When sprawl scatters the elements of a community hither and yon, forcing us to drive a mile in one direction to fetch groceries, two miles in another to take clothes to the cleaners and four miles in yet another direction to buy stamps, sprawl reduces the likelihood of running into old friends or meeting new people. When downtowns are revitalized, historic neighborhoods restored and buildings rehabilitated, there is less need to destroy forests to get lumber for new homes. There's less need to pave over farm land. Since most historic downtowns and neighborhoods are very walkable, they provide an alternative to driving when short trips are involved. The preservation of historic communities offers one way to reduce the environmental damage caused by the fossil fuel emissions of automobiles.
Historic preservation is thus a big part of the solution to the problem of sprawl.