March 10, 2021 Cryptocurrency is a notorious climate culprit. A Cambridge University study in February concluded that the global network of Bitcoin “miners”—operating legions of computers that compete to unlock coins by solving increasingly difficult math problems—sucks about as much electricity annually as the nation of Argentina. In terms of greenhouse gas emissions, according to a Mar. 10 article in the journal Joule, that’s equivalent to the emissions of the London metro area as Bitcoin mining volumes have surged along with prices. That’s a lot of carbon pollution for a service that benefits a relatively tiny number of miners, traders, and cryptocurrency investors. And it’s a potential liability for companies like Tesla or Square that purport to be climate-friendly but own a significant volume of Bitcoin. So a small but growing number of companies are looking at ways to clean the Bitcoin market up. Unfortunately, the way digital currency works today rewards energy waste—and it’s not clear that even a good-faith effort to use cleaner sources could justify the market’s insatiable appetite for power.