A lot of people are asking this question especially after Tesla said they would accept Bitcoin for their EV's which is counter-intuitive since Bitcoin mining produces huge amounts of greenhouse gas. This guy did the math on it:
This is how insanely bad Bitcoin is for the environment : If you buy a Tesla car (around 40 000 $) in Bitcoins, the impact of the mining of those bitcoins is around 80 tons of CO2. This is 4 times more than the saving of CO2 you can expect from this car (compared to a gasoline one) on its entire lifetime (around -20 tons).
Of course, the Bitcoins you use here will eventually be used for other transactions. But still, it gives a good point of comparison : Suppose you want to buy this car with gold. It would take 3 to 5 less energy to mine this gold than to mine the same value in Bitcoins.
What about the transaction only ?
What is the footprint of the transaction on existing bitcoins only ? Since the principle of “proof of work” is to secure the transferred funds, it is fair to split the mining cost per value transferred, rather than by number of transaction. This paper suggest that a stable ratio of 1% of transferred funds is burnt in energy.
1% of 40,000$ = 400$. At 5cts / kWh (average cost of the electricity for mining), this is 8000 kWh. This is about the consumption of an average french family for two years. We showed that bitcoin mining is uses mainly fossil fuel, with an average carbon footprint of 830 g CO2 / kWh : worse than the USA mix.
8,000 * 0.830 = 6.6 tons of CO2
The footprint of the transaction erases 1/3 of the carbon saving of a Tesla car. Why would anyone do that ?
https:// medium.com/crypto-lucid/buying-a-tesla-in-bitcoins-cancels-4-times-the-co2-savings-for-its-whole-lifetime-c28b042e3b9a
And I also think it's very interesting that many wealth countries do have declining populations. It's not really a bad thing unless you add in our economic systems which all seem to work on a Ponzi scheme where our only option is growth. I really think the best way out of this is degrowth, but that's not a very popular opinion.