The monthly average concentration of carbon dioxide in the atmosphere jumped by a record 4.7 parts per million between March 2023 and March 2024, according to new data from NOAA’s Mauna Loa Observatory in Hawaii.
The jump, reported by the University of California, San Diego’s Scripps Institution of Oceanography on Wednesday, reveals “the increasing rate of addition of CO2 to the atmosphere by human activities,” the university said.
“I would make this a lead story in every newspaper and newscast on the planet,” author and longtime climate activist Bill McKibbenwrote on social media in response to the news. “If we don’t understand the depth of the climate crisis, we won’t act in time.”
“Human activity has caused CO2 to jump up. That saddens me more than anything. It’s sad what we do.’
Scientists have tracked rising CO2 concentrations from Mauna Loa since 1958, and their upward trajectory is known as the “Keeling curve,” named after Charles Keeling, who began the measurements. The curve has become an important symbol of the climate crisis – showing how burning fossil fuels and cutting down vegetation releases more and more CO2 into the atmosphere, where it traps heat escaping into space and raises global temperatures.
For most of human history, concentrations hovered around 280 ppm, and the first measurement of the curve put them at 313. Sixty-five years later, C02 concentrations averaged 419.3 ppm in 2023, the level , not seen since 4.3 million years ago, when sea levels were about 75 feet higher and parts of today’s arctic tundra were forested. From Wednesday, the Keeling curve reported daily concentration of 426.72 ppm.
The record spike from March 2023 to March 2024 surpasses the last record spike of 4.1 ppm from June 2015 to June 2016.
“Unfortunately, we continue to break records for the rate of increase in CO2,” said Ralph Keeling, Charles’ son, who now directs the Scripps CO2 program. “The ultimate cause is the continued global growth in fossil fuel consumption.”
The record spikes from both 2015-2016 and 2023-2024 were also influenced by active El Niño events. El Niño increases carbon dioxide in the atmosphere because it leads to warmer and drier temperatures in the tropics, which reduces vegetation and encourages fires. Atmospheric CO2 levels tend to rise particularly rapidly towards the end of the El Niño cycle, and CO2 levels last March were unusually low, resulting in a larger difference over the 12-month period.
This year’s rate of increase during the current El Niño is significantly greater than what occurred in 2016. As Scripps explained:
The increase from February 2023 to February this year is 4.0 ppm, compared to 3.7 for El Niño in 2016. The increase from January 2023 to January this year is 3.4 ppm, compared to 2. 6 for El Niño in 2016.
The growth rate from April 2023 to April 2024 has dropped to 3.6 ppm, but considering the first four months of 2024, the growth rate is well above that of 2016. If this El Niño follows the pattern of the last El Niño, the world could have a very high growth rate for several more months, Keeling said.
However, any regular changes in climate, such as El Niño, occur over the long term in both fossil fuel emissions and greenhouse gas levels.
“The rate of increase is almost certainly going to decrease, but it’s still going up, and to stabilize the climate, you need the CO2 level to fall,” Keeling saidThe Guardian. “Clearly that’s not happening. Human activity has caused CO2 to skyrocket. That saddens me more than anything. It’s sad what we do.’
Jeff Goodell, author of The heat will kill you first, wrote in response, “We travel on the Venus Express.”
The record jump in CO2 concentrations comes as 2023 was the hottest year both on record and in about 100,000 years. Of the 12 months covered by the March 2023 to March 2024 period, 10 of them (June to March) were the hottest for that month on record.
