Level of the most critical greenhouse gas, carbon dioxide (CO2), surged at an unprecedented rate last year, scientists report, threatening the goal of limiting global warming to 1.5°C above pre-industrial levels. CO2 concentrations now exceed pre-industrial levels by over 50%.
Record-high fossil fuel emissions in 2024, combined with diminished natural absorption due to wildfires and droughts, contributed to this sharp increase. The rapid rise in CO2 is deemed “incompatible” with the international climate pledge set in the 2015 Paris Agreement, according to the Met Office.
While 2024 became the hottest year on record, surpassing 1.5°C above pre-industrial levels for the first time in a calendar year, this did not violate the Paris target, which is based on long-term averages. However, sustained CO2 accumulation indicates that breaching this threshold is likely inevitable.
Richard Betts of the Met Office highlights that instead of slowing, CO2 levels are accelerating due to human activities, particularly the burning of fossil fuels and deforestation. Historical climate data suggests current CO2 levels are the highest in at least two million years.
The annual increase in CO2 is influenced by variations in natural absorption and human emissions. In 2024, fossil fuel emissions hit new highs, and the El Niño phenomenon contributed to reduced carbon absorption by natural sinks. Wildfires also released additional CO2.
Between 2023 and 2024, CO2 levels rose by nearly 3.6 ppm, reaching a record 424 ppm, the highest yearly increase since monitoring began at Mauna Loa in 1958. Prof. Ralph Keeling warns that these findings confirm we are rapidly entering uncharted climate territory.
Concerns are growing that natural carbon sinks may lose their capacity to absorb CO2 over time. The Arctic tundra is becoming a CO2 source due to warming and fires, while the Amazon rainforest’s absorption capacity is being compromised by drought, wildfires, and deforestation.
The Met Office predicts a less extreme CO2 increase in 2025 due to La Niña conditions, which allow for greater carbon absorption. However, as Prof. Betts notes, the build-up of CO2 will continue, ensuring that warming resumes.
, surged at an unprecedented rate last year, scientists report){kind=link}