WMO report: Greenhouse gas emissions reached record highs in 2021

Oct. 26 (UPI) -- The United Nations' World Meteorological Organization said Wednesday that in "yet another ominous warning," emissions levels for the three main greenhouse gases -- carbon dioxide, methane and nitrous oxide all reached record highs in 2021.

The WMO's Greenhouse Gas Bulletin said that methane measurements in 2020 and 2021 detected within-year increases of 15 and 18 parts per billion, respectively, the largest increases in atmospheric methane since systematic measurements began in the 1980s.

The analysis was done by the WMO Global Atmosphere Watch program.

According to the WMO, the reason for the exceptional increase isn't clear, but seems to be "a result of both biological and human-induced processes."

The WMO said in a statement that atmospheric carbon dioxide reached 149% of the pre-industrial level in 2021, primarily because emissions of from fossil fuels and cement production.

The report said global emissions have rebounded since the pandemic-related lockdowns in 2020. Of the total human activities emissions during the 2011-2020 period, roughly 48% accumulated in the atmosphere, 26% in the ocean and 29% on land.

"There is concern that the ability of land ecosystems and oceans to act as 'sinks' may become less effective in future, thus reducing their ability to absorb carbon dioxide and act as a buffer against larger temperature increase," the WMO statement said.

"In some parts of the world, the transition of the land sink into CO2 source is already happening."

Methane is the second biggest contributor to climate change, according to the WMO.

Nitrous Oxide is the third most important greenhouse gas and between 2020 and 2021 those emissions were higher than the average annual growth rate over the past ten years, according to the WMO.