Wildfire activity in the western U.S. is linked to warming in the Arctic, according to a recent study.
Researchers Peter Soulé and Paul Knapp are geography professors at Appalachian State University and UNC-Greensboro, respectively. They found evidence that Arctic sea-ice extent affects the upper-level jet stream above the U.S. — which in turn affects the atmosphere in places such as California.
Knapp said years with low Arctic sea-ice extent correlate to a tendency of ridging in the western U.S. According to the researchers, ridging is when the upper-level jet stream bends northward and creates high atmospheric pressure. Below the ridge, or high atmospheric pressure, air sinks and leads to warmer, drier conditions. Such conditions are conducive to wildfire activity.
According to the study, the connection between Arctic sea-ice and the jet-stream in lower latitudes is an example of what climatologists call teleconnection, where what happens in one part of the world impacts the weather in other parts.
“We’re in a very connected world, so changes in one spot can potentially have significant impacts in another area,” Knapp said. “I think if we continue to have reductions in Arctic sea-ice, we more than likely will have continued changes in the way the jet stream is behaving. It’s going to probably have a more meridional type of flow to it, which is going to create places that have unusually warm or unusually cool conditions because of that.”