For the first time in 4 million years, Antarctica registered carbon dioxide levels over the symbolic threshold of 400 parts per million, according to the National Oceanic and Atmospheric Administration (NOAA), the U.S. government agency responsible for monitoring conditions of the oceans and atmosphere.
Scientists at NOAA say the South Pole “has shown the same, relentless upward trend in CO2 as the rest of world,” but that it took longer for it to register.
“The far southern hemisphere was the last place on earth where CO2 had not yet reached this mark,” said Pieter Tans, the lead scientist of NOAA's Global Greenhouse Gas Reference Network. “Global CO2 levels will not return to values below 400 ppm in our lifetimes, and almost certainly for much longer.”
CO2 levels tend to rise in colder months, since the warmer months in the northern hemisphere see plants capture some of it.
But NOAA says that plants aren’t enough, as CO2 levels have risen every year since 1958, when measurements began.
The agency said that last year saw global CO2 reach 399 ppm, which it says means 2016 will almost surely reach 400 or more. The annual rate of increase jumped by more than three ppm last year, the largest increase ever measured.
“We know from abundant and solid evidence that the CO2 increase is caused entirely by human activities,” Tans said. “Since emissions from fossil fuel burning have been at a record high during the last several years, the rate of CO2 increase has also been at a record high. And we know some of it will remain in the atmosphere for thousands of years.”