An orbital ring was just bombed by a terrorist group, causing just enough damage to push the ring out of orbit too far for a readjustment to save it. Assuming that all escape craft have already launched from the ring and stranded people onboard, the space elevators are destroyed, and that it will eventually impact earth, what would the damage be to earth? would we have another mass extinction like the dinosaurs? would the ring kill everything on earth? would spaceships be able to get in and out of atmosphere to evacuate survivors(as long as the atmosphere isn't on fire or filled with flying debris or something like that, rescue ships should be able to land)? would earth still be habitable afterwards?

The orbital ring is made out of steel, a very strong version of concrete, some glass, and a bunch of boosters and rocket equipment. probably best compared to a hollow cross section of the death star large enough to encircle the earth.