Your Children’s Yellowstone Will Be Radically Different

Some elk now stay in valleys outside the park, nibbling lawns and alfalfa fields, Dr. Hansen said. And where they go, wolves follow. “It is a very interesting mix of land-use change and climate change, possibly leading to quite dramatic shifts in migration and to thousands of elk on private land,” he said.

Drier summers also mean that fires are a greater threat. The conditions that gave rise to the fires of 1988, when a third of the park burned, could become common.

By the end of the century, “the weather like the summer of ’88 will likely be there all the time rather than being the very rare exception,” said Monica G. Turner of the University of Wisconsin-Madison. “As the climate is warming, we are getting fires that are happening more often. We are starting to have the young forests burn again before they have had a chance to recover.”