CLIMATEWIRE | The strongest Arctic cyclone² ever observed ripped across the icy waters west of Greenland in January 2022. With wind speeds topping 67 miles per hour and waves more than 26 feet high, the storm chewed through thick winter sea ice.

 

More than 154,000 square miles of ice disappeared across the Barents, Kara and Laptev seas in a matter of days, scientists later determined³. It was the largest six-day sea ice loss ever recorded in the area.

 

That’s a sharp blow in a region where skyrocketing temperatures have steadily⁴ eaten away at sea ice cover for decades. The Arctic is warming as much as four times faster than the global average, and some studies warn that the Arctic Ocean could see its first ice-free summer within a decade or so.

 

Strong cyclones can speed up the ice cover’s demise⁵. And events like the tempest of 2022 may happen more often in the future, scientists warn. New research finds that Arctic cyclones are growing stronger as the climate warms. In fact, they’ve been strengthening for decades.

 

The study, published Oct. 2 in the journal Communications Earth & Environment, helps address a long-standing debate about trends in Arctic cyclones. Scientists predict that the storms should intensify⁶ with continued warming. But different studies have come to different conclusions about whether or not Arctic cyclones are actually strengthening over time.

 

That’s partly because previous research often has focused on bits and pieces of the Arctic cyclone puzzle, said lead study author Xiangdong Zhang, a senior scientist at the North Carolina Institute for Climate Studies at North Carolina State University. Some scientists have looked only at the total number of Arctic cyclones, some have examined only their intensity⁷ and others have investigated how long they last.

 

The new study attempts to put all the pieces together, Zhang said. The researchers integrated measurements of all the different aspects of Arctic cyclone behavior to develop a new index of cyclone activity.

 

The study finds that strong Arctic cyclones have been happening more frequently since the 1950s. They’re also lasting⁸ longer, giving them more time to wreak⁹ havoc¹⁰ on the icy seas. And the trend has accelerated in the last few decades.

 

A few factors have contributed to the strengthening storms, the research suggests. And some of them have clear links to climate change.

 

Temperatures already tend to differ over land masses, open ocean and sea ice. Arctic warming has further sharpened the temperature gradient between these different zones. The change in these gradients affects the formation of storms over the Arctic Ocean, helping¹¹ cyclones grow more intense.

 

Changes in the Earth’s jet streams also have played a part, Zhang said, especially in the winter. Jet streams are fast-flowing currents of air circling the planet, with a strong influence on global weather patterns.

 

Some research suggests that winter jet streams are growing more wavy¹² — meandering¹³ up and down as they flow around the Earth. That’s helping the air currents steer¹⁴ more cyclones into the Arctic.

 

Changes in the jet stream may be related to climate change, although scientists are still debating the exact mechanisms¹⁵. Some research suggests that rapid Arctic warming is altering the atmosphere in ways that affect the flow of air around the Earth. But that’s still the subject of ongoing¹⁶ research.

 

Meanwhile, a strengthening vortex of polar air currents in the troposphere has helped strengthen summer cyclones. It’s still unclear why the vortex is shifting, according to Zhang.

 

“This is also potentially associated with the warming trend,” he said. “It’s still an open question. Research is still going on.”

 

Strengthening cyclones may have some serious implications for the Arctic.

 

These storms transfer heat and moisture into the region, while stirring up the oceans with strong winds and high waves. This can speed up the melting of Arctic sea ice and expose more open ocean to the atmosphere, allowing the water to soak up more heat from the sun. It also can mix up the water, transferring heat from deeper layers of the ocean to the surface, melting even more ice.

 

Warming and melting in the Arctic Ocean may transform the marine¹⁷ ecosystem¹⁸, scientists warn. Some polar fish species may be forced to migrate even closer to the North Pole or risk extinction¹⁹, while new species begin moving in. Animals such as polar bears and walruses²⁰, who use the sea ice to hunt or rest, will suffer.

 

The warming ocean also will help further accelerate the overall rate of Arctic climate change, Zhang added. And while it’s still a subject of debate, Arctic warming has the potential to cause further shifts in the jet streams — which could alter weather patterns across the Northern Hemisphere.

 

Arctic cyclones interact with a wide variety of elements in the Earth’s climate system. That makes them a prime subject for research, Zhang said.

 

“Arctic cyclone study is a hot topic,” he said. “There’s a large number of people and colleagues working on this.”

 

Reprinted from E&E News with permission from POLITICO, LLC. Copyright 2023. E&E News provides essential news for energy and environment professionals.

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