Air Date: Week of July 10, 1998

The wild fires that forced more than a hundred thousand people to evacuate their homes this month in the Pinelands of North Florida are not unique; they are the latest in a wave of massive blazes around the world. Since last year, millions of acres have burned in Indonesia, Malaysia, Guatemala, Venezuela, Mexico, and Brazil. Changes in the world’s weather, including the effects of El Niño, have been blamed for much of the incineration. To help us understand the connections between changes in the planet’s climate and the epidemic of wildfires, Steve Curwood spoke with forest ecologist Daniel Nepstad of the Woods Hole Research Center at his Massachusetts office, in between trips to the Amazon in Brazil. Dr. Nepstad has observed many forest fires in his career.

Transcript

CURWOOD: This is Living on Earth. I'm Steve Curwood. The wildfires that forced more than a 100,000 people to evacuate their homes this month in the pinelands of north Florida are not unique. They are just the latest in a wave of massive blazes around the world. Since last year, millions of acres have burned in Indonesia, Malaysia, Guatemala, Venezuela, Mexico, and Brazil. Changes in the world's weather, including the effects of El Nino, have been blamed for much of the incineration. To help us understand the connections between changes in the planet's climate and the epidemic of wildfires, we turn to forest ecologist Daniel Nepstad of the Woods Hole Research Center. We caught up with him at his Massachusetts office on a break from his research in the Amazon. Dr. Nepstad has observed many forest fires in his career.

NEPSTAD: When you wake up at sunrise and you're lying in your hammock, you realize that your lungs are burning. The rural poor of the Amazon, who live at the forest edge, spend months breathing smoke. When you walk through a burning forest, it's like walking through a ghost land. Nothing is moving. There are some insects that have been displaced that are sweeping in. You run across tortoise carcasses and lizard carcasses; many animals simply cannot get away from the fire. It's a very depressing, depressing sight to walk through an area burning because you know that that forest will never be the same.

CURWOOD: Are we actually seeing more fires than usual? Or are we just simply noticing it more?

NEPSTAD: We're definitely seeing more fires than usual. Just in the Amazon this year, for example, there are 8 times more fires than there were last year, which was already a record number of fires.

CURWOOD: Now, what's caused all these fires?

NEPSTAD: Most of the fires are caused by severe drought. If you can think of rainforests perched upon a sponge, the soil acts as a sponge, what happened in 1997 is that sponge was dried out, and the forest couldn't draw any more water out of that sponge. And they started to shed their leaves. And the leaves accumulated on the ground. And the sun filtered through the dense rainforest canopy, making a tinderbox out of rainforests.

CURWOOD: El Nino is brought up as the culprit. Is that responsible for these fires? And how is El Nino related to climate change, if at all?

NEPSTAD: Well, I think this is the beginning of one of the effects of climate that's changing. El Nino events are central in this change. They're more frequent, they're more intensive, and it looks like they're probably related to the accumulation of carbon dioxide in the atmosphere. What increasing drought does is pushes forests that are already close to the edge of the amount of rainfall it takes to keep them going and to keep them protected from fire. It pushes them over that edge so that several months a year they become vulnerable to fire.

CURWOOD: Explain to me why Florida became such a problem this year.

NEPSTAD: Well, it appears that Florida was hit with, really, a one-two punch -- flooding followed by severe drought. One thing that flooding does is it kills plants. Dead plants are excellent fuel for fires. Whether or not the crazy weather in Florida is related to El Nino or not is really up for grabs. The El Nino is really a warming of the ocean temperature, which affects circulation patterns around the planet. So it's hard to pin down exactly what is an El Nino effect and what is not.

CURWOOD: The prognosticators are saying that the El Nino effect is dissipating now, that we should see a La Nina, its counterpart, over this next year. Does that mean that we'll see fewer fires...if we don't know about Florida, at least in, say, Indonesia or in the Amazon?

NEPSTAD: We're at the end of this particular episode of severe burning. As La Nina kicks in, there should be more rain in both Southeast Asia and in the Amazon Basin and in the northeast of South America and some of the other places that have been catching fire. My concern, though, is in the long term. If this is part of a new pattern where El Nino, instead of being an event that occurs every 4 to 7 years, is something that comes around every 2 to 4 years and sticks around for longer than it used to stick around, that to me is a concern. That means that areas that right now support rainforests are going to be invaded by grasses, by fire- prone savannah ecosystems.

CURWOOD: Well, the fires themselves add more and more carbon dioxide, which is one of the things that's blamed for global climate change, for global warming. With more fires, do we get more climate change?

NEPSTAD: Certainly the prospect of replacing rainforest with savannah would release an enormous amount of carbon into the atmosphere. Even if a small corner of the Amazon were to burn, we could release as much carbon in the atmosphere as a year's worth of fossil fuel consumption. That didn't happen this year, but the risk is there. To the extent that carbon dioxide accumulation in the atmosphere is provoking global warming and perhaps an increase in El Nino events, there is the potential for a positive feedback loop, where burning fosters greater severity of El Nino events which foster greater burning.

CURWOOD: These fires around the world, are they a warning to us ecologically, Dr. Nepstad?

NEPSTAD: The fires that we've seen in 1997 and '98 I see as really a harbinger of things going awry on a big scale. We're getting beyond the ability of huge areas of forests to tolerate drought. And the scary thing is that this could be part of the new pattern; it's not just an anomalous event that we can forget about.

CURWOOD: Daniel Nepstad is a tropical forest ecologist with the Woods Hole Research Center in Woods Hole, Massachusetts. Thank you, sir.

NEPSTAD: Thank you, Steve.