The main factor contributing to declines in coral-reef health is proximity to human populations, says new research in the journal Proceedings of the Royal Society of London B. A study of 322 reef sites in the Caribbean found that many suffered significant damage from overfishing and agricultural runoff. Author Camilo Mora estimates that reefs in the region provide some $4 billion in economic benefits due to fishing, tourism, and coastal protection, but warns, “The expected increase of the world’s human population from 6 billion today to 9 billion for the year 2050 suggests that coral reefs are likely to witness a significant ecological crisis in the coming half century if effective conservation strategies, including policies on population planning, are not implemented soon.” One might say we’ve got a coral obligation to do so.