The world is now on track to surpass one of the most critical climate thresholds — 1.5 degrees Celsius above preindustrial temperatures — by 2027, according to alarming new data released by the World Meteorological Organization (WMO) on Wednesday. This stark forecast arrives years ahead of previous predictions and signals the accelerating pace of climate change and the mounting challenges facing the international community.
Seven years ago, the U.N. Intergovernmental Panel on Climate Change (IPCC) forecasted that global temperatures wouldn’t rise above 1.5°C until around 2040. However, just two years ago, the panel revised that estimate to sometime between 2030 and 2035. Now, based on recent findings reported by The Washington Post, the WMO says the threshold will likely be breached in just two years — by 2027.
The updated timeline is the result of a convergence of factors: several years of record-breaking heat, declining levels of air pollution that had been slightly offsetting warming, and an unrelenting increase in global greenhouse gas emissions. Despite the rapid expansion of renewable energy sources, emissions continue to climb, driving the planet closer to irreversible climate tipping points — such as the collapse of Arctic ice sheets and coral reef systems.
“There is no way, barring geoengineering, to prevent global temperatures from going over 1.5 degrees,” said Zeke Hausfather, a climate scientist and climate research lead at Stripe. Geoengineering, which includes controversial methods like injecting aerosols into the atmosphere to artificially cool the Earth, remains highly debated among experts.
The 1.5°C target, enshrined in the 2015 Paris Agreement and once seen as a beacon of hope for climate activists and vulnerable nations, now appears increasingly unattainable. The deal committed over 190 nations to “pursue efforts” to limit warming to 1.5°C, a goal passionately advocated by small-island nations facing existential threats from sea-level rise.
Although the scientific community has often emphasized that the 1.5°C threshold refers to a long-term average over decades — not a single year — the new WMO data suggests that the five-year global temperature average is poised to cross this critical line imminently. A temporary El Niño pattern is further intensifying global temperatures.
Hausfather warned that based on current trajectories and recent heat trends, 2027 is likely to be the first year where the 20- to 30-year global average temperature exceeds the 1.5°C target.
Since its adoption, the 1.5°C threshold has become a rallying cry for climate action. Activists have marched under banners reading “Keep 1.5 Alive,” and scientists have detailed the devastating consequences of surpassing it — including crop failures, the spread of infectious diseases, and more extreme weather events.
However, even at the time of the Paris Agreement, some scientists questioned the feasibility of the 1.5°C goal. “There’s tremendous inertia in the industrial system,” said David Victor, a public policy professor at the University of California, San Diego. “It doesn’t change quickly.”
Despite the rapid growth of renewable energy technologies such as solar, wind, and batteries, fossil fuels still dominate roughly two-thirds of the global energy mix. Simultaneously, worldwide energy demand continues to climb, further complicating the transition.
Missing the 1.5°C target represents not just a scientific and environmental setback, but also a pivotal moment for global climate diplomacy. It raises difficult questions for policymakers who have pinned hopes on the goal as a motivator for emissions reductions. U.N. Secretary General António Guterres has previously said that the target is “on life support” and “will soon be dead.”
What comes next is uncertain. Some experts suggest pivoting to a focus on the Paris Agreement’s less ambitious goal of keeping warming “well below” 2°C — a target that remains technically feasible, but is also slipping out of reach. The planet is currently on track for around 2.5°C of warming, barring major shifts in policy and energy infrastructure.
Others propose “overshoot” strategies, where humanity temporarily surpasses the 1.5°C limit and later pulls temperatures back down through large-scale carbon removal. But Hausfather is skeptical: “I’m personally very skeptical about our willingness to spend tens of trillions of dollars on dealing with overshoot,” he said.
Ultimately, the latest WMO forecast marks the end of a hopeful chapter in the climate story — and the beginning of a period of greater risk and harder choices. “It’s just the longer we wait, the harder it’s going to be,” Hausfather said. “After another decade of doing nothing, we’re going to talk about the 2-degree target much like we talk about the 1.5-degree target.”
