When we talk about carbon pricing, we usually refer to an actual price paid for emitting a tonne of CO2. That price can be fixed as a tax or be the result of permit trading. So, mostly politics with a bit of economics. The «social cost of carbon», is an attempt to define the real cost of carbon emissions, both for current and future generations. Money quote: «The social cost of carbon was needed because otherwise the benefits will always be measured in tonnes of carbon, and the costs in dollars, and the dollars will always win.»

From Weekly Filet #372, in November 2021.