The last Ice Age persisted for about 100,000 years, during which human progress was incredibly slow -- a few improvements in hunting tools and some cave sketches, that's all. Over the last 12 millennia of interglacial warmth, however, modern man has advanced rapidly. As the climate turned more hospitable, agriculture developed everywhere -- in the Middle East, China, North and South America, and Africa, an event of inestimable significance.

The domestication of plants and animals allowed for a population explosion and the founding of cities. A large settled community could afford specialists who made farm tools, crafted pots, and traded not only with locals but with outsiders. Art and science flowered because those with wealth could afford to maintain individuals who would create elaborate pottery, textiles, and musical instruments and who could record eclipses and star movements.

In Europe and the Near East, the first warm period produced a technological revolution -- the use of bronze, the fermentation of wine, and the invention of writing. With a more benign climate and less severe storms, the Baltic region shipped amber along the Atlantic coast to the Mediterranean. During the late Bronze Age, the Alpine glaciers shrank to one-fifth of their nineteenth century span, enabling merchants to carry goods through the Brenner Pass, the gateway between northern and southern Europe.

Cold, wet, and stormy weather returned from 550 A.D. until around 800. Trade within Europe dwindled or disappeared as the mountain passes became choked with ice and snow. From the ninth century, when the climate was still quite cool, to the eleventh, which was somewhat warmer, medieval Europe was almost totally agricultural. The few cities that survived consisted mainly of religious seats with their clerics and lay attendants.

The three centuries beginning with the eleventh, during which the climate became distinctly more benign, witnessed a profound revolution which, by the late 1200s had transformed the landscape into an economy filled with merchants, vibrant towns and great fairs. Crop failures became less frequent; new territories were brought under control. With a more clement climate and a more reliable food supply, the population mushroomed.

The historian Charles Van Doren claimed that: "the ... three centuries, from about 1000 to about 1300, became one of the most optimistic, prosperous, and progressive periods in European history." All across Europe, the population went on an unparalleled building spree, erecting at huge cost spectacular cathedrals and public edifices. Ponderous Romanesque churches gave way to soaring Gothic cathedrals. Virtually all the magnificent religious shrines that we visit in awe today were started by the optimistic populations of the eleventh through the thirteenth centuries, although many remained unfinished for centuries.

Throughout the continent, economic activity blossomed. Banking, insurance, and finance developed; a money economy became well entrenched; manufacturing of textiles expanded to levels never seen before. Farmers in medieval England launched a thriving wine industry. Good wines demand warm springs free of frosts, substantial summer warmth and sunshine without too much rain, and sunny days in the fall. Winters cannot dip below zero Fahrenheit for any significant period. The northern limit for grapes during the Middle Ages was about 300 miles above the current commercial wine areas in France and Germany.

The medieval warm period, which started a century earlier in Asia, benefited the rest of the globe as well. From the ninth through the thirteenth centuries, farming spread into northern portions of Russia. In the Far East, Chinese and Japanese farmers migrated north into Manchuria, the Amur Valley and northern Japan. The Vikings founded colonies in Iceland and Greenland, then actually green. Scandinavian seafarers discovered "Vinland" along the East Coast of North America.

During the Northern Sung Dynasty (961 A.D. to 1127), one of the warmest times, real earnings in China reached a level not seen again until late in the twentieth century. The wealth of those centuries gave rise to a great flowering of art, writing, science, and the highest rate of technological advance in Chinese history. Chinese landscape painting with its exquisite detail and color achieved its apotheosis.

Over roughly the same period, the peoples of the Indian subcontinent also prospered. Society was rich enough to create impressive temples, beautiful sculpture, and elaborate carvings. Seafaring empires thrived in Java and Sumatra. In the early twelfth century, the predecessors of the Cambodians, the Khmers, built the magnificent temple of Angkor Wat. In the eleventh century Burmese civilization reached a pinnacle with the construction of thousands of temples in its capital, Pagan.

In the ninth century, the indigenous peoples of North America pushed their agriculture northward up the Mississippi, Missouri, and Illinois river basins. By 1000 they were farming in southwestern and western Wisconsin and eastern Minnesota. The Anasazi civilization of Mesa Verde flourished; the Mexicans began constructing their pyramids.

The end of the medieval warmth and the start of the Mini Ice Age brought hardship around the world. The poorer climate in Europe after the thirteenth century halted the economic boom of the High Middle Ages. Innovation slowed sharply. Except for military advances, technological improvements ceased for the next 150 years. The economic slump of 1337 brought on the collapse of the great Italian bank, Scali, leading to one of the first recorded major financial crises. Construction on churches and cathedrals stopped. The Mini Ice Age cut off the colonists in Greenland, leading to their eventual demise.

At its coldest, the Mini Ice Age devastated the fishing industry as cod disappeared from the North Atlantic. Besides forcing the Anasazis out of their pueblos, the poor weather reduced incomes in China, raised food prices, and killed the orange trees in Kiangsi province.

If the climate is to become warmer or colder, let's hope for the warmer world. Humans would be better off with higher temperatures. History shows that people did well during the hottest periods and poorly during the coldest. If the climate becomes warmer, we should welcome the shift.

References:

Ammerman, Albert J. and L.L. Cavalli-Sforza. [1984]. The Neolithic Transition and the Genetics of Populations in Europe, Princeton, NJ: Princeton University Press..

Carruth, Gorton. [1993]. The Encyclopedia of World Facts and Dates, New York: Harper Collins.

Chao, Kang [1986]. Man and Land in Chinese History: An Economic Analysis, Stanford CA: Stanford University Press.

Claiborne, Robert [1970]. Climate, Man, and History, New York: W. W. Norton.

Deland, Antoinette [1987]. Fielding's Far East, New York: Fielding Travel Books.

Donkin, R. A. [1973]. "Changes in the Early Middle Ages," Chapter 3 in H. C. Darby, ed. A New Historical Geography of England, Cambridge: University Press.

Gimpel, Jean [1983]. The Cathedral Builders, trans. by Teresa Waugh, London: Pimlico edition.

Gore, Albert, [1992]. Earth in the Balance, Boston : Houghton Mifflin.

Lamb, Hubert H. [1977]. Climatic History and the Future, Princeton: Princeton University Press, Vol. 2 1985.

Lamb, Hubert H. [1982]. Climate, History and the Modern World, New York: Methuen.

Langer, William L. [1968]. An Encyclopedia of World History: Ancient, Medieval, and Modern Chronologically Arranged, 4th edition, Boston: Houghton Mifflin.

McNeill, William H. [1963]. The Rise of the West: A History of the Human Community, Chicago: The University of Chicago Press.

Pirenne, Henri [n.d., c. 1938]. Economic and Social History of Medieval Europe, New York: Harcourt, Brace and Co.

Van Doren, Charles [1991]. A History of Knowledge: Past, Present, and Future, New York: Ballantine Books.