The 1971 Ramsar Convention promotes wetland conservation worldwide, yet climate change impacts on wetland extent and associated biodiversity are unclear. Hydrological modelling and soil moisture estimates are used to quantify climate change-driven shifts in wetland area across 1,250 inland Ramsar sites. We estimate that net global wetland area expanded during 1980–2014, but 47% of sites experienced wetland loss. By 2100, a net area loss of at least 6,000 km2 (about 1%) is projected. The number of sites with area loss over 10% will increase by 19–65% under low emissions, 148–243% under high emissions and ~16% with global mean warming of 2 °C relative to 1.5 °C. Sites most vulnerable to shrinkage are located in the Mediterranean, Mexico, Central America and South Africa—all seasonal waterbird migration hotspots. Our findings highlight that climate mitigation is essential for future Ramsar wetlands conservation, in addition to the minimization of human disturbance. |