Nature is in crisis, and it's only getting worse. As species vanish at a rate not seen in 10 million years, more than 1 million species are currently on the brink.

Humans are driving this extinction crisis through activities that take over animal habitats, pollute nature and fuel global warming, scientists say. A new global deal to protect nature agreed on Dec. 19 has the potential to help, and scientists are urging the world’s nations to ensure the deal is a success.

When an animal species is lost, a whole set of characteristics disappears along with it — genes, behaviors, activities and interactions with other plants and animals that may have taken thousands or millions, even billions, of years to evolve.