global warming

Global warming, Is it realy happening.All indications are that it is but if so are we causing it by polluting the air,It seems to me that if we were polluting the air so bad we would be shutting off the sun from the earth and we should be getting colder instead of warmer .I was tought in school that at one time this country was all covered with ice and that has all melted so there evidently was globel warming going on here millions of years ago before we were here to pollute the air. I suspect nature is going to do what it is doing in spite of what we do. What makes more sense to me is that we may be causing earth quakes. earth quakes are caused byfaults in the earths crust slipping.When you consider all the gas .water and oil we are pumping out of the earth we are removing the substance that is supporting the crust therby causing the faults to slip. My opinion by John Zilverberg