Medieval Warming to Little Ice Age

If the warming of the late 20th Century had not come to an end, what kind of catastrophe were we headed for? Apparently one similar to the Medieval and Roman Warmings. Well, what does Ian Plimer in his wonderful book Heaven and Earth have to say about that?

The Medieval Warming period from 900 to 1300 was a period of great human advances in Europe, China, and Angkor Wat in southeast Asia. Humans generally prospered and were able to more easily feed and cloth themselves. As a result, they had enough time and resources to be able to undertake the building of cities, great cathedrals, and the start of universities throughout Europe. Europe started importing goods from China and the East Indies via the Orient. The Orient itself prospered with renewed agriculture, trade, and the establishment of institutions of learning. This period was warmer than the late 20th Century period.

The Medieval Warming was not nearly as warm as had been the longer Holocene Climate Optimum from 7000 BC to 3000 BC, but it was about the equivalent of the Roman Warming between 250 BC and 450 AD. Europe was warm, rainfall was plentiful, the climate was stable, and agricultural production became more bountiful and reliable. Farmers were able to farm to higher elevations in the mountains. Food production increased enough to allow the population to increase from 30 to 80 million in Europe. The population of China doubled in 100 years also.

There was a great expansion in trade. People could produce more than was needed for subsistence and were able to trade the excess. The warm period was accompanied by fewer storms and intense winds were less common than during the Dark Ages. Note that this is contrary to the claims of many Global Warming Alarmists today. Coastal trade and long distance ocean trade routes were widely established. Movement overland became easier. Though it rained more, there was also more sunshine to dry out the mud on roads. Mountain passes were open for longer periods.

The Vikings settled in Iceland, Greenland, and in North America. They farmed barley and raised cattle and sheep in Greenland. They had vineyards in Newfoundland. They fished for cod and hunted seals in ice-free waters. The Vikings traded extensively in Russia and Kievan Rus, down to Persia and Constantinople.

The Doomsday Book shows grapes were grown in England where they cannot be now. England was warmer and drier then than it is now. Its population grew from1.4 million to 5.5 million. the population of France tripled to become 18 million. Vineyards in Germany went to altitudes of 780 meters, though they only go to 560 meters now. This implies the average temperature was about 1.0 to 1.4 degrees C higher than now. In Norway, the land was cleared, settled, and farmed about 100 to 200 meters higher in elevation than now, suggesting a temperature average about 1 degree C higher than now. In 1000 AD, the treeline of the polar Urals was higher than it is now.

Mining in the higher Alps occurred both in the Roman and Medieval Warming periods. These mines were covered with ice in the Dark Ages and again in the Little Ice Age. Some of these mines were again exposed with the ice retreat of the late 20th Century warming. The sediments of Lake Neufchatel in Switzerland show it was warmer in the Medieval Warming than now, but that a 1.5 degree C temperature drop occurred quickly with the start of the Little Ice Age. The Baltic Sea supported tropical and sub-tropical plankton then, but cannot do so now.

A study of 600 boreholes on all continents shows that the Medieval Warming period was warmer than today. They also show a drop of 0.2 to 0.7 degrees C due to the Little Ice Age. Turkey, Northern Africa, Pakistan, southern Africa, Japan, the Great Plains of North America, Alaska, northern Quebec, southern Ontario, the Sierra Nevada Mountains, Mono Lake in California, the Anasazi Indian area, southern Alberta, Argentina, Peru and the Andes, and the South Pacific all experienced the Medieval Warming with benefits to the people of the regions. Similarly, when the Little Ice Age was experienced in all these areas, the people suffered.

Of course, these temperature changes were not caused by CO2 emissions by man. They were caused by changes in the irradiance of the Sun, changes in its magnetic fields, and in its emissions of solar wind and the resulting interactions with cosmic rays.

So, if the 20th Century warming had continued, mankind might have enjoyed the many benefits enjoyed by human civilizations in the Roman and the Medieval Warmings. Those benefits are the catastrophe the Democrats and the rabid environmentalists are trying to protect us from by bringing on catastrophic energy use restrictions and taxes. Had they simply done their homework and taken some reasonable regard for the great wealth that the Industrial Revolution has brought to mankind in increased security, longer lives, a richer intellectual life, and so much more, they would not be intent upon throwing wrenches and bolts into the gears of our economy. In the name of a phantom global warming catastrophe caused by human use of fossil fuels, they would throw many of us out of jobs, leave us in chilled homes and businesses in the winter, in swelteringly humid buildings in summers in which electronics cannot long function, deprive our businesses of profits, and restrict our travel.

As is so often the case, wrong-headed Democrats are coming close to destroying the miracle of America. Perhaps the coming Great Chill caused by our Sun will keep them from wrecking destruction via the route of energy use restrictions. Of course, the Great Chill will itself make life harder, as such chills always have. And, of course, the Democrats are always, without pause, looking for more ways to inhibit our pursuit of happiness as humans. They are especially fond of finding ways to reduce our production of the goods and services that people want.

Environmental Effects of Increased Atmospheric Carbon Dioxide

I wish to direct my readers to an excellent review of the climate literature on the subjects of global temperature and climate related to the observed increase in atmospheric carbon dioxide which has occurred since 1870. The rate of increase in CO2 has been faster since about 1950 than it was before that date. This review by Arthur B. Robinson, Noah E. Robinson, and Willie Soon was published in the Journal of American Physicians and Surgeons (2007) 12, 79-90 and was entitled Environmental Effects of Increased Atmospheric Carbon Dioxide. Because the article was written for physicians, it is well aimed for my audience of intelligent people, who may very well not be up on the latest jargon of climatologists or all the details of the many ocean cycles, etc.

The first figure of the article shows the temperature measured at the surface of the Sargasso Sea, which is a large area of the Atlantic, over a 3,000 year period using isotope ratios of marine organisms left in the sediment. The average temperature of this period is drawn as a reference and it is seen that the height of Greek civilization occurred during a warm period with a maximum temperature about 2 degrees Centigrade warmer than the average temperature, that the Roman period corresponded to a temperature period very near average, that the Fall of Rome and the Dark Ages corresponded to a period in which the temperature dropped by about 1 degree Centigrade, followed by the Medival Climate Optimum during which conditions improved in Europe, followed again by a decrease called the Little Ice Age, followed again by a return to a very nearly average temperature, where we are today. The French and Indian War and the American Revolution were during the coldest parts of the Little Ice Age, with conditions few living Americans would prefer to those of the present near average temperature. This figure is shown below:

They then show that the shortening of glaciers occurred well before increases in the atmospheric CO2 began. It began as a result of the warming ending the Little Ice Age. They show that the arctic temperature correlates very well back to 1880 with solar activity and does not correlate with atmospheric CO2. Then they show that the increase in annual mean surface temperature in the contiguous United States from 1880 to 2006 was 0.5 degree Centigrade per century. This is a temperature difference well within the 3 degree Centigrade variance over the last 3,000 years and one which few people would notice personally. A 0.5 C temperature increase is caused by an increase in solar activity of about 0.21% and the measured increase in solar activity from 1900 to 2000 was 0.19%.

During the recovery from the Little Ice Age, U.S. climate has improved with more rainfall, fewer tornadoes, and no increase in hurricane activity. Sea level has trended upward over the last 150 years at a rate of 7 inches per century. This sea level rise also began with the end of the Little Ice Age, rather than with the major increases in atmospheric CO2.

During the past 50 years, human use of hydrocarbons has increased 6-fold, but the increase in atmospheric CO2 has been only 22%. This increase in atmospheric CO2 has stimulated plant growth, which is good for both humans and other animals. Higher CO2 concentrations allow plants to grow faster and larger and to grow better in drier climates than otherwise. The Industrial Revolution has not only improved human life, but it has benefited plant life and the animals who depend upon plants. Increased warmth has also made life a bit easier for most plants and animals. The historical record of bursts in human civilizations also seems strongly to correlate with the warmer periods of the last 3,000 years.