"Would someone please explain to me how global warming causes colder weather?"

Others have had a go - I'll just add this to clarify a minor point I am quite pedantic about:

"Global Warming" doesn't mean just that things are getting hotter. When a system acquires more energy it tends to behave in a more turbulent manner. This means that extremes are more likely. In a time of year when we here in Brisbane should have been getting relatively mild temperatures for a month or two - our temps are swinging from way below average to well above average - on this coming weekend it is forecast to hit over 30 deg C - unusual for this month! We should be in the low to mid 20's for this time of year on average.


"you Yanks are completely in de Nile." ... so far you in de Mediterranean!