A researcher explains: Why the winter has been so extreme

Gabriele Messori pointing at a weather map.

Gabriele Messori follows the storm Ingunn that hit Sweden on February 1. In Stekenjokk in the southern Lapland mountains, wind speeds of 58.7 m/s were recorded in the wind gusts. Photo: Mikael Wallerstedt

Blizzards, record winds, red weather warnings and biting cold. The long winter of 2023/2024 has featured heavy precipitation and a number of extreme weather events. There are several reasons for this, one of which is high ocean temperatures.

“We’ve had unusually cold weather with a great deal of snow in some places. Not everywhere, but it was abnormally snowy in Uppland, for example. Elsewhere, it’s been unusually wet and rainy, with unusually cold periods as well,” says Gabriele Messori, Professor of Meteorology.

Messori conducts research on extreme weather and is interested in how climate change will influence these events. According to his findings, cold spells can be expected to occur more rarely in many regions while heatwaves are already more frequent than they used to be – and the models indicate that warm periods will become even more common.

North Atlantic is unusually warm

So could the violent fluctuations in the weather in Sweden this winter somehow be connected with global warming?

“One thing that could perhaps be linked to climate change is that the North Atlantic is unusually warm this year. The North Atlantic has never been as warm as it is this year,” Messori says.

He believes this probably has to do with 2023 being the warmest year ever measured globally.

“Here in Sweden, we’re more or less on the border between the cold air masses from Siberia and Russia and warmer air masses from the North Atlantic. The interaction between these two air masses determines how warm or cold it is. This year it’s very warm in the North Atlantic, which leads to storms forming there that bring warm air in over land. This can result in above-zero temperatures and rain in Uppsala in the middle of the winter. When cold air masses return, the temperature can plummet in the course of just a few hours,” Messori explains.

The storms Pia and Ingunn

On several occasions this winter, the Swedish weather service SMHI issued red weather warnings for regions such as the west coast and the mountains, with violent winds and heavy snow. Pia and Ingunn were two of the storms that swept across the country. However, in Messori’s opinion, it is doubtful whether the frequent weather alerts can be attributed to climate change.

“It’s difficult to say that individual cold spells or storms can be linked to climate change without carrying out a detailed analysis of each event, but what can be said is that the abnormally warm water and air masses in the North Atlantic can probably be linked to climate change and a warmer climate,” he says.


Åsa Malmberg

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