It's no secret that coral reefs around the world are under threat because of climate change. Coral reefs represent some of our most important natural resources, providing livelihood, food and protection for marine biodiversity. And now environmentalists say 75% of our existing coral reefs are in the danger zone.

According to a report called "Reefs at Risk Revisited," overfishing, warmer waters and pollution are among the biggest culprits endangering reefs today. Also, pwards of 500 million depend on reefs for sustenance and income. And it's only going to get worse in the next 20 to 50 years.

So what can we do? Cutting down on water consumption and pollution will in turn slash our CO2 emissions, which is a big plus. But also support reef-friendly businesses whether you're fishing, boating or snorkeling! And raising awareness is also key. Here's one way to spread the word: send coral reef e-cards from The Nature Conservancy!