Tipping Point?

More doom and gloom about the arctic from Knight-Ridder:

Alarmed by an accelerating loss of ice in the Arctic Ocean, scientists are striving to understand why the speedup is happening and what it means for humankind.

If present trends continue, as seems likely, the sea surrounding the North Pole will be completely free of ice in the summertime within the lifetime of a child born today. The loss could point the way to radical changes in the Earth's climate and weather systems.

Some researchers, such as Ron Lindsay, an Arctic scientist at the University of Washington in Seattle, fear that the polar region already may have passed a "tipping point" from which it can't recover in the foreseeable future.

[...]

Since 1980, satellite observations taken each September, the warmest month of the year in the Arctic, show that the ice cover has been shrinking by an average of almost 8 percent a year. During that time, the polar ocean lost 540,000 square miles of ice - an area twice the size of Texas, Scambos said.

The internal cause for the loss of sea ice may be even more alarming. Scientists say the polar ice pack will continue to be in trouble whether or not global temperatures continue to rise.

The reason is that ice and snow, like any light-colored surface, reflect heat from the sun. As the ice shrinks, it leaves more open, darker water to absorb the sun's heat. More open water slows the formation of fresh ice in the fall and leads to a still earlier, more extensive melt the following summer.

Why is this important?

Scientists say the great Arctic thaw will have effects all over the world, not just in the frozen north. It will magnify the global warming trend that's been recorded for the last quarter-century. It'll reshape the Earth's weather systems in unknown ways. It could alter the pattern of ocean circulation, drastically changing Europe's climate.