CO2 levels in the atmosphere have risen sharply to a new peak this year, despite the impact of the global effects of the coronavirus crisis.
The concentration of CO2 in the atmosphere reached 417.2 parts per million in May, 2.4ppm higher than the peak of 414.8ppm in 2019, according to readings from the Mauna Loa observatory in the US.
Without global lockdowns aimed at slowing the spread of Covid-19, the rise could have reached 2.8ppm, according to Ralph Keeling, a professor at the Scripps Institution of Oceanography. He said they were likely to have played a small role, but the difference was too small to show against other factors that cause fluctuations from year to year.
"People may be surprised to hear that the response to the coronavirus outbreak has not done more to influence CO2 levels," he said. “But the accumulation of CO2 is a bit like garbage in a landfill. As we keep broadcasting, it keeps piling up. The crisis has slowed emissions, but not enough to appear noticeably on Mauna Loa. What will matter much more is the path we take to get out of this situation.
Daily carbon dioxide emissions decreased by an average of about 17% worldwide in early April, according to a comprehensive study last month. However, as lockdowns are reduced, the drop in emissions for the year overall is likely to only be between 4% and 7% compared to 2019. That will not make a measurable difference in the world's ability to comply. the goals of the Paris agreement, and keeping global warming below the 2C threshold that scientists say is necessary to avoid catastrophic effects.
If emissions reductions of 20% to 30% were sustained for six to 12 months, then the rate of increase in CO2 measured at Mauna Loa would slow down, according to Scripps scientists.
This year's increase is slightly weaker than last year, but matches the average annual increase of the last decade. The amount of carbon fluctuates based on various factors, including the effects of the El Niño weather system in the Pacific.
Carbon dioxide tends to peak each year in late May, when the shocks of the Northern Hemisphere spring still have no effect, so the data for the month is compared from year to year. Measurements have been taken continuously at the remote Mauna Loa Observatory in Hawaii since 1958, providing vital information for climate scientists.
The latest data comes from Scripps scientists at the University of California, San Diego and the US National Oceanic and Atmospheric Administration.They found that CO2 levels in the atmosphere first rose above 400 ppm in 2014 The annual growth rate of emissions has accelerated.
In the 1960s, annual growth averaged around 0.8ppm, doubled to 1.6ppm per year in the 1980s, and held steady at 1.5ppm in the 1990s. The average growth rate increased to about 2.0ppm per year in the 2000s, and has increased further to about 2.4ppm over the last decade.
Environmental activists said the continued rise in emissions showed how urgently a green recovery from the Covid-19 crisis was needed.
John Sauven, the chief executive of Greenpeace UK, called on the British government to do more as hosts of the upcoming UN climate talks, Cop26, now postponed until 2021. “Just a few months of low emissions would probably not affect the hundreds of billions of tons of carbon that have accumulated over a century and a half from the burning of fossil fuels, "he said.
"That is why the drop in emissions caused by the pandemic will remain only a problem, unless governments are serious about building a cleaner, healthier and safer world."
Friends of the Earth activist Muna Suleiman said: "It is clear that climate collapse is not a distant idea, it is here now, and we have to treat it as if it were an emergency."