In a study comparing policies in Britain to Germany, the authors found that carbon pricing did more for less: setting a price for carbon helped the government reach the goal cheaper. Setting a price on emissions did more to get total emissions down than did Germany's heavy investment in renewables. The idea is that if you penalize coal consumption, for example, it will drop in the short term as well as the long term.
Update 1/14: Norway is also hiking its own carbon tax, more than doubling it from US$94 to $235 by 2030. "It will be expensive, increase costs and weaken competitiveness of the Norwegian continental shelf," said a lobbying group, and they're not wrong!
A related example is stopping gas flaring, which I have heard is one of the cheapest ways to avoid emissions. If gas can be captured rather than being flared, that will keep emissions from hitting the atmosphere right away.
