Top scientists call out date when Earth will reach 1.5C warming "point of no return"

The Earth could surpass the critical 1.5°C global warming threshold in as little as three years if carbon dioxide emissions continue at current levels.

That’s the stark warning from a new analysis by an international team of 60 climate scientists, published in Earth System Science Data, which updates the world’s core climate indicators according to The Guardian.

In 2015, nearly 200 countries committed under the Paris Agreement to limit global warming to 1.5°C above pre-industrial levels in order to avoid the most severe impacts of climate change. However, emissions remain at record highs due to continued reliance on fossil fuels and widespread deforestation, placing that target in serious jeopardy.

“Things are all moving in the wrong direction,” said lead author Professor Piers Forster, director of the Priestley Centre for Climate Futures at the University of Leeds. “We’re seeing some unprecedented changes, and we’re also seeing the heating of the Earth and sea-level rise accelerating as well.” These changes, he added, are directly linked to the persistently high levels of greenhouse gas emissions.

At the start of 2020, scientists estimated the remaining “carbon budget”—the amount of CO₂ humanity could still emit for a 50% chance of staying within 1.5°C warming—was about 500 billion tonnes. As of early 2025, that figure has shrunk to just 130 billion tonnes, driven both by unrelenting emissions and improved scientific understanding. At the current annual emission rate of around 40 billion tonnes, that budget could be exhausted within three years. While the 1.5°C threshold may not be officially breached immediately, the world would be effectively locked into crossing it soon after.

Last year was the first in which global average temperatures exceeded 1.5°C above pre-industrial levels for a full 12-month period. Though not officially considered a breach of the Paris Agreement—due in part to a natural El Niño weather pattern—it marked a sobering milestone. Scientists estimate that human activity was the dominant cause of the rise, with temperatures reaching 1.36°C above the 19th-century baseline.

Real picture far worse than earlier predictions

The planet is currently warming at a rate of 0.27°C per decade—much faster than any rate observed in the geological record. If emissions remain high, researchers expect the 1.5°C mark will be reached permanently around 2030.

Although long-term warming could theoretically be reduced by removing vast amounts of CO₂ from the atmosphere, the authors caution against banking on this as a fail-safe. The study underscores just how much the climate has already changed, particularly through “Earth’s energy imbalance”—the rate at which excess heat accumulates in the climate system.

This rate is now more than twice what it was in the 1970s and 1980s, and 25% higher than in the late 2000s and 2010s. “That’s a really large number, a very worrying number over such a short period,” said Dr Matthew Palmer of the UK Met Office and University of Bristol.

The energy trapped by greenhouse gases ends up warming the land, air, and melting ice, but around 90% is absorbed by the oceans. This causes sea levels to rise through thermal expansion and glacier melt, while also disrupting marine ecosystems.

Part of the recent uptick in heating is due to a decline in aerosols—tiny particles that reflect sunlight and temporarily cool the Earth. With pollution controls reducing aerosol output, an article by BBC reported that their moderating effect has diminished, further exacerbating warming.

Professor Joeri Rogelj of Imperial College London stressed that the shrinking carbon budget is the direct result of the world’s failure to rein in CO₂ emissions. “Under any course of action now, there is a very high chance we will reach and even exceed 1.5°C and even higher levels of warming,” he warned.

“The best moment to have started serious climate action was 1992, when the UN climate convention was adopted,” Rogelj added. “But now every year is the best year to start being serious about emissions reduction. Every fraction of warming we can avoid will result in less harm and suffering, particularly for poor and vulnerable populations, and in fewer challenges to living the lives we desire.”

With time running out, Rogelj emphasized the importance of the upcoming UN COP30 climate summit in November as a critical moment for nations to commit to dramatic emissions cuts.

By Nazrin Sadigova