I'd look beyond simply climate change. I've been accused of being a pessimist, but I tend to think there's a realistic chance of all I talk about happening in the next 100 years, to some extent or another.
There's an awful lot of stuff that is currently considered "normal" that is really an oddity of the last 200-300 years of extensive fossil fuel utilization, and that "endless growth" seems to be coming to an end, rather quickly.
We're at or past peak oil, a lot of countries are approaching peak coal (though that's based on some excessively optimistic estimates of recoverable reserves), we've been playing some truly spectacular debt-bubble games as a world, and are pretty much, in every way possible, trying to accelerate our drive to the brick wall of "Living well beyond what we can sustain becoming unsustainable."
Water is likely to be a major issue going forward, as anyone paying attention to California or Lake Mead might have noticed.
I think there's a good argument to be made that standards of living will be dropping significantly over the next century, even for those with decent resources, and I'd expect an awful lot of market shocks that may or may not ever "recover" to full value. It's hard to look at the split between the stock market and the actual reality of America (and a lot of other nations) as anything except the mother of all investment bubbles, driven by a combination of dirt cheap debt and extreme bubble blowing behavior by the Fed (and associated other central banks).
What does this mean for FI and long term planning? Good question.
I think it means that if your plan is, "Invest in index funds and travel the world," you might have a rough time in another 50 years. If you've got another 10-20 years left in your expected life, you're probably fine. But that's not really where most of us are.
What I think it does mean is that a reasonable long term plan (and I'm using 50-100 years as the term here, since this is relevant for many of us, and for our children, if you choose that path) involves looking at the likely storms on the horizon and figuring out what, if anything, you can do about them.
One entirely reasonable approach is to ignore them, keep doing what you're doing, and accept that if things go south, you want to be first to die. It's a valid way to look at things, if a bit of a cop out and, to me, not very satisfying.
I think a much more reasonable way forward is to look at how civilizations decline (since that's what this is - the decline of a civilization, just a really big, global, western industrial civilization), make some guesses, and plan for that.
I personally think this looks like being increasingly self sufficient in critical areas like food/water, and most importantly, developing useful skills that will be in demand during the transition to an early salvage economy.
If your idea of a great place to live is a cheap apartment in a city, that's all well and good, but you are utterly dependent on an awful lot of external systems for your survival. Food, water, waste disposal, power, etc - you cannot create any of those on your own. And, if things go terribly south, you can't escape.
If, on the other hand, you've got a few acres with a well, septic, backup ways of getting water (hand pump, solar pumps, etc), and a good garden, you can ride through a lot of the early shocks and disturbances that go along with decline. It's probably a good idea to get your garden going before you need it, since it generally takes new gardeners 4-5 years to really get the soil going and get good yields, but intensive gardening can feed a family on surprisingly little area (or, if not fully feed, significantly supplement other food sources). Maybe it's worth looking into permaculture and aquaponics - both look promising as long term ways to provide for at least some of one's food needs.
Useful skills are also going to matter. If things continue rattling their way down the backside of the slope of progress, being able to make do with less and fix things is going to be of great value. Unfortunately, we live in a very disposable society, and that's going to cause problems for a lot of people. But if you have practical, hands on skills in things like small electronics and appliance repair, automotive repair, gardening/food production, canning, solar heat production, and other things that will be in demand, you should be in a good position to provide for yourself and your family, even if investments don't go the way we all would like them to.
Humans have lived for an awful lot of years without the things currently considered "needs" - we pretty much need clean water, food, shelter, some heat (note that this is NOT 68 degrees, year round), and social interaction. The rest are nice-to-haves.
I think that, in general, the Mustachian way of life is going to work fairly well through the decline. A lot of the key aspects (be out of debt, live on less than you produce, better living through badassery, doing without, etc) are perfectly lined up to be less optional aspects of a declining civilization, and, to borrow a quote of John Michael Greer's, there's an aspect of "Collapse early and avoid the rush" going on that will be very valuable going forward.
This is, in general, where I'm trying to go with my life. The whole ebike thing I've been playing with lately (and rebuilding battery packs) is partly because I think they're neat and a great way to get around the Seattle metro area less miserably than driving, but partly because they may very well matter in the future - an electric cargo bike consumes a tiny fraction of the power of a truck, and can haul a lot of load incredibly efficiently for longer distances than most people can do with pedal power only. Same for gardening - knowing how to turn local soil into a high yielding garden without serious fossil based fertilizers will be a valuable skill.
And if I'm wrong? That's why I have money in index funds and other interest-bearing accounts. A few acres with a big garden and a nice workshop is useful if things decline, and if not? Well, it's still a pretty damned fine place to live, in my opinion. :)