Scientists who study wildlife are often the bearers of bad news — this species or that is headed for extinction for the usual reasons, like deforestation or climate change. Just last week, for example, I wrote about new science showing that two valuable coral species in Florida were mostly killed off by global warming.

But earlier this month, researchers announced something overwhelmingly positive: Green sea turtles, the iconic marine species made famous by Finding Nemo that were once at risk of extinction, have bounced back. Dramatically.

According to researchers at the International Union for Conservation of Nature and Natural Resources (IUCN), the leading authority on endangered species, the global population of green sea turtles — one of the seven sea turtle species found worldwide — is up 28 percent since the 1970s. IUCN reclassified the sea turtles from “endangered” to “least concern,” a category reserved for species that are not threatened with extinction and plentiful in the wild.

Scientists measure sea turtle populations by counting their nests on beaches. And in some regions, such as Florida, the number of them has surged in recent years. In the 1980s, for example, researchers detected only around 40 nests each year in and around Archie Carr National Wildlife Refuge, a protected area along Florida’s east coast. Now, they’re consistently counting more than 20,000 of them, said Kate Mansfield, a professor at the University of Central Florida who runs the monitoring program. “The green turtles have just gone absolutely, wonderfully, exponentially higher,” Mansfield told me. “I’m cautiously optimistic.”

What’s so remarkable about the recovery is that........

© Vox