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Climate Change, Meet Billy Joel

20 February 2010 8:22 pm
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Billy Joel was right. The fire really has been burning since the world's been turning. But, thanks to global climate change, it may soon be burning in a much different way. During a Friday morning session titled "Fire and Climate," Meg Krawchuk, a UC Berkeley "pyrogeographer," described her efforts to model the impacts of global warming on fire patterns across the world. She found that hotter weather doesn't necessarily mean hotter blazes—in the next few decades, some ecosystems may see more fires, while others may see less.

From sea level changes to the fate of the pika, scientists have given concerned citizens a lot to be concerned about when it comes to climate change. Environmentalists' plates are full, but fires are well worth piling on, Krawchuk said. Like shaking an etch-a-sketch, they can rewire ecosystems. Savannahs, for instance, would be forests if blazes weren't around to clear the trees. And many organisms have evolved to like it hot: pine cones on many lodgepole pines won't open without tickling flames, she said.

To model a world of ebbing and flowing burns, Krawchuk took historic fire data then mapped it forward using 16 models of changing climates from 2010 on, what the Intergovernmental Panel on Climate Change calls global climate models (GCM). The biggest factor in controlling most blazes—fuel. Krawchuk found that net primary productive, or how much green you step on while going for a hike, determines a huge chunk of inflagration. But it's complicated, she explained. Climatic factors like rainfall and temperature also determine the net primary productive. A hard nut for a modeler to crack.

Primary greenery is the reason for why Krawchuk's modeling seems so counterintuitive, or how global warming will actually cool many fires. Take a desert ecosystem—hotter weather will make cactuses and other desert plants lose water, which will mean fewer cactuses for the deserts and less fuel for a fire to burn.

The problem with using GCMs is that none of them agree, Krawchuk said. All 16 models concurred that northern Australia will experience heightened fire rates between 2010-2039 and decreased rates after that. But northern Australia is about the only place where the 16 models do agree. Certain regions will feel the burn, according to one, but are icy cool according to others.

There's a lot of uncertainty. But we're well on the wrong side of 2010, Krawchuk said, making climate change a lot less theoretical. With more data and better models pouring in, estimates for the Earth's hot and cold blazes will improve. And, sorry Joel, this time we did start the fire.