Earth has just set a record it never wanted to set: the highest ever amount of carbon dioxide in its atmosphere. In May, that number reached 419 parts per million, the highest it’s been in at least 4 million years, according to the National Oceanic and Atmospheric Administration.

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Things were looking good for a while last year, with the pandemic putting a brake on lots of humanity’s careless, polluting misdoings. But as people begin working, traveling and shopping again, greenhouse gas emissions have taken off.

Related: Hawaii declares a climate emergency

“We still have a long way to go to halt the rise, as each year more CO2 piles up in the atmosphere,” said Scripps geochemist Ralph Keeling, as reported by NPR. “We ultimately need cuts that are much larger and sustained longer than the COVID-related shutdowns of 2020.”

CO2 levels peak every May, just before growing springtime plants start sucking up the gas in earnest. Once the plants use CO2 for photosynthesis, the atmospheric level will drop a little — but not nearly enough. Human hunger for electricity and transportation far outpaces what plants can remove from the atmosphere.

NOAA and the Scripps Institution of Oceanography took May measurements on top of Hawaii’s Mauna Loa volcano. Last year, the average was two points lower at 417 parts per million.

The Pliocene period was the last time the Earth’s atmosphere had so much carbon dioxide. Back then, about 4.1 to 4.5 million years ago, the planet averaged 7 degrees Fahrenheit warmer and sea levels were 78 feet higher. The Arctic tundra may have been a forest.

“We are adding roughly 40 billion metric tons of CO2 pollution to the atmosphere per year,” Pieter Tans, a senior scientist with NOAA’s Global Monitoring Laboratory, said in a statement. “If we want to avoid catastrophic climate change, the highest priority must be to reduce CO2 pollution to zero at the earliest possible date.”

How many times have we heard this? How many more times can we hear it before the damage is irreversible?



Image via Nikola Belopitov