last updated 29th September 05
by 4ecotips.com

World is heating up much faster than scientists predicted

Arctic specialists at the US National Snow and Ice Data Centre at Colorado University, who have documented the gradual loss of polar sea ice since 1978, believe that a more dramatic melt began about four years ago, writes Steve Connor of The Independent. Sea ice reflects up to 80% of sunlight hitting it but this "albedo effect" is mostly lost when the sea is uncovered.

In September 2002 the sea ice coverage of the Arctic reached its lowest level in recorded history. Such lows have normally been followed the next year by a rebound to more normal levels, but this did not occur in the summers of either 2003 or 2004. This summer has been even worse.

According to scientist Dr Mark Serreze, "The changes we've seen in the Arctic over the past few decades are nothing short of remarkable. This will be four Septembers in a row that we've seen a downward trend. The feeling is we are reaching a tipping point or threshold beyond which sea ice will not recover."

The extent of the sea ice in September is the most valuable indicator of its health. This year's record melt means more of the long-term ice formed over many winters - so called multi-year ice - has disappeared than at any time in recorded history.

Sea ice floats on the surface of the Arctic Ocean and its neighbouring seas, and normally covers an area of about the size of Australia. However, in September 2002, this dwindled by 16% below average.

Sea ice data for August closely mirrors that for September and last month's record low - 18,2 percent below the monthly average - strongly suggests that this month will see the smallest coverage of Arctic sea ice ever recorded.

George Monbiot, prolific writer on environmental changes, says New Scientist has reported that something similar is happening in Siberia. For the first time on record, the permafrost of western Siberia is melting. As it does so, it releases the methane stored in the peat which has 20 times the greenhouse warming effect of CO2. The more gas the peat releases the more the permafrost melts.

Scientists at Cranfield University have discovered that the soils in the UK have been losing the carbon they contain: as temperatures rise, the decomposition of organic matter accelarates, which causes more warming, which causes more decomposition. Already the soil in this country has released enough carbon dioxide to counteract the emissions cuts we have made since 1990(4).

These are examples of positive feedback: self-reinforcing effects which, once started, are hard to stop. They are kicking in long before they were supposed to. The intergovernmental panel on climate change, which predicts how far the world's temperature is likely to rise, hasn't yet had time to include them in its calculations. The current forecast - of 1.4 to 5.8 degrees this century - is almost certainly too low.