One question I have is: At what point does global warming become so evident that there is no more argument as to whether it is occurring, and the argument becomes what do we do about it? I'm pretty sure we should already be there, but we aren't.
My question is: At what point does global warming no longer become the impetus for switching to renewable energy. Even if burning fossil fuels didn't cause any harm to the environment (which of course it does, but that's not the point right now) they are a very temporary solution. There's only so much oil and coal in the ground, and we're going to run out at some point. Switching to renewable energy sources is simply the pragmatic option. The longer we wait, the more of an emergency it becomes when it does run out, and we're left with hundreds of coal fired plants with nothing to fire.
Plus it makes financial sense. For anyone in a sunny region, solar panels provide very good ROI. Not investing is throwing away money.