Highest carbon dioxide level in human history
The pandemic put the global economy in lockdown last year but it did not prevent a rise in carbon dioxide levels in the atmosphere, scientists said on Monday. Measurements at the Mauna Loa observatory in Hawaii averaged 419 parts per million (ppm) during May, the highest concentration of the greenhouse gas in the atmosphere ever experienced by humans, according to the Scripps Institution of Oceanography.
Carbon dioxide is the most abundant greenhouse gas produced by human activity, from transportation and electric power generation to agriculture and deforestation, and persists in the atmosphere and oceans for thousands of years after it is emitted. Scripps said carbon dioxide levels are comparable to the Pliocene era, more than 4 billion years ago, when the average temperature was 7°F. higher than in pre-industrial times.
“The ultimate control knob on atmospheric (carbon dioxide) is fossil-fuel emissions,” said Ralph Keeling of the Scripps Institution. “We ultimately need cuts that are much larger and sustained longer than the COVID-related shutdowns of 2020.”
Scripps and the National Oceanic and Atmospheric Administration each conduct carbon dioxide measurements on Mauna Loa. Concentrations are highest in May; vegetation in the Northern Hemisphere removes carbon dioxide during the growing season. This year’s reading of 419 ppm was 1.8 ppm higher than in May 2020 and close to the average annual increase since 2010. “There was no discernible signal in the data from the global economic disruption caused by the coronavirus pandemic,” said NOAA.