As hydropower is clearly the cleanest and cheapest source of electricity and would be used first in any location, bitcoin miners are essentially shifting other power consumers to carbon-based sources.
I don't think they are shifting other consumers. More and more often we have seen that large miners either build their own mini-power plant[1] or use excess hydro power in remote areas that would otherwise be unused[2].
[1] http://thenodepole.com/2015/06/04/kncminer-to-build-new-20mw...
[2] https://bitcoinmagazine.com/articles/the-unknown-giant-a-fir...
No, many/most miners use hydropower. See next-to-last paragraph in section 1.