Arctic is warming nearly 4 times faster than the rest of the world, study shows | Environment

The Arctic is warming faster than scientists expected: about four times higher when compared to the global average temperature in the last 43 years.

This is what an article published this Thursday (11) in the scientific journal Communications Earth & Environment, by the group nature.

According to the authors of the study, this accelerated warming of the Arctic suggests that the region is more sensitive to global warming than current estimates show, given that the published data differs from the simulations reported in several previous studies, which claimed that the region is warming twice or even three times faster than the rest of the globe (a phenomenon known as Arctic amplification).

“To refer to Arctic warming as being twice as fast as global warming, as is often claimed in the scientific literature, is a clear understatement of the situation over the past 43 years since satellite observations began. [na região]”, warned the authors in the article.

Scientists say there are two main hypotheses that support this new review.: the first is that previous estimates may be out of date due to the continued warming of the arctic region and the second is that this assessment has been affected both by the how the Arctic is delimited geographically as by choice of period length over which the heating rate is calculated.

In the new study, the Arctic region was defined as the area within the Arctic Circle. (see art below) and the heating rate was calculated from 1979when more detailed satellite observations became available.

Annual average temperature trends for the Arctic Circle. — Photo: Art g1

“The Arctic was defined using the Arctic Circle because we wanted to use an area that most people perceive as the Arctic. We focused on a period starting in 1979 because observations after that year are more reliable and because strong warming started in the 1979 1970,” Mika Rantanen, a researcher at the Finnish Meteorological Institute who coordinated the study, said in a statement.

Because of this new analysis, in some regions of the Arctic, such as areas in the Eurasian sector of the Arctic Ocean near the Svalbard and Novaya Zemlya archipelagos, scientists have calculated an increase up to seven times faster than the rest of the globe.

Also according to the study, this increase in Arctic amplification over the last 43 years is caused both by climate change caused by human activity as well as the long-term natural variations of the climate in the region.

During that same time period, scientists also found that, on average, the months of October to December in the Arctic warmed five times faster than the rest of the globe, while the rate of warming between June and August is close to two.

The researchers say this is because with the end of autumn and the approach of winter in the Northern Hemisphere (October-December), newly opened, ice-free areas of water release more heat into the atmosphere.

In summer and early autumn, although the decrease in ice cover has been greater, the sea surface releases small amounts of heat precisely because the atmosphere and the sea are almost equally warm.

“Our results indicate that this new four-fold rate of Arctic warming is an extremely unlikely event, or climate models systematically tend to underestimate this amplification,” the paper’s authors concluded.

According to scientists, this inability of current climate models to simulate a realistic amplification of the Arctic could have implications for future climate projections. Therefore, the authors advocate more detailed investigations into the mechanisms behind this process and its representation in models of the type.

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