Every 10 minutes a new block is mined. A year contains 525960 minutes. So there are 52596 blocks in a year.
Currently 6.25 btc is mined in each block. That means that 52596 * 6.25 = 328725 btc is minted this year.
The estimates of the energy impact the bitcoin network has depends on the source. Cambridge centre for alternative finance gives an upper bound of 281.76 TWh, an estimated bound of 123.99 TWh and a lower bound of 42.05 TWh.
Digiconomist estimates a number of 77.78 TWh.
So let's work with 77.78 TWh.
The carbon intensity in europe is around 270g CO2 / KWh. So let's work with that number as an estimation. This would make the assumption that we manage to mine bitcoin fairly environmentally friendly as europe's environmental generation is fairly environmentally friendly. (https://www.iea.org/reports/european-union-2020)
77.78 TWh = 77780000000 KWh
Each mined BTC under this halving would consume the following KWh. 77780000000 / 328725 = 236611.149137 KWh
270g = 0.270 Kg
236611.149137 KWh * 0.270 = 63885.010267 kg CO2 = 63.88 Ton CO2
Each mined btc would have an impact of 63.88 Ton CO2.
The value of one btc today is 47219 USD. 63885 / 47219 = 1.35 kg CO2 per USD.
So the carbon impact bitcoin has today per USD is 1.35 kg / USD with the above assumptions.
The environmental impact of gold mining is about 800 kg CO2 per ounce. One ounce is worth ~1824 USD.
800 / 1824 = 0.43 kg CO2 per USD.
So the environmental impact of gold mining is about 0.43 kg CO2 per USD.
https://www.mining.com/nearly-a-tonne-of-co2-emitted-per-ounce-of-gold-produced-in-2019-report/
whereas Mora et al. (2018) project that Bitcoin alone could produce sufficient CO2 emissions to push global warming above 2°C within less than three decades. source p83
56% of the measured energy expenditure in this study (p84) includes a mix of renewable energy. Unclear how much is actually renewable energy of those 56%.
I suspect PoW will use between 1–10% of the world’s energy when this equilibrium [Nakamoto point] is reached.” —Dhruv Bansal
The energy expenditure of the BTC network has grown ~18x since 2017. See https://cbeci.org/
- Quantification of energy and carbon costs for mining cryptocurrencies
- Apples to orange comparison of btc/gold/banking energy expenditure
- POW is efficient, post by Dan Hedl
- Sheet of BTC mining, linked by Dan Hedl
- Energy consumption of gold industry worldwide and australia
- True cost of gold production