The sea ice in the Arctic Ocean has melted to its smallest point ever in a milestone that shows worst-case forecasts on climate change are coming true, US scientists said.
The extent of ice observed broke a record set in 2007 and will likely melt further with several weeks of summer still to come, according to data from the National Snow and Ice Data Centre and Nasa space agency.
The government-backed ice centre, based at the University of Colorado at Boulder, said in a statement that the decline in summer Arctic sea ice “is considered a strong signal of long-term climate warming”.
The sea ice fell to 4.10 million square kilometres, some 70,000 square kilometres less than the earlier record charted on September 18, 2007, the centre said.
Scientists said the record was all the more striking as 2007 had near perfect climate patterns for melting ice but that the weather this year was unremarkable other than a storm in early August.
Michael E. Mann, a lead author of a major UN report in 2001 on climate change, said the latest data reflected that scientists who were criticised as alarmists may have shown “perhaps too great a degree of reticence”.
“I think this is an example that points more to the worst-case scenario side of things,” said Mr Mann, director of the Earth System Science Centre at Penn State University.
“There are a number of areas where in fact, climate change seems to be proceeding faster and with a greater magnitude than what the models predicted. The sea ice decline is perhaps the most profound of those cautionary tales because the models have basically predicted that we shouldn’t see what we’re seeing now for several decades,” Mr Mann said.
Arctic ice is considered vital for the planet as it reflects heat from the sun back into space, helping keep down the planet’s temperatures.
The Arctic region is now losing about 155,000 square kilometres of ice annually, the equivalent of a US state every two years, said Walt Meier, a scientist at the National Snow and Ice Data Centre.
“The Arctic ice cover used to be a kind of big block of ice. It would melt a little bit from the edges but it was pretty solid,” Mr Meier told reporters on a conference call.