World's coral reefs in almost irreversible die-off, scientists say

world(a) warming is crossover unsafe thresholds earlier than expected, with the world's red coral reefs now in an almost irreversible die-off, marking what scientists on Monday described as the first "tipping point" in climate-driven ecosystem collapse.

The warning in the Global Tipping Points report by 160 researchers worldwide, which synthesizes groundbreaking science to estimate points of no return, comes just weeks ahead of this year's COP30 climate summit, being held at the edge of the Amazon rainforest in Brazil.

That same rainforest system is now at risk of collapsing once the average global temperature warms beyond 1.5 C based on deforestation rates, the report said, revising down the estimated threshold for the Amazon.

Also of concern if temperatures keep rising is the threat of disruption to the major ocean current called the Atlantic Meridional Overturning Circulation, or AMOC, which helps to ensure mild winters in northern Europe.

"Change is happening fast now, tragically, in parts of the climate, the biosphere," said environmental scientist Tim Lenton at the University of Exeter, who is the lead author of the report.

Lenton noted positive signs when it came to phasing out the fossil fuels most responsible for climate change. Renewables, for example, accounted for more electricity generation than coal this year for the first time, according to data from the non-profit think-tank Ember.

Coral reefs experiencing mass bleaching event

"Nobody wants to be just traumatized and disempowered," Lenton said. "We still have some agency."

The scientists implored countries at November's COP30 to work toward bringing down climate-warming carbon emissions.

Scientists have been surprised by how quickly changes are unfolding in nature, with average global temperatures already having warmed by 1.3-1.4 C above the pre-industrial average, according to data from UN and EU science agencies.

The last two years were Earth's warmest on record, with marine heat waves that stressed 84 per cent of the world's reefs to the point of bleaching and, in some cases, death. Coral reefs sustain about a quarter of marine life.

For corals to recover, the world would need to drastically ramp up climate action to reverse temperatures back down to just 1 C above the pre-industrial average, the scientists suggested.

"The new report makes clear that each year there is an increase in the scope and magnitude of the negative impacts of climate change," said Pep Canadell, a senior scientist at Australia's CSIRO Climate Science Centre.

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