Saving the Arctic, now.

AuthorPomerance, Rafe
PositionEnvironment

The Arctic is warming at more than twice the rate of the earth as a whole. Since 1979, Arctic warming has reduced summer sea ice by more than 40 percent, and many climate models now predict that all sea ice will disappear by 2030 or sooner. To put this in perspective, the amount of sea ice lost from 1980 to 2007 would cover half of the European Union.

Loss of sea ice increases Arctic warming as the increasing exposure of dark surfaces absorbs more heat. The related warming of Greenland poses a global climate "tipping point"--that point where one change (e.g. an increase in temperature) could launch a series of cascading events that drastically alter the earth's ecological balance.

The tipping point could include setting the stage for irreversible melting of a large part of the Greenland ice sheet in coming decades and centuries. In fact, according to recent satellite data, Greenland itself is already starting to lose a significant amount of ice, making a contribution to global sea-level rise every year. The complete loss of Greenland would raise world sea levels by seven meters, inundating the world's densely populated coastal areas.

The tipping point could also trigger a rapid and uncontrollable release of carbon and methane stored in Arctic permafrost, enormously increasing the concentration of C[O.sub.2] and methane in the atmosphere and therefore adding to the warming of the planet.

At present, discussions of steps to slow this warming have focused mainly on reducing C[O.sub.2] emissions. For the long-term stability of the Arctic as well as the rest of the globe, C[O.sub.2] reductions must take place as soon as possible. Once emitted into the atmosphere, C[O.sub.2] remains for centuries. We thus already have a large "bank" of C[O.sub.2] in the atmosphere that ensures continued warming, and melting, in the Arctic for many decades to come.

So have we already lost the Arctic? Many climate experts concede that its survival--with its unique flora, fauna and cultures--has begun to seem unlikely.

There is reason still for hope, however. C[O.sub.2] is not the only contributor to Arctic warming. Research shows that several short-term pollutants--specifically black carbon, tropospheric ozone (near the earth's surface) and methane--collectively have nearly the same temperature impact on the Arctic as C[O.sub.2].

Black carbon or "soot" particles emitted from diesel engines, agricultural burning, and factories cause warming in the Arctic by turning...

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