Contaminants affecting the Arctic climate, and the role of the oceans

We are increasingly impressed with the idea that the climate system must be treated globally, and, by the same token, most contaminants affecting the Arctic and its climate have global origins. This is manifestly true of carbon dioxide and its influence on surface temperature through the greenhouse effect, and of chlorofluorocarbons that affect both the surface temperature and stratospheric ozone. In both of these cases, the response of the Arctic is more dramatic than that in the lower latitudes. Another type of contaminant that affects the Arctic climate in the springtime is the light-absorbing aerosols transported northward from industrial regions. Moreover, the Arctic includes several unique regional climatic feedback mechanisms, such as the effect that a global warming can have on the release of carbon dioxide and methane locked in the tundra and taiga (probably a positive feedback), and the effect of shrinking sea ice and snowcover on the heat balance of the hemisphere (definitely a positive feedback). It has long been recognized that changes in ocean circulations, notably in the North Atlantic and Greenland Sea, can have a dominant effect on regional and global temperatures. All of these effects are unfortunately poorly treated in current climate and ecosystem models, and this introduces an element of uncertainty in predictions of global warming and the fate of contaminants in the Arctic.