Arctic Ocean was warming decades earlier than previously thought, new research shows – .

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Arctic Ocean was warming decades earlier than previously thought, new research shows – .



The study, published Wednesday in the journal Science Advances, found that the expansion of warm water from the Atlantic Ocean flowing into the Arctic, a phenomenon known as “atlantification,” caused the arctic water temperature in the study region. To increase by about 2 degrees Celsius since 1900.

Francesco Muschitiello, author of the study and assistant professor of geography at the University of Cambridge, said the results were concerning as early warming suggests there could be a flaw in the models scientists are using to predict how the climate will change.

“The Arctic Ocean has been warming for much longer than we previously thought,” Muschitiello told CNN. “And that’s something that’s a little troubling for a lot of reasons, not least because the climate models we use to project projections of future climate change don’t really simulate these kinds of changes. “

Researchers used marine sediment in the Fram Strait, where the Atlantic meets the Arctic east of Greenland, to piece together 800 years of data that paints a longer historical picture of how the water in the The Atlantic has passed into the Arctic. Marine sediments are “natural records,” the researchers wrote, which record data on past climatic conditions.

Researchers found that temperature and salinity, the salinity of ocean water, remained fairly constant until the 20th century, and then suddenly increased.
“The reconstructions suggest a substantial increase in heat and salt transport from the Atlantic Ocean to the Nordic Sea at the start of the 20th century, which is not well simulated by (climate models),” Rong Zhang, senior scientist to the geophysical fluid dynamics of NOAA. The lab, which was not involved in the study, told CNN. “It is important to understand the cause of this rapid atlantification, as well as the discrepancies between the model simulations and the reconstructions. “

Muschitiello said it is not clear to what extent human-made climate change played a role, if any, in the early warming of the Arctic, and more research is needed.

“We’re talking about the early 1900s, and by then we already supercharged the atmosphere with carbon dioxide,” he said. “The Arctic Ocean may be more sensitive to greenhouse gases than previously thought. This will require more research, of course, as we don’t have a solid grip on the actual mechanisms behind this early atlantification. “

The study notes that changes in the Atlantic Meridional Reversal Circulation (AMOC) – a system of currents that moderate temperatures in the northern hemisphere – may have played a role in the warming of the Arctic. Notably, AMOC weakened after a cooling spell ended in the mid-1800s in the North Atlantic region, which the researchers said could have led to rapid Atlanticization along the l east of the Fram Strait.

A recent study found that AMOC, often described as a ‘conveyor belt’ that carries hot water from the tropics and redistributes it north, is now showing signs of further instability due to man-made climate change. . Scientists have warned that a traffic collapse could lead to a dramatic change in weather conditions across the world – colder winters in Europe, changes in monsoons and potentially permanent drought in West Africa.

The rapid warming of temperatures in the Arctic has caused the sea ice to melt, which in turn causes further warming – while the bright white sea ice reflects the sun’s energy, while the dark ocean absorbs energy in the form of heat.

James E. Overland, NOAA Arctic scientist based at the NOAA Pacific Marine Environmental Lab in Seattle, said such long-term changes in the North Atlantic, associated with the recent loss of sea ice in the Arctic, threaten marine ecosystems.

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“The loss of sea ice and ocean currents has shifted the buffer region between the Atlantic Ocean and the Arctic Ocean to something closer to an arm of the central Atlantic,” Overland, who told CNN was not involved in the study. “Important fisheries and marine mammals are vulnerable to the reorganization of ecosystems due to such atlantification. “

A recent UN report on the state of the science on the climate crisis found that the Arctic will continue to warm faster than the rest of the planet as long as humans continue to burn fossil fuels and release fossil fuels. greenhouse gases in the atmosphere. On top of that, Muschitiello said the Arctic Ocean may experience further warming due to Atlanticization.

“When I talk to my students, I always try to make them aware that the Arctic is warming very, very quickly and much faster than any other region on the planet,” said Muschitiello. “It’s very unsettling and very disturbing, especially since we still don’t have a full understanding of comebacks.”

“We’re still slowly learning how the whole system works,” he said. “And my fear is that by the time we solve the problem, it will be too late. “

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