Science. The “Butterfly Effect” between melting ice in the Arctic and fires in North America
Madrid, 17 (European Press)
A study describes for the first time the underlying mechanism linking a decline in Arctic sea ice to an exacerbation of wildfires in the western United States.
As sea ice melts from July to October, sunlight warms the surrounding area, becoming increasingly ice-free. Ultimately, this brings favorable conditions of heat and fire to states as far away as California, Washington, and Oregon later in the fall and early winter.
The researchers claim that this relationship has the same effect as the weather patterns enhanced by El Niño and the Southern Oscillation.
“It’s not a perfect analogy, but telecommunication like this is somewhat similar to the butterfly effect,” Hailong Wang, a scientist at Pacific Northwest National Laboratory (PNNL) and co-author of the new study said in a statement. Refers to a common feature of chaos theory in which the flapping of butterfly wings is believed to have an effect on the formation of a distant tornado.
“Weather conditions in a part of the world can, over time, affect weather outcomes from thousands of miles away,” Wang said. “In our case, we found that the Arctic and the western United States have this relationship. Regional and resulting sea and surface warming lead to global warming. from the loss of sea ice to the emergence of warmer, drier conditions in the west later in the year.”
Wang presented his findings roughly at a press conference by the AGU (American Geophysical Union) exploring wildfires in a changing climate on December 16.
Wang and colleagues found that as Arctic sea ice melted and the surface of the Earth and surrounding sea warmed, an atmospheric vortex strengthened above the warm region. This vortex, which rotates counterclockwise like a cyclone, is generated by differences in air pressure.
A constantly strong vortex is pushing the polar jet stream away from its usual pattern, deflecting moist air from the western United States. With the now undulating jet stream shifting from its usual course, a second vortex, spinning clockwise, forms under the top of the polar jet over the western United States. This second vortex, similar to the vortex responsible for the intense heat of the Pacific Northwest earlier this summer, brings with it clear skies, dry conditions and other fire-friendly weather.
As the Arctic continues to warm, this could intensify the discrepancy between these two remotely connected systems, exacerbating conditions in an area already ravaged by fire. More than three million acres were burned in California alone during the 2021 wildfire season.
“This dynamically driven connection is heating up and drying up the western United States,” said Yufei Zhou, lead author and data scientist who was a postdoctoral researcher at PNNL at the time of the study. “By discovering the mechanism behind this remote communication, we hope those responsible for forest management and bushfire preparedness will be better informed.”
To explore the effect of Arctic sea ice on the formation of fire-friendly climate conditions, the study authors relied on the past four decades of recorded sea ice levels. The team isolated the mechanism in the game using modeling performed at the Scientific Computing Center for Energy Research, located at Lawrence Berkeley National Laboratory.
Arctic sea ice has declined continuously since scientists began measuring its loss in the late 1970s. Late summer sea ice cover has decreased by 13 percent each decade compared to the 1981 average. -2010, according to the National Oceanic and Atmospheric Administration (NOAA).
Arctic sea ice is expected to continue to decline, eventually leading to periods of ice-free in Arctic waters before 2050. Today, even the oldest and thickest ice still present throughout the year is now thinner and brittle.