Because the Earth's convection systems push warm air away from the equator toward the Arctic, the northern latitudes experience greater temperature increases than the lower latitudes. The extreme northern latitudes are essentially experiencing the temperature increases created by the world's fossil fuel consumption and energy choices. In the coming decades it may not be possible to ski to the North Pole.

In September of 2007, the area of Arctic Ocean sea extent reached a new record low, receding almost a million square kilometers more than the previous record low of 2005. However, the rapidly diminishing area of sea ice coverage only tells part of the melting story. Much of the 2007 melt consisted of previously resilient multi-year ice. Over the past half century the average ice thickness of the Arctic Ocean has been cut in half.

The ice and snow of the Arctic Ocean, Greenland and Antarctic are the Earth's primary reflectors of sun energy. The melting of these areas creates a positive feedback spiral. In this spiral, melting white ice or snow reveals more areas of dark-colored water and land. These dark surfaces attract more sun energy, thereby increasing temperatures and further increasing melting. This melting may lead to unpredictable climate tipping points.

Positive Feedback Sources. Albedo graphic: (c) the Green Party of Aotearoa New Zealand 1979/2005 graphic: NASA. 2007 graphic: NSIDC.	Sea Ice Extent 1979 2005 2007
t;img width="275" height="275" title="summer2007_arctic_seaice.jpg" alt="summer2007_arctic_seaice.jpg" src="/images/stories/fruit/summer2007_arctic_seaice.jpg" style="margin: 5px; float: left" />	Sea ice thickness on the Arctic Ocean has decreased steadily over the past 50 years. This creates an ice pack that is less resilient to winds, ocean currents and sunlight. The once common pans of thick sea that spread to the horizon are becoming less common; instead the thinner pans now break up more easily resulting in endless fields of broken ice rubble. Click here for the adjacent image in animation form, depicting Arctic Ocean sea ice thickness, made by Jinlun Zhang.
	Multi-year sea ice concentrations have decreased drastically in the past 25 years. Multi-year sea ice that has existed for more than one year is typically thicker than young year-old ice. Click here and scroll down for a the adjacent image in animation form, displaying the "Disappearance of Old Ice, 1982 - 2007" by the NSIDC. The animation image is found by scrolling 3/4s of the way down the linked page.