Noting that, President Obama has pledged to take action on greenhouse gas emissions if Congress cannot pass legislation.
The NOAA study underscores the urgency for better modeling and action on climate change, Overland said.
“Increased physical understanding of rapid Arctic climate shifts and improved models are needed that give a more detailed picture and timing of what to expect so we can better prepare and adapt to such changes. Early loss of Arctic sea ice gives immediacy to the issue of climate change,” Overland said.
Previous estimates pegged the Arctic for mostly iceless summers after 2050. The scientists said some ice is expected to remain north of the Canadian Archipelago and Greenland beyond that date.
Overland and Wang explored three different scenarios in their study, which was published in the American Geophysical Union publication Geophysical Research Letters.
The first, based on observed trends in the past decade, showed rapid ice melt. That model predicted nearly ice-free summers by 2020.
The second approach, which assumed “multiple, by random in time, large sea ice loss events,” resulted in mostly iceless summers by 2030.
The final calculation drew from various global climate models. In that simulation, the earliest nearly ice-free summer was around 2040, with the median being 2060.
— This story was updated at 5:36 p.m.