Arctic takes a Turney for the worse

By Bryan Walker 25/09/2009

British geologist Chris Turney is just back from fieldwork in Svalbard, the island archipelago situated halfway between Norway and the North Pole. He has written about it in his popular science blog, under the title A Warning From the North. I’ll draw attention to some of his main points here, but first a reminder that he is the author of Ice, Mud and Blood which I reviewed on Hot Topic early this year. He’s also a director of New Zealand company Carbonscape which Hot Topic has featured more than once.

The Exeter University team’s fieldwork looked into the impacts of past climate change, by probing Svalbard’s recent geological past. Ancient landforms and sediments there preserve a great record of what has happened in that part of the world over the past 20,000 years. But his main concern in the blog post is to consider what the near future holds for the Arctic. What he has to report may not be new, but it’s good to hear it directly from a scientist working on the spot who wants to communicate his concerns directly to the public. He deserves attention.

He points out that we know from ancient archives that the high Arctic experiences a far greater change in temperature than the global average. This is already evident in the effects already seen in the region from human-induced climate change, some of them spectacular, such as the opening of shipping routes through previously ice-bound waters.    

Although the amount of sea ice cover in the Arctic waxes and wanes through the year, temperatures have steadily risen through the second half of the twentieth century; on average by some 0.5 °C a decade. He points to a paper in Science magazine this month led by Darrell Kaufman showing that this warming has happened against a backdrop of cooling temperatures over the past two millennia that was driven by the changing orbit of the Earth around the Sun which contrived to cool the Arctic. The paper found that four of the warmest five decades of the last 2000 years occurred between 1950 and 2000.  Increasing greenhouse gases disrupted the natural system and warmed the the region some 1.4ËšC more than would have been the case if the natural cooling had been allowed to continue uninterrupted.

This is why the 50% summer ice cover in the Arctic in the 1970s has crashed to less than 30% and the ice has become thinner and younger. As the ice cover goes the summer heat is absorbed by the ocean and released back into the atmosphere later in the year when the next phase of sea ice is supposed to be forming. Autumn temperatures are now a staggering 5ËšC above normal for the region. As the oceans warm the overlying air these temperatures start to reach far inland, melting areas of permanently frozen land.  Year on year the feedbacks become stronger increasing the warming over the region relative to the rest of the planet. As a result, recent Arctic warming is almost twice the global average. 

Ban Ki-moon visited Svalbard while the team was there, a welcome raising of the international profile of a fragile environment.  The rest of Turney’s post somewhat anxiously tracks recent political developments on the road to Copenhagen.

’Will world leaders pull the iron out of the fire and get a deal?  I do hope so.  I love Svalbard and would hate it to become a property hotspot in a warming world.’