Atmospheric carbon dioxide levels are higher than they’ve been in the last 3.6 million years, and methane concentrations surged in 2020, all despite restrictions brought on by the COVID-19 pandemic, according to preliminary data released this week by the U.S. National Oceanic and Atmospheric Administration (NOAA).
After exceeding 420 parts per million for the first time in recent measurements, carbon dioxide concentrations measured at the Mauna Loa Observatory in Hawai’i are now a full 50% above pre-industrial levels, The Guardian reports. Average CO2 hit an all-time high in March 2021 at 417.64 ppm, and is expected to reach 419.5 ppm this year, researchers say.
Those figures represent a 3.6 million-year high, writes CBS News.
“It is very scary indeed,” said Euan Nisbet, professor of earth sciences at Royal Holloway University of London.
“It is easy to forget just how much and just how fast fossil fuel emissions are affecting our planet,” said Prof. Simon Lewis of Imperial College London. “It took over 200 years to increase the amount of carbon dioxide in the atmosphere by 25%, and just 30 years to reach 50% above pre-industrial levels. This dramatic change is like a human meteorite hitting Earth.”
But even so, “if countries make plans now to put society on a path of sustained and dramatic cuts to emissions from today, we can avoid ever-rising emissions and the dangerously accelerating impacts of climate change.”
NOAA’s Global Monitoring Laboratory (GML) reports methane concentrations rising from 1,874.6 to 1,892.3 parts per billion between December 2019 and December 2020—the largest annual increase in the 37 years the agency has been collecting data. Methane is 84 times as potent a greenhouse gas than CO2 over the 20-year span when humanity will be scrambling to get climate change under control.
“Human activity is driving climate change,” said GML Assistant Deputy Director Colm Sweeney. “If we want to mitigate the worst impacts, it’s going to take a deliberate focus on reducing fossil fuels emissions to near zero—and even then we’ll need to look for ways to further remove greenhouse gasses from the atmosphere.”
“Although increased fossil emissions may not be fully responsible for the recent growth in methane levels,” added NOAA research chemist Ed Dlugokencky, “reducing fossil methane emissions is an important step toward mitigating climate change.”
Atmospheric carbon dioxide levels “fluctuate slightly during the year, dropping as some is absorbed during the spring and summer by plants growing in the northern hemisphere, before it rises again in autumn and winter,” The Guardian explains, citing the UK Met Office. “But the long-term trend in rising concentrations of carbon dioxide is caused by human activity, mainly through the burning of fossil fuels and also from deforestation.”
Atmospheric concentrations are continuing to add up despite a 7% drop in greenhouse gas emissions in 2020.
“Emissions may have been reduced but we are still emitting lots of carbon dioxide, and so its atmospheric concentration is bound to go up—and will continue to do so until we get to somewhere near net-zero emissions,” Prof. Martin Siegert of the Grantham Institute at Imperial College London told The Guardian. “Our path to net zero is obvious, challenging, and necessary, and we must get on with the transition urgently.”