Great Barrier Reef suffers another bleaching event ahead of United Nations assessment visit

The Great Barrier Reef Marine Park Authority has shared that a widespread but variable bleaching event is unfolding in multiple regions on the Great Barrier Reef.

While not yet officially declared a mass bleaching event, this devastating news comes ahead of the UNESCO/IUCN Reef Monitoring Mission which is due to arrive in Australia next week at Australia's request to assess the Australian and Queensland Government’s protection of the Reef for the World Heritage Committee.  

Unless conditions ease in the next couple of weeks, the World Heritage-listed site could be in for its fourth mass bleaching event in six years.

Great Barrier Reef Marine Park Authority advised "bleaching has been detected across the marine park — it is widespread but variable, across multiple regions, ranging in impact from minor to severe” with the Authority's chief scientist David Wachenfeld stating that more frequent and severe bleaching events are evidence of the growing impacts of climate change, which is driving up ocean temperatures.

Weather conditions over the next fortnight will determine how bad things get, but accumulated heat stress for corals over much of the reef match what was seen during the 2016, 2017 and 2020 bleachings.

Dr Wachenfeld says not all bleached corals die and they can recover if heat stress eases, but their immune and reproductive systems inevitably suffer.

Aerial surveillance missions that began last weekend should be finished by mid-week, providing a comprehensive picture of the scale of the incident.

Dr Wachenfeld says the results will be part of the briefing to the United Nations Reef Monitoring mission.

Federal Environment Minister Sussan Ley says any bleaching event is cause for concern and that's why the government is spending an extra $1 billion on reef resilience.

Conservation groups say the government's enduring support for fossil fuel industries and its emission reduction targets that lag behind other nations are incompatible with reef protection.

Australian Marine Conservation Society Great Barrier Reef campaign manager Dr Lissa Schindler notes “While not yet officially declared a mass bleaching event, this is still disastrous news for our Reef, the marine life and communities that rely on its health.

“What is most concerning is that this widespread bleaching is happening during a La Nina weather event, which is normally characterised by rain and cloud cover on the east coast of Australia often helping to cool waters. It shows the consistent pressure our Reef is now under from global heating. A healthy reef can recover from coral bleaching but it needs time. More frequent marine heatwaves primarily driven by the burning of coal and gas means it is not getting this time.

“Global heating is the single biggest threat to the future of our Reef. There is still hope if we act now to reduce emissions so we hold global temperature rises to 1.5 degrees – a crucial threshold for coral reefs.

“By divesting from coal, decarbonising the economy and making Australia a renewable energy superpower, we can drive down emissions while creating good paying jobs.”

Australian Conservation Foundation Chief Executive Kelly O'Shanassy adds "If the Morrison government wants to avoid an 'in danger' listing for the reef, it must strengthen its climate targets and policies in line with the science.”

Greenpeace said it was incredibly alarming that bleaching was unfolding under the La Niña weather phenomenon that typically keeps ocean temperatures lower.

Earlier this month, a major report by the Intergovernmental Panel on Climate Change said the reef was in crisis and could be bleaching every year after 2044.