The evidence clearly shows that the earth has been periodically warming up and cooling off for many millions of years. What is unacceptable is the idea that it's anthropologically caused, or that it can be controlled. To suddenly blame the current trend (assuming there is one) on what mankind has been doing over the last 100 years or so, or that we can influence that trend, is simply ludicrous. May as well bark at the moon.
There was a science fiction writer, Michael Crichton, who said something similar, and he got quite viciously castigated as, you know, the usual, "he hates my grandchildren!" etc. And if you quite reasonably suggest that instead of thinking your effecting things by separating your recyclables, you'd be doing more for the grandchildren by ABANDONING NEW ORLEANS, MIAMI, NEW YORK CITY, SAN FRANCISCO, LOS ANGELES AND EVERY SINGLE OTHER PORT CITY IN THE WORLD AND MOVING 150 MILES INLAND, because that's where the new beaches will be - well, then, YOU'RE the radical. Curious.
I must say, it does appear to me that the human species does carry the seeds of our own extinction within us, but it's not caused by litterbugs, more by the selection for size, aggressiveness and greed that is part and parcel of the two-sex mating selection process. Considering that fish and bugs and even plants come in boys and girls, you have to dig pretty deep to eradicate that.