Global carbon dioxide levels surged to a record high in 2024, marking the largest single-year increase since measurements began in 1957. The World Meteorological Organization (WMO) has reported that the global average concentration of CO2 reached 423.9 parts per million (ppm) in 2024, a significant jump from 377.1 ppm in 2004 when the Greenhouse Gas Bulletin was first published. The increase of 3.5 ppm from 2023 to 2024 is a cause for serious concern, signaling an acceleration in the pace of global warming.
This record increase is attributed to a combination of factors, including continued emissions from human activities, a surge in wildfires, and a reduced capacity of land and ocean "carbon sinks" to absorb CO2. Wildfires, exacerbated by hotter and drier conditions, released historic levels of emissions, particularly in the Americas. Additionally, the strong El Niño weather pattern in 2024 further reduced the effectiveness of carbon sinks due to drier vegetation and increased forest fires.
The rise in CO2 levels is not an isolated issue. The WMO report also highlighted that concentrations of other major greenhouse gases, such as methane and nitrous oxide, have also reached record highs. Methane, the second most significant long-lived greenhouse gas, reached 1,942 parts per billion (ppb) in 2024, representing a 166% increase above pre-industrial levels. Nitrous oxide also saw a significant increase, further contributing to global warming.
The consequences of these escalating greenhouse gas concentrations are far-reaching. The WMO Deputy Secretary-General, Ko Barrett, emphasized that the heat trapped by CO2 and other greenhouse gases is "turbo-charging our climate," leading to more extreme weather events and threatening economic security and community well-being. The State of the Global Climate 2024 report confirmed that 2024 was likely the first calendar year to exceed 1.5°C above the pre-industrial era, with a global mean near-surface temperature of 1.55 ± 0.13 °C above the 1850-1900 average. The report also noted that the past ten years, from 2015 to 2024, were the warmest ten years on record.
The increasing CO2 levels have raised concerns among scientists about the weakening of natural carbon sinks. Oceans are getting warmer and can absorb less CO2, while hotter and drier conditions on land, along with more wildfires, mean less plant growth and carbon absorption. Oksana Tarasova, Senior Scientific Officer at the WMO, warned that the reduced effectiveness of these sinks could further accelerate global warming.
While the long-term warming remains below 1.5°C, the record greenhouse gas concentrations combined with El Niño and other factors drove record heat in 2024. The report underlines the massive economic and social disruptions caused by extreme weather. The rise in CO2 levels necessitates urgent action to reduce emissions and transition to a sustainable, low-carbon economy. The upcoming UN Climate Change Conference COP30 in Belém, Brazil, will be a crucial opportunity for global stakeholders to ramp up support for climate action and commit to more ambitious emissions reduction targets.
