The real cost is the cost of doing nothing.
That's always the mantra: serious climate policy is too pricey, especially in this economy.
To that I say: watch this excellent video from King 5 News. (It's almost 16 minutes long, but well worth it.) The impacts of climate change, such as flooding, carry a very steep cost. And judging by the video, the costs aren't mostly borne by the rich -- they're paid for by those who can least afford it.
I want to be perfectly clear. The floods in Western Washington -- this year and in several recent years -- are completely consistent with what the climate science has been predicting for the Northwest. It doesn't really matter whether or not these particular floods are the direct result of global warming (that's an untestable hypothesis), what matters is that this is exactly what we should expect in the future. If the scientists are right, get ready for more.
So if you think carbon pricing is too expensive, just wait until you see the bill for failing to put a price on carbon.
I learned recently a 'fact' about green house gases that I sort of knew but didn't fully appreciate. The gases oxygen and nitrogen don't trap gas period. Seeing it this way just intensifies for me the meaning of these "small" percentage gases and their actions. Just like what blood alcohol content these percentages must be appreciated as not order of magnitude but essence of being.