Potent Long-Lived Greenhouse Gas Discovered

Researchers at the University of Toronto (Toronto, Canada), funded by the Natural Sciences and Engineering Research Council of Canada, have discovered a potential long-lived greenhouse gas, perfluorotributylamine (PFTBA), that could be a contributing factor towards global climate change.¹ Published in the journal Geophysical Research Letters, the study performed gas chromatography–mass spectrometry (GC–MS) and spectroscopic techniques to suggest that PFTBA can have a bigger impact on climate than carbon dioxide.

Climate change is a global issue. The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) to monitor, review, and assess research related to climate change worldwide and then feedback relevant information to policy makers. In a press release dated 27 September 2013, the IPCC stated that the “human influence on climate is clear”, and “it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century”. ² To tackle the issue, drastic changes have to be made to levels of greenhouse gases in the atmosphere. Predictions of potential future effects are made by modelling current atmospheric concentrations of greenhouse gases.

PFTBA is a member of the perfluoroalkyl amine class of compounds that, according to the paper, have not been previously investigated as long‑lived greenhouse gases. Used since the 20th century in electrical equipment and as heat transfer agents, PFTBA is not produced naturally; rather it is the result of human activity. It can remain in the lower atmosphere for hundreds of years, but it is destroyed in the upper atmosphere.

The researchers sampled atmospheric air samples from above Toronto between November and December 2012. GC–MS was performed to quantify levels of PFTBA in the ambient air samples, and nuclear magnetic resonance (NMR) spectroscopy followed by Fourier-transform infrared (FT-IR) spectroscopy to determine radiative efficiency. Radiative efficiency is measured by the impact of the molecule on climate multiplied by its concentration in the atmosphere. The researchers stated that the atmospheric samples of PFTBA showed slight dissimilarity compared to standards used in the chromatogram, but that this was most likely a result of varying concentrations of isomers.

Lead author of the paper, Angela Hong, said: “PFTBA is extremely long-lived in the atmosphere and it has a very high radiative efficiency; the result of this is a very high global warming potential. If we release the same mass of PFTBA as CO2, PFTBA is 7100 times as impactful as CO2 over 100 years.” - B.D.

References

1. A.C. Hong et al., Geophysical Research Letters40, 1–6 (2013).

2. IPCC Press release, 27 September 2013, http://www.ipcc.ch/news_and_events/docs/ar5/press_release_ar5_wgi_en.pdf This story originally appeared in The Column. Click here to view that issue.