Five years ago, I took a backpacking trip to Alaska because, as I wryly put it then, I wanted to “see the place before it melted.” Like most tourists to the Last Frontier, I was blown away by the burly beauty of the state, the ease with which you can find yourself in the wild. But a pall shadowed my enjoyment. As a first-time visitor, I couldn’t help but notice that huge swaths of Alaskan forest were dead or dying. In many places, groves of brown trees broke the greenery. At times, I saw entire mountain slopes that had perished.
The problem, I learned, was the mountain pine beetle. The beetle has lived for millennia in northern forests, and through evolution had reached a kind of equilibrium with mixed conifer ecosystems. Then warming temperatures started to throw things off. Higher temperatures increased the beetles’ metabolism, encouraging them to eat through more wood. Worse, the lengthening summers meant that the beetles could reproduce twice in a season – instead of just once – boosting their numbers. The result: Millions of acres of pine forest had been destroyed.
The wounded landscape of Alaska revealed two important lessons to me. The first was the awesome power of global warming, how even modest changes can have extreme consequences. The second was the myopic ease with which humans, ever adaptable, can learn to live with frightening changes in the environment.
In the last century, the mean global temperature has increased about 1°F. This temperature change has been enough to spur the beetle onslaught that is now devouring forests from British Columbia to as far south as Colorado. The great fear is that the beetles might jump the Rocky Mountains, and start a march to the Atlantic that would destroy the vast boreal forests. This would be a disaster – not only for the forests themselves and the fauna that reside there – but for the entire globe. Because forests play such an important role as a carbon sink, their destruction threatens to create a negative feedback loop that would spur even hotter temperatures – and further forest loss.
Yet many people have greeted the prospect of cataclysm with a shrug. I can’t forget the man who gave me a ride from Anchorage to Homer, and during the five-hour drive expressed nothing more than ambivalence at the miles of shredded trees. As a part-time logger, he had benefited from the beetle devastation, as it boosted the salvage logging business. But then the trees decayed to the point where they weren’t even good for pulp, and the logging industry retrenched and cut jobs – his included. For my driver, such forces were as inalterable as the constellations. The idea that we humans are fundamentally altering the atmosphere wasn’t worth thinking about.
If the prospect of drowning polar bears and submerged cities hasn’t been enough to focus our attention on the threat of climate change, perhaps the massive loss of our forests will be. As Daniel McGlynn reports in this issue (“Fever in the Forests”), the pine beetle is just one of several climate change-related threats to forest ecosystems. Pathogens such as Swiss needle cast and red band needle blight are also taking their toll on trees.
Environmental groups like to say that the world’s forests are the “lungs of the planet.” Yes, indeed – and we’ve treated them as poorly as a pack-a-day smoker. This is a slow-motion suicide. Because if we lose our forests, it will eventually be difficult for any living creature on this planet to breathe comfortably.
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