Global Warming (what's wrong with climate change?)

In the past decade the people have been told we must lower carbon dioxide to prevent climate change. While I agree that we should clean up our messes we make and that we should not pollute, there is scientific evidence and fossil records that show global warming is actually a good thing and here's why. First the warmer the planet gets the longer the growing season which means more food. Second with global warming earth experiences fewer devastating storms than during global cooling. Third with global warming the number of diseases goes down and all animal life gets healthier. Now with that said what we are seeing is nothing compared to what the Earth has experienced in it's geological past. Ever since the formation of our planet the Earth would experience a 10 degree temperature swings, i.e. 5 degree yearly increases and 5 degree yearly decreases with carbon dioxide levels many times higher than today. Environmentalists have claimed that this 3 degree temperature rise is not natural. They are right and this is why. This static climate we've seen for the past 10,000 years is not natural. From all of geological record the temperature changes are supposed to be greater and we are supposed to have more climate change than we've seen. Fourth, this 3 degree temperature rise we're seeing was last seen from 900 to 1300 AD. The only difference between then and now (other than technology) is that we have a weakening magnetic field in the process of reversing which has not happened (according to geologists & vulcanologists) in over 700,000 years. The problem with this is that no one know exactly what the effects will be. Prevailing theory is that during the process not only will auroras be seen everywhere but we will also have 4 poles (north,south,east, and west) and cancer rates will rise other than this no one knows how bad it could get. So the question I'm asking is this, " With the increasing number of earthquakes and volcanic eruptions and the "'strange weather"' could the weakening of Earth magnetic field and eventual reversal have anything to do with what we are seeing"? That people is the question we need to ask.