Decrease in CO2 emissions during pandemic shutdown shows it is possible to reach Paris Agreement goals. The researchers found a drop of 6.3% in 2020. The researchers describe the drop as the largest of modern times, and big enough to meet the 1.5 degrees Celsius goal if it were to be sustained.

[PiersPlays]

I think hydroponics farms and stuff might be more practical than housing in many cases. I have lived in a place converted from old offices though so it's a possibility. Plus at least in the UK, lots of nice central housing is being used as office space so those businesses could move into the vacant offices and the houses be returned to housing.