Some climate impacts happening faster than anticipated
December 17, 2008A 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
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Is there anything that Global Warming can't do?
Global Warming- The cause of and the solution to all problems.
"Damn it they figured out that we're full of it and haven't really done any science, now what do we do?"
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.
http://canadafree...cle/6855
inactivity?
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
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.
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.
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.
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
melting?
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.
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.
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.
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...
"...as 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.