By Kim Young-il

The very first course I took during my U.S. university education in 1960 was ‘Climatic Changes." Without being aware of how hot the issue would be 45 years later, I simply took the course out of pure curiosity. The subject itself was quite provocative as it was very contradictory to what I had learned. Until then, I firmly believed the global climate permanently spun around at an average 15 degrees centigrade as most textbooks stated. In any case, as a result of this course, I kept up my interest in paleo-climatology and ended up later translating Stewart Boyle's "The Greenhouse Effect" into Korean.

There is now plenty of evidence that we are experiencing global warming trends throughout the world. Without any doubt, I believe coping with this warming trend is our overriding task and our responsibility for our future generations. However, it is worth to call into question whether the main cause of global warming is really from increments of atmospheric Co2.

There are records that reveal that during some glacial periods in the Pleistocene era, Co2 levels on the surface of the earth was sixteen times greater than they are now. We also know that the cause of the Medieval Warming Periods between the 10th and 14th centuries were not the result of Co2 gases such as those produced from automobiles. The Little Ice Age followed immediately after the Medieval Warming Periods and throughout both the Little Ice Age and Medieval Warming Periods, there are records that suggest the atmospheric Co2 level maintained the same intensity. This evidence is self-explanatory in that it shows that Co2 was not itself the main cause of global warming.

What's more, scientists who claim that Co2 is the main cause of global warming cannot present any clear-cut convincing evidence..Of the 2,500 scientists who participated in producing the 2007 Intergovernmental Panel on Climate Change Report, I believe no one can really quantify the conclusion in the final section of the report that global warming in later part of 20th century is "by and large" caused by increments of Co2. It is appropriate to state that the increased level of Co2 in the atmosphere is the result of global warming created by other events. In other words, the high Co2 level is a symptom of warming, not the cause.

If that is the case, we may have to find out what else is causing global warming. The wobbling of the Earth's axis, variations in sun radiation output by fluctuations of the sun's magnetic field, variations in gamma rays and atmospheric humidity, variations in the salinity of ocean water and ocean currents could be some of the causes.

Of these explanations, the most interesting and convincing is the Milankovitch theory, named after the Serbian geophysicist and astronomer Milutin Milankovic, who postulated that changes in Earth's axis tilt determines climatic patterns.

According to the theory, the earth's axis tilt does not maintain the same angle all the time. The angle between the Earth's rotational axis and normal to the plane of its orbit moves from 22.1 degrees to 24.5 degrees and back again on a 41,000 - year cycle. Currently this angle is 23.44 degrees and is decreasing.

When the angle is at the lower end of 22.1 degrees, the northern hemisphere receives the least insulation during the summer from the sun but the most in winter. In this situation, the earth experiences cool summers and relatively warm winters. Warm winters tend to stir up active atmospheric convection which results in abundant snowfall and cooler summers which will slow down the melting of the accumulated snow that will then lead to an ice age in the northern hemisphere.

Since the angle of the wobbling axis is decreasing, the Earth is heading toward another ice age. Based on this reasoning, it can be calculated that the peak of next ice age will be around A.D. 12,000. This theory matches the claims of many scientists who say the Earth is already in the process of moving toward another Ice Age. Although this is a concern of future generations, they have to learn how to cope with a cooling Earth rather than warming.

So perhaps we should acknowledge the fact that a warmer Earth may be more bearable than a cooling one.

Kim Young-Il, a former CEO of Kyung-In Energy, is now vice president of the United Nations Association in Korea. He can be reached at kim@unarok.org.