(PFCs) and sulphur hexafluoride (SF6) are greenhouse gases with
atmospheric lifetimes of more than 1000 years. They are powerful
greenhouse gases and today's emissions will still be affecting
earth's climate in the next millennium.
Increases in these greenhouse gases are almost entirely a result
of man's activity. Man's use of fluorites has given rise to significant
emissions of both PFCs and SF6 in recent years. The only known
sinks for these greenhouse gases are light destruction (photolysis)
or ion reactions in our mesosphere.
A new and worrying development has been the discovery of a hybrid
greenhouse gas derived from PFCs and SF6 (SF5CF3), which is the
most powerful greenhouse gas yet discovered and whose concentration
is rising rapidly.
Through our production of fluorites we cause significant amounts
of both PFCs and SF6 to be released into our atmosphere. Though
their concentrations are very small compared to the main greenhouse
gases like carbon dioxide, the huge lifespan of these gases in
our atmosphere makes them important in global greenhouse gas budgets.
Potential for control
Addressing emission of PFCs and SF6 in the same way as we currently
address emissions of carbon dioxide and methane would be a step
towards limiting the emission of these greenhouse gases. Awareness
is key, if government was fully aware of the potential of these
gases to contribute to global warming for millennia then legislation
may be better targeted at limiting this greenhouse gas source
before it reached its full potential.