Climate Scientists Warn 1.5°C Threshold Could Arrive by 2029

The world could cross the 1.5 degrees Celsius warming threshold set by the 2015 Paris Agreement as early as 2029, more than a decade sooner than first projected, according to a new bulletin from the European Union's Copernicus climate change service, reported by Inside Climate News and Ars Technica. The finding emerged this week at the United Nations COP31 climate conference in Antalya, Turkey.

What do the new reports say?

Two separate analyses released at COP31 point to the same conclusion: current policy is not closing the gap. Climate Action Tracker, a nonprofit that monitors national climate pledges, found the planet remains on track to warm nearly 5 degrees Fahrenheit by 2100. That level of warming would damage coral reefs, disrupt agriculture and forests, and melt most of the world's ice, according to the group's analysis.

Climate Analytics, an international climate science and policy institute, said in a statement that government action has not meaningfully improved the end-of-century outlook. "Collective government action on climate change has stalled for the fifth consecutive year," said Sarah Heck, a climate policy analyst with the institute.

Why has the warming timeline moved up?

When the Paris Agreement was signed in 2015, scientists projected the world would not cross the pact's 2.7-degree-Fahrenheit threshold — equivalent to 1.5 degrees Celsius — until around 2045. Copernicus now projects that benchmark could be reached by 2029, a shift of roughly 16 years in just over a decade.

"This striking change suggests that global warming has accelerated in recent years," Copernicus scientists wrote in the bulletin. The agency said it does not fully understand every driver of the acceleration but stated plainly that rising greenhouse gas concentrations from human activity remain the main cause.

What is happening at COP31?

The Antalya conference opened this month with what Inside Climate News described as upbeat presentations on green technology alongside notices for evening receptions. Swedish activist Greta Thunberg is attending the talks for the first time since 2021.

"The climate crisis is a matter of life and death. The actions from those in power here are completely detached from reality. As we speak, we are losing priceless lives, ecosystems and species that we will never get back."

Thunberg's remarks, delivered on site, underscored a gap between the conference's tone and the data released alongside it.

What happens if the 1.5°C line is crossed?

Climate scientists have long treated 1.5 degrees Celsius as a marker past which impacts grow substantially more severe, including more frequent extreme heat, faster sea-level rise and greater risk to coral reef systems. The current level of warming has already produced deadly floods, wildfires and glacier collapses, according to the reports cited at COP31.

Even under the most optimistic scenario modeled by Climate Action Tracker — one that assumes full implementation of every existing policy and pledge — global temperatures would still rise 3.4 degrees Fahrenheit above preindustrial levels by 2100. Climate scientists cited in the report called that level of warming extremely dangerous.

Why has climate policy stalled?

Climate Analytics attributed the stall to two offsetting forces. New oil and gas drilling projects have continued to expand even as renewable energy deployment grows, the group said. At the same time, a number of governments have been "delaying, weakening or rolling back their climate policies," according to the Climate Analytics assessment cited by Inside Climate News.

The result, according to the group, is a fifth straight year without meaningful improvement in the long-term temperature outlook, despite continued negotiations at successive UN climate summits since Paris.

Neither Copernicus nor Climate Action Tracker set a single, universally agreed date for crossing 1.5 degrees Celsius. The projections depend on emissions trends over the next several years, and researchers caution that near-term natural variability — including ocean and atmospheric cycles — can shift the timing in either direction. But the bulletins released this week agree on the underlying trend: the gap between stated climate goals and actual policy has not closed, and the clock on the Paris threshold is moving faster than it was a decade ago.