ESS220
Prof. Jin-Yi Yu
Why Large Greenhouse Effect On Venus?
q Venus is too close to the Sun
è Venus temperature is very high
è Very difficult for Venus’s atmosphere to get
saturated in water vapor
è Evaporation keep on bringing water vapor into
Venus’s atmosphere
è Greenhouse effect is very large
è A “run away” greenhouse happened on
Venus
è Water vapor is dissociated into hydrogen and
oxygen
è Hydrogen then escaped to space and oxygen
reacted with carbon to form carbon dioxide
è No water left on Venus (and no
more chemical weathering)