Actually, the nutcase left is also against building dams. But not because they cause greenhouse gas (most of the nutcase left didn't know about this previously) but because anything that aids in the economic development of the human race is evil to the nutcase left, and the nutcase left wants to destroy.
It is true, though, that nutcase left opposition to nuke power and fossil fuel power has made building dams more attractive than it might otherwise have been.
Ah, the nutcase left. Were would we be without them? I know! Way up there. Way far ahead of where we are now.
Completely oil independent with about 2000 nuclear reactors in the country. Electricity would be extremely cheap, maybe enough to power cars properly.
It is true, though, that nutcase left opposition to nuke power and fossil fuel power has made building dams more attractive than it might otherwise have been.
There is quite a bit of opposition to hydropower among so-called environmental activists (really Luddites). There was a hydropower dam in Maine that lost it's operating license a few years back because of opposition from some local groups, who claimed the presence of the low-head dam (which had been there for something like 40-50 years) was "disrupting the natural flow of the stream". Well, duh, that's what dams do. So they got the thing shut down and eventually blew it up.
That case is ironic because other "environmental" groups who agitate against nuclear and fossil-fueled baseload plants always tout low-head hydropower as the Golden Child of distributed power generation. To hear them tell it, there are thousands and thousands and millions and billions of suitable sites for development of low-head hydropower. Well, make up your minds, you idiots. Are you for it or against it?
There was a group out West that was demanding the "removal" (i.e., blowing up) of the Glen Canyon dam, because it had irretrievably altered the natural environment. These people are truly certifiable.