Absolutely the Earth goes through natural cycles.

BUT:

a) what if this is not a natural cycle? if 95% of scientists were to say that some product is potentially dangerous to our children, it would be yanked from the shelves immediately. But our president (and his crowbar supporters) say we need to wait for the other 5% before we act.

b) "natural cycles" have led to many mass extinctions. If we are contributing in even a very small way, shouldn't we do something? Or are we willing to take a chance that we will be among the 5 to 30 percent (based on past mass extinction numbers) of species that survive? Hmmm, let's see, is the Hummer worth it to me.....

Hummer, children's survival
Hummer, children's survival
Hummer, children's survival

Damn, this is a tough call.