The Danger of Chlorofluorocarbons
Troy Walker
[email protected]
Science and Global Change Scholars Program
Bioengineering
Question: To what extent are chlorofluorocarbons (CFCs) the greatest
danger to global warming and climate change in comparison to carbon
dioxide?
CFC History
CFCs first became marketed in
the 1930’s as a “safe”
component of coolants,
refrigerants, and propellants.
After much growth, the harm
they produce on the
environment was revealed in
the late 1970’s through
numerous scientific reports.
Response to this newfound
information came in the form
of the Montreal Protocol of
1987 which banned all
production and usage of
CFCs.
Atmospheric Composition
Nitrous
Oxide
7%
Methane
13%
79%
Carbon Dioxide
CFCs vs CO2
•
Effects of CFCs
When CFCs enter the
atmosphere, UV rays cause
them to break apart, exposing
the chlorine that is a part of
their chemical structure. A
single chlorine molecule can
then go and bind and break
apart thousands of ozone
molecules. This process
depletes the ozone layer.
•
•
•
Future Threat
CFCs have an atmospheric
lifetime of 20-100 years. Since
CFC emissions were at their
highest right before the
Montreal Protocol of 1987,
many particles still pose a
threat for another 50 or more
years. Additionally, recent
loopholes in the Protocol have
allowed for new CFCs to be
produced.
Other
1%
•
•
CO2 makes up 65% of all
greenhouse gases (not
counting water vapor) while
CFCs make up a small fraction
of 2%
CO2 traps heat in the
troposphere while CFCs
deplete the ozone layer and
trap heat to a much lesser
extent
CFC production has been
halted while CO2 production
is continuing to increase
CO2 is both a naturally
occurring and artificial
compound while CFCs are
completely artificial
CO2 molecules have lifetimes
around 30-75 years while
CFCs have lifetimes around
20-100 years (this is why they
are able to destroy so much
ozone)
All countries have laws in
place against CFCs since the
Montreal Protocol was a
global treaty
What is Being Done
CFCs have been completely
banned from production
through the Montreal Protocol.
The ozone layer was going to
be allowed to heal naturally
over time, but with the recent
discovery of loopholes in the
Protocol, the expected time of
complete healing has been
pushed back as lawmakers look
to address the loopholes.
Potential Danger
Conclusion
Contrary to what I expected,
the collected data and opinions
of experts I asked has
convinced me that CFCs are
less of a threat than most other
greenhouse gases. For starters,
they are significantly less
responsible for global warming
because they are as good at
trapping heat as other GHGs
but are significantly less
plentiful. Additionally, through
the efforts of international
treaties and cooperation, their
severe impact on the ozone
layer is lessening as more
molecule’s lifetimes end.
My thanks to Drs. Holtz, Merck, and Eubanks for their assistance throughout my two
years in the Scholars Program