New
long-lived greenhouse gas discovered: Highest global-warming impact of any
compound to date
Radiative efficiency describes how effectively a molecule can
affect climate. This value is then multiplied by its atmospheric concentration
to determine the total climate impact.
PFTBA has been in use since the mid-20th century for various
applications in electrical equipment and is currently used in thermally and
chemically stable liquids marketed for use in electronic testing and as heat
transfer agents. It does not occur naturally, that is, it is produced by
humans. There are no known processes that would destroy or remove PFTBA in the
lower atmosphere so it has a very long lifetime, possibly hundreds of years,
and is destroyed in the upper atmosphere.
"Global warming potential is a metric used to compare the
cumulative effects of different greenhouse gases on climate over a specified
time period," said Cora Young who was part of the U of T team, along with
Angela Hong and their supervisor, Scott Mabury. Time is incorporated in the
global warming potential metric as different compounds stay in the atmosphere
for different lengths of time, which determines how long-lasting the climate
impacts are.
Carbon dioxide (CO2) is used as the baseline for
comparison since it is the most important greenhouse gas responsible for
human-induced climate change. "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. Calculated over a 100-year timeframe, a
single molecule of PFTBA has the equivalent climate impact as 7100 molecules of
CO2," said Hong.
Share this story on Facebook, Twitter, and Google:
Story Source:
The above story is based on materials provided by University of Toronto.
Note: Materials may be edited for content and
length. For further information, please contact the source cited above.
No comments:
Post a Comment