Arctic sea ice now lowest on satellite record

The extent of sea ice in the Arctic region has dropped sharply in the last few months.

Only in April, Arctic sea ice had staged an impressive recovery and was close to the 1979-2012 average, reaching levels not seen in April for over 10 years.

But yesterday, the National Snow and Ice data centre reported that the extent of Arctic sea ice shrank to 1.58 million square miles, breaking the previous record set in the summer of 2007, based on satellite data which was first gathered in 1979.

Usually the minimum ice extent is not reached until September, suggesting that further ice loss is likely.

Including this year, the six lowest ice extents in the satellite record have occurred in the last six years.

And most scientists, whilst accepting that some of the decline in sea ice is likely to be down to natural factors such as prevailing weather conditions and natural ocean cycles, believe a substantial proportion is down to man-made influences such as global warming due to higher greenhouse gases in the atmosphere.

The big worry is that continued melting sea ice would cause serious feedback mechanisms to kick-in.

Firstly with less sea ice to reflect incoming solar radiation back into space, the sea will warm more quickly than would otherwise be the case, speeding up global warming.

And secondly, natural methane trapped under the sea-bed by permafrost could be released. Methane is a much more powerful greenhouse gas than carbon dioxide, and would also accelerate global warming.

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