Scientists said: 'Combining our results with temperature data show that the (warmer) northern GBR (Great Barrier Reef) 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'. It could even mean the extinction of that group of animals, the biggest population of green sea turtles in the world.
In some northern beaches near Australia's Great Barrier Reef, scientists found that virtually every juvenile turtle was female, and over 85 per cent of the adults. The embryos inside respond to the temperature, developing as male if colder and female if warmer.
"With average global temperature predicted to increase 2.6 degrees Celsius by 2100, many sea turtle populations are in danger of high egg mortality and female-only offspring production", said the report.
Development of sex in humans and some other mammals depend upon chromosomes but in case of turtle, the temperature under which the eggs incubate determines the sex.
"Any variation on that of about one to two degrees, could risk producing all females or perhaps embryonic death".
After collecting 411 for analysis and release, they found a "moderate female sex bias" in turtles from beaches in the cooler, southern Great Barrier Reef, where about 65-69 percent were female.
"One possibility is shade cloth erected over key nesting beaches, like at Raine Island, to lower nest temperatures to produce more males", he said.
According to researchers, the increasing number of females is not the problem for sea turtle populations as it could, in fact, boost their reproductive potential.
"While these turtles may be half a world away, action to reduce carbon emissions in the United Kingdom can play a vital role in limiting the impact of global warming on green turtles and countless other marine species", he said. The new study has given some significant information about the current situation of the green sea turtles, informed lead author Dr. Michael Jensen, the National Oceanic and Atmospheric Administration.
"Knowing what the sex ratios in the adult breeding population are today and what they might look like five, 10 and 20 years from now when these young turtles grow up and become adults is going to be incredibly valuable".
Climate changes due to the warmer Earth are increasingly affecting our planet globally. "We know that species evolve in response to climate and other environmental changes, but they need time for that". It affects the temperature-dependent sex determination (TSD).