Carbon Dioxide in the Atmosphere Hits Record High Monthly Average

In Daily Measurements, Measurement Notes by Rob Monroe

April monthly average exceeds 410 parts per million for the first time in recorded history

The average concentration of carbon dioxide in the atmosphere was 410.31 parts per million (ppm) for the month of April, according to the Keeling Curve measurement series made at the Mauna Loa Observatory in Hawaii.

This marks the first time in the history of the Mauna Loa record that a monthly average has exceeded 410 parts per million. This also represents a 30-percent increase in carbon dioxide concentration in the global atmosphere since the Keeling Curve began in 1958. In March, Scripps Institution of Oceanography at the University of California San Diego observed the 60th anniversary of the data series, the first measurements of which were 315 ppm.

The Keeling Curve draws its name from its creator and the shape of its dataset, a seasonally seesawing trend of steadily rising CO2 readings that exceeded 400 ppm in air for the first time in human history in 2013. Prior to the onset of the Industrial Revolution, CO2  levels had fluctuated over the millennia but had never exceeded 300 ppm at any point in the last 800,000 years.

Carbon dioxide is called a greenhouse gas for its ability to trap solar radiation and keep it confined to the atmosphere. It is the most prevalent among all greenhouse gases produced by human activities, attributed to the burning of fossil fuels.

The Scripps CO2 Program is directed by geochemist Ralph Keeling,the son of the late Keeling Curve creator Charles David Keeling

“We keep burning fossil fuels. Carbon dioxide keeps building up in the air,” said Ralph Keeling. “It’s essentially as simple as that.”