The critically endangered species, already facing threats that include egg poaching and human fishing practices, could see egg and hatchling survival drop by half in the next 100 years as a result of global climate change, researchers at Drexel University in Philadelphia said.
"We have discovered a clear link between climate and survival of this endangered sea turtle population," environmental scientist James Spotila said.
The researchers examined the relationship between regional climate patterns and leatherback turtles' nesting success over six consecutive nesting seasons at Playa Grande in Costa Rica, the major nesting site for leatherback turtles in the eastern Pacific Ocean.
"Temperature and humidity inside the nest are significant factors affecting egg and hatchling survival," Spotila said.
The turtles' hatching success and success emerging from the nest was linked with weather patterns associated with the El Nino Southern Oscillation, with warmer, dryer El Nino conditions associated with significantly higher mortality for eggs and hatchlings.
"Action is needed, both to mitigate this effect and, ultimately, to reverse it to avoid extinction," Spotila said. "We need to change fishing practices that kill turtles at sea, intervene to cool the beach to save the developing eggs and find a way to stop global warming. Otherwise, the leatherback and many other species will be lost."