Source: International Arctic Research Center
As Australian politicians fiddle with the details of an extremely insufficient climate change policy, I’ve been watching Arctic sea ice news with increasing dismay. Summer sea ice in the Arctic is fast melting away, accelerated by amplifying feedbacks in what has been called a “death spiral”. The disappearance of Arctic summer sea ice is a key tipping point.
Sea ice floats on the ocean surface and is not to be confused with ice sheets on land. Arctic sea ice grows and shrinks seasonally, with an annual minimum in September. This year, eight independent datasets show we’ve already reached record low sea ice cover in the last week or so, with still weeks to go before the annual minimum.
In the IJIS Arctic sea ice extent dataset (pictured above), the previous record was 4.3 million square km on 24 September 2007 (with the 2011 minimum not far behind). This year we’re only up to 29 August, yet extent has already plummeted to 3.9 million square km. As if that’s not astonishing enough, the ice continues to shrink by 100,000 square km per day. Normally at this time of year, melting slows down as the melt season draws to a close – but this time it seems to be still accelerating, which is unprecedented in decades of observations. Nobody can predict what will happen next. Read the rest of this entry ?