FLAGSTAFF, Arizona Just outside this mountain town, where the acresof ponderosa pine turn into a Christmas green blur, Tom Whitham eyes the weary,struggling forest.
Death is everywhere. Their limbs bare and bark brittle, the trees quickly turnthis forest into an aching reminder of the devastation of drought and a massivebark beetle infestation.
Whitham pulls his pickup truck over and gestures to the dead trees 75percent in this area alone.
Forget talk of global warming and speculation of what it might do in 50 years,or 100. Here and across the West, climate change already is happening.Temperatures are warmer, ocean levels are rising, the snowpack is dwindling andmelting earlier, flowers bloom earlier, mountain glaciers are disappearing, anda six-year drought is killing trees by the millions.
Most scientists agree humans are to blame for at least part of that warmingtrend, but to what degree?
“That’s the $64,000 question,” said Whitham, a regents’ professor ofbiology at Northern Arizona University. “If we aren’t causing it, we’recertainly contributing to it. Humans can take a drought and make it even worse.”
The West is unique in that it depends so heavily on snowpack; melting snowprovides three-fourths of the water in streams. Over the past 35 years,temperatures across the region have inched up 1 to 3 degrees, causing the snowto melt as much as three weeks earlier, said Kelly Redmond, regionalclimatologist for the Western Regional Climate Center in Reno, Nevada.
Lilac and honeysuckle bloom up to 10 days earlier. Warmer temperatures lead to ahuge surge in woody plants that thrive in warm, wet conditions. Glaciers areretreating, roads are buckling in Alaska and shifting some supports on the800-mile, trans-Alaska oil pipeline. Already-low reservoirs are called upon towater fields and quench thirst for longer and longer periods after the seasonalsnowpack is gone.
“The West has become habitated because of the ability to store and have areliable water supply,” said Martin Hoerling, a research meteorologist whostudies climate for the National Oceanic and Atmospheric Administration (NOAA).”Simply the temperature effect is going to put a much greater strain onwater availability.”
Bennie Hodges of the Pershing County Water Conservation District in rural Nevadasaid the drought has forced him to allot farmers such a meager amount of waterthat they can only farm a fraction of their land. The county’s only reservoir isat 17 percent capacity.
“We’re in tough shape here. Is it global warming? I don’t know,”Hodges said. “When you’re in the desert, the wet and dry cycles come and go.I ask myself many times, ‘Are we having global warming?’ What do we do? We justtry to get through.”
Many scientists blame greenhouse gases such as carbon dioxide and ozone forcausing global warming because the pollutants tend to trap the sun’s heat in theatmosphere. But some contend the warming is just natural climate variability andhumans have nothing to do with it.
Environmentalists preach conservation, especially with an uncertain snowpack andpeak runoff occurring earlier. If that continues, “You would have a realproblem that the current reservoir systems aren’t designed to deal with,”said Daniel Lashof of the Natural Resources Defense Council’s (NRDC) ClimateCenter. “It’s sort of like a cancer,” he said. “We still have anopportunity to avoid the most severe consequences, but we have to act now.”
Mike Wagner saw it coming. He predicted a beetle outbreak years ago in northernArizona when he saw how abundant older trees were in overcrowded forests. Whenthe drought began, the beetles were ready. By 2002, trees weakened by droughtwere unable to fend off the beetles, and they were soon overcome. Tens ofmillions of trees across the West have been killed at a rate never seen before.
“Absolutely unprecedented,” said Wagner, a regents’ professor offorest entomology at Northern Arizona. “We’ve never had these conditionsbefore, never had that combination.”
Scientists expect another devastating beetle outbreak this year. Warmertemperatures only help the beetles reproduce more quickly, leading to more losttrees. Some types of beetles who used to propagate two generations in ayear now can produce three.
“This is all due to temperature,” said Barbara Bentz, a researchentomologist with the U.S. Forest Service who is studying bark beetles. “Twoor three degrees is enough to do it.”
Outside Cody, Wyoming, an entire forest has been killed by the drought andbeetles.
“It used to be a nice spruce forest,” said Kurt Allen, a ForestService entomologist. “It’s gone now. You’re not going to get thoseconditions back for 200 or 300 years. We’re really not going to have what a lotof people would consider a forest.”
Already, warmer temperatures have allowed the mountain pine beetle to be moresuccessful in attacking high elevation pines, Bentz said.
“What we’re seeing is consistent with what we expect to happen under globalwarming,” said Evan Mills, scientist at the Energy Department’s LawrenceBerkeley National Laboratory. “We will expect more beetle infestation, moredrought, more wildfires.”
Not everyone subscribes to the global warming theory. Frontiers of Freedom, aWashington, D.C. public policy group, doesn’t believe humans have anything to dowith the gradual warming of the Earth.
“These things happen. That’s just the way nature has always been,”said George Landrith, president of Frontiers of Freedom. “Variability hasalways existed. There’s nothing new about that.”
Landrith dismisses global warming as politically motivated. “It’s aboutmaking energy scarce and expensive,” he said.
Jeff Kueter, executive director of the George C. Marshall Institute, anotherpublic policy group, said more research needs to be done because there is toomuch uncertainty about global warming and the role humans play in it. “Wedon’t buy into alarmists’ speculation of what’s going to happen in the future,”he said. “There’s so much we don’t know about how the climate systemoperates.”
In a meadow near Crested Butte, Colorado, wildflowers of purple, red, white, andblue pop out under three electric heaters. Tourists flock to these lush meadows,dubbed the wildflower capital of Colorado, but John Harte is looking at theworld 50 years from now, when it could be 4 degrees warmer.
For 14 years, Harte, an environmental science professor at the University ofCalifornia-Berkeley, has artificially heated wildflowers and documented whatwarmer temperatures can do to them. He has seen firsthand the Rocky Mountainsnow melt earlier, felt the temperature warm, the soil dry, and watched hiswildflowers bloom earlier.
“We’re projecting, from these experiments, there’s going to be a tremendousdecline in the abundance of the flowers,” he said. “You think ofmeadows strewn with gorgeous flowers. Many of those flowering plants are goingto be decimated.”
Scientists say continued warming across the West will mean a smaller snowpackthat could affect ecosystems that depend on stream flows and water temperature.Soils and vegetation will be drier, increasing fire risk and prolonging the fireseason. Plants and trees will be able to grow at higher elevations, threateningski resorts. Sea levels will continue to rise, putting beaches and cities atrisk.
In Flagstaff, home to the world’s largest contiguous ponderosa pine forest, TomWhitham wonders how much more devastation the drought and beetles will cause,and to what extent humans will contribute to it.
“The thing that would make me really sad is if this were human caused,”he said, glancing at the bare trees towering over his pickup truck. “If youlose a 200-year-old forest, you can’t get it back.”