600 milion years of climate change; a critique of the anthropogenic global warming hypotesis from a time-space perspective

The paper reviews the climatic changes that took place during the Quaternary, in articular those of the Holocene, including the historical time. The role of carbon dioxide, as a greenhouse gas, is emphasized since it is an important factor influencing the global climate. During the last century, a non-negligible increase in the atmospheric concentration of CO2 brought about a rise in global temperature attributed by many scientists to a man-made cause and labeled “anthropogenic global warming “. It is claimed that a rapid (even exponential) increase in the content of man-made greenhouse gases (of which CO2 is the most important) in the atmosphere may have grave consequences for human society, such as a rise in the see level, desertification processes on a large scale, with ensuing water shortages, biological mass extinctions, many more violent  eteorological phenomena, etc. A large group of scientists claimed that mathematical-statistical models predicted extremely alarming worldwide events and proceeded to popularize such consequences of global warming, emphasizing their catastrophic impact upon planet Earth and, especially, upon human society. Strong easures to counteract these man-made climatic changes were recommended. Against such alarmist point of view other scientists advocated more research, since climate and its variations represent the most complex natural phenomenon. They questioned many conclusions of the adepts of global warming, conclusions drawn from the climate-statistical models (Global Circulation Models). This paper agrees with the skeptical scientists and advocates that more research is necessary before reaching a definitive conclusion, that it is indeed only mankind which is responsible for the present and future climate change and that the o-called science of anthropogenic climate change is settled and no more doubts should be expressed. In particular, the role and accuracy of mathematical models and the influence of climate feedbacks need much more research to confirm or negate the process of global anthropogenic warming. It is concluded that skepticism is a healthy scientific position and that alarmist and confrontational iew points are not helpful in an ongoing discussion and, thus, a moderate and reasonable approach is recommended.