Renovating gives off less CO2 than tearing down, building a house

According to The Asahi Shimbun, carbon dioxide (CO2) emissions from renovating a house are about half the amount from demolishing and rebuilding one, according to a new study by a real estate development company.
Sumitomo Realty and Development Co. conducted the study along with a group of researchers at the University of Tokyo and Musashino University involving three houses it was renovating.
The amount of CO2 emissions from the entire construction work was 47 percent less than the amount seen in rebuilding from scratch.

https://www.asahi.com/ajw/articles/14663390