Let's face it, the politics of a GND are, at this point, pretty murky. This discussion on the 538 website takes up the topic and the participants don't really come to any firm conclusions, but I think they do raise most of the important issues. Nate Silver usefully points out:
"It seems like the Green New Deal raises two major tactical questions:
1) Incrementalism vs. swinging for the fences.
2) Separating climate change from other issues vs. lumping them together."
and later says:
"My guess is that GND activists are right (politically) about the Overton Window stuff — wanting big, bold sweeping initiatives instead of incrementalism. But that they’re wrong (politically) about the strategy of lumping environmental policy along with a grab bag of other left-ish policy positions, instead of being more targeted."
And still later he says:
"[Y]ou need some kind of paradigm shift...A paradigm shift where even action that seems incremental is actually quite bold, just because the goalposts have shifted so much....
I think the shift would just be a generational one. There’s a *lot* of evidence that people under about age 40 are willing to consider left-wing worldviews that a previous generation might have considered too radical.People under age 40 have also lived with two really unpopular Republican presidents, Bush and Trump (along with one semi-popular Democratic one). So I think there’s a decent chance that policy in the U.S. shifts significantly to the left as those young people grow older and gain influence and power."
So it might work. Or at least parts of it might work. Especially if there's a paradigm shift. Or something.