long rocks once covered by ice have been exposed to cosmic radiation, estimates of ice retreat based on radiocarbon dates from organic material as well as changes in ocean salinity.

Source: University of Wisconsin-Madison

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MikeB
2.1 / 5 (7) Aug 31, 2008
Hmmm, the sea level rise in "An Inconvenient Truth" was much, much more than 1 or 2 feet per century.
bobwinners
3.3 / 5 (8) Aug 31, 2008
"Hmmm, the sea level rise in "An Inconvenient Truth" was much, much more than 1 or 2 feet per century."
I believe this article is addressing just ice melt from the Greenland ice sheet. Ice is melting in both hemispheres and ocean temperatures are rising too, which causes the expansion of total ocean water volume.
DKA
2.7 / 5 (7) Aug 31, 2008
Hmmm, the sea level rise in "An Inconvenient Truth" was much, much more than 1 or 2 feet per century.


The data from IPCC are much more conservative than those shown in the movie. Frankly speaking, scientists have complained that in order to get the US to sign the IPCC document, they needed to reduce the impact of "GW" (Global warming). Also many scientist are affraid to be finger pointed as alarmist and they need to be much too cautious. It is said that it is accepted that GW is caused by humans (Co2/dioxines) at about 95% certainty, but there are discussions over how fast the impacts are developing. So far, the "skeptiest" have been proven wrong quite dramatically and the arctic is melting much much faster than the conservative IPCC document is predicting. The truth is that things are very seriously wrong, and if it does not take until 2050-2080 for the Arctic to be melted (IPCC), than you realise that the impacts are happening at a much faster pace than we are officialy told in mass communications.

Jesse
1.4 / 5 (10) Sep 01, 2008
I am also realizing that this world is being affected by spiritual things. This link is a nine minute video about the earth and the meaning of whats happening on here.
http://www.youtub...-KorhkM8&feature=related
SmartK8
3 / 5 (10) Sep 01, 2008
Yeah, everything will always happen in next one hundred years :D
gmurphy
2.7 / 5 (6) Sep 01, 2008
what is this spiritual dimension bullshit?, I thought this was supposed to be a scientific web site. If I'd wanted spiritual mumbo jumbo as an explanation for my existence I'd have taken up religion.
Sav
1.7 / 5 (6) Sep 01, 2008
We should be beware of the effects of the increasing global temperature that may cause sea levels to rise, and the increase in the weather intensity.. Other effects of global warming include major changes in the agricultural yields, modifications of trade routes, extinctions of various species and the increase in the various ranges of disease factors.

---------------
Savio

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Joey_Tavares
1.7 / 5 (6) Sep 01, 2008
I like spirituality mixed with science. Thank you for the link sattvik, very interesting...
Excalibur
3.4 / 5 (5) Sep 01, 2008
Its pretty obvious that the world is deteriorating quickly. It is pretty obvious is it not? Just look around.

RT
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Excalibur
2.5 / 5 (4) Sep 01, 2008
We should be beware of the effects of the increasing global temperature that may cause sea levels to rise, and the increase in the weather intensity.. Other effects of global warming include major changes in the agricultural yields, modifications of trade routes, extinctions of various species and the increase in the various ranges of disease factors.

---------------
Savio

SPAM LINK
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deepsand
3.4 / 5 (5) Sep 01, 2008
Its pretty obvious that the world is deteriorating quickly. It is pretty obvious is it not? Just look around.

RT
Why the BS link?
deepsand
4 / 5 (4) Sep 01, 2008
We should be beware of the effects of the increasing global temperature that may cause sea levels to rise, and the increase in the weather intensity.. Other effects of global warming include major changes in the agricultural yields, modifications of trade routes, extinctions of various species and the increase in the various ranges of disease factors.

---------------
Savio

Yet another BS link.
Velanarris
3 / 5 (8) Sep 03, 2008

The data from IPCC are much more conservative than those shown in the movie. Frankly speaking, scientists have complained that in order to get the US to sign the IPCC document, they needed to reduce the impact of "GW" (Global warming). Also many scientist are affraid to be finger pointed as alarmist and they need to be much too cautious. It is said that it is accepted that GW is caused by humans (Co2/dioxines) at about 95% certainty, but there are discussions over how fast the impacts are developing. So far, the "skeptiest" have been proven wrong quite dramatically and the arctic is melting much much faster than the conservative IPCC document is predicting. The truth is that things are very seriously wrong, and if it does not take until 2050-2080 for the Arctic to be melted (IPCC), than you realise that the impacts are happening at a much faster pace than we are officialy told in mass communications.


The above statement is factually false.
Velanarris
3.1 / 5 (10) Sep 03, 2008
"Hmmm, the sea level rise in "An Inconvenient Truth" was much, much more than 1 or 2 feet per century."
I believe this article is addressing just ice melt from the Greenland ice sheet. Ice is melting in both hemispheres and ocean temperatures are rising too, which causes the expansion of total ocean water volume.


And FYI the warm ocean currents are melting the ice, not atmospheric warming.

Simple backyard test, take a glass of warm water and an overzealous 5 year old with good wind.

Put an ice cube in front of the kid and put an ice cube in the glass. See which vanishes first, the ice cube in the warm water or the ice cube being constantly blown on by the kid.
deepsand
2.1 / 5 (8) Sep 03, 2008
"Hmmm, the sea level rise in "An Inconvenient Truth" was much, much more than 1 or 2 feet per century."
I believe this article is addressing just ice melt from the Greenland ice sheet. Ice is melting in both hemispheres and ocean temperatures are rising too, which causes the expansion of total ocean water volume.


And FYI the warm ocean currents are melting the ice, not atmospheric warming.

Simple backyard test, take a glass of warm water and an overzealous 5 year old with good wind.

Put an ice cube in front of the kid and put an ice cube in the glass. See which vanishes first, the ice cube in the warm water or the ice cube being constantly blown on by the kid.
Relevance?

Are water temperatures independent of those of air and land?
Velanarris
3 / 5 (8) Sep 03, 2008
Relevance?

Are water temperatures independent of those of air and land?


Here you go, the AGW theory states we're warming the air and that's causing glacial melt over the land and sea.

Reason why the sea level isn't rising as forcasted by AGW is because the oceans are warming due to tectonic processes, these processes then melt the ice that is IN the water. Ice that is already in the water is already being supported by the water so the total volume of the oceans don't change, like a glass of soda with ice on a hot day. The glass never overflows, it simply warms up.

Now here's where the misrepresentation occurs. We are losing our water ice, however, the ice sheets are thickening over land. This is raising the albedo of the earth as there si more reflective ice and snow as opposed to low albedo land.

This is causing cooling, not warming. AGW is false, we're headed for cooler times. This is the same mechanic theorized as being responsible for the ice ages this planet has undergone.

A fully natural process regardless of what we do. So let's drop the legislation and expense of creating a theoretical "pollution free" world and realize how really small we are in the scheme of things.

The AGW camp is misguided and arrogant in it's claims. Claims which are costing everyone their livelyhoods, finance, and in some cases ability to live.
Excalibur
2.3 / 5 (7) Sep 04, 2008
Relevance?

Are water temperatures independent of those of air and land?


Here you go, the AGW theory states we're warming the air and that's causing glacial melt over the land and sea.

Reason why the sea level isn't rising as forcasted by AGW is because the oceans are warming due to tectonic processes, these processes then melt the ice that is IN the water. Ice that is already in the water is already being supported by the water so the total volume of the oceans don't change, like a glass of soda with ice on a hot day. The glass never overflows, it simply warms up.

Now here's where the misrepresentation occurs. We are losing our water ice, however, the ice sheets are thickening over land. This is raising the albedo of the earth as there si more reflective ice and snow as opposed to low albedo land.

This is causing cooling, not warming. AGW is false, we're headed for cooler times. This is the same mechanic theorized as being responsible for the ice ages this planet has undergone.

A fully natural process regardless of what we do. So let's drop the legislation and expense of creating a theoretical "pollution free" world and realize how really small we are in the scheme of things.

The AGW camp is misguided and arrogant in it's claims. Claims which are costing everyone their livelyhoods, finance, and in some cases ability to live.
As usual, evades the question.

Try directly answering the question posed by deepsand.
Velanarris
3.1 / 5 (9) Sep 04, 2008
As usual, evades the question.

Try directly answering the question posed by deepsand.


First two paragraphs big guy.
deepsand
2.2 / 5 (6) Sep 04, 2008
As usual, evades the question.

Try directly answering the question posed by deepsand.


First two paragraphs big guy.
You really do have a problem with providing direct answwers, don't you.

It's a "yes" or "no" question.

Pick one.
Velanarris
3 / 5 (7) Sep 04, 2008
As usual, evades the question.

Try directly answering the question posed by deepsand.


First two paragraphs big guy.
You really do have a problem with providing direct answwers, don't you.

It's a "yes" or "no" question.

Pick one.


This isn't a napkin you pass around in class asking if I'll take you to the prom.

Put a frame of reference to the question and you'll get a yes or no answer.
deepsand
2.4 / 5 (8) Sep 06, 2008
For the feeble minded & intellectually lazy/dishonest, the frame of reference = Earth
Velanarris
2.6 / 5 (5) Sep 06, 2008
For the feeble minded & intellectually lazy/dishonest, the frame of reference = Earth


Are water temperatures independant from those of sea and land in regard to Earth....

That's not a proper question. In the system "Earth" yes they're linked, but they're also disassociated. Atmospheric temperature has very little potential to heat the sea where as land has great potential to heat the sea.

So what answer are you looking for?
GrayMouser
2.3 / 5 (3) Sep 07, 2008
For the feeble minded & intellectually lazy/dishonest, the frame of reference = Earth


Are water temperatures independant from those of sea and land in regard to Earth....

That's not a proper question. In the system "Earth" yes they're linked, but they're also disassociated. Atmospheric temperature has very little potential to heat the sea where as land has great potential to heat the sea.

So what answer are you looking for?


I have to agree with Velanarris. The local air temperatures are independent of the local sea temperatures. And a warm wind will have an effect on the rate of melting that is different from a cold wind. I expect that the humidity also is germane.
Velanarris
1 / 5 (3) Sep 08, 2008
I have to agree with Velanarris. The local air temperatures are independent of the local sea temperatures. And a warm wind will have an effect on the rate of melting that is different from a cold wind. I expect that the humidity also is germane.


Well here's the kicker. The elevation of the antarctic ice sheet is increasing, which would make most people believe the ice is getting thicker, but it's not.
http://www.worldc..._vol.JPG
The AGW crowd thinks it's AGW causing the ice to melt. But it's not.

Tada, tectonic process.

http://wattsupwit...tic-ice/

Same thing is happening under the artic ice caps. Welcome to non AGW ice melt, scientifically proven but the current side scanning sonar and space based ladar mapping projects undertaken by the UN to map out the resource allocation at the poles.


Bazz
3.7 / 5 (3) Sep 27, 2008
That proves my point.
Velanarris
1 / 5 (3) Sep 27, 2008
That proves my point.


The heat from volcanos melting the antartic ice proves your point of AGW due to human GHG emission?

I think I missed something there. Could you elaborate?
Bazz
3.7 / 5 (3) Sep 28, 2008
No,yes,you dont seem to care about that anyway.