Sea ice’s reckoning has come: As predicted a couple of weeks ago, the level of ice in the Arctic Ocean has dropped to its lowest level.
It did so on September 16, scientists at the National Snow and Ice Data Center (NSIDC) announced on Wednesday. At 1.32 million square miles, it is the lowest level that Arctic summer ice has been since the U.S. government started keeping satellite records 33 years ago, and 293,000 square miles below the previous low in 2007. Moreover, even though the annual melt has stopped, the number could drop further once the final data are analyzed, the center said.
The melt is not only happening faster than earlier models predicted but also is in and of itself accelerating climate change in untold ways.
“We are now in uncharted territory,” said NSIDC Director Mark Serreze in a statement. “While we’ve long known that as the planet warms up, changes would be seen first and be most pronounced in the Arctic, few of us were prepared for how rapidly the changes would actually occur.”
Several factors contributed to this and compounded both the melt and its effects. The summer was harder than usual on the ice. High-temperature records were broken, and a stubborn storm churned over the Arctic for several days, pounding the thin ice even further, The New York Times and other outlets reported in August.
The ice melt was breaking records all summer, passing the 2007 record low of 1.61 million square miles by hitting 1.58 million square miles, the NSIDC said. And on September 4 the ice extent—defined by the NSIDC as the area covered with at least 15 percent of ice—fell below 1.54 million square miles for the first time on record. In addition, the minimum extent occurred three days later than September 13, which was average minimum date from 1979 to 2000, the NSIDC said.
“The strong late season decline is indicative of how thin the ice cover is,” said NSIDC scientist Walt Meier in the statement. “Ice has to be quite thin to continue melting away as the sun goes down and fall approaches.”
The minimum this year is about half the size of the average ice extent between 1979 and 2000, NASA said in a media release. The lead scientist on the NSIDC team, Ted Scambos, said in the agency’s statement that thinning ice combined with early loss of snow are rapidly warming the Arctic.
“But a wider impact may come from the increased heat and moisture the warmer Arctic is adding to the climate system,” he said. “This will gradually affect climate in the areas where we live. We have a less polar pole—and so there will be more variations and extremes.”
Separately, another leading climate scientists said the change signifies outright disaster.
“As the sea ice retreats in summer the ocean warms up [to 44.6F in 2011] and this warms the seabed too,” said Professor Peter Wadhams of Cambridge University in England, to the Guardian.
“The continental shelves of the Arctic are composed of offshore permafrost, frozen sediment left over from the last ice age. As the water warms the permafrost melts and releases huge quantities of trapped methane, a very powerful greenhouse gas so this will give a big boost to global warming.”