The precise moment Earth would reach its climate tipping points—instances where human-driven climate change triggers irreversible planetary shifts—has long been a subject of scientific inquiry. However, these points might be closer than previously thought. A new report released today indicates that the Earth has already surpassed its initial climate tipping point.
The second “Global Tipping Points” report, published by the University of Exeter, discovered that warm-water coral reefs are now exceeding their tipping point. Escalating ocean temperatures, acidification, overfishing, and pollution are collectively causing widespread coral bleaching and mortality. This implies that a significant number of coral reefs will be lost unless global temperatures revert towards 1°C warming or below.
“We are facing a new climate reality,” stated Tim Lenton, founding director at the Global Systems Institute at the University of Exeter, who led the report. “We have crossed a tipping point within the climate system, and it is now certain that we will proceed beyond 1.5°C of global warming above pre-industrial levels, which will place us in a precarious position for triggering more climate tipping points.” The planet is projected to surpass the 1.5°C threshold within the next five years, according to a separate report. Once this limit is reached, the planet will experience more frequent and intense extreme weather, along with increased pressures on food production and water access—impacts already visible in many climate-vulnerable nations.
The authors define a tipping point as “occurring when changes in a system become self-perpetuating and difficult to reverse beyond a threshold, leading to substantial, widespread impacts.” Scientists have identified as many as 25 major tipping points, including the Amazon rainforest transitioning from a lush, carbon-storing forest to an arid savannah, and the permanent melting of polar sea ice, where the exposed dark open water absorbs more heat than reflective white snow, thereby encouraging further melting.
160 scientists across 23 countries compiled the latest data and research on the subject. They found that, in the years since the report’s initial release in 2023, reefs globally have begun to exceed their thermal tipping point. “We have observed 80% of coral reefs experiencing unprecedented heat waves, bleaching events, and subsequent decline,” Lenton noted. The extensive collapse of reef ecosystems would be catastrophic for both marine life and human populations—reefs support fisheries and protect coastlines from storm surges and rising sea levels. Among all potential tipping points, coral reefs exhibit one of the lowest tolerances for rising temperatures, making their status as the first to be breached unsurprising.
Scientists are also observing other indicators of environmental health. A September report revealed that seven of the nine “planetary boundaries” have already been crossed (including increasing ocean acidity and the alteration of natural landscapes)—these represent critical thresholds that maintain Earth’s systems hospitable to life and prevent the crossing of a tipping point.
Today’s report also determined that the global temperature increase required to trigger widespread dieback in the Amazon rainforest is lower than previously thought, with the bottom of the estimated range now at 1.5°C. The authors underscored the need for urgent measures to avert this outcome, including targeted investments in conservation and restoration, to safeguard the forest for the more than hundred million people who rely on it. They additionally warned that the Atlantic Meridional Overturning Circulation (AMOC), a system of ocean currents that circulates water within the Atlantic Ocean, is at risk of collapse below an increase of 2°C of global warming above pre-industrial temperatures. Should this occur, it would lead to harsher winters in north-west Europe, disrupt monsoon patterns in West Africa and India, and reduce agricultural yields across much of the world.
Naturally, several positive changes are taking place globally, as green alternatives like electric vehicles and solar panels become more widely adopted—and affordable. “There is increasing evidence of what we call ‘positive tipping points,’ where the shift towards zero-emission technologies and behaviors is also becoming self-sustaining,” Lenton observes.
However, Lenton adds that more progress is necessary if we aim to avoid exceeding further climate tipping points. “We recognize that solutions must accelerate if we are to limit warming to a degree that can mitigate the risks posed by adverse tipping points and the climate.”
