Lecture entitled (chemistry of global warming)

27 March 2019

As part of the cultural season of the Environmental Research Center / University of Technology, Assist. Prof. Dr. Saadi Mohammed Dhaher  delivered a lecture titled on (chemistry of global warming) on Wednesday, 27/3/2019, where the lecture summarized the following:

Scientific studies revealed that global warming over the past two centuries is the result of the accumulation of greenhouse gases. But there is no conclusive evidence that climate changes in this era are not natural. The climate has become warmer due to the internal anarchic dynamics in the Earth-atmosphere system (ie no external influence) as well as the direct increase in solar energy production. When studying the possibility of blaming greenhouse gases, spectral calculations show that these gases cannot exceed their effects. Water covers three quarters of the earth is very effective, a steady state since the dawn of history and combined greenhouse gases cannot have this effect. The data also show that absorption of solar radiation is mainly due to water vapor in the atmosphere. The rest of the gas components exist in small amounts that do not qualify them to be the main factor in global warming. From the above it turns out that the rise of carbon dioxide in the atmosphere is not the main culprit in raising the degree of air drag.

On the other hand, the phenomenon of global dimming which alert scientists since 1950 can be the reason. The extent of blackout varies depending on location, but total solar radiation on the Earth's surface decreased by 4% in a period spanning three decades from 1960 to 1990. But after 1990, the value of solar radiation began to increase slightly, with the exception of 1991, when the eruption of Mount Benato. Global dimming is believed to have resulted from an increased concentration of pollutants in the atmosphere due to human activity. The tendency to move from global dimming to global lighting is the result of decreasing atmospheric haze. Global dimming has been associated with the water cycle, where evaporation rate is lower and may be associated with decreased precipitation in other regions. Global blackout also creates a cooling effect of the Earth, leading to partial inhibition of global warming. That the increase in the presence of carbon black minutes and thus significantly increase global dimming could be attributed to an increase due to humanitarian activities associated with the inefficient combustion of oil derivatives and coal as well as volcanic eruptions and forest fires. The deposition of carbon black minutes on the northern and southern poles may be the main reason behind the reduction of the reflection of an important part of the solar radiation outside the atmosphere and thus raise the temperature. The equation below can be formulated to justify the rise or fall of atmospheric temperature in an approximate mathematical manner:

CBtotal  = CBairborne + CBpoles

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