Skip to comments.Arctic sea ice not melting: new research
Posted on 11/08/2004 11:00:30 PM PST by Exton1
Arctic sea ice not melting: new research
By BOB WEBER-- The Canadian Press
IQALUIT, Nunavut (CP) -- A Canadian scientist is pouring cold, unfrozen water on the notion that global warming is melting arctic sea ice like a Popsicle at the beach.
Greg Holloway galvanized an international meeting of arctic scientists Tuesday by saying there is little evidence of a rapid decline of the volume of ice in the northern oceans.
Despite breathless media reports and speculation of an ice-free Northwest Passage, he suggests that it's far more likely that the ice has just been moved around in the cycles of Arctic winds.
"It's more complicated than we thought," said Holloway, a scientist with the Institute of Ocean Science in Victoria.
The original theory was based on declassified records from the trips of U.S. submarines under the ice.
Satellite pictures have clearly shown that the surface area of the ice has decreased about three per cent a year for the last 20 years.
But the question was, How thick was it?
The submarine data generated headlines and cover stories from the New York Times to Time Magazine when it seemed to indicate that ice volume had decreased by 43 per cent between 1958 and 1997.
The evidence seemed good. There were only eight different voyages, but they had generated 29 different locations across the central Arctic where there were enough readings to make comparisons.
Holloway, however, couldn't make that conclusion jibe with any of his computer models.
"We couldn't understand how the reduction could be so rapid," he said.
"My first thought was, What is it we don't understand?"
Holloway knew that there was a regular pattern of sea ice being blown into the North Atlantic. He decided to examine if the wind patterns across the circumpolar North could have had something to do with the missing ice.
Wind patterns blow across the Arctic in a 50-year cycle.
At different points in the cycle, ice tends to cluster in the centre of the Arctic. At other points, the ice is blown out to the margins along the Canadian shorelines, where the subs were not allowed to go because of sovereignty concerns.
When Holloway lined up the submarine visits with what he knew about the wind cycles, the explanation for the missing ice became clear: "The submarine sampled ice during a time of oscillation of ice toward the centre of the Arctic. They went back during a time when ice was oscillating to the Canadian side."
Holloway had found the missing ice.
"I believe it is most probably explained with the shifting ice within the Arctic locations," he said to applause from scientific delegates from Norway to China.
If the submarines had made their first visit one year earlier and their return one year later, Holloway says they would have found no change in the thickness of the sea ice at all.
Holloway cautions that his research doesn't force a total re-evaluation of the theory of global warming. Temperatures on average are rising around the world, he says.
It does, however, deflate excitement about the possibility of an ice-free Northwest Passage.
The chance of a year-round northern shipping route has thrilled commercial shippers, worried environmentalists, and concerned those worried about Canada's ability to enforce sovereignty in those waters.
"At this time, we do not have the basis to predict an open Northwest Passage," said Holloway.
It also calls into question some of the findings and recommendations of the International Panel on Climate Change, which accepted the 43 per cent hypothesis in its report to various governments.
More data is coming in as further reports from American and British submarines are released. But the furore over the first results contains a lesson for both scientists and the public, Holloway says.
"It's a very small amount of time and a very limited number of places those submarines could go," he said.
"The cautionary tale to all this is the undersimplifying of a big and complex system."
"Who know what's going on out there?"
Which is certain to cause crustal displacement! We're still doomed! The liberals were right, Gaia is lashing out! Dubya did it! Minorities and children will be hit hardest! AAAaaaack!
Gee, what a disappointment for all those Majore Media people who were packing their bathing suits for a trip to the artic beaches, and bringing food to feed the starving polar bears.
No joke - they just had a story about how the disaster is depriving the polar bears.
They wouldn't have to bring the food...they themselves would be the food!
It's complicated, Jim.
Even if China does control the Panama Canal, we have an alternate route.
ARRRGGGGGGHHHHHH! Melting or not melting.....LOL
It's certainly not grand if someone thinks that they're passing off three-year-old research as new! As I suggested to this poster, they need to read this entire article:
Here's some excerpts, but there are some great graphics on this site that help explain what's been observed:
"In support of this evidence of a changing Arctic climate, Comiso shows in a new paper that most of the Arctic warmed significantly in the 1990s compared to the 1980s. The study also finds that the seasons when sea ice melts, between early spring and late fall, have gotten longer and warmer each decade, and that Arctic regions within North America have warmed more per decade than other Arctic areas."
"Researchers suspect that loss of Arctic sea ice may be caused partly by global warming and partly by changing atmospheric pressure and wind patterns over the Arctic that move sea ice around, which also help to warm Arctic temperatures. Changes in air pressure and wind patterns may likewise be a result of greenhouse gas buildup in the atmosphere."
The Y-axis, which I couldn't grab, is sea ice extent in millions of square kilometers. The top value would be 8.0 millions of square kilometers, and the bottom value would be 6.5 millions of square kilometers.
The point is that all of this is more complex than a graph such as yours suggests. That's what's grand.
It's not a joke. As an example, the reduction of sea ice on Hudson Bay may be affecting the weight of the famous Churchill, Manitoba polar bears, and their "cubbing success" might be decreasing. Because Hudson Bay is a southern extension of the Arctic environment, scientists have suggested that the effects on the Hudson Bay polar bear population are an example of what will happen to the Arctic population as the Arctic gets warmer.
Read post 15 and also the linked article for additional information.
Hmmmm. The bears will move north? Just a wild guess, mind you.
You're correct that the article is about volume and not extent. Now being me, I like to be current on what's being researched. How more current could one be than abstracts from a meeting that will take place in December? So here's some (by the way, the meeting's in San Francisco. You could go.)
"Explaining the Recent Decreases in Sea Ice on the Arctic Ocean"
Three of the past six summers have exhibited record low sea-ice extent on the Arctic Ocean, and this summer appears to be on pace to set a new record minimum. Simultaneous decreases in sea ice thickness have also been observed (Rothrock, et al. 1999). Taken together, these observations imply a precipitous decline in the total volume of sea ice on the Arctic Ocean. Is this decline due to changes in the advection of heat into the Arctic, or due to a simple change in winds and the drift of sea ice on the Arctic Ocean? Rigor, et al. (2002) showed that the winter wind anomalies associated with the high-index AO conditions increases the advection of ice away from the Eurasian and Alaskan coasts. This advection increases the production of thin ice in the flaw leads along the coast during winter, and preconditions the sea-ice to be more prone to melt during the following spring and summer. During summer, low-index AO conditions favor southeasterly wind anomalies which increase the advection of ice away from the Alaskan coast and increase the advection of warm air onto the ocean, both of which act to decrease the amount of ice in the Beaufort and Chukchi seas. However, the impact of the summer AO on sea-ice extent appears to be preconditioned by the state of the AO during the previous winter, and in recent years the correlations between the summer AO-index and sea-ice extent are not as strong as they were in prior years. For example, during the summers of 2002 and 2003, the summer AO was in a high-index phase, which favors above normal ice concentrations along the Alaskan coast, and yet record minima were observed during both years. We hypothesize that the minima in Arctic sea ice extent may have been dynamically induced by changes in the surface winds. Based on results of a simple model that keeps track of the age of ice as it moves about on the Arctic Ocean, we argue that the areal coverage of thick multi-year ice decreased precipitously during 1989-1990 when the Arctic Oscillation was in an extreme "high index" state, and has remained low since that time. Under these conditions, younger, thinner ice anomalies recirculate back to the Alaskan coast more quickly, decreasing the time that new ice has to ridge and thicken before returning for another melt season. During the 2002 and 2003 summers this anomalously younger, thinner ice was advected into Alaskan coastal waters where extensive melting was observed, even though temperatures were locally colder than normal. The age of sea-ice explains more than half of the variance in summer sea-ice extent.
"Recent Change of Arctic Sea Ice Cover"
A high resolution coupled ice-ocean model of the Pan-Arctic region forced with realistic atmospheric data is used to investigate causes and long-term variability trends of the Arctic Ocean and its sea ice. Model results suggest that the recent decrease of sea ice cover might be in part due to the delayed effect of thermodynamic interactions at the ice-ocean interface, in particular upward heat fluxes, resulting from increased advection of warm Atlantic and summer Pacific waters into the central Arctic Ocean during the 1990s. More importantly, the modeled rate of decrease of sea ice thickness and volume, especially during the last several years, appears to be larger than that of ice extent and concentration as determined from satellite data. Through air-sea-ice interactions the recent decrease of total sea ice volume leads to an increase of freshwater content, which when exported out of the Arctic Ocean into the active convection regions of the sub-polar North Atlantic can potentially provide an even larger freshwater signal than that of the 1980s to mid-1990s. Such changes will have major consequences to the global ocean thermohaline circulation as well as to the long term global ocean heat and salt transports and climate. The warming trend, if continued, will not only significantly affect global climate but will also change the strategic and economic importance of the Arctic Ocean through its use for commercial shipping routes and increased exploration of natural resources.
A Steven Wright question: what's north of the North Pole?
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