Scientists say Arctic may have passed 'tipping-point' towards ice-free summers
Tue 16 December 2008
View all news
US scientists say they have found evidence that climate change-induced ice melting in the Arctic has crossed a 'tipping point' beyond which it may not go back. The evidence suggests that the Arctic region is warming at a faster rate than the rest of the World and years before it was predicted to do so.
Scientists from the National Snow and Ice Data Centre (NSIDC) in Boulder, Colorado say that the amount of summer ice at the North Pole has steadily declined since 1979. Computer models predict that this trend will continue, leaving the Arctic completely ice-free during the summers as early as 2030.
The Arctic is considered one of the most sensitive regions in terms of climate change and the changes occurring there will have a direct impact on other parts of the northern hemisphere, as well more indirect effects around the world.
In a new US study scientists showed that the effect in which Arctic temperatures are raised by more than other parts of the world - known as arctic amplification - has been under way for the past five years and is likely to continue. Scientists did not expect to see this effect occurring for at least another ten years.
The Arctic Ocean has 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.
Dr Julienne Stroeve, of the NSIDC (quoted in The Independent) said: "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.
"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. 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."
Computer models have predicted totally ice-free summers in the Arctic by 2070, but many scientists now believe that the first ice-free summer may even occur within the next 20 years.
Related Links
< Back to news list