The planet is facing a critical juncture as record-breaking levels of CO2 are fueling fears of an accelerating global heating crisis. According to the World Meteorological Organization, the global average concentration of carbon dioxide surged by 3.5 parts per million to 424ppm in 2024, marking the largest increase since modern measurements began in 1957. This alarming trend is not only impacting the global climate but also poses a threat to lives and livelihoods worldwide.
The primary concern lies in the weakening of natural land and ocean "sinks" that remove CO2 from the air. Scientists are worried that global heating is causing these sinks to become less effective, creating a vicious cycle that could drive temperatures up even faster. The oceans, which absorb about half of the CO2 emissions each year, are getting hotter and can therefore absorb less CO2. Meanwhile, hotter and drier conditions on land, coupled with more wildfires, are reducing plant growth and further diminishing the carbon sinks.
The situation is further complicated by the fact that carbon sinks were already known to be less effective in El Niño years, such as 2023 and 2024. Human-caused global heating has already raised the average world temperatures by about 1.3C, and researchers have recorded an "unprecedented failure of the land sink" in 2023 and 2024. This could be weakening the sinks even further, creating a dangerous feedback loop.
Dr Oksana Tarasova, a WMO senior scientific officer, expressed concern over the situation, stating that "terrestrial and ocean CO2 sinks are becoming less effective, which will increase the amount of CO2 that stays in the atmosphere, thereby accelerating global warming. Sustained and strengthened greenhouse gas monitoring is critical to understanding these loops."
The impact of rising CO2 emissions will be felt for hundreds of years due to the gas's long lifetime in the atmosphere, according to the WMO. Ko Barrett, the WMO deputy secretary general, emphasized the urgency of the situation, stating that "the heat trapped by CO2 and other greenhouse gases is turbo-charging our climate and leading to more extreme weather. Reducing emissions is therefore essential not just for our climate but also for our economic security and community wellbeing."
Atmospheric concentrations of methane and nitrous oxide, the second and third most important greenhouse gases related to human activities, also rose to record levels in 2024. Scientists are concerned that global heating is leading to more methane production in wetlands, creating another potential feedback loop. Human-caused nitrous oxide emissions include those from overuse of fertilizer by farmers and some industrial processes.
The WMO released its annual greenhouse gas bulletin a month before Cop30, the UN climate change summit in Belém, Brazil, where representatives from the world's countries will attempt to ramp up climate action. The data comes from a network of 500 monitoring stations around the world.
