Again, I ask how it is known with any certainty that man is responsible for any warming? Surely, in the history of the planet there have been periods of warming and cooling that occurred long before man was on the planet and since man was on the planet and didn't use "fossil" fuels. Don't get me started on the "fossil" part of "fossil" fuels either. There simply is no way to know, the data is too recent and shows no real history. We're talking eons here, not a century or two. The whole thing started off with East Cambria cherry picking one set of tree rings, from an entire forest of tree rings, that supported their precious theory. Now NASA and NOAA are moving sensors closer to cities and claiming that the higher temperatures are clear indicators of global warming. Let's see, move a thermometer closer to a heat source and it'll read higher. What a new concept!