A global sea turtle climate vulnerability assessment

Climate change presents challenges to the conservation of sea turtle populations that are already experiencing multiple cumulative anthropogenic stressors including persistent stressors such as harvest, bycatch, and habitat destruction. To inform management and conservation decision-making, we applied a climate vulnerability assessment (CVA) using expert elicitation to provide a qualitative assessment of vulnerability, exposure, and sensitivity to climate change of 49 sea turtle management units (i.e., Regional Management Units and Distinct Population Segments). Eighteen sea turtle experts scored climate exposure (projected changes in climate and ocean conditions within the current population distribution compared with historical conditions) and climate sensitivity (using life history traits as proxies). Results indicate that all management units have either very high (88% of units) or high (12% of units) exposure to climate change, with the most influential factors across all regions being temperature, ocean acidification, dissolved oxygen, and sea level rise. Forty-three percent of the management units have very high sensitivity to climate change, 49% have high sensitivity, and 8% moderate sensitivity. Key factors for sensitivity included nest/egg sensitivity to temperature, in-water habitat specificity, abundance, and trend in population abundance, although primary drivers varied by species and region. The resulting climate vulnerability score was very high for 88% of the management units, high for 10%, and moderate for 2%. This assessment quantified the vulnerability of individual sea turtle management units to climate change, identified data gaps to help guide research, and established a baseline for comparison with future sea turtle assessment efforts.