Aerial surveys have confirmed the Great Barrier Reef is experiencing its third mass coral bleaching event in five years.

Over the past fortnight, a small team of researchers have been carrying out aerial surveys to document coral bleaching along the Great Barrier Reef.

Among the crew is Professor Terry Hughes, director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, who has been documenting the survey on Twitter.

Day 8: Southern nearshore #GreatBarrierReef has widespread, severe #coral bleaching. pic.twitter.com/HspGURBarh

— Terry Hughes (@ProfTerryHughes) March 26, 2020

Friday will be the ninth and final flight of the campaign, which aimed to cover roughly 10,000 kilometres of reef off Queensland's eastern tropical coastline.

While it will take some weeks for researchers to analyse the information and build a complete picture of what's gone on in the reed, the extent of bleaching has been confirmed.

The Great Barrier Reef Marine Park Authority (GBRMPA) released a statement on Thursday confirming that mass bleaching is occurring on the Great Barrier Reef, with very widespread bleaching detected. This is the third mass bleaching in five years, following a back-to-back episode in 2016 and 2017.

Bleaching occurs when corals are exposed to warmer-than-usual water for a prolonged period of time. The current bleaching episode was driven by a build-up of warm water along the Great Barrier Reef during the summer of 2019/20, particularly in February and early March.

After finishing a tiring day of surveying bleached reefs on Thursday, Terrey Hughes said "I feel like an art lover wandering through the Louvre....as it burns to the ground."

The GBRMPA pointed out that "actions to support the resilience of the Reef are now more important than ever" and "climate change remains the single greatest challenge to the Reef."