SYDNEY (AP) — The head of a U.S. scientific agency says ocean acidification is now one of the biggest threats to coral reefs across the world, acting as the “osteoporosis of the sea.”

National Oceanic and Atmospheric Administration chief Jane Lubchenco told The Associated Press on Monday that the speed by which the oceans’ acid levels has risen surprised scientists. She says the problem could threaten everything from food supplies to tourism to livelihoods.