News from the polar regions in August includes alarming news for Arctic sea ice, polar bears, and Greenland’s massive glaciers and insights into Antarctica’s past climate and current response to global climate change. Missed these stories the first time? Read on!

While news early in the month predicted that the 2008 Arctic sea ice minimum would not break the all-time record low set in 2007, the end of the month brought the disturbing news that with several weeks left in the melt season, the extent of summer sea ice had already dipped below the 2005 level. There is thus the possibility that this year’s minimum may indeed break the 2007 record. While the decline of sea ice slowed during August 2005, this has not been the case during August 2008, despite a relatively cool summer in the Arctic. The observed decline in sea ice during this summer season shows that 2007’s all-time low was not an anomaly, and demonstrates the profound ongoing impact of global warming.

Much of the recent melt has occurred in the Chukchi Sea off Alaska’s northwest coast, and the East Siberian Seas off the coast of eastern Russia. Home to one of two Alaskan polar bear populations, the Chukchi Sea also made news this month as nine polar bears were spotted swimming in open ocean water 15 to 65 miles offshore. Some of the bears were swimming north, possibly trying to reach the polar ice edge, 400 miles away. While polar bears do swim, the sighting confirms ongoing concern about the species’ ability to survive as sea ice, a necessary platform for their survival, declines.

Arctic sea ice isn’t the only ice in decline. Two of Greenland’s largest glaciers have experienced breakup in the last two months. Researchers monitoring daily satellite images of the Petermann Glacier observed the loss of an 11-square-mile (29-square-kilometer) chunk of ice, equal to half the size of Manhattan Island. Even more worrisome is what appears to be a massive crack further back from the margin of Petermann Glacier, which may signal an imminent, much larger breakup. Additionally, the Jakobshavn Glacier has shown breakup as well. The margin of this massive glacier has retreated further inland than at any time in the past 150 years it has been observed. Greenland and Antarctica are home to the world’s large ice sheets, although both are exhibiting increased ice loss due to the effects of climate change.

As scientists try to model and predict the future impact of climate change, a team of Penn State biologists have offered a unique perspective. Computer models indicate that shrubs will thrive and spread as a result of warming, leading some scientists to believe that increased shrub cover will absorb some carbon dioxide gas and thus lessen the impact of climate change. Early data from a five-year experiment in West Greenland, however, indicates that grazing by musk oxen and caribou will reduce the carbon-mitigating benefit of increased shrub cover. The researchers conclude that “on the practical and policy sides of this story, we need to be aware that the ‘carbon dioxide sponge’ – represented especially by shrubs and trees – may not be as big as we thought it was. This finding is another reason to think carefully about reducing carbon dioxide emissions.”

Climate change will not only impact the natural world, but human civilization as well. International security experts believe that climate change-related trends such as degradation of freshwater resources, food insecurity, natural disasters, and environmental migration may increasingly serve as triggers for wars and conflicts in the future. They point to similar conflicts, not necessarily induced by climate change, that are already affecting life in areas such as Darfur, the Middle East, Central Asia, and South America. Historical evidence also supports a possible link between climate change and conflict, as a drop in temperature known as the “Little Ice Age” was associated with loss of harvest, population decline, riots, and military conflicts in Europe and Asia.

As sea ice declines and the need for new oil, gas, and mineral deposits increases, increased international conflict is a possibility. A recent USGS assessment revealed that the area north of the Arctic Circle has an estimated 90 billion barrels of oil, 1,670 trillion cubic feet of natural gas, and 44 billion barrels of natural gas liquids, all technically recoverable. Researchers at Durham University have created the first map to show possible disputed territories within the region.

As international competition in the area heats up, military leaders, Arctic experts, and lawmakers assert that the United States is losing its ability to patrol and safeguard Arctic waters due to an inadequate fleet of icebreakers. They recommend that the White House issue a presidential directive that emphasizes the need for increased oversight of the Arctic and for new ships. The Coast Guard also recognizes increased Arctic traffic from oil tankers, fishing vessels, and even cruise ships, opening two temporary stations in Barrow and Prudhoe Bay, Alaska.

It isn’t only humans that are traveling farther into the Arctic Ocean as a result of global warming. Scientists predict that as the Arctic Ocean warms, shellfish, snails, and other animals from the Pacific Ocean will expand their habitat into the Arctic Ocean and possibly into the Atlantic. Researchers reviewed the fossil record from the Pliocene era, a time of a nearly ice-free Arctic, and found evidence of species invasion from the Pacific to the Atlantic. Current research conducted by the Alfred Wegner Institute via the Polarstern icebreaker, ocean floor moorings, and an autonomous seaglider also confirm the presence of water masses that originate in the Pacific and travel to the north Atlantic via the Bering Strait and Arctic Ocean.

Finally, detailed measurements from a Greenland ice core show high levels of pollutants from coal burning. The toxic heavy metals cadmium, thallium, and lead contaminated the Arctic in the 1900s and potentially affected ecosystems and human health in and around the polar regions. Although current levels of heavy-metal pollution in the North Atlantic sector of the Arctic are substantially lower today than a century ago, researchers warn that other sectors of the Arctic may be increasingly polluted as other countries (particularly in Asia) grow and rely heavily on coal. Food chain contamination is a particular concern.

In Antarctica, elephant seals fitted with special oceanographic sensors are providing a 30-fold increase in data about the Southern Ocean, including areas under winter sea ice. This data will help scientists understand changes in the ocean due to global warming.

New analysis of West Antarctic ice cores show that the dramatic year-to-year temperature swings and a century-long warming trend in the region are linked to conditions in the tropical Pacific Ocean, including El Nino events. The study reveals that West Antarctica’s climate is influenced by changes in the atmosphere and oceans thousands of miles to the north, suggesting that as the tropics warm, so too will West Antarctica.

Two studies have demonstrated a much warmer and even ice-free Antarctica millions of years ago. One analysis of marine microorganisms called foraminifers showed that 40 million years ago, in a time of relatively high carbon dioxide levels, temperatures were much higher and ice sheets were either much smaller or completely absent. The second, a serendipitous discovery of well preserved moss, diatoms, and ostracods in the McMurdo Dry Valleys, paints a picture of a tundra-covered area just prior to a dramatic temperature drop 14 million years ago. Reconstructing the climate and environment of the past helps scientists better model and predict the response of Antarctica’s ice sheets and the Southern Ocean to global warming.

Know of another significant news story from August that you’d like to share? Reactions to one of the stories discussed here? Post a comment – we’d love to hear from you!