Every year there are oscillations in the weather patterns in the Arctic: more or less sea ice, colder or warmer winters, a more or less long rainy season. However, according to a study by scientists from the National Center for Atmospheric Research (NCAR) in the United States, current records are outside the limits of the fluctuations known in past decades, mainly since satellites began to be used for measurements in 1979. So much so that the work concludes that this region of the world is already changing to a totally different climatic state.
“There is a quote from Mark Twain that says that the climate is what you expect and the time you really have, well, the weather patterns that we are seeing in the Arctic are no longer as expected, they are completely different,” he says. Laura Landrum, Principal Investigator of this study published in Nature Climate Change. “This is a period of such rapid change that observations of past weather patterns no longer show what to expect next year.”
While other scientists have long analyzed the new dynamics of open water in the Arctic, along with changes in the permafrost (the permanently frozen ice sheet), land and sea ice at these latitudes, according to NCAR researchers, they do not there has been work before that determines the timing and nature of the emergence of a new arctic climate in land and ocean areas. As they detail, it is very complex to characterize the climate at a time of rapid climate change in regions such as the Arctic, where observational data is scarce and limited, mainly, to the era of modern satellites.
“The information from the satellites is relatively recent, but I use climate models that have been validated, I use climate simulations from 1950 to 2100, which allows me to compare,” says Landrum.
To conclude that the Arctic is already moving to a new climate state, in which extremes are the new routine, scientists use three key variables: the minimum extent of sea ice, the surface air temperature, and the precipitation phases of rain (instead of snow).
It is now in September when the sea ice reaches its smallest extent of the year. However, as the study highlights, the minimum surface area recorded in the Arctic in the last 13 years has been lower than in all previous years of the satellite era. In fact, its average extension in September is now 31% lower compared to the decade between 1979 and 1988.
The region’s climate is changing at a much faster rate than in lower latitudes due to a process known as arctic amplification. This occurs because the sea ice, which reflects much of the heat it receives, is replaced by the dark waters of the ocean, which absorb that heat.
Of the five models used by the researchers, three suggest that by 2100 the Arctic will be completely ice-free for three to four months of the year. Similarly, the work warns in its conclusions that if the emissions that cause global warming are not reduced, rains will replace snowfall, with an extension of the rainy season from two to four months, and that temperatures autumn-winter daily temperatures will rise between 16 and 28 ° C in most of the Arctic Ocean. Some changes with “extreme consequences for Arctic communities and local ecosystems.”
Can this situation be reversed? “I’m not sure it can be done in a human lifetime, in my lifetime,” says Landrum. “We still have an opportunity to reduce emissions, but if the question is whether we can go back to the previous Arctic climate, although theoretically yes, this is going to be more complicated.”