The current average hash rate of the Bitcoin network is ....
It's currently using about ... of power (estimated).
If this all happened in the UK, this would equate to roughly ... of CO2 per .
Bitcoin uses hashing to process transactions. This involves lots of computers competing to see who can "solve" a problem the fastest.
This competition is very intensive, and therefore uses a lot of energy, which to generate by traditional means emits a lot of CO2.
In short: not very. These are very rough estimates.
It's impossible to tell the exact hash rate of the network, we can only work out an estimate based on how long it took to process previous blocks (from Blockchain API).
On top of this, we don't know what computer hardware people are using to mine Bitcoin, and therefore how much energy is being consumed to do so. The above calculations are based on the Antminer S17 Pro, which is modern and efficient. In reality, the hardware being used is probably less efficient.
It's also impossible to know how the energy consumed is being produced. If it was all being generated via solar, the carbon output would be zero (ignoring PV cell manufacturing/shipping). If it was generated from coal-fired power stations, the carbon output would be significantly worse.
The above is based on the current UK grid carbon intensity (from Carbon Intensity API). This fluctuates quite a lot depending on time of day, and additionally is not representitive of most of the world.
We either stop using Bitcoin altogether (unlikely to happen), or we need to rethink how the network processes transations. The Ethereum project is planning to switch to a "proof of stake" algorithm at the beginning of 2020, with eliminates the concept of "mining".
Based on above stats, the Bitcoin network emits ~... of CO2 per block, and ~... per coin mined.
Created by hackers at HackUPC Fall 2017. Updated in June 2019. Source on GitHub.