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New long-lived greenhouse gas discovered by University of Toronto chemistry team

December 9, 2013

Chemical appears to have highest global-warming impact of any compound to date

TORONTO, ON - Sci­en­tists from U of T’s Depart­ment of Chem­istry have dis­cov­ered a nov­el chem­i­cal lurk­ing in the atmos­phere that appears to be a long-lived green­house gas (LLGHG).  The chem­i­cal – per­flu­o­rotributy­lamine (PFTBA) – is the most radia­tive­ly effi­cient chem­i­cal found to date, break­ing all oth­er chem­i­cal records for its poten­tial to impact cli­mate.

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.  If we release the same mass of PFTBA as CO2, PFTBA is 7100 times as impact­ful as CO2 over 100 years,” said Hong.

The research was fund­ed by the Nat­ur­al Sci­ences and Engi­neer­ing Research Coun­cil of Cana­da and was pub­lished online at Geo­phys­i­cal Research Let­ters on Novem­ber 27, 2013.



Angela C. Hong
Depart­ment of Chem­istry, Uni­ver­si­ty of Toron­to