Wildfires and fossil fuel burning in 2024 contributed to the biggest annual rise in atmospheric CO2 levels ever recorded at the Mauna Loa Observatory in Hawaii
By Michael Le Page
17 January 2025
The Mauna Loa Observatory in Hawaii has been recording atmospheric carbon dioxide levels since 1958
FRED ESPENAK/SCIENCE PHOTO LIBRARY
The level of carbon dioxide in the atmosphere measured by a weather station at the Mauna Loa Observatory in Hawaii increased by 3.58 parts per million in 2024 – the biggest jump since records began there in 1958.
“We’re still going in the wrong direction,” says climate scientist Richard Betts at the Met Office, the UK’s weather service.
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The record increase is partly due to CO2 emissions from fossil fuel burning and other human actions, such as cutting down forests, hitting a record high in 2024. Adding to this were a large number of wildfires, fuelled by record-smashing global temperatures boosted by the El Niño weather pattern on top of the long-term warming.
Betts is forecasting that atmospheric CO2 levels as measured at Mauna Loa will this year rise by 2.26 parts per million (ppm), with a margin of error of 0.56 ppm either way. That’s a lot less than the 2024 record, but it will take us above the last possible pathway for limiting the increase in global surface temperatures to 1.5°C above preindustrial levels.
“You could regard it as another nail in the coffin of 1.5°C,” says Betts. “That’s now vanishingly unlikely.”