Projected climate zone shifts could undermine the effectiveness of global protected areas for biodiversity conservation by mid-to-late century

Climate change is driving broad-scale redistribution of species and is expected to accelerate in the coming decades, potentially undermining the effectiveness of existing protected areas (PAs) for biodiversity conservation. We develop a measure of climate zone velocity—the speed and direction at which climatic conditions shift across time and space—to assess exposure of global PAs to climate risks under future climate scenarios. We find that by mid-century, around 20 % of global protected land area is projected to undergo climate zone shifts under all future scenarios and more than half of global terrestrial PAs will face mean velocities greater than 0.1 km yr⁻¹. Under RCP 8.5, the rate of climate zone velocity will continue to intensify through the end of this century, potentially impacting 40 % of existing PA land area. The current climate zones for approximately 15 % of the land area are expected to shift outside the existing PA network and into human-modified areas, indicating that the existing network will not absorb those changes. About 15 % of current protected land area will also be exposed to emerging climatic conditions with no precedent or loss of existing climatic conditions, potentially undermining the effectiveness of the existing network. Strategic and adaptive conservation planning that explicitly considers climate zone shifts will enable greater resilience for conservation interventions under climate change.