Climate change is a complicated subject. To predict the future, we need to understand what happened in the past, but several myths have grown up.

Since the end of the last ice age, the climate has gone and up down quite naturally. But some of the stories are not quite what they seem. Much has been made of a warm period in medieval times that became a golden age for growing vines in England. But vines were not that widespread and, in any case, vine-growing carried on for the next millennium, even when the climate turned cooler. As Phil Jones, of the University of East Anglia, pointed out recently in Weather: “Past vine-growing in England reflects little, if any, on the relative climate changes in the region since medieval times.” When the Romans invaded England, the climate was supposed to be very warm. But in The Winelands of Britain Richard Selley describes how vineyards flourished largely in southern England, whereas today’s vineyards grow further north.

Critics say that the warm Roman and medieval periods prove how today’s high temperatures are simply another natural bout of warm climate. But today’s climate is the warmest in history, and the temperatures are rising unlike anything we have seen before.