Carbon Level Crosses Dangerous Threshold

The amount of carbon in the Earth's atmosphere is now officially off the charts, as the planet last week breached the 410 parts per million milestone for the first time in human history.

"It's a new atmosphere that humanity will have to contend with, one that's trapping more heat and causing the climate to change at a quickening rate," wrote Climate Central's Brian Kahn. "Carbon dioxide hasn't reached that height in millions of years."

The milestone was recorded on April 18 at the Mauna Loa Observatory in Hawaii by the Keeling Curve, a program of the Scripps Institution of Oceanography at University of California San Diego, EcoWatch reported.

Since the planet reached the dangerous new normal of 400 ppm last year, scientists have warned that the accelerated rate at which concentrations of carbon dioxide are rising means that humanity is marching further and further past the symbolic redline toward climatic chaos.

“It's pretty depressing that it’s only a couple of years since the 400 ppm milestone was toppled,” Gavin Foster, a paleoclimate researcher at the University of Southampton told Climate Central last month.

“These milestones are just numbers, but they give us an opportunity to pause and take stock and act as useful yardsticks for comparisons to the geological record.”

What's more, the recording was taken before carbon levels are expected to reach their annual peak, meaning they could soon notch even higher.

Carbon dioxide concentrations have skyrocketed over the past two years in part due to natural factors like El Nino, causing more of it to end up in the atmosphere. But it’s mostly driven by the record amounts of carbon dioxide humans are creating by burning fossil fuels.

“The rate of increase will go down when emissions decrease,” Pieter Tans, an atmospheric scientist at the US National Oceanic and Atmospheric Administration, said. “But carbon dioxide will still be going up, albeit more slowly. Only when emissions are cut in half will atmospheric carbon dioxide level off initially.”

Even when concentrations of carbon dioxide level off, the impacts of climate change will extend centuries into the future.

The planet has already warmed 1°C, including a run of 627 months in a row of above-normal heat. Sea levels have risen about a foot and oceans have acidified. Extreme heat has become more common, Scientific American reported.

All of these impacts will last longer and intensify into the future even if we cut carbon emissions. But we face a choice of just how intense they become, based on when we stop polluting the atmosphere.

Right now, the planet is on track to create a climate unseen in 50 million years by mid-century.