The fact that we can even argue about something so important while in the midst of it.. that's the real slow moving disaster. The biosphere is going to fall out from under us before we've even agreed there is a problem. At this point, it is literally like arguing whether the eye of the incoming category 5 hurricane is going to hit Miami or Fort Lauderdale; it doesn't matter, lots of people are fucked.
I'm sure humans will survive just fine, at least the rich ones. But maybe not. You see... Even 100 years of scarce basic resources would do unimaginable damage to our species, let alone 1,000.. or 10,000. When precipitation patterns change and cropland "moves", it doesn't happen overnight. We don't have 10 years to watch the new precipitation patterns mature - and what if it takes 100, or 1000 years for them to mature? These are such small time scales geologically, but they would extinct most of us.. in a geologic heartbeat.
If any of you don't understand the time scales we are dealing with here, you need to open your eyes. Sure, we would have no problems living on a planet with 1,000PPM CO2 and temps that are 8C warmer than they are now... If we found ourselves in such conditions at the beginning of the industrial revolution. What's the problem, you say? Everything will grow great! Arctic farmland! Easy to armchair quarterback that one.
But that's not the way things are going to play out. We're here right now with 7 billion people and growing, and we can largely no longer rely on the climate we have relied on for the last 10,000 years. We no longer live in our parents climate. It has changed noticeably, in just 30 years. That's bad. We are stripping our planet of resources and causing change on the planetary scale at unfathomable rates - much faster than typical geologic processes. You would have to fast forward perhaps 100,000 years to see a stable planet under the conditions we are advancing - new life beginning to fill all of the empty niches, etc.
I don't know when it's going to get really bad.. but it's not anymore a matter of IF, but WHEN all of these horrible predictions about acidic anoxic oceans losing 90% of their biodiversity, sea level rise, fires, floods, droughts, etc come to be, especially if we continue business as usual. They are already happening. The snowball has been rolling for about 150 years now, and it's finally starting to get really, really big with each year that rolls by. The scientists - the people on the front lines, who witness this stuff first hand, have been yelling and screaming about it for the last 35 years+. But now the snowball is so big that even regular people can see the changes. That's really bad.
We basically have no real idea what we're doing, and that's why so many of us are crying danger. If it takes 10,000 years for our climate to stabilize, we are so very royally fucked. All because we didn't play our exponential growth cards right.
Suppose that's probably the answer to the fermi paradox. Nobody ever does. Bummer.