The UK Met Office forecast underscores the need to cut emissions of gases that warm the climate, scientists say.
Human activity will push the concentrations of carbon dioxide (CO2) that warms the planet in the atmosphere to levels 50% higher than before this year’s industrial revolution, crossing a symbolic threshold of climate change, said on Friday. the UK Meteorological Office in a forecast.
As 2021 is seen as a critical year for the implementation of the 2015 Paris Agreement to avert catastrophic climate change, scientists said the forecast underscored the need for swift action to reduce emissions. of CO2 from the combustion of coal, oil and natural gas.
“The accumulation of man-made CO2 in the atmosphere is accelerating,” said Richard Betts, climatologist at the Bureau of Meteorology. “It took over 200 years for the levels to rise by 25%, but now just over 30 years later we are approaching a 50% increase.”
Fossil fuel emissions and deforestation will cause further accumulation of CO2 in the atmosphere in 2021, with concentrations expected to exceed 417 parts per million (ppm) for several weeks from April to June for the first time.
This record level would be 50% higher than the concentration of 278 ppm at the dawn of the industrial era in the late 18th century, the Meteorological Bureau said.
The annual peak will likely be followed by a cyclical drop, as plants growing in the northern hemisphere in summer absorb CO2. From September, CO2 levels will start to rise again, with an average annual greenhouse gas concentration of around 416.3 ppm, the Meteorological Bureau said.
CO2 levels have long exceeded levels considered safe by climatologists. At a climate summit in Madrid in December 2019, United Nations Secretary-General Antonio Guterres warned that 400 ppm had once been seen as “an unthinkable tipping point”.
After falling sharply last spring as economies were hit by the coronavirus, emissions are now mostly back to pre-pandemic levels, the Meteorological Office said.
Still, CO2 build-up is expected to be slightly slower than usual in 2021, as weather conditions linked to a La Nina event are expected to favor a tropical forest growth spurt that will absorb some emissions, the Met Office said.