The research, published in Current Biology, found more than 99 per cent of juvenile and sub-adult turtles studied at a site in the northern Great Barrier Reef are now female.
The pivotal temperature that determines whether sea turtles nesting in the northern Great Barrier Reef are male or female is about 29.3 degrees. An increase of half a degree warmer can skew the population in favour of females, The Sydney Morning Herald reports.
"This research is so important because it provides us with a new and a better understanding of what these populations are dealing with," said Michael Jensen, a marine biologist with the US's National Oceanic Atmospheric Administration and lead author of the report.
While it’s normal for the male green sea turtle species to mate with several females, the problem is that it’s not known how many males are needed to support a population.
Although the results have been described as alarming, there's still hope for the turtles.
"These results on the northern Great Barrier Reef are concerning, alarm bells are ringing, but there's still time [to save the turtles]," Jensen said.
"Knowing the sex ratio in that adult breeding population today and what that may look like five or 10 or 20 years from now ... [is] going to be incredibly valuable for conservation managers."