A research team led by Son Nghiem of NASA’s Jet Propulsion Laboratory in Pasadena, California, used satellite data to examine sea ice extent in the Beaufort Sea from 1979 to 2012 and compared it to reports of discharge into the sea from the Mackenzie River. They also used satellite data to measure the surface temperature of the waters discharging from the river during the summer of 2012.
The results suggested that the record largest extent of open water in the Beaufort Sea occurred in 1998, which corresponded to the year with a record high discharge from the river. Closer examination of the data revealed that during summer 2012, the breaching of a sea ice barrier that was holding river discharge close to its delta saw a 6.5°C increase in the average surface temperature of the area of open water.
‘River discharge is a key factor contributing to the high sensitivity of Arctic sea ice to climate change,’ said Nghiem. ‘We found that rivers are effective conveyers of heat across immense watersheds in the Northern Hemisphere. These watersheds undergo continental warming in summertime, unleashing an enormous amount of energy into the Arctic Ocean, and enhancing sea ice melt.’
This story was published in the April 2014 edition of Geographical Magazine