Will We See A New Record Low Arctic Sea Ice Extent in 2007?

SCitizen
14 May, 2007 12:45 pm 

The decrease in Arctic summer ice cover, particularly evident in the western Arctic, is a well-documented and striking example of changing Arctic conditions. Over the past several decades, numerous studies have shown decreasing trends in sea-ice characteristics such as ice extent, area, age, and thickness. Yet the Arctic sea ice pack is located far from most population centers on Earth; does it really matter what is happening on top of the world?

In short, yes. Changes in the Arctic ice pack will influence Earth's climate as well as the world's economy, and it may influence other things as well. So, no matter where you live, a reduction in Arctic sea ice might affect you in several ways. For instance, scientists have noted that a decline in Arctic sea ice might lead to less precipitation in the western USA, an area already battling water resource issues. In contrast, Europe might see an increase in precipitation as weather patterns change in response to the sea ice.

Furthermore, reduced Arctic sea ice could lead to opening of the Arctic Ocean as a viable transcontinental shipping route. Given that transit between the western USA and Europe can be up to 3 weeks shorter if vessels travel through the Arctic rather than through the Panama Canal, the world's supply line and the resulting economy could shift noticeably. In addition, there is some evidence that reduced ice cover will enhance the Arctic fishery industry and lead to more exploration of oil and gas in previously inaccessible areas.

In order to realize the benefits and prepare for vulnerabilities associated with changes in the Arctic sea ice cover, Dr. Sheldon Drobot and other scientists at the University of Colorado-Boulder have been developing seasonal forecasts of Arctic sea ice conditions over the past few years. 

One of the more popular forecasts is the annual Arctic sea ice summer minimum extent (http://ccar.colorado.edu/arifs), which has served as a benchmark for climate change. Based on satellite data available at the start of April 2007, this year's forecast for the Arctic sea ice summer minimum extent indicates a 33% chance that the 2007 Arctic sea ice summer minimum extent will reach a new record low (less than 5.57 million square kilometers).

Additionally, there is a 57% chance that the 2007 minimum Arctic sea-ice extent will be lower than last year's minimum ice extent (5.87 million square kilometers), and a 70% chance that the 2007 minimum Arctic sea-ice extent will rank within the five lowest years on record (less than 6.05 million square kilometers). This year's forecast is based on below-average sea ice coverage in the eastern Arctic, as well as below-average old ice extent in the central Arctic Ocean. If summer temperatures are also above average, then the chance of experiencing a record low will be even higher. 

Reference:
Drobot, S.D., J.A. Maslanik, and C.F. Fowler, 2006: A long-range forecast of Arctic summer sea-ice minimum extent. Geophysical Research Letters, 33, L10501, doi:10.1029/2006GL026216.

Drobot, S.D., 2003: Long-range statistical forecasting of ice severity in the Beaufort/Chukchi Sea, Weather and Forecasting, 18:1161 - 1176.

More details on the forecasting methods are available in several recent publications (available at http://ccar.colorado.edu/~drobot/publications.html)