https://www.theguardian.com/technology/2021/apr/07/china-bitcoin-mining-climate-targets-nature-study

China powers nearly 80% of the global cryptocurrencies trade, but the energy required could jeopardise its pledge to peak carbon emissions by 2030

China’s electricity-hungry bitcoin mines that power nearly 80% of the global trade in cryptocurrencies risk undercutting the country’s climate goals, a study in the journal Nature has said.