Leftist solution: everyone gets in a circle and loudly argues about what the ideal solution would be in a perfect world if only they didn't have any political opposition. They can't agree, so they don't take any action, while the liberal has called the fire department.
Yes, yes, absolutely, every communist country has been a wonderful environmental steward! Just don't pay attention to the USSR's history of environmental neglect or China's use of coal or reality in general.
Also, while leftists may talk about shutting off the pipeline that's driving the world economy instead of reforming it to be green, they won't actually do anything, because leftists don't have either the numbers or the organization to effect change by themselves and they are often so hostile to collaboration within a political coalition that they are a political non-force. The serious leftists just become Democrats or members of other social liberal parties when they grow up and realize that writing lit memes isn't enough to change the world.
You not being able to envisage a world outside of the box you were socialised in doesn't mean there aren't solutions, it just means your ego is too fragile to hear them because they challenge your comfort too much.