There are so many things being mixed up here!
Greenhouse gasses are NOT the refrigerants (CFC's)which affect the Ozone layer. The main greenhouse gas is Carbon dioxide.
The hole in the Ozone layer is not the cause of global warming
Scientists DO know all about the various short and long term cycles (Who do you think discovered them) and take them into account in their predictions.
If global warming occurs, then it will probably not be permanent, because increased growth of plankton will eventually absorb the carbon and recycle it to the ocean floor - after many millions of years, that is. Plankton apparently account for 90% of the CO2 which is absorbed - leaving only 10% for all terrestrial plants.
How do we find out these things? by going out and measuring, not repeating propaganda and myth.