- The annual minimum Arctic ice melt appears to have been reached in early September 2016.
- Arctic ice cover, which serves the crucial role of reflecting large amounts of incoming solar radiation, has declined more quickly than most scientific models forecast.
- Sea ice extent for 2016 (a measurement derived by satellite) as reported by both the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado and Japan's JAXA space and aeronautics agency indicate that this year's minimum sea ice extent is the second-lowest as recorded by modern instrumentation.
- This post is a commentary. The views expressed are those of the author, not necessarily Mongabay.
As temperatures in higher latitudes consistently ranging from three to five degrees Celsius above normal fall averages combine with warmer ocean temperatures, Arctic sea ice has begun displaying irregular, unexpected patterns of melting and freezing.
The annual minimum Arctic ice melt appears to have been reached in early September 2016. This is a measure of the lowest amount of remaining sea ice during the year. Arctic ice cover, which serves the crucial role of reflecting large amounts of incoming solar radiation, has declined more quickly than most scientific models forecast.
Sea ice extent for 2016 (a measurement derived by satellite) as reported by both the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado and Japan’s JAXA space and aeronautics agency indicate that this year’s minimum sea ice extent is the second-lowest as recorded by modern instrumentation. The NSIDC minimum of 4.14 million square kilometers (about 1.6 million square miles) was reached on September 10, while JAXA’s lowest data point measured 4.02 million square kilometers (about 1.55 million square miles) and was reached on September 7, 2016.
Arctic air temperatures in January and February of 2016 were at record highs, leading to an atypically fast pace of melting. Record-low ice extent continued for several months, but cloudy conditions during June and July slowed the formation of melt ponds substantially. During August, however, a large Arctic Cyclone combined with warm ocean temperatures and an unfavorable pressure gradient increased melting.
Several prominent ice researchers have voiced concern over the extreme melt during a summer season characterized by very cloudy conditions in peak melting months. They reiterate that this behavior indicates a continued shift into unprecedented conditions in the Arctic.
This year’s Arctic melt featured additional irregular phenomena as the loss of ice converged with warming ocean temperatures to feed back into regional and global weather patterns. Sea ice began an unusual pattern of dispersal in regions above North America. Frozen areas that typically prevent the movement of ice from the Central Arctic Basin (CAB) have begun to fracture and allow further release of floating ice. Additionally, very old perennial ice now comprises only three percent of the total pack, whereas scientists estimate that old ice made up about 20 percent of the total as recently as 1985.
The ongoing changes in ice and temperature in the Arctic have widespread implications for regional and global conditions. Sea ice forms in open ocean water, as distinguished from ice sheets composed of packed snow and ice on land. Because sea ice directly displaces water, it contributes less to sea level rise than the thermal expansion of the oceans as well as runoff from glaciers, ice sheets, and other terrestrial sources.
The loss of sea ice, however, contributes to a variety of positive feedback loops that increase overall warming of the region and entire planet. Pronounced melting of sea ice in the Baffin Bay, for instance, appears to intensify warmer summer winds that push further melting of Greenland’s ice sheet. This runoff of massive land ice into the Atlantic Ocean has become a contributor to overall ocean level rise and may be already altering the Atlantic Meridional Ocean Cycle (AMOC). Recent analyses indicate that melt water from Greenland has added some 13,000 cubic kilometers (about 3,120 cubic miles) of water into the ocean since the onset of the 20th century.
The dramatic retreat of Arctic sea ice is believed to accelerate warming as reflection of solar radiation is substantially reduced. This appears to have a wide variety of regional and global climactic effects, most of which will likely contribute to positive feedback loops in warming. Many ice researchers expect that this trend will result in an “ice-free” Arctic within less than a decade and possibly as soon as September of 2017.