Scientists Warn Rising Beach Temperatures Are Skewing Sea Turtle Sex Ratios — Intervention May Be Needed

Rising temperatures on sea turtle nesting beaches are producing far more female hatchlings and creating a dangerous imbalance that could threaten populations worldwide.

Researchers report that sand temperature determines whether developing sea turtle embryos become male or female: warmer sands tend to produce females, while cooler sands produce males. This temperature-dependent sex determination has functioned for millions of years, but recent atmospheric warming and pollution are tipping the balance.

Alarming local data: At one Indian nesting beach, scientists observed that 71% of hatchlings emerging over a nine-year period were female, and in some years more than 97% of hatchlings were female. These findings were reported by Mongabay and highlighted by Graeme C. Hays of Deakin University.

"In the long term, there need to be enough adult males to ensure mating and clutch fertility. So, highly skewed hatchling sex ratios are a concern, and, at some point, there may need to be intervention to cool some clutches to produce more males," Graeme C. Hays told Mongabay.

Compounding threats: Rising ocean temperatures are also forcing turtles to shift their feeding grounds into cooler waters — often placing them in busy shipping lanes where boat strikes already kill many adults. Warmer nests increase egg mortality and can produce weaker hatchlings, raising the odds that fewer young survive to adulthood.

Scientists warn that as climate change progresses, up to half of current sea turtle habitats could be lost by 2050. Range shifts driven by warming waters are therefore likely to increase encounters with commercial fishing and shipping activity, amplifying adult mortality.

Conservation responses

Conservationists are adapting with targeted interventions. Scientists are testing ways to lower nest temperatures, including shading nests, relocating eggs to cooler sites, and managing nest vegetation. These techniques aim to increase the proportion of male hatchlings where sex ratios are dangerously skewed.

Researchers are also pushing for adaptive ocean protections that follow turtle movements: satellite tracking can identify seasonal hotspots where managers could impose temporary speed limits for ships or fishing restrictions to reduce collisions. Advocates point to global goals such as protecting 30% of ocean areas by 2030 as a way to create safer zones for turtles.

How you can help

Support reputable sea turtle conservation organizations, reduce your carbon footprint, and urge elected officials to back climate action and marine protections. Even small actions — from reducing single-use plastics to supporting marine protected areas — can contribute to healthier oceans and safer habitats for turtles.

Source: Reporting and analysis in Mongabay; comments from Graeme C. Hays, Deakin University.