.jpg "Arctic cyclones, such as this one in August 2012, can destroy sea ice and endanger people living and traveling in the region. JESSE ALLEN AND ROBERT SIMMON, NASA EARTH OBSERVATORY IMAGE USING VIIRS DATA") |
| JESSE ALLEN AND ROBERT SIMMON, NASA EARTH OBSERVATORY IMAGE USING VIIRS DATA |
CHICAGO (WLS) – A cyclone blitzed a large expanse of ice-covered ocean between Greenland and Russia in January 2022. Frenzied gusts galvanized 8-meter-high waves that pummeled the region's hapless flotillas of sea ice, while a deluge of warm rain and a surge of southerly heat laid siege from the air.
Six days after the assault began, roughly a quarter of the vast area's sea ice had disappeared, resulting in a record weekly loss for the region.
The storm is the most powerful Arctic cyclone ever recorded. But that title may not last long. Researchers reported on December 13 at the American Geophysical Union's fall meeting that cyclones in the Arctic have become more frequent and intense in recent decades, posing risks to both sea ice and people. "This trend is expected to continue as the region continues to warm rapidly in the future," says University of Wisconsin-Madison climate scientist Stephen Vavrus.
Rapid Arctic warming and more powerful storms
The Arctic Circle is warming four times faster than the rest of the planet (SN: 8/11/22). The loss of sea ice due to human-caused climate change is a major driver. Floating ice reflects far more solar radiation back into space than open water, influencing global climate (SN: 10/14/21). Cyclones have been observed to amplify sea ice losses on average during August, the heart of the sea ice melting season, exacerbating warming.
There's even more: Boreal vortices, like hurricanes, can wreak havoc on people living and traveling in the Arctic (SN: 12/11/19). "Stronger winds pose a risk for marine navigation by generating higher waves," Vavrus says, "as well as for coastal erosion, which has already become a serious problem throughout much of the Arctic, forcing some communities to consider relocating inland."
Storms are intensifying further south as a result of climate change (SN: 11/11/20). However, it is unclear how Arctic cyclones will change as the world warms. Previous research suggested that pressures in the cores of Arctic cyclones have decreased on average in recent decades. Lower pressures are generally associated with more intense storms, with "stronger winds, larger temperature variations, and heavier rainfall [and] snowfall," according to atmospheric scientist Xiangdong Zhang of the University of Alaska Fairbanks.
Storms are intensifying further south as a result of climate change (SN: 11/11/20). However, it is unclear how Arctic cyclones will change as the world warms. Previous research suggested that pressures in the cores of Arctic cyclones have decreased on average in recent decades. Lower pressures are generally associated with more intense storms, with "stronger winds, larger temperature variations, and heavier rainfall [and] snowfall," according to atmospheric scientist Xiangdong Zhang of the University of Alaska Fairbanks.
Arctic cyclone activity has increased in strength and frequency in recent decades, according to Zhang. Pressures in the hearts of today's boreal vortices are 9 millibars lower on average than in the 1950s. To put this in context, a pressure shift of this magnitude would be roughly equivalent to bumping a strong category 1 hurricane into category 2 territory. Vortices also became more common during the winters in the North Atlantic Arctic and the summers in the Arctic north of Eurasia.
Storm surge
Strong vortices with central pressures less than 990 millibars have appeared in the Arctic more frequently in the last decade than in the 1950s, increasing by about 20% in the winter and 35% in the summer.
Furthermore, August cyclones appear to be causing more damage to sea ice than in the past, according to meteorologist Peter Finocchio of the US Naval Research Laboratory in Monterey, Calif. He and his colleagues looked at how northern sea ice responded to summer cyclones in the 1990s and 2010.
August vortices in the latter decade were followed by a 10% loss of sea ice area on average, up from a 3% loss in the previous decade. This could be due to warmer water upwelling from below, which can melt the ice pack's underbelly, as well as winds pushing the thinner, easier-to-move ice around, according to Finocchio.
Stronger spring storms spell trouble too
Climate change may cause cyclones to intensify again in the spring, according to climate scientist Chelsea Parker, who spoke at the meeting. This is a problem because spring vortices can prepare sea ice for melting later in the summer.
Parker and her colleagues at NASA's Goddard Space Flight Center in Greenbelt, Maryland, ran computer simulations of spring cyclone behavior in the Arctic under past, current, and projected climate conditions. The researchers discovered that by the end of the century, the maximum near-surface wind speeds of spring cyclones, which are currently around 11 kilometers per hour, could reach 60 kilometers per hour. Future spring cyclones may continue to swirl at maximum intensity for up to a quarter of their lives, up from around 1% today. The storms will most likely travel further as well, according to the team.
"Declining sea ice cover will allow warmer Arctic seas to fuel these storms and likely allow them to penetrate deeper into the Arctic," says Vavrus, who was not involved in the research.
Parker and her colleagues intend to look into the future evolution of Arctic cyclones in other seasons in order to get a better picture of how climate change is affecting the storms.
For the time being, it appears that Arctic cyclones are here to stay. What is less clear is how humanity will deal with the storms' increasing fury.
CITATIONS
Zhang, X. Arctic cyclone activity is continuing to intensify. The American Geophysical Union's fall meeting will be held in Chicago on December 13, 2022.
P. Finocchio. Late-summer cyclones accelerate sea-ice loss in the new Arctic. The American Geophysical Union's fall meeting will be held in Chicago on December 13, 2022.
Arctic cyclones in an era of rapid climate change, C. Parker. The American Geophysical Union's fall meeting will be held in Chicago on December 13, 2022.
Blanchard-Wrigglesworth, E., et al. Characteristics, impacts, and predictability of the January 2022 Arctic cyclone. e2022JD037161, Journal of Geophysical Research: Atmospheres, Vol. 127, November 16, 2022, doi: 10.1029/2022JD037161.