It seems like the left has 3 camps, not two. In order of influence:
-Mainstream types (lifetime Senators, Nancy, Clintons, etc) who don't give a flying ***** about any of it and are in it to line their own pockets
-Nutjobs and blowhards who preach 'Green New Deal' but don't have the slightest idea how any of that could reasonably be achieved, or done without creating more harm than they are saving,
-Serious people interested in dealing with the hard question and technical difficulties as you point out.
Of course, the 3d camp isn't part of 'the left' at all....those are mostly people in the private sector who are motivated (by both money and creating long term solutions), to work those problems and create those solutions. And that is happening every day. The narrative that we're not doing anything to address climate change is of course pure bunk.