Warming Arctic, Drier Regions, and Wildfires: Is There a Link?

Many scientists believe the Arctic, one of the fastest-changing places on the planet, could drive change in other parts of the world, including wildfire-ravaged Southern California.

In a recent NASA mission called Oceans Melting Greenland (OMG), climate scientist Josh Willis embarked on a journey to study ice in Greenland and surrounding oceans and how much oceans are eating away at the ice around the edges of the ice sheet. The data collected included the ocean’s temperature and salinity, and the shape and depth of the sea floor.

“The shape of the sea floor determines how much the warm water can reach in and touch the glaciers,” said Willis, who works at NASA’s Jet Propulsion Laboratory near Los Angeles.

“Warm water is widespread across the Greenland shelf, and it is very much a major threat to the glaciers,” Willis said. “The thing we really don’t know is how fast is Greenland’s ice going to disappear.

“If it takes a thousand years or two thousand years, then we can probably adapt. But if it happens in a few hundred, we should already be evacuating cities around the world,” he added.

Impact of sea ice

A separate study from Lawrence Livermore National Laboratory suggests a link between sea ice melting in the Arctic and drier conditions in California. A new simulation that only looks at sea ice in the next two decades, shows a pressure ridge pushing the winter air masses north into Alaska and Canada, which impacts California.

“We saw quite substantial drying of California so with (looking at) the sea ice alone, we saw 10 to 15 percent decrease in precipitation over a 20-year period,” said Ivana Cvijanovic, an atmospheric scientist and post-doctoral researcher at the national laboratory.

Other factors such as greenhouse gases and particulate pollution can also affect the future of rainfall in California. The modeling framework used in the study at Lawrence Livermore helps scientists understand the impact of sea ice in isolation to these other factors.

“Ice is disappearing on the Arctic Ocean. It’s disappearing from Greenland and this is reshaping climate patterns all across the planet,” Willis said.

He and other scientists predict that as Arctic regions warm, the American Southwest will feel the impact.

“We will probably see drier conditions in the long run in the second half of the [21st] century in the Southwest and that means we’re going to struggle with water needs and also fire,” Willis said.

Intersection of wildland, people

Dry conditions plus a growing population and urban sprawl equals more wildfires and costly devastation, such as the ones in Southern California.

“We are in Southern California and a lot of the fires we find that happen right where people intersect with wildland happen because of people,” said Natasha Stavros, an applied science system engineer and fire expert at NASA’s Jet Propulsion Laboratory.

As the weather evolves and more wildfires burn, Stavros expects other environmental changes.

“As we experience climate changes and things become hotter and dryer, fire acts kind of like an eraser. It erases the landscape and it actually allows new ecosystems to establish because they don’t have to compete with what was there,” Stavros said.

The American Southwest is not the only place where change is predicted.

“As the atmosphere heats up, it becomes a better pipe for carrying water for picking it up from one place and dumping it in another,” Willis said. “This means that dry places are more likely to get drier and wet places are likely to get wetter. It also means that bigger more torrential downpours become more likely.”

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