WMO warns of intensifying extreme weather as CO₂ levels hit record high

The World Meteorological Organisation (WMO) has released a new report revealing that global carbon dioxide (CO₂) levels have reached a record high, potentially accelerating global warming and triggering more frequent extreme weather events.

The report, published ahead of next month’s United Nations Climate Change Conference in Brazil, stated that the average global concentration of CO₂ rose by 3.5 parts per million (ppm) between 2023 and 2024 — the fastest increase since systematic measurements began in 1957.

Key drivers behind the surge in CO₂ levels include fossil fuel combustion and a significant rise in wildfires, particularly in South America. The report stressed the urgent need for stronger measures to cut greenhouse gas emissions.

The heat trapped by carbon dioxide and other greenhouse gases is driving faster changes in our climate, leading to more frequent and more severe extreme weather events, said Ko Barrett, WMO Deputy Secretary-General.

In addition to CO₂, the report noted that other major greenhouse gases — methane and nitrous oxide — have also reached record highs, with methane levels up by 16% and nitrous oxide by 25% compared to pre-industrial levels, while CO₂ has risen by 52%.

Carbon dioxide accumulates in the atmosphere and remains there for a very long time. Every molecule emitted affects the entire Earth system, said Dr Oksana Tarasova, WMO Senior Scientific Officer, during a press briefing in Geneva.

Although roughly half of CO₂ emissions are absorbed by forests, soil, and oceans — known as natural carbon sinks — these systems are becoming less effective at capturing carbon.

We depend on these natural systems to offset the impact of human activities, but they are under increasing stress and beginning to lose their ability to help, Dr Tarasova warned.

In 2023, the Amazon rainforest faced severe stress from rising temperatures and declining rainfall due to the El Niño phenomenon in the eastern Pacific Ocean, leading to prolonged drought conditions that persisted into 2024.

When trees experience heat stress and water scarcity, they can no longer photosynthesise effectively, Dr Tarasova added.