Is crypto bad for the environment?

Whether crypto is bad for the environment depends mostly on how a blockchain is secured. Networks that use proof of work, led by Bitcoin, consume large amounts of electricity. Networks that use proof of stake use only a tiny fraction of that. The evidence on Bitcoin's emissions is real but disputed, because researchers measure the energy mix in different ways.

Is Bitcoin bad for the environment?

Bitcoin mining uses electricity because miners compete with specialised computers to add each block, as explained in our guide to how Bitcoin mining works. The Cambridge Digital Mining Industry Report, published in 2025, estimated annual use at about 138 TWh, roughly 0.54% of global electricity. It put annual emissions at about 39.8 million tonnes of CO2 equivalent, around 0.08% of the global total, while noting that the result depends heavily on method.

In the US, the Energy Information Administration estimated in February 2024 that crypto mining may account for 0.6% to 2.3% of national electricity use. Both figures are estimates rather than metered totals.

Is crypto mining bad for the environment?

The debate centres on the energy source. Miners surveyed by Cambridge reported that 52.4% of their energy came from sustainable sources, 42.6% renewables plus 9.8% nuclear, with natural gas the largest single source. These are self-reported figures.

A peer-reviewed United Nations University study, published in October 2023 in Earth's Future, looked at 2020 and 2021 and reached a darker view. It found about 67% of mining electricity came from fossil fuels, with coal at 45%, and estimated emissions above 85 million tonnes of CO2. It also measured water and land footprints. The gap partly reflects different years and different methods, since mining has moved between countries over time.

Hardware waste is another concern. Mining machines wear out or become obsolete. Cambridge estimated Bitcoin mining e-waste at about 2.3 kilotonnes for 2024, and said most retired hardware is resold, repurposed or recycled.

Is Ethereum bad for the environment?

Ethereum switched from mining to staking in an upgrade known as The Merge. Ethereum.org cites an estimate from the Crypto Carbon Ratings Institute that this cut the network's electricity use by more than 99.988%, to roughly 0.0026 TWh a year. Our guide to proof of work vs proof of stake explains why staking needs so little power.

Is blockchain bad for the environment?

Blockchain is a technology, not one network, so there is no single answer. Its footprint depends on how each network reaches agreement and where its computers get their power. Cambridge's index notes that country comparisons offer limited insight without context. To judge any network, look at its consensus mechanism, its energy sources and the date of any estimate, since these figures change over time.