Rising sea temperatures are turning a green sea turtle population in Australia's Great Barrier Reef female, threatening the species future, researchers have found.
A sea turtle's sex is dependent on temperature, and the number of female hatchlings rises with the temperature.
Researchers from the National Oceanic and Atmospheric Administration, California State University and Worldwide Fund for Nature Australia examined two populations of the species and found the group living further north in Australia (where it was warmer) were 99% female.
"Combining our results with temperature data show that the northern GBR green turtle rookeries have been producing primarily females for more than two decades and that the complete feminisation of this population is possible in the near future," the study, published in Current Biology, noted.
"With warming global temperatures and most sea turtle populations naturally producing offspring above the pivotal temperature, it is clear that climate change poses a serious threat to the persistence of these populations."
Rising temperatures don't just threaten the reef's turtle population, but the UNESCO site itself.
All the Australian government's efforts to save the Great Barrier Reef will be for nothing if climate change isn't halted, a report published last year in scientific journal Nature found.
The government's Reef 2050 plan includes a range of measures aimed at improving water quality, managing land use, updating fishing and shipping regulations, and protecting the reef's wildlife.
But researchers from James Cook University in Queensland said all the measures contained in the Reef 2050 plan would mean little if sea temperatures continued to rise.
Coral bleaching occurs when abnormally high sea temperatures cause corals to expel tiny photosynthetic algae known as zooxanthellae, turning the coral white, and often killing it.
The 2016 coral die-off was the worst on record, with more than two-thirds of corals killed in some areas, and almost 90% of surveyed reefs affected.