Atmospheric CO2 levels reach ‘highest in human history’

Concentrations of carbon dioxide in the global atmosphere have reached 400 parts per million (ppm) for the first time in human history, according to the latest data.

Last week, the daily mean concentration of carbon dioxide in the atmosphere at a US government agency lab in Mauna Loa, Hawaii, surpassed 400 parts per million (ppm) for the first time since measurements began in 1958.

According to Scripps Institution of Oceanography , the results mark an important milestone because Mauna Loa, as the oldest continuous carbon dioxide (CO2) measurement station in the world, is the primary global benchmark site.

On May 9 2013, Scripps Institution of Oceanography at UC San Diego recorded a reading of 400.08 ppm for the 24-hour period.

Carbon dioxide concentration has increased every year since scientists started making measurements on the slopes of the Mauna Loa volcano more than five decades ago, while the rate of increase has accelerated since the measurements started, from about 0.7 ppm per year in the late 1950s to 2.1 ppm per year during the last 10 years.

National Oceanic and Atmospheric Administration (NOAA) senior scientist Pieter Tans said: “That increase is not a surprise to scientists”.

“The evidence is conclusive that the strong growth of global CO2 emissions from the burning of coal, oil, and natural gas is driving the acceleration,” he added.

At last month’s international discussions on climate change in Bonn the UN warned that a growing sense of urgency is needed as greenhouse gas emissions looked to hit record levels.

The discussions followed CO2 data released by Scripps, which at the time stood at 399.72 ppm.

Leigh Stringer

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