evidence: Water Vapor—The Major Greenhouse Gas [...] Among all of the planets in our solar system, Earth is unique in that its ‘solid’ surface is mostly covered by the liquid form of H2O, water. A much smaller amount of H2O is in the solid phase, ice, concentrated in the Polar Regions. A much smaller fraction of H2O is present in its gaseous phase, as vapor in the atmosphere where it acts as a greenhouse gas. [...] Hay, W.W. (2021). Water Vapor—The Major Greenhouse Gas.