IN 2021, carbon dioxide in the atmosphere will reach levels 50% higher than before the industrial revolution due to human-caused emissions, says a Met Office forecast.
Weather patterns linked to the current La Niña event are expected to promote a temporary burst of growth in tropical forests that soak up some of humanity’s emissions.
Despite these La Niña-related effects, CO2 will still continue to build up in the atmosphere, and will exceed 417 ppm for several weeks from April to June.
This is 50% higher than the level of 278 ppm in the late 18thC when widespread industrial activity began.
Professor Richard Betts, who leads the production of the Met Office’s annual CO2 forecast, said: “Since CO2 stays in the atmosphere for a very long time, each year’s emissions add to those from previous years and cause the amount of CO2 in the atmosphere to keep increasing.
“Although the Covid-19 pandemic meant that 7% less CO2 was emitted worldwide in 2020 than in previous years, that still added to the ongoing build-up in the atmosphere.
“The human-caused build-up of CO2 in the atmosphere is accelerating. It took over 200 years for levels to increase by 25%, but now just over 30 years later we are approaching a 50% increase.
“Reversing this trend and slowing the atmospheric CO2 rise will need global emissions to reduce, and bringing them to a halt will need global emissions to be brought down to net zero. This needs to happen within about the next 30 years if global warming is to be limited to 1.5°C.”