Increase in atmospheric methane set another record during 2021
Carbon dioxide levels also record a big jump
For the second year in a row, NOAA scientists observed a record annual increase in atmospheric levels of methane, a powerful, heat-trapping greenhouse gas that’s the second biggest contributor to human-caused global warming after carbon dioxide.
NOAA’s preliminary analysis showed the annual increase in atmospheric methane during 2021 was 17 parts per billion (ppb), the largest annual increase recorded since systematic measurements began in 1983. The increase during 2020 was 15.3 ppb. Atmospheric methane levels averaged 1,895.7 ppb during 2021, or around 162% greater than pre-industrial levels. From NOAA’s observations, scientists estimate global methane emissions in 2021 are 15% higher than the 1984-2006 period.
Meanwhile, levels of carbon dioxide also continue to increase at historically high rates. The global surface average for carbon dioxide during 2021 was 414.7 parts per million (ppm), which is an increase of 2.66 ppm over the 2020 average. This marks the 10th consecutive year that carbon dioxide increased by more than 2 parts per million, which represents the fastest sustained rate of increase in the 63 years since monitoring began.
“Our data show that global emissions continue to move in the wrong direction at a rapid pace,” said Rick Spinrad, Ph.D., NOAA Administrator. “The evidence is consistent, alarming and undeniable. We need to build a Climate Ready Nation to adapt for what’s already here and prepare for what’s to come. At the same time, we can no longer afford to delay urgent and effective action needed to address the cause of the problem — greenhouse gas pollution.”
Carbon dioxide remains the biggest climate change threat
While there’s been scientific debate on the cause of the ongoing surge in methane levels, carbon dioxide pollution has always been the primary driver of human-caused climate change. An estimated 36 billion tons of carbon dioxide were emitted into the atmosphere last year by human activity; roughly 640 million tons of methane were emitted during the same period. The atmospheric residence time of methane is approximately nine years, whereas some of the carbon dioxide emitted today will continue to warm the planet for thousands of years.
Atmospheric levels of carbon dioxide are now comparable to where they were during the mid-Pliocene epoch offsite link, around 4.3 million years ago. During that period, sea level was about 75 feet higher than today, the average temperature was 7 degrees Fahrenheit higher than in pre-industrial times, and studies indicate offsite link large forests occupied areas of the Arctic that are now tundra.
Atmospheric levels of carbon dioxide are now comparable to where they were during the mid-Pliocene epoch offsite link, around 4.3 million years ago. During that period, sea level was about 75 feet higher than today, the average temperature was 7 degrees Fahrenheit higher than in pre-industrial times, and studies indicate offsite link large forests occupied areas of the Arctic that are now tundra.
Source
NOAA 2022 | Theo Stein
