Is Bitcoin mining an environmental disaster?

This question has undoubtedly sparked a lot of heated debate since Bitcoin has come under public scrutiny for its enormous energy consumption on par with that of whole nations. The energy mix plays a vital role in finding a conclusive answer to this question. Until additional and better data on the network’s power mix become available, strong assertions on either side of the debate should be considered with caution.

A radical thought experiment can provide an alternative perspective on this question. What would be Bitcoin’s environmental footprint assuming the absolute worst case? For this experiment, let’s use the annualised power consumption estimate from CBECI as of July 13th, 2021, which corresponds to roughly 70 TWh. Let’s also assume that all this energy comes exclusively from coal (the most-polluting fossil fuel) and is generated in one of the world’s least efficient coal-fired power plants (the now-decommissioned Hazelwood Power Station in Victoria, Australia). In this worst-case scenario, the Bitcoin network would be responsible for about 111 Mt (million metric tons) of carbon dioxide emissions, accounting for roughly 0.35% of the world's total yearly emissions.