Has the Arctic melt passed the point of no return?
Tuesday, 16 December 2008
ALAMY
The Beaufort Sea, just north of Alaska, where near-surface air temperatures are 7C higher than normal
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Scientists have found the first unequivocal evidence that the Arctic region is warming at a faster rate than the rest of the world at least a decade before it was predicted to happen.
Climate-change researchers have found that air temperatures in the region are higher than would be normally expected during the autumn because the increased melting of the summer Arctic sea ice is accumulating heat in the ocean. The phenomenon, known as Arctic amplification, was not expected to be seen for at least another 10 or 15 years and the findings will further raise concerns that the Arctic has already passed the climatic tipping-point towards ice-free summers, beyond which it may not recover.
The Arctic is considered one of the most sensitive regions in terms of climate change and its transition to another climatic state will have a direct impact on other parts of the northern hemisphere, as well more indirect effects around the world.
Although researchers have documented a catastrophic loss of sea ice during the summer months over the past 20 years, they have not until now detected the definitive temperature signal that they could link with greenhouse-gas emissions.
However, in a study to be presented later today to the annual meeting of the American Geophysical Union in San Francisco, scientists will show that Arctic amplification has been under way for the past five years, and it will continue to intensify Arctic warming for the foreseeable future.
Computer models of the global climate have for years suggested the Arctic will warm at a faster rate than the rest of the world due to Arctic amplification but many scientists believed this effect would only become measurable in the coming decades.
However, a study by scientists from the US National Snow and Ice Data Centre (NSIDC) in Colorado has found that amplification is already showing up as a marked increase in surface air temperatures within the Arctic region during the autumn period, when the sea ice begins to reform after the summer melting period.
Julienne Stroeve, of the NSIDC, who led the study with her colleague Mark Serreze, said that autumn air temperatures this year and in recent years have been anomalously high. The Arctic Ocean warmed more than usual because heat from the sun was absorbed more easily by the dark areas of open water compared to the highly reflective surface of a frozen sea. "Autumn 2008 saw very strong surface temperature anomalies over the areas where the sea ice was lost," Dr Stroeve told The Independent ahead of her presentation today.
"The observed autumn warming that we've seen over the Arctic Ocean, not just this year but over the past five years or so, represents Arctic amplification, the notion that rises in surface air temperatures in response to increased atmospheric greenhouse gas concentrations will be larger in the Arctic than elsewhere over the globe," she said. "The warming climate is leading to more open water in the Arctic Ocean. As these open water areas develop through spring and summer, they absorb most of the sun's energy, leading to ocean warming.
"In autumn, as the sun sets in the Arctic, most of the heat that was gained in the ocean during summer is released back to the atmosphere, acting to warm the atmosphere. It is this heat-release back to the atmosphere that gives us Arctic amplification."
Temperature readings for this October were significantly higher than normal across the entire Arctic region – between 3C and 5C above average – but some areas were dramatically higher. In the Beaufort Sea, north of Alaska, for instance, near-surface air temperatures were more than 7C higher than normal for this time of year. The scientists believe the only reasonable explanation for such high autumn readings is that the ocean heat accumulated during the summer because of the loss of sea ice is being released back into the atmosphere from the sea before winter sea ice has chance to reform.
"One of the reasons we focus on Arctic amplification is that it is a good test of greenhouse warming theory. Even our earliest climate models were telling us that we should see this Arctic amplification emerge as we lose the summer ice cover," Dr Stroeve said. "This is exactly what we are not starting to see in the observations. Simply put, it's a case of we hate to say we told you so, but we did," she added.
Computer models have also predicted totally ice-free summers in the Arctic by 2070, but many scientists now believe that the first ice-free summer could occur far earlier than this, perhaps within the next 20 years.
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180 Comments
One of the aspects not considered is the effect of the global ocean current ACROSS the North Pole. In the beginning, one may expect any realignment of the oceanic undersea currents caused by dramatically COLDER ocean waters from the Arctic (because no current flows across the pole as yet) may have a disastrous short-term effect on climate. No one has done any modeling of the potential scenarios that may result.
Posted by bzag | 17.12.08, 04:32 GMT
C. Edge, here's something I know about. This last summer, both my house and my office, and my employees' house, all miles away from each other, were struck by lightning in an unusually active summer. The year before we all lost roof shingles in another unusually active summer. Dr. Palmer, how has the weather been over there in England? Anything unusual? Anyone worried about agriculture on the British Isles?
Posted by Canman | 17.12.08, 02:35 GMT
'Al Gore's view'? Mainstream climate sciences' view would be more apt. Articles that contradict the major scientific consensus are hard to find in the literature and try not to cling to false balance, like the majority of the mainstream media try to, there is not balance in the majority scientific opinion.
Posted by Wayne | 17.12.08, 02:06 GMT
Not wanting to be disrespectful in any way, if you thesis was not in climate or meteorology quite specialised areas....
Posted by Wayne | 17.12.08, 02:03 GMT
"Current global warming information articles for public consumption can be found at algore.com."
But sadly no articles that conflict with Al Gore's view. That is the real assault on reason.
Posted by Dr. Calvin Palmer | 17.12.08, 02:02 GMT
Mr. Edge,
As someone who believes the truth to be sacrosanct, yes there are still some of us around, it would be hypocritical of me to claim to be something I wasn't.
My doctorate, not doctorship, is in geography and was awarded by the University of Manchester in 1977. My credentials would, therefore, appear to be superior to those of both Al Gore and Steve Connor when it comes to the subject of climate change.
Posted by Dr. Calvin Palmer | 17.12.08, 01:43 GMT
Stef, please let me address your points:
1. "Scientists" actually said that the north pole summer would be ice-free this century, not this year
2. The article is reporting on the phenomenon of air temperature being affected by a positive feedback loop (open water absorbing more energy than reflective ice). If you look in other sources, you will see that studies in water temperature, etc, have already been done, or are ongoing.
3. This article is a news article reporting on a paper being presented to the American Geophysical Union. News articles typically do not have an extensive bibliography, but I bet you will find one in the actual paper being published. Current global warming information articles for public consumption can be found at algore.com.
Posted by Canman | 17.12.08, 01:42 GMT
Patrick,
Here on Cyprus, the reservoirs are dry. We have been importing water from Greece at great expense. It is hoped that desalination plants will be online next summer to make seawater drinkable. Otherwise, the island's economy will collapse.
Ten of the regular-as-clockwork Coptic storms failed last year. This year is no better, so far.
Officially, (see Cyprus Mail website, Dec 4 2008): “We have seen a 1.6 degrees Celsius increase in temperature here, which means Cyprus warms up faster than the rest of the world where the global mean increase is 0.8 degrees Celsius,”.
To produce drinkable water from seawater uses one hell of a lot of energy, which should make the oil-billionaire Bush family happy, anyway.
I do wish that people would write about things that they know at least SOMETHING about. ("Oh well, 't weather in Ashton-under-Lyme's a bit chilly, so 't global warmings all my backside, sitthee")
Posted by C. Edge | 17.12.08, 01:19 GMT
Patrick when you cherry pick a starting point in a limited historical timeframe to look at a trend, you can 'find' anything you want - increase the historical window, which for climate(not to be confused with weather) is about 30yrs and you'll see something a lot different, go back further, and the upward trend is supported still, and yes the record does show periods of reduced warming but the overall trend is up and up.
Action on climate change will not necessarily disadvantage the poor but knowing our politicians they'll ensure that it does.
And Stef, who publishes referenced scientific articles in national newspapers? Check out the website of the scientists in question, perhaps you'll find the links you want. If not, email them and politely ask for a copy of their presentation paper for the American geophysical society meeting, they may just oblige.
Posted by Wayne | 17.12.08, 01:09 GMT
Patrick, that is just about the most reasononed and reasonable response I have ever heard from a climate-sceptic. Unfortunately, though, the famines caused by climate change are likely to be far more severe than what might be caused by tackling it. How are you going to 'adjust' for, for example, the millions of Bangladeshi people who are likely to be made homeless by climate-change-induced flooding? What did you make of the Stern report? The academic consensus is that the economic costs of climate climate change will be far worse than the costs of prevention.
Posted by Imogen | 17.12.08, 00:45 GMT
180 Comments