evidence: Water vapor is a powerful greenhouse gas. The amount of water vapor in the air depends on temperature. Its saturation level doubles with every 10 °C increase in temperature. Its concentration also depends on availability of sources such as water surfaces and vegetation. Because of its strong temperature dependence its role as a greenhouse gas is limited to the equatorial region and the tropics diminishing to nil in the polar regions. [...] Hay, W.W. (2013). In: Experimenting on a Small Planet. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-28560-8_19