A grim signal: Atmospheric CO2 soared in 2024

The latest anomaly in the climate system that can’t be fully explained by researchers is a record annual jump in the global mean concentration of carbon dioxide in the atmosphere measured in 2024.

The concentration, measured in parts per million, has been increasing rapidly since human civilizations started burning coal and oil in the mid-1800s from the pre-industrial level of 280 ppm.

In recent decades, the increase has often been in annual increments of 1 to 2 ppm. But last year, the increase measured by the National Oceanic and Atmospheric Administration’s Global Monitoring Laboratory was 3.75 ppm, according to the lab’s early April update of atmospheric greenhouse gas concentrations.