Friday, February 15, 2013

NASA images confirm Arctic Ocean sea ice is thinning at alarming rate

A team of University of Washington and University of London researchers have reportedly obtained enough data to confirm Arctic Ocean sea ice really is thinning. 

The team, using data collected by NASA’s Ice, Cloud and Land Elevation Satellite (ICESat) and the European Space Agency’s CryoSat-2 satellite, say Arctic sea ice volume declined 36 percent in the autumn and 9 percent in the winter over the last decade. The figures, which build on previous studies, match predictions made by models that show sea ice thinning over the coming decade.

The report, published online in the journal Geophysical Research Letters, provides a 34-year monthly picture of the Arctic. Researchers reportedly developed the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) in an attempt to combine weather records, sea-surface temperature, and satellite images in order to determine the total volume of sea ice. The program checked its readings against a database of actual sea ice volume measurements collected by researchers over the years. According to the report, the figures were largely accurate.

Important to note, the findings confirm for the first time that the decline in sea-ice coverage in the Arctic has been accompanied by a substantial decline in ice volume. Climate scientists around the world had largely suspected that thinning sea ice was correlated with the decline in sea ice volume. Some scientists had suggested that upwards of 75 to 80 percent of ice volume loss was occurring in the region, while others speculated less than 20 percent ice volume loss.

While researchers say the results are alarming, they warned against reading too much into them. The team of researchers cautioned that past trends may not necessarily continue at the same rate, and predicting when the Arctic might be largely ice-free in summer is a different question. They noted that the current study could provide scientists with a better set of data, eventually providing them with the necessary information to more accurately predict how the region reacts to the effects of global warming.

The report is the latest to examine the effects of global warming. A number of recent studies have focus on sea ice in the Arctic, part of an attempt to better understand the impact of global warming on everything from sea levels to atmospheric changes. Arctic sea ice reached an all-time low in 2012, prompting speculation that current climate models are failing to accurately assess the damage inflicted by rising temperatures around the world. According to the 2012 climate report released by the National Climatic Data Center (NCDC), August 2012 was the fourth warmest August in the Arctic ever recorded since record keeping began in 1880. Meanwhile, a number of reports examined the cause of the 2012 decline in sea ice, many of which concluded that a rise in temperatures was to blame.

That said, it remains unclear whether the report will have any impact on how policy makers plan to address the issue. Already, the thinning sea ice has opened shipping lanes in the north previously closed during winter months. The shipping lanes, along with access to natural resources buried beneath the ocean, could offset concerns over the natural environment in the region.

Source: The Space Reporter

Image courtesy of U.S. Geological Survey via Flickr (CC BY 2.0)