Officials with the Great Barrier Reef Marine Park Authority and the Australian Institute of Marine Science found severe bleaching in the central part of the Great Barrier Reef Thursday during a six-hour flight between Townsville and Cairns. The area was spared the severe widespread bleaching seen last year.
"How this event unfolds will depend very much on local weather conditions over the next few weeks," said David Wachenfeld, director of reef recovery for the Marine Park Authority.
Wachenfeld emphasized that it's unlikely that all the bleached coral found Thursday will die.
"As we saw last year bleaching and mortality can be highly variable across the 344,000 square kilometer (133,000 square mile) Marine Park — an area bigger than Italy," he said.
The first global bleaching event occurred in 1998, when 16 percent of corals died. The problem spiraled dramatically in 2015-2016 amid an extended El Nino natural weather phenomenon that warmed Pacific waters near the equator and triggered the most widespread bleaching ever documented. This third global bleaching event, as it is known, continues today, even after El Nino ended.
The Associated Press contributed to this report.