Atmospheric CO2 levels defy the pandemic to hit record high
Scientists measuring concentrations of CO2 in the atmosphere at the Mauna Loa Atmospheric Baseline Observatory have reported the highest levels on record, and ones not seen on Earth in more than four million years. The average atmospheric CO2 levels of 419.13 parts per million (ppm) across May are far in excess of what experts consider safe, and demonstrate that it will take a lot more than the type of lockdowns seen recently across the globe to address this alarming trend.
Each May before plants in the Northern Hemisphere begin to absorb large amounts of CO2 as part of a yearly cycle, atmospheric scientists take measurements to observe the greenhouse gas at its highest levels. Two years ago these observations produced record readings, revealing levels of 415.26 ppm, a concentration that had never been reached before.
May last year then saw an average concentration of 416.2 ppm, in spite of the stringent coronavirus-related shutdowns across much of the globe. This might seem counterintuitive, as these lockdowns did lead to significant declines in some types of air pollution, including dips in carbon emissions in some locations.
But in some ways it is the perfect illustration of how real-time carbon emissions are a very separate phenomenon to the buildup of the greenhouse gas in the atmosphere through decades and decades of fossil fuel use, where it persists for thousands of years. It also shows how these small declines are difficult to distinguish amidst the natural variability of the carbon cycle, which is influenced by plants, soils, humidity and temperature, among many other factors.
“We are adding roughly 40 billion metric tons of CO2 pollution to the atmosphere per year,” says Pieter Tans, a senior scientist with NOAA’s Global Monitoring Laboratory. “That is a mountain of carbon that we dig up out of the Earth, burn, and release into the atmosphere as CO2 – year after year. If we want to avoid catastrophic climate change, the highest priority must be to reduce CO2 pollution to zero at the earliest possible date.”
According to the NOAA scientists, the types of atmospheric levels of CO2 we are now experiencing have not been seen on Earth for somewhere between 4.1 and 4.5 million years, during the Pliocene Climatic Optimum. At that time, the average temperature was around 7 °F (3.9 °C) warmer than pre-industrial times, and sea levels were around 78 ft (23.7 m) higher.
“The solution is right before our eyes,” says Tans. “Solar energy and wind are already cheaper than fossil fuels and they work at the scales that are required. If we take real action soon, we might still be able to avoid catastrophic climate change.”