Arctic Ocean may be ice-free for part of year by 2044: Study

Human-caused climate change is on track to make Arctic Ocean functionally ice-free for part of each year starting sometime between 2044 and 2067, according to a study. Researchers at University of California, Los Angeles (UCLA) in US ted that as long as humans have been on Earth, planet has h a large-cap of sea ice at Arctic Circle that expands each winter and contracts each summer. Satellite observations show that since 1979, amount of sea ice in Arctic in September -- month when re is least sea ice before water starts freezing again -- has declined by 13 per cent per dece, researchers said.

Scientists have been attempting to predict future of Arctic sea ice for several deces, relying on an array of global climate models that simulate how climate system will react to all of carbon dioxide entering atmosphere. However, models' predictions have disagreed widely, according to study published in journal Nature Climate Change. Among current generation of models, some show ice-free Septembers as early as 2026, while ors suggest phemen will begin as late as 2132. study's le author, Ch Thackeray, an assistant researcher at UCLA, said one reason predictions about sea ice loss diverge so much is that y differ in how y consider a process called sea ice-albedo feedback.

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When does  process occur?

process occurs when a patch of sea ice completely melts, uncovering a seawater surface that is darker and absorbs more sunlight than ice would have. That changed in surface's reflectivity of sunlight, or albedo, causes greater local warming, which in turn les to furr ice melt, researchers said. cycle exacerbates warming -- one reason Arctic is heating up twice as fast as rest of globe, y said.

Thackeray and co-author Alex Hall, a UCLA professor, ted that sea ice-albedo feedback t only happens over long periods of time due to climate change but also happens every summer when sea ice melts for season. Satellite observations over past few deces have tracked that seasonal melt and resulting albedo feedback, y said. Thackeray and Hall assessed 23 models' depiction of seasonal ice melt between 1980 and 2015 and compared m with satellite observations. y retained six models that best captured actual historical results and discarded ones that h proven to be off base, enabling m to narrow range of predictions for ice-free September in Arctic.

"Arctic sea ice is a key component of earth system because of its highly reflective nature, which keeps global climate relatively cool," Thackeray said.

re are or environmental and ecomic implications to ice loss as well, researchers said. Sea ice is critical to Arctic ecosystem, and to fishing industry and indigeus peoples who depend on that ecosystem, y said. researchers explained that as Arctic ice is lost, more waters are used for commercial shipping and oil and gas exploration, which presents an ecomic opportunity for some nations. However, y ted, this also contributes to furr greenhouse gas emissions and climate change.

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