Arctic warms to highest level yet as researchers fear tipping points

Jeremy Hance
February 13, 2012

 Scientists expect that the Arctic will be fully ice-free during summer sometime during this century.
Scientists expect that the Arctic will be fully ice-free during summer sometime during this century. Graph by: Dominiklenne.

Last year the Arctic, which is warming faster than anywhere else on Earth due to global climate change, experienced its warmest twelve months yet. According to recent data by NASA, average Arctic temperatures in 2011 were 2.28 degrees Celsius (4.1 degrees Fahrenheit) above those recorded from 1951-1980. As the Arctic warms, imperiling its biodiversity and indigenous people, researchers are increasingly concerned that the region will hit climatic tipping points that could severely impact the rest of the world. A recent commentary in Nature Climate Change highlighted a number of tipping points that keep scientists awake at night.

"If set in motion, [tipping points] can generate profound climate change which places the Arctic not at the periphery but at the core of the Earth system," Professor Duarte, a climatologist with the University of Western Australia's Ocean Institute and co-author other paper, said in a press release. "There is evidence that these forces are starting to be set in motion. This has major consequences for the future of human kind as climate change progresses."

One of the tipping points is sea ice loss. The Arctic wasn't just relatively hot last year—beating the previous record set in 2010 by 0.17 degrees Celsius (0.3 degrees Fahrenheit)—it also experienced the lowest sea ice volume yet recorded, and the second-lowest extent. Sea ice is essential to many Arctic species, from polar bears to walrus, and narwhals to seals. In just over 30 years, sea ice volume has dropped precipitously, declining by 76 percent from 1979 (16,855 cubic kilometers) to 2011 (4,017 cubic kilometers). This loss of sea ice also leads to greater regional and global warming, as the Arctic's sea reflects the sun's light back into space, cooling not only the region but the world.

The Arctic as viewed by NASA's MODIS Satellite in June 2010. Greenland is the bright island on the bottom-left.
The Arctic as viewed by NASA's MODIS Satellite in June 2010. Greenland is the bright island on the bottom-left.
Sea ice loss may also be having a direct impact on weather in the mid-latitudes. In fact, recent research has suggested that, perhaps unintuitively, the extreme cold spell experienced by Europe this winter was linked to the sea ice decline in the Arctic. Researchers argue that the Arctic Oscillation, which is partially responsible for weather conditions in the Northern Hemisphere in winter, has become unhinged by the sea ice decline, causing more extreme winters, such as Europe's cold spell and the massive blizzards that hit the U.S. in 2009 and 2010.

But it's not just sea ice loss that has produced stark concerns: greenhouse gases from thawing permafrost could be just as disastrous. A study published in Nature late last year warned that greenhouse gas emissions due to permafrost thaw could equal the amount currently emitted by deforestation worldwide, a significantly larger estimate than has been put forward before. Moreover, since permafrost thaw emissions include methane, a more potent greenhouse gas than carbon, it could have an impact 2.5 times larger than deforestation overall.

"The larger estimate is due to the inclusion of processes missing from current models and new estimates of the amount of organic carbon stored deep in frozen soils," co-author Benjamin Abbott, a University of Alaska Fairbanks graduate student, explained in a press release. "There's more organic carbon in northern soils than there is in all living things combined; it's kind of mind boggling."

University of Florida researcher Edward Schuur says he doesn't expect permafrost greenhouse gas emission to trump anthropogenic (human-caused) greenhouse gas emissions anytime soon, however they could become "an important amplifier of climate change."

Polar bears approach a U.S. attack sub 280 miles from the North Pole in an encounter that would have been unimaginable a century ago. As the sea ice melts and the Arctic warms, many nations see not a climate warming, but an opportunity to exploit the region for resources. Photo by: U.S. Navy.
Polar bears approach a U.S. attack sub 280 miles from the North Pole in an encounter that would have been unimaginable a century ago. As the sea ice melts and the Arctic warms, many nations see not a climate warming, but an opportunity to exploit the region for resources. Photo by: U.S. Navy.
Further tipping points include an input of freshwater into the Atlantic Ocean from melting ice and glaciers, already increased by 30 percent, which Durate says "may affect the whole ocean current system and, as a result, the climate at a regional level."

Governments have responded to warming in the Arctic with a resource race. Governments with Arctic territories plan to drastically expand oil and gas exploitation, utilize new shipping routes, and increase mining. The industrialization of the Arctic, according to Duarte, may only accelerate impacts on the fragile region and push tipping points.

"[Arctic tipping points] represents a test of our capacity as scientists, and as societies to respond to abrupt climate change," Duarte said. "We need to stop debating the existence of tipping points in the Arctic and start managing the reality of dangerous climate change. We argue that tipping points do not have to be points of no return. Several tipping points, such as the loss of summer sea ice, may be reversible in principle—although hard in practice. However, should these changes involve extinction of key species—such as polar bears, walruses, ice-dependent seals and more than 1,000 species of ice algae—the changes could represent a point of no return."

The solution, Durate says, is to cut the fossil fuel emissions that are causing climate change.

CITATIONS: Carlos M. Duarte, Timothy M. Lenton, Peter Wadhams, Paul Wassmann. Abrupt climate change in the Arctic. Nature Climate Change, 2012; 2 (2): 60 DOI: 10.1038/nclimate1386.

Schuur, Edward A. G.; Abbott, Benjamin. Climate change: High risk of permafrost thaw. Nature. 480, 32–33. 2011. doi:10.1038/480032a.

A NASA animation showing regional temperature changes on a map of the Earth from 1880-2011. On the map, blues represent temperatures lower than baseline averages, while reds indicate temperatures higher than the average. As the 131 years pass, the map turns from bluish-white to increasingly yellow and red. Notice the Arctic over the last 30 years. Caused by the burning of fossil fuels, deforestation, agricultural practices, and other human impacts, climate change has currently raised global temperatures 0.8 degrees Celsius (1.44 degrees Fahrenheit) higher than the Industrial Revolution average.

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Jeremy Hance
mongabay.com (February 13, 2012).

Arctic warms to highest level yet as researchers fear tipping points.