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Further evidence of link between loss of sea ice and Arctic warming
Posted by Bridget in Climate change, Life
Reduced sea ice cover found to be responsible for increasing warming in the Arctic region
James Screen, of the University of Melbourne, Australia, who led the recent study, says that his team observed ice-temperature feedbacks, long predicted as a potential cause of warming across the whole region. The idea of a positive feedback between ice loss and temperature rise is not new and has led to the suggestion that there is a ‘tipping point’ at which the warming in the region cannot be reversed.
(Thumbnail image: This data visualisation from the AMSR-E instrument on the Aqua satellite show the maximum sea ice extent for 2008-09, which occurred on Feb. 28, 2009. Credit: NASA Goddard’s Scientific Visualization Studio)
Screen and his team, writing in the journal Nature, say that their data actually show these predicted feedbacks, although the data do not necessarily show that there is, in fact, a tipping point. Most estimates say that the Arctic will not be free of ice in the summer until the middle of this century, there are other models that suggest that this could happen within 10 years.
What scientists do know is that temperatures in the Arctic have risen twice as fast as the rest of the world in recent decades, which is called Arctic amplification. Many scientists think that loss of sea ice was responsible, but other factors such as changes in wind, clouds and ocean currents have also been blamed.
Something called the albedo effect, is thought to be one factor that causes this amplification. White ice, which reflects the Sun’s heat, is being replaced with dark water, which absorbs more of the Sun’s heat. The lack of ice has also led to more summer evaporation of water, resulting in water vapour, which acts as a powerful greenhouse gas in the atmosphere, and increases the rate of temperature rise.
Screen said: “The albedo effect is very important here, but there are other factors related to the loss of sea ice that likely play a role.”
Source: Nature
