> The problem is, by the time you start seeing serious climate problems it will be far too late to prevent things getting much worse.
I have a really, really hard time thinking that climate engineering won't be possible in a hundred years, and climate change doesn't happen fast enough to wipe out humanity in that time frame. IMHO we'll be able to put the climate wherever we want it.
> And what would the next most important concern be? Maybe the horrible pollution and environmental destruction being wreaked by our quest for more fossil fuels - fracking, strip-mining of pristine wilderness for tar sands, etc?
Nope. These are extremely low priority to me.
> Or maybe reducing the threat of global violence inherent in having our economies dependent on relatively rare fuel deposits while our need for energy to adapt to a changing world steadily increases?
This is also extremely low priority for me, as it's already happening anyway, and while some part of global violence is related to oil money, there's plenty of other reasons for people to blow each other up. Subsaharan africa and north korea are cases in point.
> This century is going to see a *lot* of geopolitical stresses as agriculture becomes far less reliable due to the already inevitable climate destabilization.
Agriculture has always been extremely unreliable, and yearly swings in weather dominate it, not climate change. Climate change is far more gradual than the time needed for agriculture to change.
> And perhaps most importantly - even if we had fusion mastered today, it would still likely take several decades to migrate the infrastructure.
Why is this any different from getting any other alternative energy source going? If anything, I'd expect continuous fusion plants to integrate just fine as they're similar to fission nukes, and ICF fusion plants to integrate just fine, as they're similar to gas turbine generators. Compared to what's needed for wind and solar, it's nothing.
Regarding population growth, most of the growth is in poor countries, where life extension will be less available, and where other dangers still cause a lot of death. While life extension does raise the projected plateau, how far it's raised depends on how fast it hits, how cheap it is, and how stable we're able to make the rest of the world. I'd bet 50/50 odds that the population in 2050 doesn't exceeed ten billion.
> assuming that neither you nor anyone you know would get the chance of being immortal, what arguments would you offer in it's favor? What rational reason do we have to extend the length of our lives?
Let me pose the same question to you, with a couple modifications:
- Assume that neither you nor any you know is dying of cancer. What arguments would you offer in favor of researching a cure? What arguments would you offer against such research?
- Assume that neither you nor anyone you know has alzheimers disease. What arguments would you offer in favor of researching a cure? What arguments would you offer against such research?
- Assume that neither you nor anyone you know lives in poor africa, where the average lifespan is barely above 40 years old. What arguments would you offer in favor of trying to help the people in this region? What arguments would you offer against it?
Aging is a horrible thing, something which frankly should not be tolerated in polite society, any more than cancer, alzheimers, and ebola. To simple take it 'off the table' as though it were uncurable and shouldn't be cured is reprehensible.