Humanity has been climbing a treacherous path, and now, looking down from such great heights, our footprints are clear to see.
In the middle of May, carbon dioxide (CO2) levels in our planet’s atmosphere climbed over and above 415 parts per million (ppm) for the first time since the dawn of our species. That was a single-day high. Now, for the second time in two months, scientists at the Scripps Institution of Oceanography and NOAA have bad news.
Atop Hawaii’s largest volcano, the team has recorded the highest monthly average of atmospheric CO2 since the measurements first began, 61 years ago. At 414.8 ppm, this new record sits on top of a seven-year chain of steep increases, as compared year-on-year each May.
Looking out over the past few decades, the path we took is plain to see. Scientists at the Mauna Loa Atmospheric Baseline Observatory have been taking these readings as far back as 1958, and in that time they have plotted these values on what is known as a “Keeling Curve” – named after Charles David Keeling, who first noticed a strange trend.
In the early days at Mauna Loa, the average increase of atmospheric CO2 from one year to the next was roughly 0.7 ppm. By the 1990s that was more like 1.5 ppm. Then, during the next decade, it snuck up to 2.2 ppm.
It gets worse. In 2019, both NOAA and Scripps found that this May monthly average – the highest point each year – is 3.5 ppm higher than it was in 2018. And while a single sky-high reading can be dismissed as an anomaly, exponential averages like this new record are harder to ignore.
“The more you back off and look at the big picture the more you see the hand of human beings affecting the atmosphere,” Ralph Keeling, the director of the Scripp’s CO2 program (and son of Charles David Keeling) told Inverse.
“We’re in kind of surreal territory right now.”
On top of humankind’s record-breaking fossil fuel use – which drives the vast majority of all this change – Keeling says these high rates of CO2 may also be helped along by mild El Niño conditions, like a quick rev to the engine.
Unlike climate models and other projections, which tend to underplay the rapid pace of global warming, these new measurements are real and give us reliable clues about where we are, where we have been and maybe even where we’re going.
“It’s critically important to have these accurate, long-term measurements of CO2 in order to understand how quickly fossil fuel pollution is changing our climate,” says Pieter Tans, an atmospheric scientist with NOAA’s Global Monitoring Division.
Nowadays, however, these changes are happening so rapidly, they have a way of sneaking up on us. In April of this year, the Mauna Loa observatory measured an average of more than 410 ppm, breaking an 800,000 year upper threshold.
In May, after breaking the ultimate record, Keeling made a prediction that this year’s May monthly average increase would be around 3 ppm, rather than the recent 2.5 ppm. We now know it’s even higher.
“Many proposals have been made to mitigate global warming, but without a rapid decrease of CO2 emissions from fossil fuels they are pretty much futile,” says Tans.
The recent findings were announced by The Scripps Institution of Oceanography.