Global coral reef bleaching event is largest on record, report says
New data from the National Oceanic and Atmospheric Administration has scientists ringing alarm bells about the health of the world's oceans. Seventy-seven percent of the world's coral reefs have experienced "bleaching-level heat stress" over the last 22 months. Derek Manzello, coordinator of NOAA's Coral Reef Watch program, joins CBS News to dive deeper into the research.