Greenhouse gas concentrations in the atmosphere have continued to rise to new record highs, despite an expected drop due to Covid-19 lockdowns, says the World Meteorological Organisation (WMO).
Levels of carbon dioxide saw a record increase in 2019 compared to 2018 and to the past ten years, according to WMO’s annual Greenhouse gas bulletin, which provides an overview of CO2, methane and nitrous oxide in the atmosphere.
“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,” said WMO director-general Professor Petteri Taalas at a press briefing.
Slight fall in 2020. He pointed out that carbon emissions are expected to drop by four to seven per cent this year on account of lockdowns and the economic slowdown. However, this will be “tiny blip on the long-term graph” as it “is in fact no bigger than the normal year to year fluctuations in the carbon cycle and the high natural variability in carbon sinks like vegetation”.
While emissions are the particles and gases put into the air, concentrations represent what remains in the atmosphere after a part of those emissions are absorbed by plants, oceans and land.
Dr Oksana Tarasova, chief of the atmospheric and environment research division at WMO described the rate of increase as “dramatic”.
“This is comparable with the level of CO2 changes which happen when the atmosphere passes from interglacial to glacial period. [These] are called abrupt changes and they happen between 100 and 200 years. Now we have done it in four years,” she said.
What this means. Carbon dioxide is the biggest contributor to global warming out of all greenhouse gases. These trap heat in the atmosphere, causing temperatures to rise.
“Carbon dioxide remains in the atmosphere for centuries and in the ocean for even longer. The last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago, when the temperature was 2-3°C warmer and sea level was 10-20 meters higher than now. But there weren’t 7.7 billion inhabitants,” said Professor Taalas.
What can be done. Returning to pre-industrial levels of carbon emissions is not likely as the negative trend will continue for the next four decades despite all efforts, professor Taalas warned. However, achieving the Paris agreement goal of limiting global warming to 1.5 C is still possible, he added.
He applauded commitments to reach carbon neutrality recently announced by states, including China, South Korea, Japan as well as Joe Biden’s pledge to rejoin the Paris accords and invest significantly in clean energy.