IPCC's Hayhoe in her 2009 book: "Water vapor absorbs so completely that, for centuries, scientists thought water vapor was doing all the work of keeping Earth’s temperatures in check."

"The most important gas that helps maintain this much-needed temperature balance on Earth is water vapor. Water vapor absorbs so completely that, for centuries, scientists thought water vapor was doing all the work of keeping Earth's temperatures in check. Not until this last century did they discover that there are other greenhouse gases that also absorb the earth's heat. These other gases, including carbon dioxide, methane, and nitrous oxide, account for 15–35 percent of the natural heat-trapping greenhouse effect. This natural greenhouse effect is what makes our planet livable and unique among all the other planets. The natural greenhouse effect is a beautiful example of the care God has taken in creating a planet so perfectly suited for life. Earth has been carefully balanced to provide a comfortable home for the human race."