- A nationwide analysis finds most U.S. national parks are highly vulnerable to climate change, with many facing risks of irreversible ecological transformation rather than gradual decline. Wildfire, drought, pests, and sea-level rise are converging to reshape landscapes the parks were created to preserve.
- Vulnerability is uneven: parks in the Midwest and eastern United States tend to face the greatest cumulative risk due to fragmented habitats, pollution, invasive species, and limited capacity for ecosystems to adapt. Many western parks appear more resilient but are exposed to multiple severe disturbances at once.
- Coastal parks are threatened by rising seas and storm surge, while inland forests face compound stresses that can trigger long-term shifts from forest to shrubland or grassland. Once such transitions occur, returning to previous ecological conditions may be impossible.
- As climate pressures intensify and policy responses weaken, park managers are shifting from preserving historical conditions to managing ongoing transformation. America’s parks may increasingly serve less as static sanctuaries and more as living records of how nature reorganizes under accelerating change.
America’s national parks were conceived as sanctuaries from the forces remaking the rest of the continent. Climate change is now breaching that boundary. A recent assessment of park vulnerability suggests that many of these landscapes are not simply warming or drying in familiar ways. They are being pushed toward ecological states that may be fundamentally different from those they were created to preserve.
The study, published in Conservation Letters, evaluates 259 park units across the contiguous United States using a framework common in climate science: exposure, sensitivity, and adaptive capacity. Exposure measures the scale of climatic change; sensitivity captures how strongly ecosystems respond; adaptive capacity reflects the ability of landscapes and species to adjust. Taken together, these dimensions describe not just how much parks will change, but how likely they are to experience transformation.
By that measure, vulnerability is widespread. Two-thirds of parks were identified as highly exposed to at least one potentially transformative threat, including wildfire, drought, forest pests, or sea-level rise. In total, 77% ranked as highly vulnerable either overall or to a specific high-impact hazard. The implication is not that all parks face catastrophe, but that few can expect stability.
Geography matters. Parks in the Midwest and eastern United States tend to have the highest cumulative vulnerability. These landscapes are often embedded within heavily modified surroundings, with fragmented habitats, high air pollution, invasive species pressure, and limited topographic variation. Such conditions reduce adaptive capacity. Species attempting to track shifting climates must move across farmland, suburbs, or highways, obstacles that did not exist when the parks were established.
Western parks, by contrast, often appear less vulnerable in aggregate analyses. Their rugged terrain creates microclimates that can serve as refuges. Elevation gradients allow species to move upslope rather than across developed land. Lower surrounding human density also helps. Yet this apparent resilience is misleading. Many western parks are exposed to multiple “transformational” disturbances simultaneously, particularly fire, prolonged drought, and insect outbreaks.
The interaction among these disturbances is crucial. Severe drought weakens forests, making them more susceptible to bark beetles; beetle-killed trees increase fuel loads; fires burn hotter and more extensively; post-fire recovery may fail altogether. In some places, forests are already converting to shrubland or grassland. Such shifts are not temporary damage but ecological reorganization.
Coastal parks face a different trajectory. Rising seas and storm surge threaten salt marshes, mangroves, and coastal forests, while development inland blocks their migration. The study identifies dozens of parks along the Atlantic and Gulf coasts at risk of significant inundation. Once drowned, these ecosystems cannot simply be restored to previous conditions.
What emerges is a pattern of uneven vulnerability. Some parks face gradual degradation; others abrupt change. The greatest risk is not necessarily where warming is fastest, but where exposure combines with low capacity to adapt. Flat terrain, intense surrounding land use, and existing ecological stressors can make even moderate climate shifts consequential.
Management philosophy is beginning to reflect this reality. The National Park Service has adopted a framework known as “resist, accept, direct.” In some cases managers attempt to maintain historical conditions; in others they allow change to proceed; in still others they guide ecosystems toward new states that may preserve key functions or species. The approach implicitly acknowledges that preserving parks as static “vignettes” of an earlier America is no longer feasible.
Recent policy developments complicate this challenge. Federal actions that weaken climate mitigation—such as the revocation of the Environmental Protection Agency’s endangerment finding—reduce the likelihood that underlying drivers of change will be addressed at national scale. Simultaneously, proposals to expand resource extraction on nearby public lands and to reopen protected marine areas to commercial fishing increase external pressures on park ecosystems. Staffing reductions and funding constraints reported across the park system further limit the capacity to monitor and respond to emerging threats.
The result is a widening gap between the scale of ecological change and the institutional ability to manage it. Climate impacts accumulate slowly until they do not. A drought year becomes a megadrought; a large fire season becomes a regime; shoreline erosion becomes permanent inundation. Because parks are embedded in broader landscapes, many drivers originate outside their boundaries, beyond the authority of park managers.
None of this means national parks will cease to matter. On the contrary, they may become even more valuable as refuges for biodiversity and as benchmarks of environmental change. But their role will shift. Rather than preserving fixed snapshots of nature, they may increasingly function as laboratories of adaptation, documenting how ecosystems reorganize under pressure.
The study’s most sobering insight is that vulnerability is not evenly distributed. Some of the most iconic parks of the American West possess enough environmental diversity to buffer change, at least for now. Many lesser-known parks in the East and Midwest do not. Their landscapes are flatter, more fragmented, and more exposed to pollution and invasive species. In these places, climate change interacts with long-standing human pressures to produce outsized effects.
The park system was designed around permanence: fixed boundaries, enduring landscapes, and the assumption that nature inside would remain broadly recognizable. Climate change is eroding that premise. Whether parks can retain their ecological identity will depend less on legal protection than on geography, surrounding land use, and the speed of global warming itself.
In the coming decades, visitors may still encounter familiar scenery: forests, wetlands, deserts, mountains. What may be harder to perceive is how rapidly these environments are shifting beneath the surface. National parks were once imagined as places outside of time. Increasingly, they are becoming places where time is accelerating.
Citation:
- Michalak, J. L., C. E. Littlefield, J. E. Gross, T. G. Mozelewski, and J. J. Lawler. 2026. “ Relative Vulnerability of US National Parks to Cumulative and Transformational Climate Impacts.” Conservation Letters 19, no. 1: e70020. https://doi.org/10.1111/con4.70020
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