Insects, too, stand ready to play an ever-greater role in this onrushing disaster. Warm temperatures lengthen the growing season, and with extra weeks to reproduce, a population of bark beetles may spawn additional generations over the course of a hot summer, boosting the number of their kin that that make it to winter. Then, if the winter is warm, more larvae survive to spring, releasing ever-larger swarms to reproduce again. For as long as winters remain mild, summers long, and trees vulnerable, the beetles' numbers will continue to grow, ultimately overwhelming the defenses of even healthy trees.
We now see this throughout the Rockies. A mountain pine beetle epidemic has decimated lodgepole pine stands from Colorado to Canada. About five million acres of Colorado's best scenery has turned red with dead needles, a blow to tourism as well as the environment. The losses are far greater in British Columbia, where beetles have laid waste to more than 33 million forest acres, killing a volume of trees three times greater than Canada's annual timber harvest.
Foresters there call the beetle irruption "the largest known insect infestation in North American history," and they point to even more chilling possibilities. Until recently, the frigid climate of the Canadian Rockies prevented beetles from crossing the Continental Divide to the interior where they were, until recently, unknown. Unfortunately, warming temperatures have enabled the beetles to top the passes of the Peace River country and penetrate northern Alberta. Now a continent of jack pines lies before them, a boreal smorgasbord 3,000 miles long. If the beetles adapt effectively to their new hosts, the path is clear for them to chew their way eastward virtually to the Atlantic and to generate transformative ecological effects on a gigantic scale.
The mainstream media, prodded by recent drought declarations and other news, seem finally to be awakening to the severity of these prospects. Certainly, we should be grateful. Nevertheless, it seems a tad anticlimactic when Sam Champion, ABC News weather editor, says with this-just-in urgency to anchor Diane Sawyer, "If you want my opinion, Diane, now's the time we start limiting manmade greenhouse gases."
One might ask, "Why now, Sam?" Why not last year, or a decade ago, or several decades back? The news now overwhelming the West is, in truth, old news. We saw the changes coming. There should be no surprise that they have arrived.
It's never too late to take action, but now, even if all greenhouse gas emissions were halted immediately, Earth's climate would continue warming for at least another generation. Even if we surprise ourselves and do all the right things, the forest fires, the insect outbreaks, the heat-driven die-offs, and other sweeping transformations of the American West and the planet will continue.
One upshot will be the emergence of whole new ecologies. The landscape changes brought on by climate change are affecting areas so vast that many previous tenants of the land -- ponderosa pines, for instance -- cannot be expected to recolonize their former territory. Their seeds don't normally spread far from the parent tree, and their seedlings require conditions that big, hot, open spaces don't provide.
What will develop in their absence? What will the mountains and mesa tops of the New West look like? Already it is plain to see that scrub oak, locust, and other plants that reproduce by root suckers are prospering in places where the big pines used to stand. These plants can be burned to the ground and yet resprout vigorously a season later. One ecologist friend offers this advice, "If you have to be reincarnated as a plant in the West, try not to come back as a tree. Choose a clonal shrub, instead. The future looks good for them."
In the meantime, forget about any sylvan dreams you might have had: this is no time to build your house in the trees.
William deBuys, a TomDispatch regular, is the author of seven books, most recently A Great Aridness: Climate Change and the Future of the American Southwest (Oxford, 2011). He has long been involved in environmental affairs in the Southwest, including service as founding chairman of the Valles Caldera Trust, which administers the 87,000-acre Valles Caldera National Preserve in New Mexico. To listen to Timothy MacBain's latest Tomcast audio interview in which deBuys discusses where heat, fire, and climate change are taking us, click here or download it to your iPod here.
Copyright 2012 William deBuys
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