by Malte Humpert New Research from the Massachusetts Institute of Technology (MIT) suggests that the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report from 2007 may be too conservative when forecasting a summer ice-free Arctic by 2100.
According to Pierre Rampal, the lead author of a study to be published in the Journal of Geophysical Research - Oceans, the IPCC "fails to capture trends in Arctic sea-ice-thinning and drift" and "substantially underestimates these trends."
The study concludes that Arctic sea ice is thinning up to four times faster and drifting twice a quickly, as previous models suggested. Thus, an ice-free Arctic summer may occur well before 2100.
According to Pierre Rampal, the lead author of a study to be published in the Journal of Geophysical Research - Oceans, the IPCC "fails to capture trends in Arctic sea-ice-thinning and drift" and "substantially underestimates these trends."
The study concludes that Arctic sea ice is thinning up to four times faster and drifting twice a quickly, as previous models suggested. Thus, an ice-free Arctic summer may occur well before 2100.
Thus far, the IPCC has primarily relied on changes in temperature to predict ice coverage. According to new research by Rampal and his team, however, mechanics can be just as important.
Traditionally, most of the Arctic Ocean was covered with a thick sheet of multi-year ice. But Arctic ice has become significantly thinner over the past decades as volume decreased by almost 70%. Thinner ice in turn is more vulnerable to ocean currents and wind and may cause it to break up into small pieces.
Furthermore, ice-flows are more prone to escape from the Arctic basin, primarily through the Fram Strait, between Greenland and the Norwegian archipelago of Svalbard, than larger sheets of ice. According to the research, the smaller the floes, the more likely they are to find their way into the Atlantic where they will encounter warmer water and melt.
The importance of ocean currents and wind patterns in predicting the future of Arctic ice and recognizing it as a positive feedback potentially accelerating melting had previously been recognized by Alun Anderson.
A second study published today by the National Center for Atmospheric Research, suggests that although Arctic sea ice appears to melt rapidly as the climate continues to warm, there may in fact be periods over the coming decades where ice temporarily stabilizes or even expands.
According to Jennifer Kay, the lead author, they were surprised to discover that under current climate conditions the ice was as likely to expand as it was to contract for about the next decade. The study, however, concludes that as one begins to look at longer-term trends, "there is no escaping the loss of ice in the summer."
-01.png){kind=small}
