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Nearly all of the Arctic’s sea ice could melt by the summer of 2027, a group of international scientists has warned.
Sea ice – frozen seawater that floats on the ocean’s surface – in the region has diminished to near-historic lows following decades of shrinking and thinning in one of the fastest-warming areas on the planet. The warming has been driven by ever-increasing greenhouse gas emissions: the result of humanity’s reliance on fossil fuels. The day when the majority of the ice disappears is greatly concerning to researchers, who aren’t yet sure what repercussions it might have.
Research published Tuesday in the journal Nature Communications finds the Arctic will be “ice-free” when it has less than 1 million square kilometers of ice. The least amount of sea ice, which typically melts and reforms with the changing of the seasons, in a day this year was at 1.65 million square miles: a stark decline compared to the average between 1979 and 1992.
“The climate models show that unless we can stay below 1.5 degrees Celsius globally in the climatological average, which is becoming less and less likely every month basically, it’s guaranteed that we will see ice-free conditions this century,” Alexandra Jahn, an associate professor of atmospheric and oceanic sciences at the University of Colorado Boulder and co-author of the research, told The Independent on Monday.
Nations agreed in 2015 to limit global warming to 1.5 degrees Celsius of warming. But, the United Nations said in October that Earth is on the track for as much as 3.1 degrees – and that this could be “catastrophic.”
The Arctic has already lost about half of its sea ice, compared to the 1980s at the end of the summer. It is known that more warming has delayed ice formation, and resulted in thinner sea ice growth. The ice is easier to melt and more of it melts in higher temperatures in the spring. And, a high pressure system over the Central Arctic has been observed keeping warm air there. When the ice is thin, more storms form in the spring and summer that can break up the ice and further accelerate ice melt. These things happen for several years in a row, leading to a massive reduction in Arctic sea ice.
Models project that storms and heat waves will continue to increase in the future, as the climate continues to warm.
“Emissions are still increasing, we’re having record warm years year after year, and so that’s just all leading to changes in all aspects of the climate system…” Jahn said.
It’s because of these changes, and in a “perfect storm,” that an ice-free day could happen “sooner than most people expect.”
But, it will be “one of the most clear changes in the natural environment due to anthropogenic-driven climate change,” she noted.
“When we reach ice-free conditions then the majority of the Arctic Ocean, 94 percent of it, will have no ice anymore. So, we’re going from a white Arctic ocean to a blue Arctic ocean. And so, visually that’s a really big change and really illustrates how much anthropogenic greenhouse gases can change the natural environment,” Jahn explained.
Based on satellite data from the National Snow and Ice Data Center, researchers are certain that the Arctic will lose more ice. Most models predicted that the first ice-free day could happen within nine to 20 years after 2023, regardless of how humans alter their greenhouse gas emissions.
“As we approach an ice-free Arctic, there’s a multitude of impacts on the climate system and on the ecosystem, as well as on the people living in the Arctic. On how they can use the sea ice for transportation and hunting and things like that,” Jahn said.
But, whether or not it happens, remains up in the air. There’s uncertainty in projections based on climate models. So, it could happen between three years and 50 years.
“These projections are probabilistic, so we’re not saying an ice-free Arctic will happen in three to six years. It’s really three to 50 years. That’s what the models are showing, depending on the variability and the strength of the global emissions … But, it could happen earlier than people might expect …” she said.
To avoid an ice-free day, the world must limit global warming, researchers warn. There is still a possibility that, if the world urgently acts, ice-free conditions may not ever come about, they say.
“So, under the lowest emissions scenario there are several models that don’t have an ice-free day before the end of the century. But, several also do. If we can stay there, then it’s kind of up to chance whether we get a rapid ice-loss event some years where we get to ice-free conditions, anyway,” said Jahn.
“Whereas, if we go above 1.5 degrees, we’re basically guaranteed to see ice-free conditions. So, reducing greenhouse gas emissions by any amount will have an impact on how much ice remains in the Arctic Ocean.”
Source: independent.co.uk
