The amount of carbon dioxide in the atmosphere is still rising, even though people are driving and flying less during the COVID-19 pandemic. CO2 reached an all-time daily high on May 3rd, hitting levels that haven’t been seen in the more than 60 years since records began.
The annual average is also expected to rise, according to an analysis published today by scientists at the national meteorological service for the UK and the Scripps Institution of Oceanography. They found that the overall amount of CO2 in the atmosphere is still climbing steadily, and that the dramatic changes from the pandemic barely slowed it down.
Yesterday, the highest ever greenhouse gas concentration in history was observed at Mauna Loa Observatory: 418.12 parts per million CO2 in the atmosphere.
— UN Climate Change (@UNFCCC) May 4, 2020
The data shows how much more ambitious efforts need to be in order to stop heating up our planet. The temporary drop in greenhouse gas emissions as people stay in during the pandemic just isn’t enough to undo the decades of damage humans have inflicted by burning fossil fuels.
“Humanity’s waste pile is in the atmosphere and that doesn’t go away,” says Scripps Oceanography geochemist Ralph Keeling. “The CO2 is building up in response to not just what we’re emitting right now but what we have emitted over the past century.”
It may feel like the world has come to a virtual stop amid orders to shut down businesses and shelter in place during the pandemic. The effect that’s had on how much planet-heating pollution people pump out is already about six times greater than the 2008 Great Recession had on carbon emissions. But the total drop in global greenhouse gas emissions this year as a result of the COVID-19 crisis is projected to be just about 8 percent, according to the International Energy Agency.
“Eight percent is not an awful lot in the grand scheme of things,” says Sean Sublette, a meteorologist at the nonprofit Climate Central. The difference it will make in slowing down climate change is marginal.
An important thing to keep in mind is that carbon dioxide can persist in the atmosphere for hundreds to thousands of years after it escapes our factories and tailpipes. “It’s like a bathtub and you’ve had the spigot on full blast for a while, and you turn it back 10%, but you’re still filling the bathtub,” says Sublette. “You haven’t really stopped filling the bathtub, you’ve just slowed it a tiny bit.”
May is a key time to pay attention to carbon dioxide levels because it’s when concentrations in the atmosphere typically peak. Levels fluctuate slightly throughout the year based on the seasons. In the summer, plants in the Northern Hemisphere — where there’s more land mass — are in full gear drawing down carbon dioxide through photosynthesis. They’re less active in the fall and winter, and when their leaves drop and decompose, they release carbon dioxide. The cycle ultimately leads to a spike in atmospheric carbon dioxide in May, as spring transforms plants from leafless to bushy again, followed by a drop as summer approaches.
Carbon dioxide concentrations have peaked each year since record-keeping began at the Mauna Loa Observatory in Hawaii in 1958. From a starting point of 318 parts per million of carbon dioxide in the atmosphere in May 1958, the all-time high recorded this month reached 418.12 parts per million. The upward trend is called the Keeling Curve, after the scientist Charles David Keeling who began making the measurements.
To flatten that curve, emissions need to permanently drop by at least 50 percent, according to Ralph Keeling, who continues the research his father started. That will likely require a combination of behavior change — like we’re seeing now — and sweeping structural changes. “The changes are too big to expect it to happen just because of individual choices,” he says.
Ultimately, greenhouse gas emissions need to reach virtually zero by 2050 to avoid worst-case scenarios with climate change, according to the United Nations Intergovernmental Panel on Climate Change.