The concentration of carbon dioxide in Earth's atmosphere set an all-time high last year, and the growth rate also turned out to be the fastest on record.
The World Meteorological Organization (WMO) said in its Greenhouse Gas Bulletin released on the 15th (local time) that last year's global average carbon dioxide concentration reached 423.9 ppm. That is 52% higher than the preindustrial level, the highest on record.
According to the report, the carbon dioxide concentration increased by 3.5 ppm between 2023 and 2024. That is the largest annual increase since observations began in 1957. The 10-year average growth rate for 2011–2020 was three times that of the 1960s. The WMO said the current atmospheric carbon dioxide concentration is at a level never experienced since human civilization emerged and rivals Earth's environment 800,000 years ago.
Not only carbon dioxide but also other major greenhouse gases such as methane and nitrous oxide all hit record highs. The WMO analyzed that this increase is accelerating due to unabated fossil fuel use and more frequent wildfires. At the same time, it added that climate change is weakening the carbon dioxide absorption capacity of forests and oceans, creating a vicious cycle that further intensifies warming.
Ko Barrett, WMO deputy secretary-general, said, "Heat trapped by greenhouse gases, including carbon dioxide, is fueling global warming and bringing more extreme weather," and emphasized, "Cutting greenhouse gases is not just a climate issue but an essential task for economic security and the well-being of local communities."
The WMO warned that without fundamental cuts in greenhouse gas emissions, it will be impossible to achieve the core goal of the 2015 Paris climate agreement to limit the rise in the global average temperature to within 1.5 degrees. Although last year the global average temperature temporarily exceeded 1.5 degrees, the WMO noted that "what matters is not a single year's record but the long-term trend," stressing the need for sustained action.
Meanwhile, the Greenhouse Gas Bulletin is scheduled to be officially reported at the 30th Conference of the Parties to the United Nations Framework Convention on Climate Change (COP30), to be held in Brazil next month.