I think a new thread is in order, since this is really a change of topic. For the purpose of this thread, let's make the simplifying assumption that the core climate science presented in the most recent IPCC report is entirely correct.
But more interestingly, I would be interested to hear your views on what could, if anything, be practically done to remedy the changes GW will create?
As davew said, it's going to be far cheaper to prevent change than it is to mop up afterwords. And, just as importantly, the sooner we act to prevent change, the less expensive action will be. It's kinda like we are all in a large bus driving towards a cliff. Right now, the driver has his foot on the accelerator, and the bus is speeding up. The sooner we get him to take his foot of the gas, and start applying the brake, the easier it'll be to slow down before hitting the cliff. But if we can't convince the driver to stop accelerating, then basic physics starts to make a disaster inevitable: after a point, you simply can't brake hard enough to stop in time.
So, I'm going to start talking about prevention, and then come back to adaptation. We have to stop increasing the concentration of greenhouse gasses in the atmosphere, and then we need to start reducing that concentration from whatever the peak level reached to a safer level. To achieve that, there's a million different things that need to be done, and I think we need to do a little bit of all of them. However, 2/3rd of those million things become much easier if we start with two basic changes:
First, we have to put a $$ price on greenhouse gas emissions (mostly carbon dioxide and methane). This should be blatantly obvious, but people are resisting for all sorts of silly reasons. As I see it, you have to pay a fee/fine if you pollute the oceans, you pay a fee/fine if you pollute rivers & streams, you even pay a fee to dump your trash into a landfill. Why should dumping pollution into the atmosphere somehow be free? There are arguments about a cap & trade system vs a simple carbon tax, and the arguments are worthwhile on both sides, but we can come back to that.
As soon as you put a higher price on carbon emissions, then all sorts of changes gain a big economic advantage. Clean energy (wind, solar photovoltaic, solar thermal, hydro, geothermal, wave, biomass, landfill methane, etc) all become cost competitive over dirty energy, and the conversion starts immediately. In addition to making clean energy, people also become more willing to spend money on using less energy, meaning that efficiency takes off. We could actually halt all increases in energy use in this country right now, never needing a brand new power plant (replacement construction only), if we just took some basic steps towards efficiency, both in transportation and in building energy use. (California has already done this, halting energy consumption increases with no obvious penalty to economic growth.)
The second big change that we need to make, and this is a much harder one to manage, is to work towards 'sustainable' population levels. Right now, we can't quite feed everyone on the planet, and a warming and more chaotic climate will only make that harder. The fundamental inequality of wealth isn't going to be fixed anytime soon, so we're essentially guaranteed that there will be increasing hardship and death from famine and water shortages. Increases in agricultural production are not likely or sustainable, wealthy populations will never give up eating meat, and decreases in raw crop yields appear inevitable. At some point down the line, population is either going to crash hard or be reduced gracefully, and I'd much rather see gracefully.
How do you actually manage world populations? War is the cheap and easy way, but I don't consider that to be a moral solution. The moral way is actually education and financial opportunity for women. We have to promote legal and social equality for women worldwide, and try to reduce the frequency of endemic poverty. The natural result of treating women better has always been a reduction in population growth, not to mention the fact that they lead much more enjoyable lives. And happier women always translates into happier men, so everyone wins.