CREATE TABLE table_73264 ("Gas name" TEXT, "Chemical formula" TEXT, "Lifetime  ( years ) " TEXT, "20-yr" TEXT, "100-yr" TEXT, "500-yr" TEXT)

What is the 100 year for Carbon Dioxide?
SELECT "100-yr" FROM table_73264 WHERE "Gas name" = 'Carbon dioxide'
SELECT "100-yr" FROM "table_73264" WHERE "Gas name" = 'Carbon dioxide'