Bitcoin is the only project that is running PoW on a higher scale but even with that higher scale it doesn't come anywhere near in the top list that contributes to environmental damage aka climate change and whatever they claim it to be.
Reducing the hah power will give more chance for someone to get 51% of the total network then they can able to manipulate the blocks so the higher the hash rates the better the decentralization will be.
Thank you very much for the discussion, and first of all I want to say that I agree with most of your points. I also think POS is far less secure than POW, and POS greatly weakens decentralization, which is the core feature of the blockchain. And I don’t think energy consumption and carbon emissions will be a big problem. But what I care about is actually the network maintenance costs caused by energy consumption. In other words, the purpose of reducing energy consumption is not to protect the environment, but to reduce network maintenance costs.
Because in the long run, energy costs will account for the majority of mining costs, and only when the benefits are greater than the costs will the miners work and the network will be safe. As the block reward is halved, if the price remains unchanged, the miners' income will also be halved. At this time, some mining machines may have to shut down. Bitcoin is unlikely to experience a price surge after every halving. Once the block reward reaches a certain level, it may pose a threat to the security of the entire network. To avoid this, we might have to set a minimum block reward for miners, like Monero does, but I don't think that solves the problem.
What I want to ask is, is there a way for us to continue to use POW and reduce energy consumption without reducing the hash rate ?