The beat goes on.

Levels of carbon dioxide in Earth’s atmosphere reached another record high last month, scientists from the National Oceanic and Atmospheric Administration and the Scripps Institution of Oceanography announced Monday.

In fact, those levels continued “a steady climb further into territory not seen for millions of years,” NOAA said.

“Sadly we’re setting a new record,” said Scripps Oceanography geoscientist Ralph Keeling, who oversees the iconic Keeling Curve record established by his father 65 years ago.

The carbon dioxide (CO2) level measured in May in Hawaii averaged 424 parts per million, NOAA said. That’s 3 parts per million more than last year’s May average and 51% higher than pre-industrial levels of 280 ppm. It also represents the fourth-largest annual increase on record.

‘A long way to go’

“What we’d like to see is the curve plateauing and even falling because carbon dioxide as high as 420 or 425 parts per million is not good,” Keeling said in a statement. “It shows as much as we’ve done to mitigate and reduce emissions, we still have a long way to go.”

NOAA Administrator Rick Spinrad said “every year we see carbon dioxide levels in our atmosphere increase as a direct result of human activity. Every year, we see the impacts of climate change in the heat waves, droughts, flooding, wildfires and storms happening all around us.

“While we will have to adapt to the climate impacts we cannot avoid, we must expend every effort to slash carbon pollution and safeguard this planet and the life that calls it home.” 

How does carbon dioxide contribute to global warming?

The burning of fossil fuels such as coal, oil and gas releases “greenhouse” gases such as carbon dioxide and methane into Earth’s atmosphere and oceans.

Like other greenhouse gases, CO2 traps heat radiating from the planet’s surface that would otherwise escape into space, amplifying extreme weather events, such as heat waves, drought and wildfires, as well as precipitation and flooding, NOAA said.

In addition, rising CO2 levels also pose a threat to the world’s oceans, which absorb both CO2 gas and excess heat from the atmosphere. Impacts include increasing ocean temperatures and the disruption of marine ecosystems, rising sea levels and ocean acidification, NOAA reported.

‘A massive experiment’

“We are absolutely at levels unseen in human civilization,” University of Oklahoma meteorology professor Jason Furtado said. “Humans are running a massive experiment on the Earth climate system via burning carbon, and the results are turning out not great for a lot of people on this planet.”

And according to NOAA’s Arlyn Andrews, CO2 now is higher than any time in the last 4 to 4.5 million years, when the atmosphere was about 7 degrees warmer and sea levels were 16 to 82 feet higher.