a University of Cambridge analysis estimated that bitcoin mining consumes 121.36 terawatt hours a year. This is more than all of Argentina consumes, or more than the consumption of Google, Apple, Facebook and Microsoft combined.
And it is only getting worse because miners must continually increase their computing power to compete with other miners. Moreover, because rewards are continually cut in half, to make mining financially worthwhile, miners have to process more transactions or reduce the amount of electricity they use. As a result, miners need to seek out the cheapest electricity and upgrade to faster, more energy-intensive computers. Between 2015 and March of 2021, Bitcoin energy consumption increased almost 62-fold. According to Cambridge University, only 39 percent of this energy comes from renewable sources, and that is mostly from hydropower, which can have harmful impacts on ecosystems and biodiversity.
In 2020, China controlled over 65 percent of the global processing power that runs the Bitcoin network; miners took advantage of its cheap electricity from hydropower and dirty coal power plants.
Globally, Bitcoin's power consumption has dire implications for climate change and achieving the goals of the Paris Accord because it translates into an estimated 22 to 22.9 million metric tons of CO2 emissions each year"equivalent to the CO2 emissions from the energy use of 2.6 to 2.7 billion homes for one year. One study warned that Bitcoin could push global warming beyond 2C. Another estimated that bitcoin mining in China alone could generate 130 million metric tons of CO2 by 2024. With more mining moving to the U.S. and other countries, however, this amount could grow even larger unless more renewable energy is used.