Water vapor accounts for the largest percentage of the greenhouse effect, between 36% and 66% for clear sky conditions and between 66% and 85% when including clouds.
Veeauru protsentuaalne panus kasvuhooneefekti on võrreldes teiste kasvuhoonegaasidega suurim: kui taevas on selge, siis 36–66%, ja pilvisuse korral 66–85%.