Coral: acidity plays a crucial role in reefs

Rising acid levels in the world's oceans have emerged as one of the biggest threats to coral reefs, acting as the "osteoporosis of the sea" and threatening everything from food security to tourism to livelihoods.

Oceans absorb excess carbon dioxide in the atmosphere, leading to an increase in acidity. Scientists are worried about how that increase will affect sea life, particularly reefs, as higher acid levels make it tough for coral skeletons to form.

Not convinced that this is a big deal? World Resources Institute has created a great short video that explains what coral reefs are, why they're so important, and the threats we're posing to their health.