||P.1066 right column 2nd paragraph: "All bodies (including gases) radiate amounts of thermal energy corresponding to the fourth power of their absolute temperature. The resultant heat balance depends on the temperature of the body and its surroundings. Warm bodies lose heat to cold bodies, experiencing a net radiational loss. For plants under a clear sky at night, heat loss to “space” by thermal radiation may be considerable. Plant leaves may then be 3–5 K colder than the surrounding air, potentially leading to radiation frost damage. (To avoid confusion, temperature is indicated in ˚C, whereas temperature differences are given in Kelvin (K, McVicar and Körner 2012)). Clouds and fog reduce this effect."