Global Warming

Western Europe is being battered by storm after storm, North Eastern Europe is having it's mildest winter in living memory, (Moscow is a tropical 30 degrees above its usual january temperature), the same for the North Eastern US. Yet in California the oranges are frozen (sod the oranges... what about the grapes!!!!), Ice storms and blizzards are causing chaos across the mid west and it's not been above freezing here in Seoul since christmas.

BUT.....

Are all these effects more attributable to a shift in the weather patterns we have come to accept as normal, rather than a global warming.
Or has global warming caused this shift in weather patterns?

I know much of the American weather is more related to El Nino than global warming, although because there are so many records being broken, I feel like global warming is still playing a factor.

Ah yes... I forgot it was an El ni–o year!
Still, I guess 30 degree temperature differences in Moscow (+5 instead of -25) and the big freeze in California will give strength to the argument that we (mankind) are not causing global warming.

After all, it's weather patterns not a 1-2 degree rise in global average temperature that are causing Moscows warmth and Californias cold.
But we don't really know why El ni–o happens.