There are crypto currencies by actual computer scientists, like Algorand by Silvio Micali, that seem to be much further ahead than others when it comes to low-emissions proof-of-stake implementations. In Algorand's case, they even offset the carbon emissions of the network and as such their blockchain is effectively carbon neutral. Or as carbon neutral you can be when you use offsetting.

At least to me, they look more intriguing than all the older crypto currencies. I always wondered why you would bother with all these inefficiencies for some lofty idea of 'decentralisation' when we have run of the mill consensus algorithms and distributed systems that just work.