What does the perfect carbon price look like?

To most economists, putting a price on greenhouse-gas emissions is the best way to tackle climate change. It is efficient, allowing society to identify the cheapest unit of carbon-dioxide equivalent to forgo. It is fair: polluters pay; the proceeds can be redistributed. And it aids other forms of decarbonisation: complying with a carbon price forces companies to track their emissions and investors to work out which of their assets are the dirtiest.