Air Date: Week of April 29, 2005

Host Bruce Gellerman talks with Ron Neilson, a bioclimatologist with the U.S. Forest Service about the on-going drought in the Pacific Northwest and the Northern Rockies. Conditions in some parts of the region are as dry as they were during the Dust Bowl era of the 1930s, and some models predict the dry spell could last up to 20 years.

Transcript

GELLERMAN: It's Living on Earth. I'm Bruce Gellerman. And coming up—call me, Helis, a whale of a tale from New Jersey.

But first, much of the Pacific Northwest and the Northern Rockies are in the fifth year of a drought. From Washington to Montana, Wyoming to Northern California, it's as dry as it was during the Dust Bowl of the 1930s. The U.S. Forest Service is warning that conditions are ripe for return of those blinding, choking dust storms in some parts of the region and for catastrophic wild fires in others.

Ron Nielson, a bioclimatologist with the Forest Service, joins me from Corvallis, Oregon. A Dust Bowl, Ron? Really?

NIELSON: Well, we're at that level of drought that was consistent with the 1930s Dust Bowl. We're still uncertain though. The Dust Bowl lasted an extremely long period of time, longer than we have before. If this persists, this level, then very much indeed we could see that level of drought. Now, mind you, dust comes from fields that are left fallow largely and have not been growing on them so if farmers maintain their fields with something on them you may not see quite that much dust.

GELLERMAN: So, what's happening? How did things get so bad in the Northwest? Is this a normal drought cycle or is something else going on?

NIELSON: You know, we, the whole concept of normal seems to have been tossed out the window. The last 30 years has seen the whole west swing through two extreme wet-dry cycles, with the wet cycles being pinioned by the '83 and '98 El Niños and then another dry cycle in '87, '88; that's when Yellowstone went up. And then a recent dry cycle. And if you were to compare this to say the period between the 1940s and the 1970s, there's nothing like it at all. There's no high amplitude climate variability that looks like this at all. So, it's extremely unusual.

GELLERMAN: I can't imagine, Professor Nielson, that this is helping any of the animal life or plant life in the area. What is the toll on the ecology?

NIELSON: Well, there are areas in the west now in Nevada and Arizona that have experienced drought for upwards of seven or eight years and in the course of a single season we've seen whole ecosystems essentially die back. Pinion juniper ecosystems that just over broad areas of the landscape, you've seen the pinion trees die back very rapidly. There was a forest ecosystem up on the Kenai Peninsula system up in Alaska that underwent a series of seven or eight long years of drought and the entire ecosystem died back. Interestingly, when you get hit by drought, bugs also tend to come in and, essentially, produce the coup de grace on the ecosystem so whole regions can go out. Forests and ecosystems can die back almost in the wink of an eye under extraordinary, extreme drought conditions which we seem to be heading into now and so we are very concerned. They grow back, of course, much less rapidly, than they can die back.

GELLERMAN: So, how long can these drought conditions last?

NIELSON: Well, that's the question that we're all asking ourselves right now. I have colleagues who have published a paper recently and proceedings of National Academy of Science who are suggesting that we could be in the midst of one of these droughts that comes along every few centuries. They look at tree rings and see surface temperatures in the Atlantic and Pacific and concluded that the conditions are, essentially, ripe now for one of these long-term, multi-decade droughts that comes along just every few hundred years.

GELLERMAN: Multi-decade?

NIELSON: Multi-decade. Back in the period called the "medieval warm" period around 12 to 13, 1400, there were very prolonged droughts in the west. And we know that we're warming up and we're certainly at the level of temperature that was occurring back in that timeframe. And that level of drought could be returning. We really don't know for sure, but we're certainly very concerned about that.

GELLERMAN: What do we do?

NIELSON: Well, that's a very good question. I think one of the things you can do is simply keep your eye out for drought and think ahead about planning. How would you manage ecosystems, for example, if they were to go through prolonged catastrophic drought? One of the things you might consider doing both in your cropping and your ecosystems is to trim the wick. That is, keep less vegetation on the ground, pulling less moisture out of the soil. Now, that's a little difficult to do that in big, old forests that have been there for hundreds of years. So, caution is the watch-word here, I think.

GELLERMAN: Ron Nielson is a bioclimatologist with the U.S. Forest Service and a professor of forest science at Oregon State University. Professor Nielson, thank you very much.

NIELSON: It's my pleasure.