Very good example. I studied this at a Masters level, and what...

Very good example. I studied this at a Masters level, and what people may not realise is that because the ozone keeps life safe from damaging UV radiation, if the human production of chlorofluorocarbons was left unabated, destroying the ozone in the atmosphere, possibly leading to an ozone depletion chain reaction, parts of the planet could have been rendered uninhabitable.

Another interesting point is that ozone is only a trace gas, accounting for only 0.00006 percent of the atmosphere, but it is necessary for life on earth. CO2 is another trace gas, comprising 412 ppm or 0.0412 percent (up from 0.028 percent before the industrial revolution), also necessary for life as it keeps the planet warm (and getting warmer as we add more CO2, unfortunately).

Don't let anyone tell you that:

a. humans have no influence over 'mother nature'

or that

b. trace gases can have no impact on the global temperature, the climate or the survivability of life on earth.