Photo by NEOM
The world faces a “new reality” as it reaches the first of many Earth system tipping points that will cause catastrophic harm unless humanity takes urgent action, according to a landmark report released on 13th October by the University of Exeter and international partners. The Global Tipping Points Report 2025 finds that warm-water coral reefs—on which nearly a billion people and a quarter of all marine life depend—are passing their thermal tipping point, with widespread dieback now occurring.
Authored by 160 scientists from 87 institutions in 23 countries, the report warns that with current global warming at about 1.4°C above pre-industrial levels, reefs have crossed their thermal tipping point, which has a central estimate of 1.2°C. Even stabilising warming at 1.5°C means warm-water coral reefs are virtually certain—over 99% probability—to experience mass dieback. This means coral reefs on any meaningful scale will be lost unless global temperature returns towards 1°C warming or below, although fragments may be preserved with conservation action that minimises other stressors such as overfishing and pollution.
Professor Tim Lenton, from the Global Systems Institute at the University of Exeter and coordinating lead author, said: “We are rapidly approaching multiple Earth system tipping points that could transform our world, with devastating consequences for people and nature. This demands immediate, unprecedented action from leaders at COP30 and policymakers worldwide.”
Dr Mike Barrett, chief scientific advisor at WWF-UK and co-author of the report, said: “The findings of this report are incredibly alarming. That warm-water coral reefs are passing their thermal tipping point is a tragedy for nature and the people that rely on them for food and income. This grim situation must be a wake-up call that unless we act decisively now, we will also lose the Amazon rainforest, the ice sheets and vital ocean currents. In that scenario we would be looking at a truly catastrophic outcome for all humanity.”
The report, released ahead of COP30 in Belém, Brazil, beginning 10th November 2025, highlights that the planet is dangerously close to triggering other catastrophic tipping points. The temperature rise that would trigger widespread Amazon rainforest dieback is now estimated at 1.5°C at the lower end—lower than previously thought. One of the most alarming risks is the potential collapse of the Atlantic Meridional Overturning Circulation, which would push parts of the world into a deep freeze whilst heating others, disrupting monsoon seasons and raising sea levels. Barrett noted that AMOC collapse could occur within the lifetime of people living today.
Four global coral bleaching events have now been recorded, with two in the last decade. The Great Barrier Reef alone has bleached in 2016, 2017, 2020, 2022, 2024 and 2025. Lenton told The Guardian: “The world has just spent much of the last two years at 1.5°C warming, and the resulting marine heatwaves have caused unprecedented bleaching of 80 percent of the world’s reefs.” These repeat events occur too close together for recovery, triggering mass coral death. The ecosystem services reefs provide are valued at over $2 trillion annually.
However, the report also highlights progress on positive tipping points. Positive tipping points have already been crossed in solar photovoltaic power and wind power globally, as well as in electric vehicles, battery storage and heat pumps in leading markets. Since the first Global Tipping Points Report in 2023, there has been radical global acceleration in clean technology uptake. Once replaced, polluting technologies are unlikely to return because new options are cheaper and better.
Lenton said: “In the two years since the first Global Tipping Points Report, there has been a radical global acceleration in some areas, including the uptake of solar power and electric vehicles. But we need to do more—and move faster—to seize positive tipping point opportunities. By doing so, we can drastically cut greenhouse gas emissions and tip the world away from catastrophic tipping points and towards a thriving, sustainable future.”
The report concludes that tipping points pose a new type of threat that current international structures are not designed to counter, demanding unprecedented action from policymakers to prevent further irreversible changes to Earth’s life-support systems.