Human activities kickstarted the decline in Caribbean coral reefs

Fish swimming in coral reef

According to researchers, about half of Caribbean coral reefs have died since the 1970s, with the iconic elkhorn and staghorn corals being the hardest hit. However, climate change does not completely explain the loss of the reefs. So, in order to get a better picture of the drastic coral loss, Arizona State University researcher Katie Cramer has published a new paper in Science Advances.

“I am interested in going back to the scene of the crime when humans first began to significantly impact coral reefs centuries ago, to understand when, why and how much reefs have been altered by humans,” said Cramer, an assistant research professor at the Julie Ann Wrigley Global Institute of Sustainability and an Ocean Science Fellow at the Center for Oceans at Conservation International.

In the paper, Cramer combines a mix of fossil data, underwater survey data and historical records to recreate the abundance of staghorn and elkhorn corals over the past 125,000 years. Her research shows that the coral reefs began declining in the 1950s and ’60s, a timeline that is at least a decade earlier than previously thought. The implications of this discovery are significant, showing that local human activities (like fishing and land clearing) were beginning to have an impact on the reefs before climate change. What’s happened now is that these human activities, in tandem with the warming oceans due to the climate crisis, have resulted in the rapid decline of coral reefs that we now see today.

Based on this discovery, Cramer recommended that “tractable problems” such as fishing and land clearing be addressed so the reefs are better able to withstand the climate crisis.