People who think global warming doesn't matter because nature changes climate every so often anyway are kind of blowing off civilization as if civilization doesn't matter. Yes, maybe nature wipes the slate clean every once in a while with things like ice ages, asteroid strikes and times when there are palm trees at the Arctic Circle. Would we want big changes, like that, in the next few decades? Those changes happened thousands and millions of years ago; before civilization as we know it.
Going forward, nature may have not scheduled changes, like that, for a few thousand more years. Our modern civilization has only been around, maybe 200 years. Given nature, we could go another thousand, or so, years. That is if we don't blow it ourselves. Think of all the things we've accomplished in the past 200 years. What could we accomplish in just another 200 years? Do we really want to wipe the slate now?
Yes, nature could wipe the slate with something like an asteroid strike in the next few decades, but that isn't very likely. Nature works on a different time scale than our "flash in the pan" civilization. Still, I like our civilization. It would be nice to keep it around for another few hundred years at least.