In 2024, carbon dioxide levels at Mauna Loa in Hawaii jumped by 3.58 parts per million, the largest rise since 1958. This increase is mainly from record human emissions and big wildfires in the northern hemisphere. As a result, limiting global temperature rise to 1.5°C is now almost impossible
Air monitoring station records biggest ever jump in atmospheric CO2
Author: Michael Le Page
The level of carbon dioxide in the atmosphere measured 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.
The record increase is partly due to CO2 emissions from human actions like fossil fuel burning hitting a record high in 2024.
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 is 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.”
Mauna Loa is often used to represent global change in CO2 concentrations, says Richard Engelen at the European Union’s Copernicus Atmosphere Monitoring Service (CAMS), but it is important to note that it is only a local measure. Satellite observations can now measure the average global level of atmospheric CO2 directly, and according to CAMS, this rose by 2.9 ppm in 2024. That isn’t a record, but it is one of the biggest increases since satellite observations began.
The increase in CO2 at Mauna Loa is higher than the average global level due to the large number of wildfires in the northern hemisphere in 2024, says Betts. It takes time for plumes of CO2 from sources such as wildfires to mix evenly into the atmosphere around the world. “The fire emissions in the northern hemisphere were particularly large last year,” he says.
Credits: TCA, LLC.