Global warming nears point of no return: Hothouse earth warning

Scientists warn that the "point of no return" for global warming may be closer than previously estimated. Ongoing global warming could trigger climate tipping points, setting off a series of feedback loops. This could trap the world in a "hothouse Earth" scenario—far worse than the current trajectory of 2–3°C warming. Such climate conditions would be drastically different from the temperate period of the past 11,000 years, during which human civilization developed.

Even the 1.3°C warming observed in recent years has already caused extreme weather events worldwide, leading to deaths and the loss of livelihoods. Scientists stress that a 3–4°C rise could halt economies and societies, while the hothouse Earth scenario would be even more catastrophic.

PUBLIC AND POLICYMAKERS UNAWARE OF THE RISK

Researchers say that the public and policymakers are largely unaware of the risk of crossing the point of no return. While it is recognized that rapidly cutting fossil fuel use is challenging, once the hothouse path is entered, reducing emissions may no longer be enough to reverse it. U.S. scientist Dr. Christopher Wolf notes that crossing certain thresholds could lock the planet into an irreversible trajectory, global temperatures are at their highest in 125,000 years, and climate change is progressing faster than expected.

Carbon dioxide levels are estimated to be at their highest in 2 million years. Prof. Tim Lenton from the University of Exeter warns that the current trajectory risks making Earth far less habitable, and even 3°C of warming carries deep risks for humanity and societies.

CRITICAL SYSTEMS DESTABILIZING

An assessment published in One Earth brings together the latest findings on climate feedback loops and 16 tipping elements. These include the Greenland and Antarctic ice sheets, mountain glaciers, polar sea ice, Arctic sub-forests, permafrost, the Amazon rainforest, and the AMOC ocean current system, which strongly affects the global climate.

Scientists suggest that tipping may have already begun in Greenland and West Antarctica, while permafrost, mountain glaciers, and the Amazon rainforest are close to thresholds. Current climate commitments are insufficient, and weakening of the AMOC could increase the risk of Amazon collapse. Carbon released from the Amazon would intensify global warming and interact with other feedback loops.

In a hothouse Earth scenario, global temperatures could remain above even the worst current projections for thousands of years, causing massive sea-level rises that submerge coastal cities. The effects on human societies would be sudden, destructive, and irreversible.