Bitcoin mining is a process that consumes a lot of energy. However, it is difficult to determine the environmental impact it causes. To begin with, all aspects of the digital economy require energy. Think of the entire global banking system and the immense amount of energy needed to process bank transactions and provide electricity to office buildings, ATMs, bank branches, and so many other resources and processes.
Reality
A study by the New York-based Ark Investment Management concluded that "Bitcoin is much more efficient than traditional banks and global gold mining". The current percentage of that mining done with renewable energy varies between 20% and 70%, according to the Cambridge Bitcoin Electricity Consumption Index (CBECI). Researchers at the University of Cambridge concluded that "the environmental footprint of Bitcoin is currently minimal, at best."
It is possible to argue that the economic incentives inherent in Bitcoin mining help to generate innovations in terms of sustainable energy, as miners are always looking to increase profits by reducing electricity costs. In addition, mining is taking place in a world in which renewable energy is quickly becoming the cheapest option.