Global Warming

Arctic Sea Ice Is at Near Record Lows: NASA

The ice covering the Arctic is at near record lows this year, and this icy deficit may impact weather around the world, NASA reports. Every March, the Arctic's sea ice reaches its maximum cover, both in area and thickness, before it recedes to its yearly minimum in September.

This year we are seeing an extremely warm winter. Temperatures have been 10 to 15 degrees Fahrenheit [5.5 to 8.3 degrees Celsius] above normal in the Arctic.

NASA has been collecting data on Arctic sea-ice extent (a term that refers to area and volume) since the late 1970s. Last year's maximum was the fourth lowest on record, and 2016 is also among the lowest that scientists have seen in about 40 years.

Furthermore, the ice is thinner now than it has been in past years. So, we've lost about 50 percent of the volume of the sea ice, or the mass of the sea ice, since record keeping began.

These dramatic changes don't stay in the Arctic. Typically, white-colored ice reflects about 80 percent of the sun's rays back into space. With less ice cover, the ocean absorbs a lot more of these rays, which warms the water.

As you warm the water up, you're changing the contrast with the lower latitudes, And that contrast helps set up things like the jetstream and storm tracks and general weather patterns. As the Arctic warms, weather patterns in lower latitudes will also be affected.

For instance, cold air usually stays in the Arctic because of polar vortex winds, which make a circular, counter-clockwise trip around the North Pole. But as sea-ice extent diminishes, the Arctic warms, high pressures build and the polar vortex weakens, allowing cold air to flow southward and cause fiercely cold winters.