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The Face of Climate Change


I visited one of my favorite national parks in September—Yellowstone. And though it remains magnificent, climate change has left an ugly mark on the park.

Like so many places in the west, Pine Bark Beetles have destroyed thousands—possibly tens of thousands—of Yellowstone trees as they lengthen their breeding seasons in response to unusually warm weather. I took the multi-image panorama above just below Mount Washburn, one of the highest and coolest areas of the park. It’s a picture of nearly total devastation: an entire hillside of pines destroyed by beetles. And it’s just one of many ravaged hillsides in the park.

We used to plan a one- to two-week Yellowstone visit every September, a yearly celebration of Fall (and occasionally wintry) weather. Bright Aspen. Brisk temperatures. And an amazing abundance of western mammals.

But I experienced summer weather in Yellowstone last month. In Gardner, where I stayed during the trip, temperatures soared into the mid-eighties most days and just over 90° on one or two. I saw Bison and some Pronghorn on my trips to Lamar Valley. But I saw only one bear—a grizzly, way in the distance—no River Otter (the rivers were very low), no Elk, and not a single Coyote. Heat kept the mammals out of the Hayden Valley, as well. Wolf watchers waited patiently as they scoped the tree line a mile or so from the road. But the valley remained unusually quiet. And though birds—a Great Blue Heron, Mergansers, Mallards, and Tundra Swan—hunted, swam and preened in the blue waters of the Yellowstone, the river itself was lower than I’d ever seen it.

The unusually hot weather not only encourages Elk and other mammals to remain hidden among the trees (where temperatures can be 10 degrees cooler); it also allows multiple generations of bark beetles to breed. Although trees can release chemicals to repel insects and other predators, years of drought have weakened the defense systems of many of the pines, leaving them in a weakened state that makes them more susceptible to attack from the beetles, whose larvae feed on the trees from within.

The pines thus die by the thousands. And the effects ripple throughout the ecosystem.