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An increase in rays in the Arctic may be linked to climate change

Climate change may be causing more lightning in the Arctic.

Data from a global network of lightning sensors suggests that lightning frequency in the region has increased over the past decade, according to online researchers on March 22 in Geophysical Research Letters. It may be because the Arctic, historically too cold to feed many storms, is warming twice as fast as the rest of the world (SN: 02/08/19).

The new analysis used observations from the worldwide lightning location network, which has worldwide sensors that detect radio waves emitted by lightning. Researchers counted lightning in the Arctic during the stormiest months of June, July, and August from 2010 to 2020. The team counted everywhere above 65 ° N latitude, which runs through the middle of Alaska, like the Arctic.

The number of rays that the detection network accurately located in the Arctic went from about 35,000 in 2010 to about 240,000 in 2020. Part of that increase in detection may be due to the expansion of the sensor network from about 40 stations to more than 60 stations per decade. .

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And just looking at the 2010 and 2020 values ​​alone can exaggerate the increase in lightning, because "there is such variability, year after year" and 2020 has been a particularly stormy year, says Robert Holzworth, an atmospheric and space scientist at the University of Washington in Seattle . In estimating the increase in the average annual radius, “I would say we have very good evidence that the number of strokes in the Arctic has increased, say, by 300 percent,” Holzworth says.

That increase occurred as global summer temperatures rose from about 0.7 degrees Celsius above the twentieth-century average to about 0.9 degrees C above, suggesting that global warming may create more favorable conditions for lightning in the Arctic. .

It makes sense that a warmer climate could generate more lightning in historically colder climates, says Sander Veraverbeke, a terrestrial systems scientist at VU University in Amsterdam who did not participate in the work. Doing so could result in more forest fires (SN: 4/11/19). But the apparent trend in Arctic rays should be taken with a grain of salt because it covers such a short period of time and the detection network includes few observation stations in high latitudes, says Veraverbeke. "We need more stations in the high north to really control the lightning there."

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