Climate change is a classic tragedy of the commons: every country acting in its own self-interest contributes to depleting a joint resource, making the world worse for everyone. If you’ve ever lived with bad roommates, the concept will be easy to grasp. The social cost of carbon (or SCC) is a way to put a price tag on the result of that tragedy, quantifying just how much climate change will cost the world over the coming generations.
But a paper in Nature Climate Change this week tries to bring the cost closer to home by estimating what the SCC could be for each different country. These new calculations point to a wide range of different cost possibilities but with a few consistent messages: the cost is likely to be higher than previous estimates; the US will be one of the worst-hit countries; and many of the countries contributing the least to the problem will be slammed regardless.
Transparency, uncertainty, and rigor
The concept of SCC has been around for a long time, with a huge range of different ways to calculate it. Because it’s impossible to know for sure what the future holds, those estimates end up with quite different outcomes depending on the assumptions they make. For instance, it’s impossible to know for sure what economic growth will be, and so different educated guesses about that will lead to different SCC estimates.