From this past data, they found that the Arctic's average extent of September sea ice - the month when it reaches its annual minimum - is now 31% lower than the average seen during the first decade of satellite-based record keeping between 1979 and 1988. "The Arctic is already entering a completely different climate than just a few decades ago". Observations from local weather stations have shown that the average air temperatures have been consistently high for the past two years, creating the ideal circumstances for extended melt conditions. As nations court new shipping and fossil-fuel exploration opportunities, scientists warn that summertime Arctic sea ice may only have years left.
Graphs of changes in the three factors the team modeled - minimum sea ice extent, surface temperature and number of rainy days.
In August, a study showed that Greenland lost a record amount of ice during an extra-warm 2019, with the melt massive enough to cover California in more than 1.25 meters (4 feet) of water. 2019 was the hottest year for the icy country and the Arctic region is already warming twice as fast. This occurs because light-colored sea ice, which reflects heat back into space, is replaced by darker ocean water, which traps heat. For the new research, Landrum and her colleague Marika Holland at the National Center for Atmospheric Research analyzed sea ice, air temperature and precipitation data since 1950 to project climate scenarios up to the end of the century.
To answer these questions, they turned to multiple simulations from five of the world's leading climate models that have been used for an worldwide research project known as the Coupled Model Intercomparison Project 5, or CMIP5.
From this they assembled a picture of Arctic climate, allowing them to differentiate year-to-year natural climate variability from a transition to a new climate.
Box said: "What makes 79N so important is the way it's attached to the interior ice sheet, and that means that one day - if the climate warms as we expect - this region will probably become one of the major centres of action for the deglaciation of Greenland".
With that shift will come further changes in sea ice extent. The region is known for its snowy winter season, but if emissions persist at their current level, the Arctic will be seeing a lot more rain. If greenhouse gas emissions remain high, the team predicts that by the end of this century the Arctic could experience between three and 10 months a year with nearly no sea ice. Any opinions, findings and conclusions or recommendations expressed in this material do not necessarily reflect the views of the National Science Foundation.