There’s now more carbon dioxide (CO2) in the atmosphere than ever before in human history, scientists have revealed.
For the first time on record, monthly average CO2 levels exceeded 430 parts per million (ppm), according to experts at Scripps Institution of Oceanography in San Diego.
The monthly average for May 2025 reached 430.2ppm – the highest level since accurate measurements began 67 years ago.
The more CO2 in the atmosphere, the higher the rate of global warming, which could one day could make Earth’s surface too hot for humans.
At much higher concentrations, CO2 can also cause a variety of health issues.
Worryingly, this includes cognitive impairment, drowsiness, nausea and even death in the most extreme cases.
‘Another year, another record,’ said Ralph Keeling, director of the Scripps CO2 Program.
He added: ‘It’s sad.’
Like other greenhouse gases, CO2 acts like a blanket, trapping heat and warming the lower atmosphere.
This changes weather patterns and fuels extreme events, such as heat waves, droughts, wildfires, heavy rain and flooding.
Rising CO2 levels also contribute to ocean acidification, which makes it more difficult for marine organisms like crustaceans and coral to grow hard skeletons or shells.
The experts’ new measurements come from Mauna Loa Observatory, a research station situated high on the slopes of the Mauna Loa volcano, Hawaii.
At 11,141 feet above sea level, Mauna Loa Observatory measures different gases in the air by shining different kinds of light and radiation through air samples.
According to the experts, the observatory’s monthly average for May 2025 of 430.2 ppm is an increase of 3.5 ppm over May 2024’s measurement of 426.7 ppm.
Meanwhile, NOAA’s Global Monitoring Laboratory in Boulder, Colorado has separately reported an average of 430.5 ppm – an increase of 3.6 ppm over last year.
In a post on X, Jeff Berardelli, meteorologist and climate specialist for WFLA Tampa Bay, called the new record ‘concerning’.
Read More: Earth’s CO2 hits highest recorded level in human history
“I asked this question about a year ago, but surprisingly for me, it did not generate any particular interest. Because of that and because of the fact that I consider it important, I am repeating it once again in the hope that this time the interest will be greater. Some researchers believe that approximately 0.045% by volume is the maximum more or less acceptable concentration of CO2 in the atmosphere. According to them, a concentration of CO2 above that level would be disastrous for living conditions on planet Earth. Knowing that without carbon dioxide, vegetation would die out in an extremely short time (along with animals and humans), the question is, what is the minimum necessary concentration of CO2 in the atmosphere?”
“The current level is 0.04%, it has risen from 0.03% over the last few decades. At below 0.02%, plant life begins to die. The solution to the world’s ills is a drastic reduction in consumption, not carbon taxation. Polluter pays does not work because the costs of fines are just passed on to the consumer, because this is how capitalism works. The central banking cabal is getting nice and rich off carbon trading though, so at least we can console ourselves with that.”
Read More: Minimum necessary concentration of CO2 in the atmosphere
