Accepting the scientific evidence that the increased carbon-dioxide in atmosphere, introduced mainly by burning fossil fuels since the industrial revolution, is to cause global warming, the next question is the consequence; is global warming or the alternative global cooling more of a threat to mankind?

Global temperature changes are to influence regional precipitation patterns. Scientific and historical data indicate that at· times of global warming, low-latitude lands in continental interior such as China are wetter, whereas high-latitude countries such as Europe are drier. Both sets of circumstances have been beneficial to agricultural economy. At times of global cooling, low-latitude lands in continental interior are more arid, whereas high-latitude countries are wetter. Both sets of such circumstances are detrimental to agricultural economy.

History also shows epochs of peace and propserity alternating with epochs of war and famines. Those epochs seem to correspond to epochs of warmer and colder climate respectively. The two global-cooling epochs during the last two millennia were the Little Ice Age of the 16th and 17th century and the age of the Great Migrations of the late 3rd to the 6th century. In those centuries, there were droughts and famines in China, and bad harvests and popular unrest in Europe. The lesson of history suggests that a return of a little ice age would cause such an aridity in China that its 1.2 billion population cannot possibly be fed. At the same time, Europeans may sutler from bad harvest or even starvation.