evidence: When atmospheric CO2 concentrations increase, radiation into Earth’s surface increases causing temperatures to rise. This is because a larger amount of the heat radiated by the Earth’s surface is being trapped by greenhouse gases in the atmosphere. But the extent of this CO2-induced surface warming depends on how much is balanced by localised factors that cause cooling – namely, cooling caused by evaporation and cooling due to the exchange of dry heat between the land surface and the air above it. (The atmospheric warming caused by the latter also tends to inhibit cloud formation and, thus, can cause further drying of the land surface.) [...] What our equation shows is that the response of land temperature to climate change depends on two factors: ocean warming and how dry the land is in today’s climate.