GENEVA, Switzerland: The level of carbon dioxide in Earth's atmosphere has reached its highest point in recorded history, accelerating global warming and fueling more extreme weather, the World Meteorological Organization (WMO) warned in a report.

Between 2023 and 2024, the global average concentration of CO2 increased by 3.5 parts per million, the most significant annual jump since modern record-keeping began in 1957. The report comes weeks before the United Nations Climate Change Conference in Brazil, underscoring the mounting urgency for countries to cut emissions.

The WMO said the rise was driven by the continued burning of fossil fuels and a spike in wildfires, particularly across South America, where prolonged drought and heat intensified fire activity.

"The heat trapped by CO2 and other greenhouse gases is turbo-charging our climate and leading to more extreme weather," said Ko Barrett, the WMO's deputy secretary-general.

In addition to CO2, the concentrations of methane and nitrous oxide, two other primary greenhouse gases, also hit record highs. Compared with pre-industrial levels, methane has climbed 16 percent, nitrous oxide 25 percent, and carbon dioxide 52 percent, the report said.

"This gas (CO2) accumulates in the atmosphere. It has a very long lifetime," said Oksana Tarasova, a senior scientific officer at the WMO. "Every single molecule that is emitted in the atmosphere will have a global impact."

The report also warned that the planet's natural carbon sinks — forests, soils, and oceans that absorb roughly half of human-caused emissions — are showing signs of strain. Their capacity to pull carbon from the atmosphere is weakening under the stress of rising temperatures, drought, and deforestation.

"We rely on natural systems to help us offset our impacts, and those systems are so stressed that they start reducing their help," Tarasova said.

In the Amazon rainforest, for instance, trees have been weakened by rising heat and low rainfall linked to the 2023 El Niño weather pattern in the Pacific. That stress continued into 2024, sharply reducing the region's ability to absorb CO2.

"If the tree is under stress, if it doesn't have water and has a very high temperature, it does not photosynthesize," Tarasova explained.