According to the World Meteorological Organization (WMO), the concentration of carbon dioxide in the atmosphere reached a record high in 2024, leading to prolonged warming and more extreme weather events.
AZERTAC, citing UN data, reports that the continued growth of emissions linked to human activity has resulted in an increase in wildfires and dangerously high levels of carbon dioxide on land and in the oceans.
The latest WMO bulletin shows that the rate of CO₂ concentration growth has tripled since the 1960s, accelerating from an average of 0.8 parts per million (ppm) per year in 2011 to 2.4 ppm in the decade up to 2020. This figure rose to 3.5 ppm between 2023 and 2024 — the largest increase since monitoring began in 1957. About half of all CO₂ emitted into the atmosphere remains there, while the rest is absorbed by land and oceans. However, warming reduces CO₂ solubility in oceans and exacerbates droughts.
The negative indicators observed in 2024 were likely worsened by the increase in wildfires and the reduction in CO₂ absorption by land and oceans that year, which also became the warmest year on record due to a strong El Niño event.
The WMO also reported other negative climate trends. Methane and nitrous oxide — the second and third most significant long-lived greenhouse gases — also hit record levels. Atmospheric methane reached 1,942 ppb, 166% higher than pre-industrial levels, while nitrous oxide rose to 338 ppb, up 25%. WMO Deputy Secretary-General Ko Barrett stated: “The heat trapped by CO₂ and other greenhouse gases is negatively affecting our climate and causing more extreme weather events. Reducing emissions is therefore crucial not only for our climate but also for our economic security and societal well-being.”
On the other hand, there are findings suggesting that cleaning the atmosphere can also contribute to warming. Following China’s large-scale air pollution control campaign launched in 2013, sulfur dioxide (SO₂) emissions in East Asia dropped by 75%.
Scientists conducted 160 complex computer simulations based on eight global climate models to reproduce the real-world reduction in air pollution observed since 2010. The results were concrete and significant: a reduction in aerosol pollution in East Asia led to an additional 0.07°C of global warming. Previously, climatologists had estimated that warming since 2010 would total around +0.23°C, but it turned out to be closer to +0.33°C.
Modeling showed that this additional 0.1°C could largely be explained by the reduction of air pollution in East Asia. Other factors, such as lower emissions from shipping and higher methane concentrations, also played a role, but the East Asian aerosol effect proved to be the key driver.
Pollution particles — especially sulfate aerosols formed from SO₂ — either directly reflect sunlight back into space or alter cloud microphysics, making clouds brighter and more reflective. This cooling effect, scientists believe, has held back human-induced warming by as much as 0.5°C over the past century.
Computer simulations revealed yet another dimension of warming: the elimination of coal smog and similar pollutants contributes to warming, thus exposing the true scale of climate change driven by solar and atmospheric interactions.
In a report released ahead of the upcoming COP30 Climate Conference, to be held in Belém, Brazil, in November, the WMO emphasized that continuous global monitoring is vital to guide effective climate action.
