Cosmos Editorial
Levels of carbon dioxide (CO2) in the Earth’s atmosphere continue to rise despite the industrial slowdown brought on by COVID-19, according to the World Meteorological Organisation.
In its latest Greenhouse Gas Bulletin, the WMO reports a reduction in the emissions of many pollutants and greenhouse gases this year, but says the impact on CO2 concentrations was no bigger than normal year-to-year fluctuations in the carbon cycle and natural variability in carbon sinks.
Since 1990, there has been a 45% increase in total radiative forcing – the warming effect on the climate – by long-lived greenhouse gases, with CO2 accounting for 80% of this.
“We breached the global threshold of 400 parts per million in 2015 and just four years later we crossed 410 ppm. Such a rate of increase has never been seen in the history of our records,” says WMO Secretary-General Professor Petteri Taalas.
“The lockdown-related fall in emissions is just a tiny blip on the long-term graph. We need a sustained flattening of the curve.”
The Global Carbon Project estimates that daily CO2 emissions may have been reduced by up to 17% globally during the most intense period of the shutdown, but the total annual emission reduction over 2020 is unclear.
Preliminary estimates indicate a reduction in the annual global emission between 4.2% and 7.5%. At the global scale, an emissions reduction of this scale will not cause atmospheric CO2, to go down, the report says.
The Greenhouse Gas Bulletin is based on observations and measurements from WMO’s Global Atmosphere Watch and partner networks, which includes atmospheric monitoring stations in remote Polar regions, high mountains and tropical islands.
The new issue reports that emissions from the combustion of fossil fuels and cement production, deforestation and other land-use change pushed 2019 atmospheric CO2 to 148% of the pre-industrial level of 278 ppm, which represented a balance of fluxes among the atmosphere, the oceans and the land biosphere.
During last decade, about 44% of CO2 remained in the atmosphere, while 23% was absorbed by the ocean and 29% by land, with 4% unattributed.
Individual stations have shown the upward trend continuing in 2020. Monthly Average CO2 concentrations at Mauna Loa, Hawaii, were 411.29 ppm in September, up from 408.54 ppm the previous year. At Cape Grim in Tasmania, Australia) the respective figures were 410.8 and 408.58 ppm.
And CO2 is not the only greenhouse gas trending the wrong way. Methane was 260% of pre-industrial levels in 2019, at 1877 parts per billion, and nitrous oxide, which is also an ozone depleting chemical, 123%, at 332ppm.
The Greenhouse Gas Bulletin is available on the WMO website.