Some 20,000 years ago, the area that we now know as the Marjory Stoneman Douglas Wilderness in Everglades National Park (Florida) was not graced by the sprawling “river of grass,” dense mangrove forests, and the rich waters of the Florida Bay. With a sizable amount of Earth’s water locked up in continental ice caps, the present bay was high and dry, the nearest ocean shore was miles away, and the land supported pine woodlands and scrub. On the other side of the continent, the parched salt flats of today’s Death Valley Wilderness (California) were drowned under a 600-foot-deep (183 m) lake. The Yosemite Wilderness’s (California) stately forests, lush meadows, and high mountain lakes were buried under hundreds of feet of ice.

What a difference a few degrees can make! The dramatic changes described in the preceding paragraph accompanied a Pleistocene-to-the-present global warming of about 4° to 7°C (Jansen et al. 2007). Yet Earth is now poised to undergo another round of warming of comparable magnitude. Current projections indicate that a further 4° to 6°C global warming could be reached by as early as the end of this century (IPCC 2007), when global temperatures could exceed any reached in the last several million years. Earth has already gained about 0.6°C since 1975, and the pace of warming is expected to accelerate. Even the relatively modest warming so far has affected hydrology, fire regimes, and biota in national parks and wildernesses (Gonzalez 2011). The message is clear: In the coming decades wilderness seems certain to face its greatest stewardship challenge yet, in the form of profound climatic and other global changes.

Wilderness stewards must determine how best to respond to this greatest of challenges, and the goal of this article is to help them by offering relevant ideas and provoking discussion. First, we briefly reexamine the Wilderness Act in the light of rapid climatic changes, and conclude that stewards will be forced to confront trade-offs that were not anticipated by the act’s authors—trade-offs that will be accompanied by increasing impetus for management intervention in wilderness. Next, we briefly outline four broad classes of management actions (or inaction) that wilderness stewards might consider in their efforts to adapt to a rapidly changing climate. Finally, we highlight some considerations for planning in the face of rapid climatic changes.