Level of greenhouse gases in the atmosphere hits new high in 2021

The concentration of planet-warming gases in the atmosphere once again reached new highs last year, according to a new report. 

The report from the World Meteorological Organization (WMO) found that planet-warming gases carbon dioxide, methane and nitrous oxide were at 149 percent, 262 percent and 124 percent, respectively, of their pre-industrial levels.

This is a measure of how much of the gases remain trapped in the atmosphere in total, and is not a measure of new greenhouse gas emissions that are added annually. 

Because the most common greenhouse gas, carbon dioxide, lasts in the atmosphere for hundreds of years, its concentrations are expected to continue to grow rather than diminish for a very long time. 

This heats up the planet and exacerbates climate impacts such as heat waves, sea level rise and food insecurity. 

The report also found a relatively high increase in carbon dioxide concentrations, saying that the increase from 2020 to 2021 was larger than the average annual growth from the last decade. 

Meanwhile, methane concentrations saw their largest increase on record. Methane has more than 25 times the power of carbon dioxide to warm the Earth but usually only lasts for about 12 years in the atmosphere.

The head of the WMO — which is part of the United Nations — said the finding underscores the importance of taking action on climate change. 

“WMO’s Greenhouse Gas Bulletin has underlined, once again, the enormous challenge — and the vital necessity — of urgent action to cut greenhouse gas emissions and prevent global temperatures rising even further in the future,” said WMO Secretary-General Petteri Taalas.

“The continuing rise in concentrations of the main heat-trapping gases, including the record acceleration in methane levels, shows that we are heading in the wrong direction,” Taala said. 

The report, which comes just a few weeks before a major global climate conference, was released on the same day as a separate U.N. report that found that countries’ climate pledges were insufficient to take on the issue.