So you’re partially on the right track, concrete is one of the biggest problems we have with global warming, but it’s not the slabs of hardened concrete that are the problem, yes they get hot and reflect heat upwards so cities feel hotter, but that’s not causing the whole climate to change as much as the carbon dioxide produced in the manufacture and setting of concrete, which produces more of those springy balls than even airplane emissions annually.

The problem is the carbon (and other greenhouse gasses) far more than anything we do with structures and surfaces on the ground. If you were to take away every road and parking lot, it would make cities feel a little better, but the globe would still be on a runaway temperature increase. Even the idea of planting vast amounts of trees is likely not nearly enough. We had our window to act, it slipped by.