Due to the temperature at which eggs are kept determining a turtle's gender, climate change is causing far more females to be born than males.
When a person finds out that they're pregnant, they'll soon have a decision to make. Whether they want to know if they're having a boy or a girl. Parents-to-be can either find out via a scan or wait until the baby is born. Once the little one has arrived, it's normally pretty obvious if they are male or female.
Sea turtles, on the other hand, aren't so easy to sex. In most cases, vets need to use a very thin camera to check a turtle's internal organs to determine whether they are male or female. The other way of knowing is by monitoring the temperature at which the eggs are kept. Turtle eggs kept at higher temperatures produce females, while males hatch from cooler ones.
Therein lies a pretty big problem. Since global temperatures are rising due to climate change, and turtles bury their eggs in the sand, more females are being born than males. In some cases/parts of the world, the ratio has significantly changed. According to National Geographic, Camryn Allen's research revealed that in Raine Island, Australia, female turtles now outnumber the males 116 to 1.
The trouble for turtles is they face a hard enough task trying to survive as it is. When hatched, turtles are tiny and face a grueling trip from the sand to the sea. Then, once in the water, there are plenty more predators waiting for them. Less than 1% of all hatchlings actually make it to adulthood, and the vast majority of those are female thanks to the Earth's increasing temperature.
There is some good news. Turtles have existed and survived for hundreds of millions of years. They've lived through the ice age and always find a way to keep on going somehow. This time around, they appear to have done so ago. Experts have noticed that the vastly outnumbered male sea turtles have started to mate with multiple females. It's unknown whether that has always been the case, or if it is an evolutionary change brought about by male turtles' falling numbers.