E-waste from every two bitcoin transactions is the equivalent of throwing away an iPad

It’s no secret that cryptocurrency mining has a large carbon footprint. The process requires legions of electricity-hungry computers that work around the clock to unlock new coins by cracking math problems. Because these problems get increasingly complex over time, the system rewards energy waste: Any downtime makes the next coin harder to earn, and the only way to get an edge over competitors is to run more computers. And as the price of bitcoin rises—it was $47,318 on Sept. 19, below the peak above $60,000 reached in April—mining activity, and thus emissions, follows suit. The annual carbon footprint today is comparable to that of the London metro area.

But this mining system also pressures miners to run only the latest, fastest, most energy-efficiency computer chips and discard older ones. That leads to a mountain of electronic waste, according to a study published Sept. 16 in the journal Resources, Conservation, and Recycling. The average lifespan of a bitcoin mining chip is just 1.3 years, the study found, based on an analysis of the rate at which new hardware becomes available and assuming that most miners replace their chips at that rate, a sound assumption because otherwise it’s nearly impossible to turn a profit.

As a result, at current bitcoin prices, the annual volume of e-waste from bitcoin mining globally is about 30,700 metric tons—about as much as the Netherlands produces in a year from laptops, phones, and other personal computing devices. Divided by the average number of bitcoin transactions, that means just two transactions create as much waste as a disposed iPad, said Alex de Vries, a cryptocurrency economist and the study’s lead author.

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