Concentrations of CO2 in the global atmosphere have reached 400 parts per million (ppm) for the first time in human history, according to the latest data from the US government agency lab in Mauna Loa, Hawaii.
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.
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.
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 set to hit record levels.
To see what 400ppm means in an historical context, take a look at this graph taken from the IPCC Fourth Assessment Report: Changes in Atmospheric Carbon Dioxide, Methane and Nitrous Oxide found in polar ice core records of atmospheric composition dating back 650,000 years.