August 28, 2012
Bad News For Arctic Sea Ice – Lowest Extent In History Reached
April Flowers for redOrbit.com - Your Universe Online
Arctic sea ice has melted to a record low extent; the smallest ever recorded since satellites began measuring it in 1979.
Sea ice extent refers to a measurement of the area of Arctic Ocean that contains at least some sea ice. Areas with less than 15% are considered by scientists to mark the ice edge. The sea ice cap naturally grows during the cold Arctic winters and shrinks when temperatures climb in the spring and summer. The entire North Pole, or Arctic, region is an ocean that is covered with this ice cap, unlike the Antarctic region, which is a landmass covered by ice and snow.
The melting season isn't' over for this year, so the sea ice extent could be significantly smaller by the end of this summer. Melting generally continues until mid-September, so the team expects the sea ice extent to continue to dwindle.
"It's a little surprising to see the 2012 Arctic sea ice extent in August dip below the record low 2007 sea ice extent in September," Walt Meier, an NSIDC scientist, said. "It's likely we are going to surpass the record decline by a fair amount this year by the time all is said and done."
To give you some perspective on these records, the September 18, 2007 minimum extent shattered all previously held satellite records, reaching a five-day running average of 1.61 million square miles. This was about a million square miles below the running minimum average from 1979 to 2000. To understand this difference, a million square miles is roughly the size of Alaska and Texas combined.
A large Arctic storm in early August seems to be the catalyst for this early breakup and melt, but the 2012 record is part of an alarming trend, which is well outside the range of natural climate variability. Most scientists believe the shrinking Arctic sea ice is tied to global warming caused by an increase in human-produced greenhouse gases in the atmosphere.
Researchers say the old, thick multi-year ice that used to dominate the Arctic region has been replaced by young, thin ice that has survived only one or two melting seasons — ice that now makes up about 80 percent of the ice cover. Since 1979, the September Arctic sea ice extent has declined about approximately 12-13 percent per decade.
The record-breaking Arctic sea ice extent in 2012 moves the 2011 sea ice extent minimum from the second to the third lowest spot on record, behind 2007. Meier and his CU-Boulder colleagues say they believe the Arctic may be ice-free in the summers within the next several decades.
"The years from 2007 to 2012 are the six lowest years in terms of Arctic sea ice extent in the satellite record," said Meier. "In the big picture, 2012 is just another year in the sequence of declining sea ice. We have been seeing a trend toward decreasing minimum Arctic sea ice extents for the past 34 years, and there's no reason to believe this trend will change."
"It really does imply that the Arctic is moving to a new state," said NASA ice systems program scientist Tom Wagner. "The Arctic is changing."
"The persistent loss of perennial ice cover -- ice that survives the melt season -- led to this year's record summertime retreat," said Joey Comiso, senior research scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "Unlike 2007, temperatures were not unusually warm in the Arctic this summer."
"In 2007, it was actually much warmer," Comiso said. "We are losing the thick component of the ice cover. And if you lose the thick component of the ice cover, the ice in the summer becomes very vulnerable."
"By itself it's just a number, and occasionally records are going to get set," Walt Meier said about the new record. "But in the context of what's happened in the last several years and throughout the satellite record, it's an indication that the Arctic sea ice cover is fundamentally changing."
The amount of ice in the Arctic Ocean is significant because the region is a potent global weather-maker, sometimes referred to as the world's air conditioner. The bright surface of the ice reflects 80% of the sunlight that hits it back into space, whereas the dark ocean surface being exposed would absorb approximately 90% of this light, creating a positive feedback effect, and the Arctic Ocean temperature would rise and contribute to a further sea ice melt
Scientists say Arctic sea ice helps moderate temperatures further south in the winter and summer. A study earlier this year in the peer-reviewed journal Geophysical Research Letters linked some of the factors behind Arctic sea ice loss to higher probabilities of extreme weather "such as drought, flooding, cold spells and heat waves."
Scientists also say sea ice is crucial for polar bears and other animals.
The record melt not only has ramifications for global warming and animal conservation, it has economic and political effects as well. Shipping companies have been using the newly opened passageways to save time and money by sailing through the once-forbidding waters.
NSIDC scientist Ted Scambos said the melt could be blamed mostly on global warming from man-made emissions of greenhouse gases. There are natural factors involved too, including the Arctic storm in August. Nevertheless, he said, dramatic summer sea ice losses in all but one year since 2007, continuous thin ice, and warm air temperatures show a pattern that can only be explained by climate change.
Kumi Naidoo, executive director of Greenpeace, agrees, telling Reuters, "These preliminary figures provide irrefutable evidence that greenhouse gas emissions leading to global warming are damaging one of the planet's critical environments, one that helps maintain the stability of the global climate for every citizen of the world," he stated. "These figures are not the result of some freak of nature but the effects of man-made global warming caused by our reliance on dirty fossil fuels."
In the last decade and a half, the planet has endured a slew of record temperatures, with 13 of the warmest years on record, ever. There have been extreme weather patterns and events, such as severe wildfires in North America to major flooding in Asia.
Studies are showing that Greenland's ice sheet is showing a dramatic melt this summer, which could result in major consequences by raising sea levels.
Efforts to regulate emissions of these greenhouse gases have met with stiff political resistance in several nations, including the U.S. Industry groups have said that regulations would be too costly for the economy. The Center for Global Development in Washington, D.C., released data Monday finding that nations including China, India and the U.S. were reducing the intensity of their carbon emissions, but that the effort was overwhelmed by the surge in power consumption in developing nations.
Earlier this year, a national research team led by CU embarked on a two-year effort to better understand the impacts of environmental factors associated with the continuing decline of sea ice in the Arctic Ocean. The $3 million, NASA-funded project led by Research Professor James Maslanik of Aerospace Engineering Sciences includes tools ranging from unmanned aircraft and satellites to ocean buoys in order to understand the characteristics and changes in Arctic sea ice, including the Beaufort Sea and Canada Basin that are experiencing record warming and decreased sea ice extent.