Atmospheric carbon dioxide levels hit a new high last year and have only continued to climb in the first two months of 2017, federal scientists reported Friday.
The concentration of carbon dioxide in the atmosphere at a U.S. observatory in Hawaii rose by 3 parts per million (ppm) to 405.1 ppm last year, according to the National Oceanic and Atmospheric Administration (NOAA).
Carbon dioxide levels jumped by 3 ppm between 2015 and 2016 and have “surged” by 6 ppm over two years, a level of growth unseen in the Mauna Loa observatory’s 59-year history, NOAA said.
NOAA noted that it has already observed a carbon dioxide level topping 406 ppm this year. The agency called it “a real shock to the atmosphere.”
“The rate of CO2 growth over the last decade is 100 to 200 times faster than what the Earth experienced during the transition from the last Ice Age,” Pieter Tans, the lead scientist of NOAA's Global Greenhouse Gas Reference Network, said in a statement.
Many scientists warned for years that carbon dioxide levels should not rise above 400 parts per million — a level 43 percent higher than pre-industrial times — if the worst of climate change was to be avoided. The global carbon dioxide average passed that mark in 2015.
The vast majority of climate scientists agree that increased greenhouse gas emissions — driven by human activity like fossil fuel consumption — are behind global climate change.
But conservative U.S. policymakers continue to dispute that consensus view, including Environmental Protection Agency Administrator Scott Pruitt, who this week said he “would not agree” that carbon emissions are a “primarily contributor to the global warming that we see.”