U of T scientists have discovered a novel chemical lurking in the atmosphere that appears to be a long-lived greenhouse gas. The chemical – known as PFTBA, or perfluorotributylamine – is the most radiatively efficient chemical ever found in the atmosphere, which means that its potential to affect climate is greater than any other chemical on record.
“Calculated over a 100-year time frame, a single molecule of PFTBA has the equivalent climate impact of 7,100 molecules of carbon dioxide,” says Angela Hong, a PhD candidate in chemistry who was a member of the research team that made the discovery, along with Cora Young (BSc 2004 UC, PhD 2010) and Professor Scott Mabury.
Although its potential to accelerate global warming is very high, PFTBA currently exists in the atmosphere in very low concentrations – less than one part per trillion. (Carbon dioxide, which is used for comparison since it is one of the most common greenhouse gases, has been measured at more than 400 parts per million. This means there is about two million times as much carbon dioxide in the atmosphere as PFTBA.)
PFTBA has been in use since the mid-20th century in electrical equipment. It does not occur naturally, and has a very long lifetime – possibly hundreds of years. There are no known processes that would remove PFTBA from the lower atmosphere, but scientists believe that high-energy radiation destroys it in the upper atmosphere.
“PFTBA is extremely long-lived in the atmosphere and it has a very high radiative efficiency,” says Hong. “The result of this is a very high global warming potential.”
Read the original scientific paper in Geophysical Research Letters, 27 November 2013