Water vapor is the only significant greenhouse gas.
In hot deserts the temperature in the daytime can reach 45 °C/113 °F or higher in the summer, and dip to 0 °C/32°F or lower in the winter. Water acts to trap infrared radiation from both the sun and the ground, and dry desert air is incapable of blocking sunlight during the day or trapping heat during the night. Thus, during daylight most of the sun's heat reaches the ground, and as soon as the sun sets the desert cools quickly by radiating its heat into space. Urban areas in deserts lack large (more than 14 °C/25 °F) daily temperature variations, partially due to the urban heat island effect.
Yet, today, America's leaders are reenacting every folly that brought these great powers [Russia, Germany, and Japan] to ruin -- from arrogance and hubris, to assertions of global hegemony, to imperial overstretch, to trumpeting new 'crusades,' to handing out war guarantees to regions and countries where Americans have never fought before. We are piling up the kind of commitments that produced the greatest disasters of the twentieth century.
— Pat Buchanan – A Republic, Not an Empire
