On "we have to build differently with concrete": one promising development is carbon fibre reinforced concrete (https://www.compositesworld.com/news/carbon-fiber-reinforced...). Since most of the cement in conventional concrete is actually needed to protect the steel reinforcing rods from corrosion (and parts of the structure have to be stronger to support the rest of it), structures built with carbon fibre concrete can be much lighter and therefore use less resources. And because of that, it might even become cost competitive despite the higher price of carbon fibre.

But the "...or abandon it altogether" which someone left out of the title should be considered too.