The National Snow and Ice Data Center released its summary of summer sea-ice conditions in the Arctic on Tuesday, noting a substantial expansion of the extent of “second-year ice” — floes thick enough to have persisted through two summers of melting. The result could be a reprieve, at least for a while, from the recent stretch of remarkable summer meltdowns.
According to the center, second-year ice this summer made up 32 percent of the total ice cover on the Arctic Ocean, compared with 21 percent in 2007 and 9 percent in 2008. The percentage of ice that was many years old, forming thick pancaked expanses, was at its lowest since satellite observations began 30 years ago. But that could change next year as the second-year ice adds mass through the long winter freeze. The conditions also bolster the views of ice and climate specialists who have stressed that the many factors shaping Arctic conditions year by year, from winds and atmospheric pressure to highly variable ocean currents and soot, still dominate the influence of heat trapped by building greenhouse gases.
So the “ death spiral of the Arctic ice system” could well be more like a series of descending loop the loops. Whether the Arctic’s 21st-century journey ends with a tipping-point style crash or a whimper remains uncertain, but — even with the current recovery — it’s hard to find a researcher probing Arctic ice trends who does not foresee open-water summers, and all that comes with them, in coming decades, as long as greenhouse gases keep accumulating in the atmosphere. More
See related story on 9/16/09. Daily updates are available at the National Snow and Ice Data website or you can sign up for the Arctic Sea Ice News RSS feed for automatic notification of analysis updates. Updates are also available via Twitter