The concentration of atmospheric carbon dioxide (CO2) in 2021 could exceed 417 parts per million (ppm), experts at the UK National Meteorological Service said. Thus, it will increase by 50% compared to pre-industrial levels.
The team used data collected at the Mauna Loa Observatory in Hawaii. Although there was a slight decrease in global greenhouse gas emissions in 2020, it was not enough to offset the previous increase.
Scientists explained that carbon dioxide remains in the atmosphere for a very long time, so its amount continues to increase year by year, despite short-term “pauses. The fluctuations depend on the seasons. CO2 peaks in May. There is a decrease in summer as flowering plants in the Northern Hemisphere draw in some of the gas.
Although total CO2 in 2020 is down 7% from previous years, by now emissions are almost back to pre-pandemic levels. In 2021, some decline is predicted as the La Niña phenomenon (cooling of the Pacific Ocean waters) should bring a cooler second half of the year. Tropical forests grow faster at these temperatures and absorb more CO2. But even that won’t make much of a difference.
The Mauna Loa Observatory keeps the longest continuous record of atmospheric CO2 concentrations in the world. Climate scientist Charles David Keeling was the first to record carbon dioxide values in 1958.
“To reverse this trend and slow the growth of atmospheric CO2 will require reducing global emissions, and to stop it will require reducing global emissions to net zero. This should happen within about the next 30 years,” the authors of the scientific paper noted.