Record Global Carbon Dioxide Levels Surpass 400 Ppm

Carbon dioxide concentrations are skyrocketing. Scientists have found that for the first time since tracking, monthly global average concentrations of this greenhouse gas has surpassed 400 parts per million in March 2015.

"It was only a matter of time that we would average 400 parts per million globally," said Pieter Tans, lead scientist of NOAA's Global Greenhouse Gas Reference Network. "We first reported 400 ppm when all of our Arctic sites reached that value in the spring of 2012. In 2013 the record at NOAA's Mauna Loa Observatory first crossed the 400 ppm threshold. Reaching 400 parts per million as a global average is a significant milestone."

In fact, the new mile marker represents the fact that humans burning fossil fuels have caused emissions to rise more than 120 parts per million since pre-industrial times. Although the growth of global emissions from fossil fuel burning stalled in 2014 and remained at the same levels as 2013, stabilizing isn't enough to avert climate change.

The global carbon dioxide concentrations are based on air samples taken from 40 global sites. NOAA and partner scientists collect air samples in flasks while standing on cargo ship decks, on the shores of remote islands and at other locations around the world.

"We choose to sample at these sites because the atmosphere itself serves to average out gas concentrations that are being affected by human and natural forces," said Ed Dlugokencky, the NOAA scientist who manages the global network, in a news release. "At these remote sites we get a better global average."

The findings are important for better predicting global warming in the future. This is especially important for climate models.

More information on carbon dioxide concentrations can be found online here.

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