How Australian Wildfire Emissions May Impact Global Climate

The Australian bushfires have released an enormous amount of climate-warming carbon dioxide emissions. But emissions from wildfires have a complicated effect on the broader global climate.

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The firestorm in Australia has burned an area as large as West Virginia, and the smoke from those fires is making its way around the globe. NPR's Nathan Rott looks at what all of those emissions mean for the broader climate.

NATHAN ROTT, BYLINE: If you want an idea of just how much smoke is coming off of the country of Australia, listen to news reports in New Zealand, more than a thousand miles away.

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UNIDENTIFIED REPORTER #1: A searing amber sun peeking through the clouds.

UNIDENTIFIED REPORTER #2: Here, the smoke has meant another day of unusual skies.

UNIDENTIFIED REPORTER #3: Bringing darkness to the sky and a thick orange glow to the air.

ROTT: The smoke has been so pervasive that New Zealand police have had to ask residents to stop calling emergency lines about the haze.

PEP CANADELL: It is extraordinary, what's happening now.

ROTT: Pep Canadell is a lead scientist with Australia's national research agency. He lives in the southeast part of the country, where the smoke has been oppressive for weeks.

CANADELL: Just like a fog, a thick fog.

ROTT: That smoke is of particular interest to Canadell, not just because he's breathing it, but because he's also the executive director of the Global Carbon Project, a group that tracks climate warming greenhouse gas emissions globally. And these fires are a big source of greenhouse gases.

CANADELL: For these fires in the southeast, south, probably we are in the ballpark of 400 million tons of carbon.

ROTT: An estimated 400 million tons of carbon. For perspective, all of the industrial emissions in Australia last year - that's energy production, transportation and so on - was just about 530 million tons. So it's a huge number. But there's an equally big thing you need to consider. Fires are natural. They've always been here. And sure, says Rebecca Buchholz, a scientist at the National Center for Atmospheric Research here in the U.S., wildfires do release a lot of carbon when they burn up vegetation.

REBECCA BUCHHOLZ: But then over time, we expect that a lot of that carbon dioxide will be drawn down by plants growing again.

ROTT: It's a balance. That's why many fire ecologists and atmospheric scientists say wildfires tend to be carbon neutral over the long term. But there are indications that is changing. Bob Yokelson, a University of Montana researcher who focuses on fires and their impacts on the atmosphere, says climate change is making fires burn more severely, more frequently and in more places. At the same time, temperatures are increasing and rain patterns are changing, all of which could make it harder for some forests to fully regrow.

BOB YOKELSON: We could be changing the atmosphere with fossil fuels in such a way that fires in landscape ecosystems go from being neutral or harmless, as far as climate, to something that is destructive.

ROTT: There's been research in California showing that's already happening in fire-ravaged parts of the Sierra Nevada. And there are concerns that the same could be true in Australia, which has experienced record-high temperatures and drought leading up to this year's fires. Buchholz, who is from Australia and is there now visiting family for what she says has been a smoke-filled and subdued holiday, says that is the worrisome part.

BUCHHOLZ: Climate impacts the fires, and fires can potentially impact the climate. And we don't know where we're going. It's a moving goal post all the time right now. We haven't reached that new balance point.

ROTT: By studying what's going on now, though, in Australia, she says, they may be a bit closer to figuring that new balance out.

Nathan Rott, NPR News.

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