No Answer

I posed this question to a very nice, well-intentioned but scientifically-illiterate Greenie lady I sat next to at dinner on Saturday night:

"What if there really is dangerous global warming, but it turns out it isn't caused by man, but instead by natural variation from other factors that are too complex to be understood? Then what?"

There was no reply. Her brain appeared to short-circuit.

I am a fun dinner companion.