Some climate impacts happening faster than anticipated

December 17, 2008

A report released today at the annual meeting of the American Geophysical Union provides new insights on the potential for abrupt climate change and the effects it could have on the United States, identifying key concerns that include faster-than-expected loss of sea ice, rising sea levels and a possibly permanent state of drought in the American Southwest.

The analysis is one of 21 of its type developed by a number of academic and government agency researchers for the U.S. Climate Change Science Program. The work incorporates the latest scientific data more than any previous reports, experts say, including the 2007 Intergovernmental Panel on Climate Change.

While concluding that some projections of the impact of climate change have actually been too conservative – as in the case of glacier and ice sheets that are moving and decaying faster than predicted – others may not pose as immediate a threat as some scenarios had projected, such as the rapid releases of methane or dramatic shifts in the ocean current patterns that help keep Europe warm.

"We simulate the future changes with our climate models, but those models have not always incorporated some of our latest data and observations," said Peter Clark, a professor of geosciences at Oregon State University and a lead author on the report. "We now have data on glaciers moving faster, ice shelves collapsing and other climate trends emerging that allow us to improve the accuracy of some of our future projections."

Some of the changes that now appear both more immediate and more certain, the report concludes, are rapid changes at the edges of the Greenland and West Antarctic ice sheets, loss of sea ice that exceeds projections by earlier models, and hydroclimatic changes over North America and the global subtropics that will likely intensify and persist due to future greenhouse warming.

"Our report finds that drying is likely to extend poleward into the American West, increasing the likelihood of severe and persistent drought there in the future," Clark said. "If the models are accurate, it appears this has already begun. The possibility that the Southwest may be entering a permanent drought state is not yet widely appreciated."

Climate change, experts say, has happened repeatedly in Earth's history and is generally believed to be very slow and take place over hundreds or thousands of years. However, at times in the past, climate has also changed surprisingly quickly, on the order of decades.

"Abrupt climate change presents potential risks for society that are poorly understood," researchers wrote in the report.

This study, in particular, looked at four mechanisms for abrupt climate change that have taken place prehistorically, and evaluated the level of risks they pose today. These mechanisms are rapid changes in glaciers, ice sheets and sea level; widespread changes to the hydrologic cycle; abrupt changes in the "Atlantic Meridional Overturning Circulation," or AMOC, an ocean current pattern; and rapid release to the atmosphere of methane trapped in permafrost or on continental margins.

Considering those mechanisms, the report concluded:

-- Recent rapid changes at the edges of the Greenland and West Antarctic ice sheets show acceleration of flow and thinning, with the speed of some glaciers more than doubling. These "changes in ice dynamics can occur far more rapidly than previously suspected," the report said, and are not reflected in current climate models.

-- Inclusion of these changes in models will cause sea level rises that "substantially exceed" levels now projected for the end of this century, which are about two feet – but data are still inadequate to specify an exact level of rise.

-- Subtropical areas around the world, including the American West, are likely to become more arid in the future due to global warming, with an increasing likelihood of severe and persistent drought. These are "among the greatest natural hazards facing the United States and the globe today," the report stated, and if models are correct, this has already begun.

-- The strength of "AMOC" ocean circulation patterns that help give Europe a much warmer climate than it would otherwise have may weaken by about 25-30 percent during this century due to greenhouse gas increases, but will probably not collapse altogether – although that possibility cannot be entirely excluded.

-- Climate change will accelerate the emissions of methane, a potent greenhouse gas, from both hydrate sources and wetlands, and they quite likely will double within a century – but a dramatic, potentially catastrophic release is very unlikely.

The "overarching" recommendation of the report is the need for committed and sustained monitoring of these climatic forces that could trigger abrupt climate change, the researchers concluded.

Better observing systems are needed, better forecasting of droughts should be developed, a more comprehensive understanding of the AMOC system is needed, and monitoring of methane levels should be maintained, among other needs.

Source: Oregon State University

Explore further: Study on impact of climate change on manufacturing in China predict substantial losses by mid-21st century

Related Stories

Science update on climate change: from bad to worse

November 17, 2017

Scientists monitoring the Earth's climate and environment have delivered a cascade of grim news this year, adding a sense of urgency to UN talks on how best to draw down the greenhouse gases that drive global warming.

Recommended for you

New research could predict La Nina drought years in advance

November 16, 2017

Two new studies from The University of Texas at Austin have significantly improved scientists' ability to predict the strength and duration of droughts caused by La Niña - a recurrent cooling pattern in the tropical Pacific ...


Adjust slider to filter visible comments by rank

Display comments: newest first

3.4 / 5 (10) Dec 17, 2008
This article doesn't shake my deep religious faith in global warming denialism at all. I reject global warming because I have ulterior religious/economic/political agendas, agendas that my lord and savior, big oil, have asked me to advance in a vision of revelation.
2.8 / 5 (11) Dec 17, 2008
When Glaciers were retreating, it was evidence of Global Warming. Now that glaciers are advancing because of increased mass, it is also evidence of Global Warming.
Is there anything that Global Warming can't do?

Global Warming- The cause of and the solution to all problems.
3 / 5 (8) Dec 17, 2008
Global Warming simply can not cure the education crisis. Then no body would believe the Global warming alarmists.
2.6 / 5 (10) Dec 17, 2008
Exactly, MikeB. If any occurrence at all is evidence of Global Warming, then the concept of Global Warming has no predictive value whatsoever. It's a religious dogma like any other.
2.3 / 5 (9) Dec 17, 2008
The only predictions of AGCC that are happening faster than anticipated is that they're getting caught with their hands in the cookie jar.

"Damn it they figured out that we're full of it and haven't really done any science, now what do we do?"
2.8 / 5 (11) Dec 17, 2008
Problem: Increasingly irrelevant systems of government control and spending are becoming harder to justify to a more informed public unwilling to accept global concentration of power.

Reaction: Create and sustain a sense of crisis among the population with regularly released media connecting the normal activities of society with a dangerous threat to natural order.

Solution: Implement a new system of high taxation and controls on areas of life that were previously not under the authority of government, and design it as an interconnected system that reinforces the idea of global government and total social control.
2.3 / 5 (9) Dec 17, 2008
Or fiddle with the numbers so that they uphold your position in spite of the physical reality.
2.2 / 5 (10) Dec 18, 2008
lol did u see the artic grip thats has a hold on midle of the usa? lettly? the world wide avagrage temperaturue drop? due to the sun spot free

the ice caps acutally adding inches in the last 2 years?

of but dotn get fulled this due to global wariming

i mean this nazi crap they pushing is soo crazy
ucant make it up
1.7 / 5 (6) Dec 18, 2008
Only lacking someone to pass out the tinfoil hats to all the deniers.
2.5 / 5 (8) Dec 18, 2008
It'll match their "former AGW supporter turned skeptic" shirts they received when the 650 of them left the IPCC due to massive inaccuracies in data, reporting, ethics, you get the picture.
2 / 5 (6) Dec 18, 2008
global warming did not cause the
approx. 1/2 of US forests to be destroyed,
1/2 of wetlands, 1/2 of grasslands,
1/4 mammals threatened, 1/3 amphibians
(source: "Planet Earth" BBC series),
but i still seek to know what's on the horizon
concerning GW.

to the author, more specifics please.

as the models incorporate more phenomena
(and eliminate false sources), i expect
to see more precision.
2.1 / 5 (7) Dec 18, 2008
MikeB - the article did state that glaciers are advancing, but not because they are gaining mass as you stated. The article clearly stated they are thinning, so if anything their mass is holding steady or declining.
2.3 / 5 (9) Dec 18, 2008
"Recent rapid changes at the edges of the Greenland and West Antarctic ice sheets show acceleration of flow and thinning, with the speed of some glaciers more than doubling. These "changes in ice dynamics can occur far more rapidly than previously suspected," the report said, and are not reflected in current climate models."

Strange, in recent days past a receding glacier was proof positive that Global Warming was upon us. Now a receding glacier is not "thinning", it is disappearing. However now that the glaciers are advancing they must by definition be "thickening" since they were not even there to calve into the oceans and bays before. Generally speaking a glacier does not flow at all until it accumulates ice as these must be doing.
So, take a note. If the glacier is receding that is Global Warming. Conversely, if the glacier is advancing and calving, that is ALSO Global Warming.
2 / 5 (7) Dec 18, 2008
Speeding up does not necessarily imply advancing. If calving increases a glacier can speed up and retreat at the same time.

2.7 / 5 (7) Dec 18, 2008
as the models incorporate more phenomena
(and eliminate false sources), i expect
to see more precision.

I don't. They can model more phenomena in separate simulations without being able to combine those simulations in to one.

One of the problems is that these simulations are written in Fortran, or another procedural language, and (IMHO) these problems are more suited to dataflow languages.

Another problem is that assumptions are made in every model and the effects of those assumptions, in a poorly understood field like climate, can't be predicted. It makes it a guessing game.
2.7 / 5 (7) Dec 18, 2008
"If calving increases a glacier can speed up and retreat at the same time."

A retreating glacier does NOT calve. Also a glacier cannot retreat and advance at the same time, except, I suppose in the dreamland world of AGW.

See you later (or earlier) I am leaving, and arriving!!
Mike Bryant
2.5 / 5 (6) Dec 19, 2008
How does a glacier retreat if not by calving?


Also, no where in the article does it mention advancing glaciers (although some are still advancing). It says that some are thining and speeding up.

Speeding up does not necessarily imply advancing. If calving increases a glacier can speed up and retreat at the same time.
2.2 / 5 (5) Dec 19, 2008
Sorry, I tried to edit the above post but run out of time.

I tried to add this:-

A glacier moving at one meter per month and calving or melting at the rate of two meters per month is retreating. If the glacier speeds up to one and a half meters per month it is still retreating at the rate of half a meter per month. Therefore, Speeding up does not necessarily imply advancing.

2 / 5 (4) Dec 19, 2008
Do you know what "calving" means? It means it is advancing enough to push huge pieces of ice into the water. By definition a retreating glacier does not calve. How can it push ice into the water as it is retreating away from the water?
2 / 5 (4) Dec 19, 2008
Yes I know what calving means.

First definition on google

"To break at an edge, so that a portion separates."

I've looked up a few definitions and none mention water. Also anything that calves is smaller as a result, therefore anything that calves faster than it lengthens is shrinking.

Regardless of which many glaciers extend out into water and can therefore calve into water and retreat at the same time.

If the rate of calving is great enough a glacier can speed up and retreat at the same time. Speeding up does not necessarily imply advancing.
2.3 / 5 (6) Dec 19, 2008
ok, You win... Calving can take place as a glacier recedes... I was wrong. Sorry,
Mike Bryant.

However, speaking of Global Warming accelerating...

It really is!!! I think I saw it burning rubber heading south to keep ahead of the Arctic cold blasts...
1 / 5 (1) Jan 21, 2009

" the models incorporate more phenomena
(and eliminate false sources), i expect
to see more precision"

The models have not been able to predict anything so far, so I seriously suspect that by plugging in more "data", or, as they put it, "trends", which should really read, "assumptions", that the computer models will continue to get it wrong time and time again. If you use assumptions based on a very weak correlation and also biased in favour of treating the consensus of AGW theory as a fact, then the paradigm will continue.. B.S. in = B.S. out.
It's is interesting that you have to really search hard to find media reports on extended record smashing cooling right across the northern hemisphere.
Bearing in mind that:
a) the human contribution to all greenhouse gases is around 0.3% of total greenhouse gases and that water vapour is seldom talked about (although making up 95% of greenhouse effect),
b) the projections of solar scientists that we are entering an extended cooling period (empirical data for last 2 years tends to agree),
c) CO2 has been shown to greatly increase the growth of plants, make them more drought resistant, temperature tolerant and better carbon sequesterers (a handy feedback!),
then I am persuaded that spending billions and probably trillions, to reverse the increase in C02 and supposedly reduce or slow increasing temperatures is futile and foolhardy. If any person really believes he can regulate the earth's temperature in the face of natural influences on earth's climate, then scientific method is dead. RIP "Science". Long Live AGW.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.