> But it's extremely expensive and disruptive to go rebuilding existing cities, and all the construction itself would have an environmental cost. Surely air con

> But it's extremely expensive and disruptive to go rebuilding existing cities, and all the construction itself would have an environmental cost. Surely air conditioning is cheaper? It's at best a cheaper up-front investment. And while it is one thing to think about the limits of retrofitting old buildings, that is no excuse to not do better with newly constructed ones.