I have long considered global warming due to fossil fuel emissions to be a given. What concerns me is the momentum of the whole thing. As it gets worse, the increases will accelerate; at what point will it be going too fast to do anything but crawl into a bunker?

Also, what is we are only seeing changes of a few degrees because the effect is being masked by a natural cooling cycle? In other words, what if Earth was supposed to be cooling down about now--part of it's natural billion-year cycle. But we come along and try to warm the place while it;s cooling down. The cooling effect cancels most of the warming effect...at first. But when the warming effect overtakes the natural cycle--then we have this slingshot effect. Now it's not just a degree or two worldwide, suddenly it's ten degrees a year and climbing.

It'll have to be catastrophic or no one will ever do anything about it. China, one of the largest polluters in the world, won't do anything because it'll threaten their upward mobility. The US & Europe have done a little, but will be slow to do more because the cost will make us less competetive initially (but whoever gets steady on alt fuels first will reap the rewards about the time the rest of us are just switching over.)