It's all about changing to renewable energy. You can have the bitcoin network working renewable energy and everything is just fine!
I agree but the problem is with the miners. We're not sure if they will care about this issue.
It's guaranteed that they will consume a lot of time building the platform for "renewable energy" (like in building a solar powered mining centers). That would also costs them more money considering the amount for maintenance of this green source. As a normal person, I doubt they'll choose the hard way.