According to the report, from roughly 314.2 billion cashless transactions in 2017, Bitcoin’s share is estimated to be roughly 0.033%. While recognizing that “accelerated growth” is common in the early adoption phase of new technologies, the report nevertheless argues that, even if Bitcoin follows a bare minimum “median growth trend,” it could be equal to the global total cashless transactions in less than 100 years.
If this occurs, the cumulative emissions of the use of Bitcoin within 22 years would exceed the 2 C limit, if the adoption rate is similar to that of the “slowest broadly accepted technologies” or only in “11 years” if adopted at the quickest rate. The carbon footprint calculation assumes that the types of fuel used to generate electricity will remain relatively unchanged in the coming years.
For the current Carbon Footprint from Bitcoin, the report mentions recent Digiconomist research that used the following assumptions for calculation:
“60 percent of the economic return of the Bitcoin transaction verification process goes to electricity, at $0.05 per kWh and 0.7 kg of carbon dioxide-equivalent (CO2e) emitted per kWh, [resulting in an] estimate that Bitcoin usage emits 33.5 metric tons of CO2e annually, as of May 2018.”
While abstaining from forecasting Bitcoin’s “fate,” the scientists opine that economic logic will force miners to shift to areas with cheap power facility, therefore suggesting that “electricity de-carbonization could help to mitigate Bitcoin ’s carbon footprint — but only where the cost of electricity from renewable sources is cheaper than fossil fuels.”
If energy costs remain high, more competent hardware can assist to minimize its footprint, the report admits, but advises against depending on “yet-to-be-developed hardware.” It proposes instead “simple modifications to the overall system, such as adding more transactions per block or reducing the difficulty or time required to resolve the proof-of-work” in order to quickly reduce Bitcoin’s electricity usage.
Not all energy experts agree that high energy consumption is a “Achilles Heel” for Bitcoin. A report published in August criticized the exclusive focus on the energy intensive mining, stressing the importance of where the power is produced and how it is generated, saying that “electricity production can increase while still maintaining a minimal impact on the environment.”