Researchers warn the Arctic could experience its first ice-free summer within a decade, a significant milestone with global consequences. A new study from the University of Colorado Boulder predicts the Arctic Ocean could be nearly ice-free by late summer in the 2020s or 2030s, even under the most optimistic scenarios for reducing greenhouse gas emissions. This is 10 years earlier than previous models predicted.
The findings, which are published in the journal Nature Reviews Earth & Environment and are based on an analysis of existing climate data.
"Ice-free" in this context doesn't mean zero ice, but rather that the Arctic Ocean would have less than 1 million square kilometres of ice, mostly concentrated near the coast. This would still have major environmental impacts.
The study predicts consistent ice-free Septembers, the peak summer month in the Arctic, by mid-century, ranging from 2035 to 2067. The exact timing depends on how effectively we can cut emissions.
A worst-case scenario with high emissions could lead to an ice-free Arctic for up to nine months a year, fundamentally transforming the region.
Alexandra Jahn, associate professor of atmospheric and oceanic sciences and fellow at CU Boulder's Institute of Arctic and Alpine Research, set out to analyse existing literature on sea ice projections. She and her collaborators also analysed sea ice coverage data from computational climate models to assess how the Arctic might change daily in the future.
They found that the first day when sea ice coverage dips below the 1-square-kilometre threshold would occur on average four years earlier than the monthly averages, but could occur up to 18 years earlier.
"When it comes to communicating what scientists expect to happen in the Arctic, it is important to predict when we might observe the first ice-free conditions in the Arctic, which will show up in the daily satellite data," Jahn said.
The team projected the Arctic Ocean could become ice-free for the first time on a late August or early September day between the 2020s and 2030s under all emissions scenarios.
Jahn said greenhouse gas emissions are the main contributors to sea ice loss. A decrease in snow and ice cover increases the amount of heat from sunlight absorbed by the ocean, exacerbating ice melt and warming in the Arctic.
