I don't think government intervention will change anything. There will always be some government somewhere that won't restrict PoW mining.
4 years after the OP, we're still at the same point. The problem has maybe gained a wider awareness, but solutions are either not very popular (PPC, NXT...) or need yet to be proven (Ethereum's Casper PoS, Cardano's Ouroboros PoS)

edit: there's not only PoS solutions. IOTA could be an ecological alternative too.