This argument reminds me of the cigarette - lung cancer debate. The tobacco companies argued that since people who never smoked got lung cancer you couldn't blame lung cancer on smoking. No reason to change behavior, as there is no impact.

That argument carried the day for years.

By the time a person figured out smoking was bad they were dead.

People are saying that because the climate naturally varies, Man is having no impact on it. No reason to change behaviors, as there is no impact.

By the time we figure out that Man is influencing a naturally variable process it will be too late. The weather engine seems to be very large, with a long lag time.

Seems foolish to me. Or, put another way, it seems obvious that Man isn't doing it any good, might want to mitigate whatever effect He is having.

Arf