Carbon dioxide is accumulating in the atmosphere faster than ever — accelerating on a steep rise to levels far above any experienced during human existence, scientists from NOAA and Scripps Institution of Oceanography at the University of California San Diego announced today.

“Not only is CO2 now at the highest level in millions of years, it is also rising faster than ever. Each year achieves a higher maximum due to fossil-fuel burning, which releases pollution in the form of carbon dioxide into the atmosphere,” said Ralph Keeling, director of the Scripps CO2 program that manages the institution’s 56-year-old measurement series. “Fossil fuel pollution just keeps building up, much like trash in a landfill.”

The record two-year growth rate observed from 2022 to 2024 is likely a result of sustained high fossil fuel emissions combined with El Niño conditions limiting the ability of global land ecosystems to absorb atmospheric CO2, said John Miller, a carbon cycle scientist with the Global Monitoring Laboratory.

The Mauna Loa data, together with measurements from sampling stations around the world, are incorporated into the Global Greenhouse Gas Reference Network, a foundational research dataset for international climate scientists and a benchmark for policymakers attempting to address the causes and impacts of climate change.