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After the Science - Public Policy Actions 2 pages: | 1 | 2 |

by Maggie Villiger


Arctic Meltdown, Earth Meltdown?

Scientists say the Arctic is changing right now. They point to rises in temperatures, decreases in the extent of annual snow and ice cover, thinning of glaciers and sea ice. That's too bad for the Arctic, but does it really affect the majority of us who live at lower latitudes and may never see the land of the midnight sun? In a word, yes. Polar regions play a major role in the climate of the entire planet.

Image of atmospheric circulation
 
A global temperature gradient causes atmospheric circulation, with heat flowing from the equatorial regions toward the poles. This circualtion drives our weather patterns.

On average, the north and south poles receive less solar radiation than areas near the equator. Because of the tilt of our spherical planet's axis, the sun's rays hit the poles at a more oblique angle than they do in the tropics. And because of albedo, the icy polar regions are also reflecting more of whatever solar radiation reaches them back to space than are equatorial regions. There's more solar radiation leaving the atmosphere in the arctic than there is entering. So the atmosphere at the Earth's surface in the Arctic will be colder, on average, than it is at lower latitudes. This global temperature gradient causes atmospheric circulation, with heat flowing from the equatorial regions toward the poles. The atmosphere strives for equilibrium, that is, for all areas on the globe to be about the same temperature. Warm ocean currents also carry heat to the higher latitudes.

Basically all of the earth's weather is caused by these circulation patterns. And they're driven by the fact that the poles are currently heat sinks. If the Arctic warms up, the temperature gradient from the equator to the North Pole would get weaker, and that would cause weaker circulation patterns. The weather is notoriously hard to predict - just think about your local five-day forecast - so it's impossible to say what a future with weaker atmospheric circulation will look like. But it will definitely be different than the world we live in now.

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