Five of Earth’s vital systems are close to a point of irreversible change, warns a new report released by a global network of scientists ahead of the upcoming U.N. climate change conference in Brazil.
The 2025 Global Tipping Points report updates a 2023 report to assess 25 Earth systems that human societies and economies depend on, including the stability of coral reefs, forests and ice sheets. It found at least one system has likely passed a tipping point, while four others are perilously close.
The Paris Agreement set a goal of limiting global warming to 1.5° Celsius (2.7° Fahrenheit) above preindustrial levels by 2100. The report notes that Earth has already reached an average increase of 1.4°C (2.5°F) over the past couple decades.
Warm water coral reefs reached their tipping point at roughly 1.2°C (nearly 2.2°F).
Mike Barrett, chief scientific adviser at WWF-UK and report co-author, told Mongabay by email that the impacts are already visible with repeated coral bleaching events. “The most recent one started in 2023 and has impacted 80% of warm water coral cover.”
The report states that four other Earth systems — permafrost, the subpolar gyre and the Greenland and West Antarctic ice sheets — likely have a tipping point around 1.5°C.
“There is 60m [197 feet] sea level rise locked in Antarctic ice sheets alone,” Barrett said. At current temperatures several meters of sea level rise are already inevitable, and additional warming will mean even more.
Melting ice sheets reduce salinity for nearby oceans, slowing high-latitude ocean currents known as subpolar gyres. The weakening of these gyres will likely further disrupt global ocean circulation and alter weather patterns worldwide, the report notes.
Tropical forests, including the Amazon, are also perilously close to a tipping point. Previous estimates suggest a dieback threshold for the Amazon between 2°C and 6°C (3.6-10.8°F) of warming, David Armstrong McKay, report co-author and lecturer with the University of Sussex, U.K., told Mongabay by email. However, those estimates only accounted for climate change, when deforestation is factored in, parts of the Amazon could be at risk with a temperature rise as low as 1.5°C, he said.
If the Amazon collapses, roughly 10% of global biodiversity will be impacted, Barrett said. “Agriculture in the region and beyond would collapse not least as the tropical monsoon systems would be disrupted — making it impossible for billions of people to predict the rains upon which they rely,” he said.
Such cascading effects make climate change a global security concern, threatening food and water supplies worldwide. “If climate change is unchecked then mass mortality, forced displacement and severe economic losses become likely,” the report concludes.
Still, the scientists emphasize that the future is not yet fixed. Slowing deforestation could delay the tipping point for tropical forests, they say, and some corals could still recover if protected from overfishing and pollution while global temperatures are reduced.
Banner image of glacial melting in the Himalayas by Sharada Prasad via Wikimedia Commons (CC BY 2.0).
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