Scientists Warn World Has Just Three Years Left to Stay Within 1.5°C Climate Limit

The warning comes from a group of more than 60 researchers who analyzed the latest data on global warming trends. Their findings suggest that the internationally agreed target—set under the Paris Agreement in 2015—is now at serious risk of being missed.

Despite global commitments, countries continue to burn large amounts of coal, oil, and gas while also clearing forests that absorb carbon dioxide. As a result, the remaining “carbon budget”—the amount of CO₂ that can still be emitted while maintaining a 50% chance of staying below 1.5°C—has rapidly declined.

At the start of 2020, scientists estimated that humanity could emit about 500 billion tonnes of carbon dioxide. By early 2025, that figure had dropped to just 130 billion tonnes, largely due to continued high emissions and updated scientific calculations.

With global emissions currently running at around 40 billion tonnes per year, that remaining budget could be used up in approximately three years. This would effectively lock the planet into exceeding the 1.5°C threshold, even if the actual temperature rise occurs slightly later.

Researchers say the impacts of climate change are already being felt. Extreme weather events are becoming more frequent and intense, while sea levels are rising at an accelerating pace, threatening coastal populations worldwide.

Lead author Piers Forster from the University of Leeds said the situation is deteriorating rapidly. He noted that both global temperatures and sea levels are increasing faster than previously observed, driven by persistently high emissions.

Recent data shows that 2024 was the first year in which average global temperatures exceeded 1.5°C above pre-industrial levels for a full 12-month period. However, scientists caution that this alone does not yet constitute a formal breach of the Paris Agreement, as long-term averages are used for that determination.

Human activity remains the dominant cause of warming, accounting for an estimated 1.36°C of temperature increase above pre-industrial levels. The current rate of warming is approximately 0.27°C per decade—significantly faster than any rate observed in geological history.

If emissions remain high, researchers project that the world could reach sustained 1.5°C warming around 2030. While some scientists suggest that future technologies could remove carbon dioxide from the atmosphere and potentially reverse warming, experts warn against relying too heavily on such solutions.

Joeri Rogelj of Imperial College London cautioned that large-scale carbon removal may not fully offset the effects of current emissions, especially if warming significantly exceeds the target.

The report also highlights a sharp increase in the Earth’s “energy imbalance”—the rate at which excess heat is accumulating in the climate system. This rate has more than doubled compared to the late 20th century and continues to rise.

Around 90% of this excess heat is absorbed by the oceans, leading to thermal expansion of seawater and accelerating sea-level rise. Combined with melting glaciers, this has caused global sea levels to rise at twice the rate observed in the 1990s, increasing flood risks for millions living in coastal regions.

Despite the alarming trends, the researchers note that the growth rate of emissions may be slowing as renewable energy technologies expand. However, they stress that rapid and substantial reductions in emissions are now more critical than ever.

Scientists emphasize that the difference between 1.5°C and 2°C of warming is significant, with far greater risks at higher temperatures. While the 1.5°C target is often framed as a boundary between safety and danger, experts say the reality is more nuanced.

“Every fraction of a degree matters,” Rogelj said, noting that even small reductions in warming can significantly reduce harm, particularly for vulnerable populations.

The findings underline the urgency of immediate global action, as decisions made in the coming years will play a decisive role in determining the planet’s climate future.