That's not about predicting the weather.
It is when they say that the average global temperature rise by such-and-such or we'll lose x percentage of the polar icecaps amount by 2025 or whatever. Some amount of these things will almost certainly happen but I'm highly wary of the many activists who seem to be fond of quoting very specific numbers for them.
Personally I do believe in global warming, but I'm not particularly worried about it because I'm a good distance away from the coast and on a hill. I'm not gonna get flooded out by rising sea levels. And while arctic wildlife dying out is certainly sad, it's not something that affects me personally. Furthermore, I'm confident that the rich businesspeople currently standing in the way of taking measures to stop global warming will change their tune and start working to fix the environment as soon as a few of their beachfront and lakefront houses get washed away.
By then, it will be too late to avert some really, really bad effects. It's actually already too late to avert some pretty nasty stuff, as even if we all stopped emitting right now, our various greenhouse gasses would stick around in the atmosphere for a while (especially CFCs) and other things would take decades to repair on their own.
But flooding is only one effect. And even just looking at that, there are ways that would affect you. With such a huge chunk of the world's population living in at-risk areas, the remaining areas would get more crowded, which, combined with the loss of so much productive land, would have major economic effects. The loss of coastal wetlands (which are
extremely ecologically important), as well as other costal habitats, will prompt the denizens of those areas to flee further inland (or perish), causing disruption throughout the biosphere.
It's not necessarily doomsday, as some would paint it, but some things are going to suck in the within next 5 decades at least. Nothing will be completely isolated from the effects of global warming, due to everything on the planet affecting everything else to at least some degree.