> But how much will forcing those infrastructure and cultural and societal changes cost NOW, versus letting them happen naturally and gradually the same way we switched from wood to coal to petroleum and from muscle to steam to electricity?
I believe you might profitably examine your implicit assumptions about what constitutes "natural" and "gradual" adaptation of industry. As has been pointed out by another commenter, the progression has not been as linear as you have proposed: many industries in the world _still_ use wood as fuel, hence my prior deforestation comment. (Note that farmed wood promotes a monoculture ecosystem, effectively declaring creatures dependent on the prior heterogeneous environment unimportant.) Western countries have tended, historically speaking, to incentivise new industrial developments. Often this was done at the precipice of a disaster and done at great cost: much less money and life might have been spent had the work been gradual.
> Extremely simple illustration: Do you think people in Florida will be living 10 feet under water in 100 years? No, they will move before then. But they don't have to move now, so why force them?
Consider the crushing burden of mass migration, the vast human cost. There have been several such in this century already; you may go to visit them and learn why _gradual_ migration is vastly preferable. Further, do not misunderstand me: I am not advocating that all residents of Florida move at one time; this change should happen gradually as a part of a prepared plan. Such plans are difficult to construct when individuals such as yourself are content to kick the can down the road and let the future sort it out. Human civilizations adapt necessarily to their surroundings; done consciously such adaptations need not be the source of untellable human suffering.
> Similarly, do you think we'll all be driving gas-guzzling SUVs in 100 years? Hell no. Oil just won't last that long, and our car culture will have died or switched to electric (or nuclear, or secret ooze) long before then anyway.
Consider the economic implications of "running dry". So much of the United State's infrastructure carries the implicit assumption of cheap gasoline and diesel that to suddenly (meaning the sudden increased cost over the span of a decade, say) go without would cause significant harm to our economy and world standing, relative to those nations that are preparing. Again, I stress _gradual_ change, but such change must be sustained by a willingness to tackle the problem directly and _not_ simply be willing to let the future work things out. Surely they will, but at greater expense than we who now decide the course of the world can manage.
> So why force the issue?
I hope I have made myself clear. If not: the necessary adaptations of human civilization in many areas will be extensive, expensive and time consuming. We can mitigate the second concern by performing those adaptations _before_ they are vital. Consider that the upgrade of infrastructure as a part of regular maintenance cycles is more tenable than sudden overhaul. We need only come to an agreement on the way in which we will upgrade; this is impossible when influential individuals deny the basic premise or assert that the future will somehow more efficiently solve our problems though they be exacerbated by the passage of time.
> I guess I'm just not seeing the urgency here.
I believe the urgency is largely manufactured by a news media predicated on the spread of unease, over zealous Chicken Littles and anti-reactionary misinformation. We have a problem _now_. Our technological sophistication is such that we can prepare ourselves for this problem without the death or displacement of billions. What little urgency does actually exist at this point does so because the changes that must be made cannot be made fifteen years out; a period of fifty to seventy-five years, depending on global economy, is more reasonable. Cuts in significantly to your hypothetical one-hundred years, no?
> And whatever urgency there is, doesn't seem to be fixable in the short term.
No, it is not. This is why it is preferable to begin the process of adaptation before it is a matter of dire consequence.
> Ocean levels will rise. They already have. So let's focus on mitigation rather than the already failed task of prevention.
I believe you read my original statement with a biased eye. We must necessarily adapt--by the time we began to notice the effect our habits had on the global climate it was likely too late to reverse the process. That said, we would do well to live up to our self-given taxonomic title and not exacerbate the problem. It looks like we will continue, especially as developing countries fire up their own furnaces.