This winter had the fifth lowest total area of the since scientists began tracking it 30 years ago. also reported today that according to satellite observations the six thinnest polar ice covers have come in the past six years.

"Ice extent is an important measure of the health of the Arctic, but it only gives us a two-dimensional view of the ice cover," said Walter Meier, research scientist at the and the in Boulder, in a statement. "Thickness is important, especially in the winter, because it is the best overall indicator of the health of the ice cover. As the ice cover in the Arctic grows thinner, it grows more vulnerable to melting in the summer."

Last year, a team of researchers led by scientists at the Jet Propulsion Laboratory in Pasadena, Calif., created the first map of sea ice thickness for the entire Arctic basin, according to NASA. The scientists used two years of data compiled from (ICESat).

The Jet Propulsion Laboratory noted that Arctic sea ice acts as an air conditioner for the climate system not just in the north but around the world. Ice cools air and water, is a critical factor in ocean circulation, and reflects solar radiation back into space.

The problem is that in recent years, the ice in the Arctic sea has been declining at what scientists call a surprising rate.