c5bad647_Methane_Catastrophe__Gas
[Symbol] H¸2O [Significance] The primary greenhouse gas, but not one that humans have much to do with, because of the vast amount of water covering the surface of the Earth. This surface water is freely exchanged with the atmosphere (in geologists' terms, atmospheric water vapor and surface water are "in equilibrium"). The quantity of water vapor in the atmosphere is determined by temperature, and varies greatly from place to place. When temperature rises, surface water evaporation increases, raising the amount of water vapor in the local atmosphere; when temperature drops, water vapor condenses out, as rain or snow. Global warming allows the total quantity of atmospheric water vapor to increase. [Gas] 
Water vapor
O x y g e n
W a t e r v a p o r
C a r b o n d i o x i d e
M e t h a n e
H y d r o g e n s u l f i d e
H y d r o x y l
O z o n e
Methane Catastrophe
Gas