This is absolute nonsense....
Proof of Stake will just make it easier for FIAT rich a$$holes and Bitcoin whales to monopolize Bitcoin mining. This will jeopardize the security and decentralization of the technology.
We currently still have smaller miners having some influence over the direction that mining are going, within the mining pools where they are dumping their hashing power and with PoS, only a bunch of rich people will have all the say.
I think these environmental groups have to do some more research to see the real agenda behind this whole PoS hype that are spread by controlled mainstream media. Also, calculate the amount of "dirty" energy used by Banks and large financial firms... to see the bigger picture.