Rapidly rising temperatures threaten Yellowstone ecosystem

Reprinted with permission from Environment & Energy Publishing, LLC. Not for republication by Wyoming media.

Summer temperatures in Yellowstone National Park could rise by as much as 9.7 degrees Fahrenheit by the end of the century if global emissions of greenhouse gases are not restrained, according to a new report from a pair of environmental groups.

The changes could dramatically affect fish, wildlife and visitors to the Greater Yellowstone region, which includes Grand Teton National Park and parts of six national forests in Wyoming, Montana and Idaho, the report warns.

Warmer temperatures could further imperil the whitebark pine, a key high-elevation food source for grizzlies that is already threatened by mountain pine beetles, says the report by the Rocky Mountain Climate Organization and Greater Yellowstone Coalition.

The region can also expect a major reduction in native cutthroat trout as well as wolverines, lynx and other wildlife, it says.

Warmer temperatures have already affected the melting of spring snowpacks, which feed rivers and aquifers that sustain wildlife and downstream communities. Warmer temperatures could exacerbate that trend, the report says.

“Threads are already being pulled out of the glorious tapestry that is Greater Yellowstone,” said Stephen Saunders, president of RMCO and an Interior deputy assistant secretary under President Clinton.

The report found that temperatures in the Yellowstone region over the past decade were the hottest on record and were 1.4 degrees above the region’s 20th-century average. Globally, temperatures over the past decade have been 1 degree above the 20th-century average, the report says.

The temperature data were drawn from the government-run U.S. Historical Climatology Network using five regional weather stations. The most surprising news, Saunders said, is that Yellowstone has gotten hotter faster than other parts of the world.

But he cautioned that future climate projections are subject to change. “I’m sure there will be surprises and changes we don’t anticipate,” he said.

The report projects average summer temperatures rising 4.7 degrees by 2059 and 9.7 degrees by the end of the century under “medium-high future emissions,” which correspond to the Intergovernmental Panel on Climate Change’s “A2” scenario of atmospheric carbon concentrations of about 2.5 times today’s levels.

The “lower future emissions” scenario, which corresponds to a 40 percent increase in carbon pollution by century’s end, would result in a 5.6-degree temperature hike by 2100, the report says.

Both scenarios assume no new government policies will be passed to reduce greenhouse gas pollution. Such moves could further reduce the rate of temperature increase, Saunders said.

Scott Christensen, climate change program director for the Bozeman, Mont.-based GYC, recommended several steps that federal land managers can take to gird ecosystems for the impacts of warmer climates, including reducing existing stressors to species and habitats. Steps could include restoring cutthroat trout in Yellowstone Lake by removing non-native lake trout, he said.

In addition, the group recommended enhancing water quantity and quality, preserving migration corridors for wildlife, improving forecasts of future climate events and managing collaboratively at an ecosystem level with all landowners and jurisdictions.

Click here to read the report.

Banner image taken by Koen Blanquart.