Somewhere around 94 million years ago, a huge chunk of the ocean’s creatures died off. You probably learned about in school, scribbled a few answers on a test about it, then promptly forgot that it ever happened because 94 million years is a pretty long time and who gives a shit about the Cretaceous Period? It’s called the Oceanic Anoxic Event-2 (OAE-2 from now on, because I don’t want to type that over and over again), and it happened because the levels of oxygen in the ocean dropped relatively dramatically over the course of 50,000 years. In the end, nearly 30 percent of marine invertebrates went extinct. According to a research paper published in Science Advances, the current rates of deoxygenation are strikingly similar to those of the OEA-2, and it’s likely that’s we’re headed down the same path.
“Increased ocean deoxygenation is already apparent in the modern ocean,” the authors of the paper wrote, “because marine dioxygen has decreased by two percent over roughly the last half century, and recent models predict a continued loss of 0.5 to 3.5 per cent over the next half century, which would result in huge expansions of ocean anoxia within the next few thousand years.”