Do the first line of each verse as a Call and Response to involve the audience

(1) When C-O-2…..has been reduced
When C-O-2 has been reduced
Oh, how I want to be in that number,
When C-O-2 has been reduced

Variations:
(2) When climate change…has been reversed

(3) When we all love….our Mother Earth

(4) When climate is….still safe for all

(5) When polar bears….still have some ice

(6) When carbon fuels….have been replaced

(7) When we all work…to save the earth