Natural and human-made CO2 differentiation possible thanks to new monitoring technique

Measurement locations in the United StatesA large diversity of gasses in the atmosphere influence air quality, climate change and the recovery of the ozone layer. Measuring the concentrations of these gases in the atmosphere is quite straightforward.

But pinpointing wether the gasses are a natural occurrence or anthropogenic in nature is a lot more complicated. Now thanks to a new monitoring system a clear picture can be drawn about which gasses are human-made and which are natural.

In a combined effort researchers from the University of Colorado Boulder, NOAA and CIRES studied atmospheric gas measurements taken by aircraft over the past six years. The results were published in the Journal of Geophysical Research.


An important difference between CO2 from natural sources and CO2 from fossil fuels is the age of the carbon it contains. Younger natural sources of CO2 are relatively rich in carbon-14. But since carbon-14 has a half-life of about 5,700 years, it can’t be found in fossil fuels that are millions of years old.

Anual emissions of various gasesUsing this difference, the research team could easily differentiate between natural CO2 emissions and anthropogenic ones. They also measured 22 other atmospheric gasses tied to human activities. The emission source of these gasses could be estimated by using the same ratio as that of fossil fuel and natural originated atmospheric CO2.

Old versus new

The current method of estimating CO2 emissions is based on reports on the use of oil, natural gas and coal by specific regions. This method may provide an accurate estimate of global CO2 emissions, but it can’t do the same for smaller regions, which the new method can.

Besides that, the new technique is based on accurate scientific measurements, while the old one is based on accounts by countries and companies  that want to reach their emissions targets.

In other words the old versus the new method could be seen as faith versus science. And that trust can be broken is illustrated by some surprising detections in the study. Over the six year measurements, the team found continued emissions of methyl chloroform and several other gasses that are banned from production in the United States.

© Jorn van Dooren |

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