Scientists: 1/3 of ocean species could die in 300 years; warming has helped extirpate at least 400 species on Earth

There have been five mass extinctions in Earth's history, and if humans don't curb their greenhouse-gas emissions, we're heading for a sixth, says a groundbreaking study in the journal Science. 

The study by Malin Pinsky and Alexa Fredston of Rutgers University says a third of all marine life could die off in the next 300 years. Those who don't live near the ocean might wonder why that matters, but Sarah Kaplan of The Washington Post points out that ecosystems are highly connected, and a die-off that large would send shockwaves throughout the planet, even on land. Billions of people depend on the ocean for food or work, and resource scarcity is often at the root of war and unrest. In other words, the warming climate is going to affect more than New England lobster fishermen.

"This climate-driven marine die-off is just one piece of a broader biodiversity crisis gripping the entire globe," Kaplan notes. "A recent report from the Intergovernmental Panel on Climate Change found that warming has already contributed to the disappearance of at least 400 species. A separate U.N. panel has found that about 1 million additional species are at risk of extinction as a result of overexploitation, habitat destruction, pollution and other human disruption of the natural world."