Climate

In The Future, Yellowstone National Park Could Turn Incredibly Dry

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Pine forests and mountain streams are two Yellowstone features threatened by climate change.

Twenty-three years ago, two scientists took a first look at what climate change might do to the ecology of Yellowstone National Park. The climate models they used were just beginning to take form, and their subsequent findings were mostly qualitative, with high levels of uncertainty.

In a recent paper published as part of a special park report on climate change, Yellowstone officials decided to ask those two scientists to revisit their research from over two decades ago — and what they found was a lot less uncertain. Climate change is set to have a potentially huge impact on Yellowstone’s ecology by the end of the century, increasing the potential for wildfires and decreasing the amount of snow the park receives. Combined with rising temperatures, these changes could alter Yellowstone’s landscape from a mostly forested mountain ecosystem to something more akin to the U.S. Southwest.

“The ecological effects of climate change will be more dramatic and far-reaching than we realized,” the report reads, noting that climate change is likely to create dry conditions in Yellowstone that haven’t been seen in the area in 10,000 years — a climatic and ecological condition the researchers describe as “uncharted territory.”

Fires like the 1988 wildfire that destroyed 36 percent of the park’s total acreage will become more common, and years without a single wildfire will become increasingly rare. This uptick in fire activity could potentially have far-reaching impacts on the area’s ecosystem, shaping the kind of vegetation that dominates Yellowstone’s landscapes.

“Fire has huge consequences for vegetation, because if things burn more frequently, it determines what kind of things can grow back in an area,” Ann Rodman, branch chief for physical science at Yellowstone Park told ThinkProgress.

As future fires become more frequent, dense stands of pine and spruce that now dominate Yellowstone’s landscape could become less common, replaced by young trees, grass, and shrubs. Without time to grow back between increasingly frequent fires, the park’s old mountain forests would, essentially, turn into open woodlands. More frequent fires could also push out native tree species like the whitebark pine, a keystone species that acts as an important source of food for grizzly bears and other wildlife in Yellowstone’s subalpine areas.

“Rather than driving through long, almost unbroken expanses of old lodgepole pine forests, as people did in the 20th century, people will drive through a landscape of younger forests interspersed with perhaps more frequent meadows and more frequent views of the surrounding mountains,” William Romme, a professor emeritus at Colorado State University and one of the report’s co-authors told E&E News.

Based on worst-case warming scenarios outlined by the IPCC, another report in the special issue projected that April 1 snowpack in Yellowstone could be reduced by up to 4.3 inches by 2100, with most of the park snow free on April 1 by 2075 — a decrease in precipitation that is already being seen throughout the West.

“We know, with certainty, trends that we’re already on a trajectory for: the snowpack is less, and that’s true all over the West and in Yellowstone as well,” Rodman said.

Less snow and an earlier melt will also impact the area’s mountain streams, which are kept cool throughout spring and summer due to snowmelt. As the climate changes, temperatures of Yellowstone’s streams are predicted to increase between 1.4 and 3.2 degrees Fahrenheit between 2050 and 2069, a change in temperature that could be good for non-native fish but bad for the native cutthroat trout, whose numbers could decline by 26 percent in response to warming streams.

Less snow could also spell trouble for native wildlife that depend on snow for habitat. “Snow-dependent species like lynx and wolverine probably are among the species that will be especially sensitive to climate change, and their populations and habitats should be monitored,” Romme said.

Yellowstone’s changing landscape might impact more than just the plants and animals that live there, however — it could also cut into the livelihood of small mountain communities that have come to depend on national parks for revenue.

“Like many treasured places around the West, Yellowstone will be experiencing devastating impacts related to climate change, from wildfire to reduced snowpack,” Diana Madson, executive director of the Mountain Pact, told ThinkProgress. “These ecosystem changes will not only hurt Yellowstone’s celebrated plant and animal species but the neighboring local economies that rely on tourism.” Climate adaptation is crucial, Madson notes, not only for the ecosystem of Yellowstone, but for small mountain communities that rely on tourism revenue.

But adaptation strategies can be difficult to implement in land management, because agencies with the same information are often under different constraints, making coordination difficult. The report, Rodman says, was intended to get people talking about the potential impacts of climate change on Yellowstone’s famous landscapes — something that park officials have already begun doing more.

“We’re talking about it a whole lot more, and that sounds like nothing but it is actually big,” Rodman said. “It’s a matter of having an awareness of where things are going, and incorporating that into decisions every day.”