Global heating means almost every sea turtle in Florida now born female

Nearly every sea turtle born on the beaches of Florida in the past four years has been female, according to scientists.

The spike in female baby turtles comes as a result of intense heatwaves triggered by a growing climate crisis that is significantly warming up the sands on some beaches, as CNN reported this week.

According to the National Ocean Service, if a turtle’s eggs incubate below 27C (82F), the turtle hatchlings will be male. If the eggs incubate above 31C (89F), the hatchlings will be female. Temperatures that waver between the two extremes will result in a mix of male and female baby turtles.

Researchers also discovered that the warmer the sand, the higher the ratio of female turtles.

“As the Earth experienced climate change, increased temperatures could result in skewed and even lethal incubation conditions, which would impact turtle species and other reptiles,” the National Ocean Service said.

In a statement to Reuters, Bette Zirkelbach, manager of the Turtle Hospital in Marathon, Florida Keys, said: “The frightening thing is the last four summers in Florida have been the hottest summers on record.”

She added: “Scientists that are studying sea turtle hatchlings and eggs have found no boy sea turtles, so only female sea turtles for the past four years.”

The uneven male-to-female ratio is a growing concern among scientists who worry that the sea turtle population will eventually become stunted.

Melissa Rosales Rodriguez, a sea turtle keeper at the Miami Zoo’s recently opened Sea Turtle Hospital, told Reuters, “Over the years, you’re going to see a sharp decline in their population because we just don’t have the genetic diversity… We don’t have the male-to-female ratio needed in order to be able to have successful breeding sessions.”

In addition to facing an increasing number of female turtles, the Sea Turtle Hospital is also currently working to address fibropapillomatosis, a potentially deadly disease among sea turtles that causes cauliflower-like tumors to develop on the body including the eyes and mouth. The tumors could also form in internal organs.

“The Turtle hospital was the first. But, sadly … there’s a need all throughout Florida,” Zirkelbach said in regard to a growing need for more rehabilitation centers across the state.

This article was amended on 4 August 2022. An earlier version quoted Melissa Rosales Rodriguez telling Reuters that saying “sadly and fortunately” there was a need for more rehabilitation centers, which the Guardian understands as a mishearing of her words.