From my vantage point...
I don't see Tom's contributions on climate change as denial, I see them as advice to keep our eyes and minds open. And he doesn't seem to be saying "Let's just sit on our hands for a few more decades, see what happens." Far from it, in fact...look at his stance on nuclear power.
Years ago, Bowser said something to the effect that while everyone is looking in one direction, you can often make new discoveries by looking in another direction...only Bowser said it much better. Anyway, on climate change, Tom seems to be doing just that. He's not telling us that the "direction we're looking in" is invalid, he's just pointing out that there's more to be seen.