New Record High of Atmospheric Carbon Dioxide Levels Recorded at Monitoring Station

Atmospheric carbon dioxide levels measured by Hawaii’s Mauna Loa Observatory weather station increased by 3.58 parts per million in 2024, the largest increase since records began in 1958.

‘We’re still going in the wrong direction,’ climate scientists say Richard Betts At the Met Office, the UK’s weather bureau.

Part of this record increase is due to carbon dioxide emissions from human activities such as fossil fuel burning and deforestation, which reached an all-time high in 2024. Added to this were numerous wildfires caused by record global warming driven by climate change. Long-term warming plus El Niño weather patterns.

Betts predicted that atmospheric carbon dioxide concentrations measured at Mauna Loa would rise by 2.26 parts per million (ppm) this year, with a margin of error of 0.56 ppm either way. This is significantly lower than the 2024 record, but it would exceed the last possible pathway to limiting the rise in global surface temperatures to 1.5°C above pre-industrial levels.

“You can think of this as another nail in the 1.5°C coffin,” Betts says. “Now that’s highly unlikely.”

Atmospheric carbon dioxide concentration is the most important indicator when it comes to climate change, as increasing atmospheric carbon dioxide concentration is the main driver of short- and long-term warming. The first continuous measurements of CO2 levels were taken at Mauna Loa.

“Because this station has the longest observation record and is located far from major anthropogenic and natural sources of CO2 emissions and sinks, it is often used to represent changes in global CO2 concentrations. It will be done.” Richard Engelen At the EU’s Copernicus Atmospheric Monitoring Service.

However, observations from satellites have made it possible to directly measure the global average atmospheric carbon dioxide concentration. According to CAMS, it rose by 2.9 ppm in 2024. Although this is not a record, it is one of the largest increases since satellite observations began.

“The reasons for this large increase require further investigation, but are likely a combination of a recovery in emissions in much of the world after the coronavirus pandemic and interannual fluctuations in natural carbon sinks.” says Engelen. Carbon sinks refer to marine and terrestrial ecosystems that absorb about half of the carbon dioxide emitted by humans.

It has long been predicted that as the Earth warms, this excess CO2 will become less absorbed. “The concern is whether this is the beginning of that,” Betts said. “We don’t know.”

At Mauna Loa, carbon dioxide increases will be higher than global average levels in 2024 due to the large number of wildfires in the Northern Hemisphere, Betts said. CO2 plumes from sources such as wildfires take time to mix evenly into the world’s atmosphere. “Fire emissions in the Northern Hemisphere were particularly high last year,” he says.

Although it is now certain that global warming will exceed the 1.5°C threshold, Betts believes it is still the right goal to set that goal. “The Paris Agreement is carefully worded to seek to limit global warming to 1.5%. We recognized from the beginning that this would be difficult,” he says. “The idea was to set this stretch goal to motivate action, and I actually think it was successful. It galvanized action.”