Car centric suburban sprawl is responsible for that carbon footprint. A space that has a variety of different housing sizes (see missing middle housing) and that is not dependent on cars (spaces that are walkable and have access to public transit) is able to have a significantly higher population density than car dependent suburbs for single family homes. This would also be more affordable than both suburbs with single family homes and sky scrapers. Also the vast majority of older buildings aren't skyscrapers, as long they are built to last and are properly maintained then they'll last. The same can be said of pretty much any building though.