ENVIRONMENT: by Peter WestmoreNews Weekly
Is the Arctic sea ice in "a death spiral"
, September 15, 2012
A regular seasonal melting of Arctic sea ice during the northern summer has prompted alarming claims that global warming is causing the melting of the northern ice-cap. But is this true?
The reports have been fuelled by statements from the US National Snow and Ice Data Center (NSIDC), widely considered across the world as the main authority on Arctic Sea ice.
All international observers agree that the current extent of Arctic Sea ice is low, and media reports reflect this fact.
The head of the NSIDC, Mark Serreze, who has repeatedly stated that Arctic Sea ice is in “a death spiral”, issued a statement saying that the Arctic Sea ice is the lowest on record, as a result of global warming.
Extent of Arctic sea ice
What is not stated is that every year, in the northern summer, most of the Arctic Sea ice melts. The changes in the area of Arctic sea ice every year varies from a maximum of around 13 million square km to a minimum of about four million square km, as seen in the accompanying chart.
The Arctic ice is also relatively thin, averaging about two metres thick, which helps to explain how it cracks easily in storms, and how quickly it melts and freezes.
The extraordinary melting and freezing every year has a number of causes, principally the increased energy from the summer sunlight and reduced reflection into space from the sea ice, as well as the effect of the North Atlantic Current — the northern extension of the Gulf Stream — which flows northwards into the Arctic Sea, and flows of warmer ocean water from the Pacific Ocean and fresh water from both Russia and North America.
Other factors include ocean mixing caused by winds and storms, longer-term variations caused by the Arctic Oscillation, as well as the el Niño/Southern Oscillation (ENSO), the Pacific Decadal Oscillation, and changes in solar activity.
For centuries, the decline in the observed extent of Arctic sea ice has caused maritime countries to believe there was a Northwest Passage, north of Canada, linking the Atlantic and Pacific Oceans, which could provide European nations with a shorter route to China, Japan and India than the existing routes south of the Cape of Good Hope in Africa and Cape Horn in South America.
Expeditions were launched, from the 15th century onwards, seeking the Northwest Passage, commencing with John Cabot’s in 1497. In the following century, expeditions were conducted by Sir Francis Drake, as well as French and Spanish ships, seeking a way through the Arctic Sea to China.
In the 19th century were the three expeditions, led by the former governor of Van Diemen’s Land (Tasmania), Sir John Franklin. The last of these, the extremely well-equipped expedition in 1845, ended in tragedy, with the two ships becoming locked in ice during one of the violent freezes which occur, and every crew member, including Franklin, dying of scurvy or starvation, after being locked in sea ice for several years.
The first successful transit through the Arctic took place over 100 years ago, when the melting of the sea ice permitted the Norwegian explorer, Roald Amundsen — the first man to reach the South Pole — to sail from Greenland to Alaska.
Since then, a number of ships have sailed the Northwest Passage during the brief summer thaw.
But what is most interesting about the current year’s data is that in the last northern winter, the amount of Arctic Sea ice was about the same as for any one of the previous 10 years, perhaps a little more.
This coincided with the extreme cold experienced in the last northern winter, when both North America and Europe were in the grip of a deep freeze.
When the sea-ice cover was around 14 million square km, the National Snow and Ice Data Center had nothing to say about it. It has only commented when the spring/summer thaw reduced the Arctic ice cover to around 4 million square km late in August.
Barely mentioned in the alarmist talk of a melting Arctic ice cap was the fact that, in early August, there were severe storms in there which caused a significant break-up of thin ice sheets and mixing with sea water which melted a significant amount of the remaining ice.
Anthony Watts, the American meteorologist who edits one of the most popular climate change web sites, www.wattsupwiththat.com, pointed out that, despite the NSIDC’s claim that Arctic sea ice was the lowest on record, other data, including some from NSIDC itself, contradicted the claim.
Watts wrote, “Here’s a curiosity, another NSIDC product, the new and improved ‘multi-sensor’ MASIE product, shows no record low at [about] 4.7 million square kilometres.”
He added, “Another product, NOAA’s National Ice Center Interactive Multisensor Snow and Ice Mapping System (IMS) plot, also shows no reason for claiming a record at all: Their number is … [about] 5.1 million square kilometres.”
Apparently, you can find figures to support any conclusion you like.