Report: Earth has reached its first catastrophic climate tipping point

The Earth has reached its first climate tipping point, with large-scale die-offs of warm-water coral reefs indicating the severe impact of global warming, according to a new report from Global Tipping Points, authored by 160 researchers from 23 countries.

A climate tipping point refers to a threshold in the climate system at which it shifts from one stable state to another. Once this "threshold" is crossed, the state of the climate system can undergo significant and often irreversible changes, with potentially catastrophic impacts on life on Earth. Scientists have set this threshold at 1.2 degrees Celsius warming above pre-industrial. However, global temperatures have already risen 1.4 degrees Celsius above pre-industrial levels, indicating that the impacts of crossing this tipping point are already emerging.

Coral reefs, which support about a quarter of all marine species, are among the ecosystems most vulnerable to warming. The report warns that unless global temperatures are brought back toward 1.2 degrees Celsius above pre-industrial levels, and ultimately to 1 degree Celsius, no substantial warm-water coral reefs will remain on Earth.

Tim Lenton, the lead author of the report and a professor at the University of Exeter's Global Systems Institute, emphasized that we can no longer treat tipping points as a future risk. The first tipping point, a large-scale dieback of warm-water coral reefs, has already been reached.

The report 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 just 1.5 degrees Celsius 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 a major ocean current called the Atlantic Meridional Overturning Circulation, or AMOC, which helps to ensure mild winters in northern Europe.

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

(With input from Reuters)