With leatherbacks threatened with extinction (灭绝), Playa Grande’s turtle museum was abandoned three years ago and now sits among a sea of weeds. And the beachside ticket office for turtle tours was washed away by a high tide in September. “We do not promote that as a turtle tourism destination any more because we realize there are far too few turtles to please,” said Alvaro Fonseca, a park ranger (管理员).

　　Even before scientists found temperatures going up over the past decade, sea turtles were threatened by beach development, drift net fishing and Costa Ricans interest in eating turtle eggs. But climate change may cause the most serious harm to an animal that has lived in the Pacific for 150 million years.

　　Sea turtles are sensitive to numerous effects of warming. They feed on reefs, which are dying in hotter seas. They lay eggs on beaches that are being covered by rising seas and more violent waves.

　　More uniquely their gender (性别) is determined, not by genes but by the egg’s temperature during development. Small rises in beach temperatures can result in ail-female populations, obviously problematic for survival. If the sand around the eggs hits 30 degrees Celsius, the gender balance shits to females: at about 32 degrees they are all female. Above 34, you get boiled eggs.

　　On some nesting beaches, scientists are artificially cooling nests with shade or irrigation and trying to protect broader areas of coastal property from development to ensure that turtles have a place to nest as the seas rise.

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