Towering thunderheads may be commonplace closer to the equator this time of year, but just 300 miles from the North Pole? That’s pretty rare. This week the dozens of lighting strikes hit in a spot over Arctic sea ice—85 degrees North, 126 degrees East, to be exact. It prompts researchers to wonder: could this be one of the northernmost lightning strikes in recent history?
Scientists haven’t been necessarily been keeping detailed records of lightning strikes for very long, reports Andrew Freedman at the Washington Post. This particular event was detected using Vaisala’s Global Lightning Detection network, which has collected data on lightning strikes around the world going back to 2009. Other sources, including NASA data, go further back in time. Meteorologists hesitate to say that these are the most northerly strikes ever detected since forecasters haven’t really looked into the matter, but the situation is strange.
“I wouldn’t say it’s never happened before, but it’s certainly unusual, and it piqued our attention,” says National Weather Service meteorologist Ryan Metzger, who is based in Fairbanks, Alaska.
Most of the planet’s lightning storms take place at lower latitudes where high temperatures and high humidity power thunderstorms. Occasionally, lightning will occur in very intense Arctic storms, which is one reason meteorologists are hesitant to call these strikes unprecedented. But there was no intense weather event going on over the weekend, which does make the strikes unusual.
It’s an indication that things are changing rapidly in the Arctic, UCLA climate scientist Daniel Swain tells Matt Simon at Wired. He explains that typically convective storm clouds need to rise to a minimum of 15,000 feet to produce a thunderstorm. In lower latitudes, that’s not a problem. Heat and humidity are high enough to allow the clouds to form and the tropopause—the boundary between the troposphere and stratosphere—is about 10 miles up, giving large storms plenty of room to form. In the Arctic, however, the tropopause sits around five miles, creating a relatively short ceiling, which makes it much harder for storm clouds to build.
Swain says that a storm forming over the Arctic is rare in the first place. The fact that the data shows the lightning strikes taking place over sea ice is even a step weirder, since the ice provides so little heat and moisture for storm clouds to form.
“That’s pretty amazing, because the preconditions that are necessary, to the extent that they're unusual in the Arctic, they are vanishingly unusual over the sea ice in the Arctic ocean itself,” he tells Wired.
But things in the Arctic are not normal this summer. Sea ice in the Arctic is at its lowest since satellite monitoring began decade ago, but computer modelling shows it’s probably closer to a 1,500 year low, the Post’s Freedman reports. Alaska had its hottest month on record in July, and the Greenland ice sheet shed 197 billion tons of water that month as well, losing 12.5 billion tons on August 1 alone. The Arctic Circle, including areas of Alaska, Siberia, Canada and Scandinavia, is experiencing its worst wildfire season ever, with more than 100 blazes burning through dried up peat bogs, releasing megatons of carbon. Permafrost, layers of Arctic soil that remain frozen year round, are also thawing much more quickly than researchers expected, changing Arctic landscapes.
The Arctic, research has established, is warming about twice as fast as the rest of the globe. “Scientists already knew the Arctic was going to change much more rapidly than the rest of the world, and yet we’ve still been surprised at the rate of change we’ve been observing,” Swain tells Wired’s Simon. “All of those processes have started to accelerate and in many cases have accelerated even faster than had been projected.”
And he says we should be prepared for “nasty surprises” coming from Arctic warming, since we don’t understand all the possible feedback loops.
In particular, researchers worry about a process called Arctic amplification. The lack of white sea ice, which reflects solar heat, is believed to cause the Arctic to warm more quickly. That warming melts the permafrost, which begins to emit carbon as plants and animals frozen in the ice decay. Increased Arctic fires also add more carbon to the atmosphere accelerating climate changes. While researchers don’t know how all these processes work, we might not have to wait much longer to find out.