The Arctic sea coverage reached its minimum level this year, dropping as low as 4.52 million square kilometers (1.74 million square miles) on September 12, before the autumn cooling began. This has been another record year for the summertime ice extent, reinforcing the negative trend that has been contributing to the loss of Arctic ice in recent years.

This year, the ice extent reached second-lowest record in the past 30 years of satellite observations, and scientists warn that the loss of ice will continue. Not only did the ice extent hit a negative record this year, but it also revealed a longer period of ice loss compared to few years ago. For example, in the 2005 melting season, the decline in sea ice began to slow down in August, while in 2008, it continued at the same rate until mid-September.

By comparison, this year’s sea ice extent reached 4.52 million square kilometers, while in 2007, the arctic sea ice dropped to 4.28 million square kilometers. Overall, this shows an additional loss of over 2 million square kilometers in 2007 and 2008 compared to the 1979 – 2000 average minimum.

Although this year, summertime temperatures have been somewhat cooler than usual, this has not stopped the sea ice from declining at a steady pace. According to data provided by the National Snow and Ice Data Center and NASA, in 2008 the arctic sea ice was just 390,000 square kilometers above the 2007 minimum, but 15 percent less that the 2005 minimum record, and 33.1 percent less that the average extent from 1979 to 2000.

Compared to the previous year, satellite images revealed substantial ice loss in other parts of the Arctic, such as the Beaufort, Laptev and Greenland Seas. Furthermore, this year we’ve also seen an opening of the Northern Sea Route, however, Parry’s Channel of the Northwest Passage did not open this year, as it did in 2007.

In March this year, NASA revealed (based on satellite observations) that although the weather conditions favored a short term increase in sea ice extent, perennial sea ice was still declining, a clear sign that global warning had already begun showing its effects.

According to their observations at the time, the perennial ice covered only 30 percent of the Arctic, compared to 50-60 percent it used to cover in the past. Furthermore, two centuries ago, the oldest sheet of ice covered 20 percent of the Arctic and lasted for 6 years; however now, it covers only 6 percent of the Arctic.

Scientists also warned at the time that an improvement in ice level on a short-term does not necessarily imply an improvement on a long term. While the ice sheet might increase slightly under cooler temperatures, perennial ice continues its meltdown.

NSIDC explained that although we might be tempted to establish the minimums for this year, we should wait a bit longer, until the season ends decisively. According to them, “the natural variability of the climate system has frequently been known to trick human efforts at forecasting the future. It is still possible that ice extent could fall again, slightly, because of either further melting or a contraction in the area of the pack due to the motion of the ice.”

At the beginning of October, we can expect a detailed report on the possible causes behind this year’s low ice conditions, including aspects of the melt season and the winter season ahead, NSIDC revealed.