Paris Agreement Turns 10 as UN Says 1.5C Limit Can No Longer Be Held Without Overshoot

Ten years after the Paris Agreement entered into force, the world has recorded its first full calendar year more than 1.5 degrees Celsius above preindustrial temperatures, and the United Nations says the chance of holding warming to that limit without overshooting it has been lost.

The agreement, adopted by 196 parties at the UN climate summit in Paris on December 12, 2015, took effect on November 4, 2016. It bound nearly every country to hold warming well below 2C above preindustrial levels and to pursue efforts to limit it to 1.5C. Today, 194 parties, 193 countries and the European Union, belong to the deal.

In 2024, the planet was more than 1.5C warmer than preindustrial levels across a full calendar year for the first time. The past three years, 2023 to 2025, were the hottest on record and the first three-year period to average more than 1.5C of warming. The long-term warming average now stands at about 1.4C, and scientists expect it to pass 1.5C around the end of this decade, according to an Al Jazeera review of the agreement’s first decade.

The UN verdict on the 1.5C limit

In October, the UN Environment Programme said in its Emissions Gap Report 2026 that the chance of keeping warming to 1.5C without overshooting it has been lost. “Every additional fraction of a degree and additional year of warming above 1.5C increases climate impacts and risks, such as the deadly floods, heatwaves and wildfires that have plagued many nations this year,” UNEP Executive Director Inger Andersen said.

Under current policies, UNEP projects warming of about 2.8C by 2100. Even if every country fully delivers its climate pledges, known as nationally determined contributions, warming would still reach about 2.6C, the report says. The Climate Action Tracker gives a similar figure of about 2.6C under current policies, down from about 3.6C when the agreement was signed.

To return to 1.5C by 2100 after overshooting it, UNEP says global emissions must fall 18 percent by 2030, 45 percent by 2035 and 69 percent by 2040, compared with 2025 levels. Renewable energy capacity must triple by 2035, coal-fired power must fall by at least 75 percent by 2035, and methane emissions must fall by at least 25 percent by 2035. Delaying decisive action by five years locks in roughly another 0.1C of warming, the report says.

Emissions still rising

Global emissions are 9 percent higher than in 2016, the year the deal took effect. China, the United States and India now produce more than half of the world’s annual emissions. China alone emits more than the United States, India, Russia and Japan combined, although the United States has released the most carbon emissions in history, according to Al Jazeera.

Germany, Japan and the United States have cut their emissions, largely by replacing coal with renewables and gas. But growth elsewhere has outweighed those cuts, and emissions in China, India and Indonesia have kept rising as those economies burn more coal to meet power demand. Investment in clean energy is now almost double investment in fossil fuels, but the cuts in emissions have been too slow to keep 1.5C within reach.

The United States, the world’s second-largest greenhouse gas emitter after China, has joined and left the agreement twice. President Donald Trump ordered both withdrawals. The first took effect in November 2020, and President Joe Biden rejoined in February 2021. The United States left again in January this year, 12 months after Trump ordered its exit for a second time.

The agreement does not force countries to meet their targets. Each government sets its own pledge and updates it every five years, and the deal relies on transparency and international pressure to raise ambition. At the first global stocktake in 2023, governments agreed to move away from fossil fuels.

Reporting based on coverage by Al Jazeera and the UN Environment Programme.