Answer:
That is a very broad question. One thing that does not seem to be considered is the depletion of the ozone layer at high altitudes.
In the 1960's chlorofluorcarbons (CFC,s) became popular as refrigerants, spray can propellants, etc. In January 1989 the Montreal Protocol was passed which has greatly reduced the use of these substances. However, it may be several decades before the ozone layer can be replaced and again absorb harmful ulraviolet rays that may be partly responsible for the increase in global warming.
(One chlorine atom at high altitudes can be responsible for the destruction of 100,000 molecules of ozone - catalytic reaction)