The Bitcoin network uses about 138 TWh of electricity a year and emits nearly 40 million tonnes of CO2 (Cambridge 2024 data). Relative to its market value, that gives an intensity of about 33 tonnes of CO2 per million euros held per year, slightly more than a Livret A (the regulated savings account in France) and five times less than a euro fund in a French life insurance policy (in French) (in French). This footprint comes from mining, the computation-based validation mechanism of Bitcoin known as Proof of Work.
Read the source article: Bitcoin carbon footprint: 33 tCO2e/year per million euros held