The earth has reached its first catastrophic tipping point linked to greenhouse gas emissions, with warm water coral reefs now facing a long-term decline, according to a new report.
Conservationists are also warning the world is also ‘on the brink’ of reaching other crisis points, including the collapse of major ocean currents and the loss of ice sheets.
Dr Tracy Ainsworth, the vice-president of the International Coral Reef Society, said in many places reef ecosystems were changing and were either no longer dominated by corals, or were losing diversity.
‘The future of coral reefs is one of transformation, ecosystem restructure and new challenges,’ she said. ‘Our challenge now is to understand how all of these different ecosystems are reorganising and how we can ensure they continue to support diverse marine life and communities.’

The world’s coral reefs are home to about a quarter of all marine species but are considered one of the most vulnerable systems to the climate crisis.
Coral in Irreversible Decline
‘Unless we return to global mean surface temperatures of 1.2C (and eventually to at least 1C) as fast as possible, we will not retain warm-water reefs on our planet at any meaningful scale,’ the report says.
Coral reefs have been in the midst of a global bleaching event since January 2023 – the fourth and worst on record – with more than 80 per cent of reefs in more than 80 countries affected by extreme ocean temperatures.
‘We can no longer talk about tipping points as a future risk. The first tipping of widespread dieback of warm water coral reefs is already under way.’
Prof Tim Lenton, University of Exeter’s Global Systems Institute
The Global Tipping Points report, led by the University of Exeter includes contributions from 160 scientists from 87 institutions in 23 countries.
It estimates that coral reefs hit a tipping point when global temperatures reach between 1C and 1.5C above where they were in the latter half of the 19th century, with a central estimate of 1.2C. Global heating is now at about 1.4C.

Without rapid and unlikely cuts to greenhouse gases, the upper threshold of 1.5C would be hit in the next 10 years, the report says.
‘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 first tipping of widespread dieback of warm water coral reefs is already under way.’
Lenton added that parts of the west Antarctic ice sheet and the Greenland ice sheet were ‘looking perilously close’ to their tipping point, as they were losing ice at an accelerating rate.
‘We are going to overshoot 1.5C of global warming probably around 2030 on current projections,’ he said. ‘This puts the world in a greater danger zone of escalating risk of further damaging tipping points.’