Introduction to special issue

Momentous Changes at the Poles

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Science  16 Mar 2007:
Vol. 315, Issue 5818, pp. 1513
DOI: 10.1126/science.315.5818.1513

Earth's Polar Regions are priceless repositories of information about past climates, as well as harbingers of our planet's future. To get a better picture of where the Arctic and Antarctica have been and where they are going, and how changes at the poles might affect humanity's temperate perches, scientists from dozens of nations earlier this month launched a 2-year research initiative called the International Polar Year (IPY). This special issue helps raise the curtain on the IPY with an exploration of some of the more vibrant research under way at the ends of the Earth.

Polar processes exert a tremendous influence on many of our planet's ecological and biogeochemical cycles. Sea ice helps control ocean circulation, thereby influencing heat transport from low to high latitudes, rainfall patterns, ocean biology, and the composition of the atmosphere. Serreze et al. (p. 1533) examine the causes of the decrease in Arctic sea-ice coverage in recent decades and offer forecasts for the next century. Reduced sea ice could spark an Arctic version of the California Gold Rush. Krajick (p. 1525) discusses how nations are staking claims in the Arctic in the hopes of exploiting minerals and hydrocarbons locked beneath the sea floor.

How fast sea levels rise over the coming century—potentially one of the most serious consequences of global warming—will depend on how fast the polar ice sheets melt. Shepherd and Wingham (p. 1529) synthesize studies of the world's ice sheets to present a global picture, with emphasis on recent changes in the mass of the Greenland and Antarctic ice sheets. The polar seas are rich sources of marine productivity, and millions of people depend on their bounty. Warming is expected to have huge consequences for high-latitude denizens, as Bohannon (p. 1520) and Stokstad (p. 1522) show. Change is also in the air (literally) at the poles. Law and Stohl (p. 1537) examine the progress made in understanding the Arctic's atmospheric chemistry and discuss how anthropogenic and natural factors have affected, and may affect, the Arctic's role in mediating regional and global climate.

The Arctic and Antarctica offer some of the most extreme environments on the planet. For scientists, this poses logistical challenges, especially with the stepped-up research activities taking place at the poles during the IPY, as Mervis explains (p. 1514). Clery (p. 1523) discusses how astronomers are overcoming hostile conditions to install ever-bigger telescopes high on the Antarctic Plateau. At the other end of the globe, scientists are teaming up with indigenous people in the Arctic to fill gaps in their knowledge, writes Couzin (p. 1518).

The burst of scientific activity during the IPY should yield vital insights into the state of our planet for many years to come. If present trends continue, the message from our polar regions could be quite alarming indeed.

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