Levels of carbon dioxide in the atmosphere rose once again to the highest values ever recorded, despite global emissions drops due to the coronavirus pandemic. Carbon dioxide concentrations recorded at the Mauna Loa Observatory in Hawaii reached 417.2 parts per million (ppm) in May, 2.4 ppm higher than last year’s peak of 414.8 ppm (Reuters). 

“People may be surprised to hear that the response to the coronavirus outbreak hasn’t done more to influence [carbon dioxide] CO2 levels. But the buildup of CO2 is a bit like trash in a landfill. As we keep emitting, it keeps piling up,” said Ralph Keeling, a professor at the Scripps Institution of Oceanography (The Guardian). 

Carbon emissions fell by an average of 17% in early April due to the impacts of the coronavirus outbreak, with some countries experiencing a decrease of up to 26 percent (The Washington Post, Reuters). However, scientists estimate that emissions would need to drop by 20-30% for six months or longer in order to slow the rate of growth of atmospheric carbon (New York Times).

Carbon dioxide levels are compared from year to year each May, when atmospheric carbon peaks before vegetation growth in the Northern Hemisphere removes some of the carbon through photosynthesis (New York Times, The Guardian). Annual rates of increase in carbon dioxide levels have been speeding up, with an average annual growth rate of 2.4 ppm this past decade, compared to 0.8 ppm in the 1960s (The Guardian).