There’s a standard image of the Earth as seen from space that we carry in our heads: vast blue seas, green bands of forests, and frozen white caps on the top and bottom. By the summer of 2035, it may not be accurate. Scientists estimate that in just 15 years Arctic summer sea-ice could disappear for the first time since primitive humans left Africa. “The point is, this is happening soon,” says Maria-Vittoria Guarino, an Earth system modeler at the British Antarctic Survey and lead author of a study published earlier this month in the journal Nature Climate Change. “We will have less and less time to get ready for it, or less time to act upon it if we want to do something about it.”The new research is the latest in a steady stream that has moved up the predicted timeframe for the ice-free Arctic milestone. The amount of sea-ice floating atop the Arctic Ocean at summer’s end has fallen about 13% per decade since 1979. The 13 years with the smallest ice extents on record have all happened over the previous 13 years—and this summer is a sure bet to be No. 14.
That period was 4° Celsius hotter than than the pre-industrial era—a plausible preview of conditions humans are creating for the future. Current warming on average is already around 1°C, and the Arctic is warming more than twice as fast as the rest of the planet.
Guarino’s research joins a debate about the pace of global heating that has drawn in climate scientists this year. Some newly updated models, like the one Guarino’s team used, now suggest that warming will occur much, much faster than previously thought. There remains disagreement among scientists over modeling results that show accelerated warming. But, as Guarino sees it, the fact that at least one of these models with hotter-than-expected results has successfully matched physical evidence from the Last Interglacial period makes it difficult to dismiss the findings. Earlier climate models struggled to match the geological evidence from the Last Interglacial.