The Pantanal in South America is critical for fighting climate change and protecting endangered species. The race is on to protect it.

Most people have heard of the Amazon, South America’s famed rainforest and hub of biological diversity. Less well known, though no less critical, is the Pantanal, the world’s largest tropical wetland.

Like the Amazon, the Pantanal is ecologically important and imperiled. Located primarily in Brazil, it also stretches into neighboring Bolivia and Paraguay. Covering an area larger than England at more than 70,000 square miles, the massive wetland provides irreplaceable ecosystem services that include the regulation of floodwaters, nutrient renewal, river flow for navigability, groundwater recharge and carbon sequestration. The wetland also supports the economies of the four South American states it covers.

But as I learned working on a recent research project with the environmental nonprofit WWF, a combination of climate change, new development, expanding agriculture, urban growth and pollution are poised to transform this vast wetland — bringing drastic consequences for the environment, wildlife and millions of people who depend on the Pantanal’s natural hydrology.