“The first tipping of widespread dieback of warm-water coral reefs is already underway,” said Prof. Tim Lenton from the University of Exeter’s Global Systems Institute, one of the authors of the report.
By Marco Lopez
Warm-water coral across the world is facing long-term decline as the fourth global coral bleaching event persists. The Global Tipping Point report published by the University of Exeter says the world has reached the first climate tipping point with the mass die-off of warm-water coral reefs.
Climate tipping points are critical thresholds where, when passed, changes to major ecosystems occur and cause significant and often irreversible degradation in Earth’s systems. The crossing of one tipping point can increase the likelihood of triggering others.
Coral reefs are home to a quarter of all marine species and are considered the most vulnerable of Earth’s systems to global heating. A majority of the excess heat produced by human-caused greenhouse gas emissions goes to the ocean.
An estimated 1 billion people benefit directly or indirectly from the ecosystem services coral reefs provide each year.
The fourth global bleaching event was declared in 2023 – it has been the worst recorded so far. Reports suggest 80% of reefs in more than 80 countries have been impacted. The report estimates that coral reefs hit their tipping point when global temperature reached between 1°C and 1.5°C above where they were in the last half of the 19th century.
According to a study recently released by the WMO, greenhouse gas concentrations surged to new highs in 2024, with carbon dioxide levels increasing by the largest amount on record. Continued emissions from human activities and wildfires, coupled with the reduced capacity of natural carbon sinks, like forests and the ocean, continue to push the world closer to climate catastrophe.
“We can no longer talk about tipping points as a future risk,” said Prof. Tim Lenton at the University of Exeter’s Global Systems Institute.
The world needs rapid cuts to greenhouse gas emissions to avoid reaching the 1.5°C threshold in the next 10 years, the report says.
The report highlights the mass die-off of coral in the Caribbean, saying reefs in that region have been pushed toward collapse.
In Belize, unprecedented coral bleaching, illnesses like the stony coral tissue loss disease, and other threats are impacting the health of the coral that make up the second-largest coral barrier reef in the world – the Mesoamerican Reef. In 2024, the country recorded its worst bleaching event to date, according to Lisa Carne, founder of Fragments of Hope (FOH), a Belize-based non-profit focused on coral reef restoration.
While this report highlights the tipping points as “reached,” leading coral reef scientist, Prof. Peter Mumby, commented that there is evidence that coral could adapt, with some reefs remaining viable even at 2°C of global heating.
These corals and coral reefs – some known as refugia, others as super reefs – are genetically adapted to survive in harsh environments where others would die off. Protecting these places and coral species will be crucial, as they will serve as a foundation for recovery in a future world where we have hopefully managed to stabilize the climate.
Belize is an image other other climate tipping points that are at risk of being breached because of global warming.
Of note, they are also positive tipping points, like the scaling up of electric vehicle use, that can help reduce emissions and protect Earth’s ecosystems from collapse.
