Hmm, I won't comment on the Scalability issue with Bitcoin. Still, for the environmental concerns, buddy you need to realize that Bitcoin is not at all affecting the environment badly, because most of the miners use their power to run the mining setup like l=solar energy, on a large scale unit as well Now miners are putting their efforts to build self-powered units.

Even if Bitcoin miners uses the commercial electricity supply, still not an issue generated with Bitcoin, it's an issue that suppliers are not using ecosystem-friendly power generation sources, I believe maximum power is not based on renewable sources.