Arctic sea ice still disappearing, new study finds
Since 2007, skeptics of human-caused climate change have pointed to satellite images of the Arctic as evidence that the world is not warming at the rate most scientists maintain it is.
Never mind the fact that three years is too short a period of time with which to examine something as comprehensive and complicated as the climate of a planet. Skeptics held up these photos and argued that the Earth is not warming.
And indeed, the images and accompanying graphs did not provide evidence that it was.
Since 1978, scientists have used satellites to track the extent of multi-year sea ice in the Arctic. These images have shown a decline in the area of the Arctic covered by the extra thick and hard ice. But since 2007, the satellite images have indicated there is an ongoing recovery of multi-year ice.
Scientists were encouraged but puzzled. The pictures were tough to explain and fueled skepticism about the urgency to take action on climate change, which most scientists still maintained was happening at a rate too quick for life to adapt (there is more evidence of climate change than melting ice).
What’s more, the images simply did not match up with climate change models produced over 25 years which said that ice at the Arctic should be declining at an ever-faster pace.
And so in the summer of 2008, David Barber, Canada research chair for arctic system science at the University of Manitoba, took a team of researchers on an ice breaker and set out for the south Beaufort Sea. They wanted to take a closer look at the ice they had been observing through satellites.
“We shouldn’t be able to penetrate into multi-year sea ice at all,” Barber told the Straight. “It is so thick and hard, we shouldn’t be able to get into it.”
But Barber and his team hit the edge of the alleged multi-year ice at 13 knots (24 kilometres) an hour. And then they continued north for roughly 400 kilometres.
“Everybody expected this to be a recovery of multi-year sea ice,” Barber said from Inuvik, Northwest Territories. “What we showed is that there wasn’t a recovery at all.”
Barber explained that what the satellite images were classifying as multi-year ice was actually very thin, first-year ice grown over heavily-rotted multi-year ice. “This was no barrier to our ship whatsoever,” he added.
The research team’s findings were published in the November 2009 edition of the journal Geophysical Research Letters. That report states that changes observed on the summer voyage correspond with increasing regional, air, permafrost, and ocean mixed layer depth temperatures, and increasing instability in northern hemisphere glaciers.
It goes on to note that the consequences of a transformation from a multi-year sea ice cover to one dominated by seasonal ice has implications throughout the Arctic marine, terrestrial, and freshwater ecosystems, as well as impacts for indigenous populations and the security and sovereignty of northern waterways.
The U.S. National Snow and Ice Data Center is one of the leading research units monitoring annual changes in Arctic ice cover. According to an October 2009 media release which did not take into account Barber’s findings, the average ice extent over the month of September 2009 was 5.36 million square kilometres. That is 1.06 million square kilometres greater than the Arctic ice cover for September 2007—a record low for the month—and 90,000 square kilometres greater than September 2008 (the second-lowest extent on record for September).
This means that even without taking Barber’s findings into account, this past September was still the third-lowest ice extent on record.
“Arctic sea ice is now declining at a rate of 11.2 percent per decade, relative to the 1979 to 2000 average,” NSIDC’s release states, noting that Arctic sea ice reflects sunlight, making it instrumental in moderating the entire planet’s climate.
Barber emphasized that we are continuing to lose Arctic multi-year sea ice at an ever-increasing rate. “We’re down to about 19 percent of the total base,” he said.
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