WASHINGTON — Arctic sea ice has shrunk to its smallest surface area since record-keeping began, taking the world into “uncharted territory” as climate change intensifies, US scientists warned Wednesday.
Satellite images show the ice cap had melted to 1.32 million square miles (3.4 million square kilometers) as of September 16, the predicted lowest point for the year.
That’s the smallest Arctic ice cover since record-keeping began in 1979, the National Snow and Ice Data Center said.
“We are now in uncharted territory,” the center’s director, Mark Serreze, said, 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,” he added.
Arctic sea ice expands and contracts seasonally, with the lowest extent usually occurring in September.
This year’s minimum followed a season already full of records for shrinking ice, with lowest ever extents recorded on August 26 and again on September 4.
And in the last two weeks, the ice cover melted by more than 200,000 square miles (518,000 square kilometers), quite a large margin for the end of the summer, the NSIDC said.
“The strong late season decline is indicative of how thin the ice cover is,” said NSIDC scientist Walt Meier.
“Ice has to be quite thin to continue melting away as the sun goes down and fall approaches.”
Scientists use Arctic sea ice extent as an indicator of what’s happening with the overall climate. Despite year-to-year fluctuations from natural weather variations, the ice cap has shown a clear trend towards shrinking over the last 30 years, the NSIDC center said.
“This year’s minimum will be nearly 50% lower than the 1979 to 2000 average,” the statement noted.