Australia's Great Barrier Reef is undergoing its fifth mass coral bleaching event since 2016 due to heat stress and climate change.

Corals are expelling algae and turning white, increasing their vulnerability to disease.

The phenomenon is part of a global pattern, linked to El Niño and higher ocean temperatures.

Scientists call for urgent global emissions reductions to safeguard coral reefs from further climate change impacts.

The bleaching event intensifies the debate with UNESCO over listing the reef as a 'World Heritage site in danger,' which has tourism-related economic implications.

If global temperatures rise by 2 degrees, up to 99% of coral reefs could be lost, underscoring the critical need for immediate climate action.