There is one word that has come up at every climate summit for over thirty years: reduction. And there is a number that, for over thirty years, has stubbornly been doing the opposite. The World Meteorological Organization’s (WMO) Greenhouse Gas Bulletin, released today two weeks before COP31 in Antalya, records yet another record: in 2025, the global average concentration of carbon dioxide reached 426.8 parts per million (ppm), 153% of the pre-industrial level. “Another year, another record,” commented WMO Deputy Secretary-General Ko Barrett. New highs were also recorded for methane and nitrous oxide, two other greenhouse gases.
A curve that has been rising for seventy years
When Charles David Keeling began measuring carbon dioxide levels at Mauna Loa volcano in Hawaii in 1958, the air contained 313 ppm of CO2. Last May, at its seasonal peak, Mauna Loa recorded 432 ppm. But what is most concerning is the rate of increase: in the 1960s, the concentration rose by 0.8 ppm per year; in the last decade, by 2.6 ppm. In 2025, the increase was 2.8 ppm. “A further increase in concentrations is expected in 2026,” warns Oksana Tarasova of the WMO, a further surge facilitated by the new, strong El Niño.
If concentration is the bathtub, emissions are the faucet. And the faucet hasn’t been turned off yet. According to the Global Carbon Budget 2025, CO2 emissions from fossil fuels reached a record high of 38.1 billion metric tons last year (+1.1%). In 1960, they were just over 9 billion; in 1990, about 22: since the Kyoto Protocol’s base year, they have risen by about 70%. Meanwhile, the remaining carbon budget needed to stay within the safety limits set by the scientific community has shrunk to 170 billion metric tons—enough for about four years of fossil fuel emissions at current rates.
Without the UN, things would be worse
However, it would be wrong to conclude that climate diplomacy has been useless. Over the past decade, CO2 emissions have risen by 0.3% per year, compared to 1.9% in the previous decade (Global Carbon Budget), and 35 countries have reduced their emissions while continuing to grow their economies. The Climate Action Tracker notes that in 2015, on the eve of the Paris Agreement, existing policies were on track for a 3.6-degree rise by the end of the century; today, the estimate is around 2.6 degrees. This is a huge difference in a context where every tenth of a degree has significant implications for the increase in floods, droughts, and hurricane intensity.
The Cracked Shield
Yet the very multilateral system that has helped mitigate the severity of the climate crisis (even if it has not yet allowed us to reach a safe zone) is now falling apart. Donald Trump has once again pulled the United States—the world’s second-largest emitter—out of the Paris Agreement, and in January he announced the country’s withdrawal from the UN Framework Convention on Climate Change and the IPCC, the UN’s scientific panel, while canceling $4 billion in pledged funding for the Green Climate Fund. According to the Climate Action Tracker, the abandonment of U.S. targets has already caused the projection based on global commitments to rise again.
And in Europe, sovereignist parties that look to Trump’s White House as a model are pushing to derail the Green Deal. A piece of the shield built to defend us from the climate crisis has crumbled. That is why the upcoming elections —from the U.S. midterm elections on November 3 to the French presidential and Spanish parliamentary elections in 2027, and on to the German elections— also hold the key to reducing the damage and casualties of a crisis triggered by the overconsumption of fossil fuels.
When will the peak occur?
Political uncertainties make it difficult to predict when the emissions curve will begin to decline. Forecasts have already been wrong: In 2022, the International Energy Agency (IEA) predicted that 2025 would be the peak year. That didn’t happen.. Today, the most encouraging signs are coming from China, which accounts for about one-third of global CO2 emissions: according to an analysis by Carbon Brief Its fossil fuel emissions have remained essentially stable and have not exceeded the peak reached in March 2024. According to the IEA (World Energy Outlook 2025), with the announced policies, demand for coal has already peaked, while demand for oil will peak around 2030 and demand for natural gas around 2035. The most plausible scenario, therefore, is a prolonged plateau in the second half of the decade, followed by a slow decline. Too slow: To stay on track to limit global warming to 1.5 degrees, UNEP points out, emissions would need to fall by 55% by 2035. Reaching the peak isn’t enough; what matters is the speed of the decline.
COP31 in Antalya, from November 9 to 20, will serve as a test of the innovation capacity of the key players in the climate debate. At stake is not only collective security but also political primacy: if Europe and the United States fail to remove the barriers to green innovation, Beijing’s dominance over the 21st-century economy will likely be unrivaled.
