Sea turtle sex is determined by nest temperature during incubation. Rising temperatures from climate change are skewing sex ratios toward females, with profound welfare and population implications.
Climate change is creating a slow-motion welfare and conservation crisis for sea turtles through temperature-dependent sex determination. As sand temperatures rise, individual embryos developing in hotter nests experience heat stress, with mortality rates increasing above certain temperature thresholds — these embryos die before hatching. Hatchlings that do emerge from very hot nests are smaller and less fit, with reduced survival prospects. At the population level, extreme feminisation of hatchling cohorts will eventually deplete males below viable breeding thresholds. Intervention options include vegetation shading of critical nesting beaches to reduce sand temperatures, beach shading structures, and water application to cool sand during incubation — all practical measures being trialled at key nesting sites. Long-term solutions require addressing the underlying climate change driving temperature increases.