A New Normal In Drought, Fire

The fire Nate McDowell can see evenings from his Los Alamos home, dumping ash on his roof and yard, should die soon as New Mexico’s summer rains return. But “the new normal” that led to them, if you can call it that, seems here to stay.

What that new normal might mean for the forests of New Mexico, and people who live in and around them and love them, is an enormous, open question.

A brilliant Los Alamos National Laboratory forest ecologist (Fulbright Scholar, winner of a prestigious Department of Energy Early Career Research award), McDowell usually spends his time quietly tending to patches of woods, carefully measuring moisture stress to try to understand how drought kills trees. But these days, nature is getting out ahead of the questions McDowell and the forest scientists he works with are able to ask.

“It’s hotter now. It is drier now. There’s less humidity,” McDowell told me.

All of that is part of the new normal. New Mexico temperatures for the first six months of 2011 were 1.3 degrees above the average over the last century, according to the latest data from the National Climatic Data Center released late last week. That in a sense is not unusual, representing our share of a warming trend around the globe. Only one year in the last decade was below average. Chalk that up to the new normal in a warmer world.

This year’s dryness, though, is off-the-charts unusual, the driest first six months of a year in records here that go back to 1896. While NCDC data suggest New Mexico has been in a generally drying trend (with quite a few ups and downs) for at least a couple of decades, 2011 has been so dry as to be downright freaky. Statewide, we had averaged just 1.19 inches of precipitation by June 30, less than a quarter of the normal amount and by far the driest year going back to 1896.

Dry and warm here is, as McDowell points out, consistent with what scientists have been predicting as greenhouse gases in our atmosphere rise.

“Connecting a process as general as climate change with an event as specific as a fire is impossible,” said Santa Fe environmental historian Bill deBuys, whose upcoming book “A Great Aridness” looks at the future of the Southwest in a changing climate. But, he added in an interview, “There are a lot of extraordinary dots out there and it’s not that hard to connect them.”

But there is more than climate to the human influence on the mountains outside the windows of McDowell’s Los Alamos home, far more to the new normal.

We are living in what some scientists have taken to calling the “Anthropocene,” a geologic era during which human influence dominates the landscape around us in ways that will be easily detectable long after we are gone. In the woods above Los Alamos, a big part of that influence dates to the arrival of the Chile Line trains in the late 1800s and the expansion of grazing animals that accompanied it.

“They ate all the grass,” McDowell said.

That grass provided the fuel for frequent, low-intensity surface fires that cleared out undergrowth while leaving the forest’s great Ponderosa pines intact.

Well-intentioned and effective but ultimately counter-productive efforts to snuff out every fire before it could spread added to the problems that finally blew up in the mountains bordering Los Alamos and Santa Clara Pueblo in the last two-plus weeks.

The buildup of fuel and the relative impact of climate change and forest management on fire risk is a complicated question, varying across the West with different forest types having different natural fire regimes, suffering differently in recent decades as a result. But in the arid-climate ponderosa forests like those burning outside McDowell’s window, scientists agree we’re in uncharted territory now, with vast, destructive blazes like Las Conchas creating unprecedented conditions.

Which raises the most important question about the new normal: What comes next?

Human efforts are under way to intervene and manually clear out what hasn’t yet burned, through manual thinning and controlled burns. But an analysis by the Congressional Research Service suggests the acreage of troubled U.S. forests far exceeds the ability of humans to get in and fix the problems.

“I don’t think that we can treat our way out of this problem,” said Julio Betancourt, a U.S. Geological Survey ecologist in Tucson.

Which means fires, whether controlled or not, are likely to do the job of resetting the system for us.

Will the forests then return in some form approximating what was lost?

DeBuys is skeptical. The big fires are blowing holes so large in the ecosystems that it is unlikely they will recover in a way that resembles what once was found there, he said.

But really, no one knows what the new normal brings next.

As an anonymous reader said in a comment on my blog over the weekend, “The speed of destruction of ecosystems and advancement of (the) Anthropocene are no match for our glacial advancement of knowledge on these complex topics.”

UpFront is a daily front-page opinion column. Comment directly to John Fleck at 823-3916 or jfleck@abqjournal.com. Go to www.abqjournal.com/letters/new to submit a letter to the editor.