Recently, ABC News reported:

An area of Arctic sea ice the size of Florida has melted away in just the last six days as melting at the top of the planet continues at a record rate.

2007 has already broken the record for the lowest amount of sea ice ever recorded, say scientists, smashing the old record set in 2005.

Currently, there are about 1.63 million square miles of Arctic ice, according to the National Snow and Ice Data Center in Boulder, Colo. That is well below the record of 2.05 million square miles set two summers ago and could drop even lower before the final numbers are in...

Scientists say the rate of melting in 2007 has been unprecedented, and veteran ice researchers worry the Arctic is on track to be completely ice-free much earlier than previous research and climate models have suggested.

"If you had asked me a few years ago about how fast the Arctic would be ice free in summer, I would have said somewhere between about 2070 and the turn of the century," said scientist Mark Serreze, polar ice expert at the NSIDC. "My view has changed. I think that an ice-free Arctic as early as 2030 is not unreasonable."

Record low Northern Hemisphere snow cover has coincided with the record low Arctic ice coverage. As an indication that the fall in summer snow cover in the Northern Hemisphere has been accelerating in recent years, 16 of the lowest 20 (80%) weekly figures have occurred beginning in 2000 and 11 (55%) have occurred in 2005 or later. All of the 12 lowest figures have occurred in 2004 or later.

Since the 1970s, summer snow cover (weeks 30-35) in the Northern Hemisphere has fallen almost 47%. During the 2000-07 period, it has averaged more than 26% lower than during the 1990-99 timeframe.

Average Northern Hemisphere Snow Cover (Weeks 30-35) in square kilometers:
1970-79: 4,554,840
1980-89: 3,807,467
1990-99: 3,286,811
2000-07: 2,416,893

The Week 30-35 period has seen Northern Hemisphere snow cover average 2,056,475 square kilometers. Until this year, only one week saw snow cover fall below that figure (Week 34 in 2006 with 2,038,986 square kilometers).

One scientist suggested that the Arctic warming could beget only more warming as the earth thaws and methane is released into the atmosphere. NPR reported:

Alaska scientist Katey Walter studies an aspect of climate change that has been largely overlooked: methane emissions.

Methane is a greenhouse gas that is 23 times more powerful than carbon dioxide, which means it is much more efficient at trapping heat. As a result, methane feeds into a loop of global warming.

As global temperatures rise, permafrost thaws. Ponds and lakes form in the depressions left behind by melting chunks of ice in the ground. In the bottoms of ponds and lakes, bacteria feed on the carbon that previously had been frozen underground and burp it out as methane.

And because methane emissions from lakes haven't been carefully studied, scientists worry that projections for global warming could be far worse than currently estimated.

As global temperatures rise, permafrost thaws. Ponds and lakes form in the depressions left behind by melting chunks of ice in the ground. In the bottoms of ponds and lakes, bacteria feed on the carbon that previously had been frozen underground and burp it out as methane. donsutherland1