Seen science reports stating that the Earth's magnetic field is changing. This has been shown by some to happen in the far distant past. These shifts can change weather patterns being that the Earth's magnetic shield helps protect us from the Sun's solar energy.
Another report I somewhat agree with is that tiny pollution particles are being carried along in jet streams/clouds which in turn is affecting weather patterns due to the particles UV reflective capabilities.
I'm not all that convinced about the so-called affect of 'greenhouse' gases. The ozone layer has repaired itself of recent, from what I have gathered.
As mentioned above, IMO, the changes in the magnetic field has had the most effect on our recent weather patterns. However, I don't feel it has been that extreme to the point that we are in any kind of 'Doomsday' trouble here as others would have you believe with respect to 'greenhouse' gases and such. Just remember, back in the 70's many were talking about another ice age in our near future.