The increase of carbon dioxide in the atmosphere and its possible negative effects on the biosphere and mankind

Some scientists of “Anthropogenic Global Warming” (AGW), such as M. T. Boy Koff, A. M. McCright et al., claim that the increase in atmosphere of greenhouse gas carbon dioxide (CO2) coming from anthropogenic burning fossil fuels will cause a rising of air temperature that, in a few decades, will create severe uncountable problems for mankind and the biosphere. On the contrary, other scientists who support the thesis of “Not Anthropogenic Global Warming” (NAGW), the so-called “skeptics”, such as L. Weinstain, N. Scafetta et al., affirm that the increase of CO2 coming from the various human activities will not be able to increase air temperature in the atmosphere in such a way as to cause dangerous consequences for the biosphere. For “skeptics” the rising of temperature in the atmosphere is caused mainly by a natural mechanism of the planetary system and other natural causes not strictly connected with anthropogenic activities. Moreover, they rely on theories based on the thermodynamic and physicalchemical equilibrium on the Earth’s atmosphere and based on the variation of both CO2 concentration and air temperatures down the ages. The aim of this paper is to demonstrate that both AGW and “skeptics” scientists, when analyzing the different problems caused to mankind and the biosphere were referring to only one of the two sides of the same medal. Based on this concept, the paper investigates: • the changes on the increase of CO2 in the Earth’s atmosphere both in a human and in a geological scale of time; • the most convincing theories that justify the “skeptics’” statements; • the negative effects of rising CO2 concentration in the human scale of time.