Accelerating Polar Ice Melt: Climate Change's Arctic and Antarctic Impacts

Global warming is being felt most intensely in the Arctic and coastal regions of Antarctica, where a world based on ice and snow has been melting away. Arctic sea ice cover shrank more dramatically between 2000 and 2015 than at any time since detailed records have been kept. A report produced by 250 scientists under the auspices of the Arctic Council found that Arctic sea ice was half as thick in 2003 as it was thirty years earlier. Erosion of ice cover continued after that until at least 2015.

Pal Prestrud, vice-chairman of the steering committee for the report, said: “Climate change is not just about the future; it is happening now. The Arctic is warming at twice the global rate” (Harvey 2004: 1). Since that report, ice loss has accelerated, most notably during 2007 and 2008, giving rise to forecasts of an ice-free Arctic Ocean in summer between 2030 and 2040.

Melting of the Arctic ice cap could lead to summertime ice-free ocean conditions not seen in the area in a million years, a group of scientists wrote during 2005 in EOS, the transactions of the American Geophysical Union. Jonathan Overpeck of the University of Arizona and chairman of the National Science Foundation’s Arctic System Science Committee and colleagues wrote that the Arctic during the twenty-first century is moving beyond the glacial and interglacial cycle that has characterized the last million years. “At the present rate of change,” they wrote, “a summer ice-free Arctic Ocean within a century is a real possibility . . . a state [that is] driven largely by feedback-enhanced global climate warming . . . [into] a ‘super interglacial’ state” (Overpeck . 2005: 309).

The US federal government’s National Oceanic and Atmospheric Administration (NOAA) eighth annual “Arctic Report Card,” issued in 2014, said that Arctic ice continued to melt, as darkening surfaces absorbed more sunlight and heat. Spring snow cover was at a record low in spring 2014 across Europe and Asia. Greenland’s reflectivity was lower in August of that year than at any other time since records have been kept. Sixty-three scientists from thirteen countries were involved in compiling the report.

“We can’t expect records every year. It need not be spectacular for the Arctic to continue to be changing,” said report lead editor Martin Jeffries, an Arctic scientist for the Office of Naval Research (Borenstein 2014). The Arctic’s drop in reflectivity is crucial because “it plays a role like a thermostat in regulating global climate,” Jeffries said. As the bright areas are replaced, even temporarily, with heat-absorbing dark areas “[t]hat has global implications” (Borenstein 2014). Between 2000 and 2014, NASA calculates that solar radiation absorbed in the Arctic during summer increased by 5 percent, due to changes in reflectivity, called “albedo” by scientists.

In 1906, Robert Peary first surveyed 3,900 square miles of ice shelves, of which 90 percent have now broken up, said Luke Copland, the director of the University of Ottawa’s Laboratory for Cryospheric Research. “The quick pace of these changes right now is what stands out,” he said (Revkin 2007). In 1907, when Peary traversed the northern coast of Ellesmere Island on a dog sled, he described a “glacial fringe” along most of the area. At the time, Peary was describing a continuous ice shelf covering about 8,900 square kilometers (or about 3,500 square miles). Half a century later, a large part of that ice had disintegrated. By July 2008, only five isolated ice shelves remained: Serson, Petersen, Milne, Ward Hunt, and Markham (The Ayles Ice Shelf had broken off in 2005). These were the last remaining ice shelves in Canada.

The speed of ice melt is important because it changes Earth’s carbon cycle, usually in ways that accelerate the rise in atmospheric greenhouse gases worldwide. For example, melting Arctic sea ice exposes darker water, which absorbs more heat. Before 2000, 40 to 50 percent of Arctic sea ice remained frozen for several years; by 2008, that ratio was down to 10 percent, according to a team of University of Colorado, Boulder, scientists led by Charles Fowler. “Ice extent is an important measure of the health of the Arctic, but it only gives us a two-dimensional view of the ice cover,” said Walter Meier, research scientist at the center and the University of Colorado, Boulder. “Thickness is important, especially in the winter, because it is the best overall indicator of the health of the ice cover. As the ice cover in the Arctic grows thinner, it grows more vulnerable to melting in the summer” (NASA Earth Observatory 2009).

Although attention has focused on the instability of the West Antarctic Ice Sheet, an even larger body of ice in East Antarctica (with a drainage, or catchment, area the size of California) is being surveyed for its stability: the Totten Glacier, which, if melted, could raise world oceans by about 13 feet. This ice mass melted during the Pliocene, three million years ago, when atmospheric carbon dioxide was at 400 parts per million, its present level.

Measurements taken in 2022 and 2023, in both the Arctic Ocean and Antarctica, suggest troubling futures. Since entering the third decade of the twenty-first century, sea ice has rapidly declined. For instance, Arctic ice melt in the summer has been accelerating to over 12 percent per decade. Some scientists suggest the Arctic Ocean might be entirely ice-free by 2030, a decade before the standard predictions. Similarly, several ice sheets are on the verge of collapsing or breaking off in western Antarctica. The effects of such rapid ice melt can already be felt. The most apparent consequence is the steady sea-level rises that could, with the collapse of the Western Antarctic sheets, exceed 10 feet. The disappearance of ice in the Arctic could lead to new transportation routes and increasing commodity and tourist traffic in this area. Decreasing albedo effects could cause additional warming, which could have a cascading impact on glacier melts in Greenland. Lastly, changing winter patterns can already be felt in Canada and the central United States as polar jet streams are dipping south, bringing icy temperatures.

FURTHER READING: Aitken, Alan R. A., Jason L. Roberts, Tas D. van Ommen, Duncan A. Young, Nick R. Golledge, Jason S. Greenbaum, . . . Martin J. Siegert. 2016. “Repeated Large-Scale Retreat and Advance of Totten Glacier Indicated by Inland Bed Erosion.” Nature 533: 385-9.

Borenstein, Seth. 2014. “Report: Arctic Loses Snow, Ice; Absorbs More Heat.” Houston Chronicle, December 20. https://www.houstonchronicle.com/news/politics/article/Report-Arctic-loses-snow -ice-absorbs-more-heat-5971210.php?cmpid=gsa-chron-result. Accessed March 14, 2018.

Chang, Kenneth. 2014. “Snow is Down and Heat is Up in the Arctic, Report Says.” The New York Times, December 18. http://www.nytimes.com/2014/12/18/science/snow-is-down-and-heat-is-up -in-the-arctic-report-says.html. Accessed March 14, 2018.

Harvey, Fiona. 2004. “Arctic May Have No Ice in Summer by 2070, Warns Climate Change Report.” London Financial Times, November 2, 1.

NASA Earth Observatory. 2009. “Satellites Show Arctic Literally on Thin Ice.” http://earthobservatory. nasa.gov/Newsroom/view.php?id = 37803&src = eoa-nnews. Accessed February 17, 2009.

Overpeck, J. T., M. Strum, J. A. Francis, D. K. Perovich, M. C. Serreze, R. Benner, . . . C. Vorosmarty. 2005. “Arctic System on Trajectory to New, Seasonally Ice-Free State.” EOS: Transactions of the American Geophysical Union 86 (34): 309, 312.

Revkin, Andrew C. 2007. “Arctic Update: Resilient Bears, Shrinking Ice.” The New York Times, December 13. http://dotearth.blogs.nytimes.com/2007/12/12/arctic-update-resilient-bears -vanishing-ice/index.html. Accessed January 13, 2018.