This is a difficult question. Mining must be costly, costless mining could not constitute an equilibrium. In general, it is costly to produce money, for example mining of real gold is costly. Yet existence of money is altogether certainly very ecological, as money allow much more efficient society than barter. Whether Bitcoin is a "good" money is an open question. It could be that people will come up with better currency where mining is less energy intensive because protocol is different etc. High mining cost of Bitcoin indicates that at the moment, people trust that Bitcoin is a "good" currency.

Many cryptocurrencies are Proof Of Stake in contrast with Proof Of Work (like Bitcoin), so it wastes far less. Some coins are hybrid.

Also, using electricity is not always a big deal.

Some countries produce the majority of their electricity using green sources like dams.

With an efficient Proof Of Work algorithm, the benefits of the technology could far outweight the cost in natural resources in the future anyway.

I agree that Proof of Work might only be a transition phase into more environmentally friendly procedures.

Additionally, I would like to point out that you also need to compare the total costs of Bitcoin with its alternatives. There seem to be a lot of conflicting opinions. For example:

Bitcoin mining is more polluting than gold mining:

https://digiconomist.net/bitcoin-mining-more-polluting-than-gold-mining

Mining gold requires 20x the energy of Bitcoin mining:

https://www.ccn.com/mining-gold-requires-20x-the-energy-of-bitcoin-mining/

Here a comparison of economic costs:

https://bitcoinexchangeguide.com/bitcoin-mining-economic-costs-comparison-to-gold-and-banks-fiat-currency/

How did they measure those impacts? Whom should we believe?