SYDNEY, AUSTRALIA - Researchers say climate change is responsible for the vast majority of green sea turtles in the northern Great Barrier Reef off Australia being female.

Scientists from the U.S. National Oceanic and Atmospheric Administration say the temperature at which turtle eggs incubate determines the sex of hatchlings, and warn that warmer conditions are creating a dangerous gender imbalance.

Almost the entire green turtle population in parts of the northern Great Barrier Reef in Australia is now female. A study of about 200,000 animals in the reef’s northern waters found them to be overwhelmingly female. The research was published in the journal Current Biology. There are concerns that the future of the endangered reptile is increasingly precarious.

In the southern Barrier Reef, where conditions are cooler, about two-thirds are female. Researchers say that while they hope for some milder years to produce more males, they expect temperatures to continue to rise.

One possible solution to the gender imbalance is to put up tents over beaches where turtles nest to give them shade.

Colin Limpus, Queensland chief scientist, says that cloud seeding is another option.

“There is consideration being given to having artificial rain. It is being considered primarily for how we can get the turtles nesting successfully; at the same time it is going to cool the sand and should shift the sex ratio towards an increase in males,” Limpus said.

The green turtle is one of the largest sea turtles and the only herbivore among the different species. They are named for the greenish color of their cartilage and fat, not their shells.

They are classified as endangered, and are threatened by habitat loss, over-harvesting of their eggs, and the hunting of adults.

The Great Barrier Reef stretches for 2,300 kilometers down Australia’s northeast coast. It is home to a spectacular range of wildlife, including more than 130 species of sharks, 500 types of worms and 1,600 varieties of fish.



The reef faces a range of threats from the run-off of pesticides and soil from farms, and warmer ocean temperatures that have caused the mass bleaching of the coral in the past two years.