Heat-trapping carbon dioxide and methane levels in the air last year spiked to record highs again

The levels of the crucial heat-trapping gases in the atmosphere reached historic highs last year, growing at near-record fast paces, according to the U.S. National Oceanic and Atmospheric Administration.

Carbon dioxide, the most important and abundant of the greenhouse gases caused by humans, rose in 2023 by the third highest amount in 65 years of record keeping, NOAA announced Friday. Scientists are also worried about the rapid rise in atmospheric levels of methane, a shorter-lived but more potent heat-trapping gas. Both jumped 5.5% over the past decade.

The 2.8 parts per million increase in carbon dioxide airborne levels from January 2023 to December, wasn't as high as the jumps were in 2014 and 2015, but they were larger than every other year since 1959, when precise records started. Carbon dioxide's average level for 2023 was 419.3 parts per million, up 50% from pre-industrial times.

Last year's methane's jump of 11.1 parts per billion was lower than record annual rises from 2020 to 2022. It averaged 1922.6 parts per billion last year. It has risen 3% in just the past five years and jumped 160% from pre-industrial levels showing faster rates of increase than carbon dioxide, said Xin “Lindsay” Lan, the University of Colorado and NOAA atmospheric scientist who did the calculations.