Scientists in Belgrade came up with the idea of “planting” large tanks of water and algae in places where trees can’t grow. The tanks are 10-50x more efficient than a normal tree for the space it takes up and is in general highly sustainable, even creating excellent fertilizer in the process. You can skip about halfway through the video for the actual information about them.
That’s looking at it as a zero-sum thing. You’re not choosing between an algae tank and a utopian solarpunk city with no cars, tree lined streets, and bikes and grassy trams every where. You’re choosing between an algae tank and all its benefits, or no algae tank. I would choose the algae tank over nothing any day. Would I take it in place of a perfect solarpunk city where we all live in trees and get around with rope bridges? hell no.
Good point