Лекция: Climate and Man

It’s easy to think of the earth’s climate as unchanging, and for many purposes this would be an adequate assumption. However, the climate does change, slowly but continually. Paleoclimatologists have found convincing evidence of major climatic variations. Recorded history going back some 2,000 years clearly shows changes in climate and their effects on man, animals, plants and the landscape. Great migrations of people and animals accompanied periods of unusual cold and prolonged droughts. The movement of plant communities toward different latitudes and different elevations indicate important alterations in climate. The rise and fall of lake levels, particularly those more or less closed from the sea, show period of wet or dry climate. The extent of sea ice and its effect on shipping to the ports of northern Europe point to the warming or cooling of the earth’s atmosphere.

There is no doubt that climate changes continually, and that it did so long before man and his technology came on the scene.

Until fairly recent times, man’s effect on climate must have been insignificant. The discovery and the Industrial Revolution signalled the start of man’s competition with nature on a major scale. Internal combustion engines using such fossil-fuel-powered furnaces and so forth, began to introduce into the atmosphere huge masses of gases, particles, and grey amounts of heat.

As the population of the earth has been increasing at an alarming rate, the quantity of pollutants put into the air has done likewise. There is growing conviction that the increasing concentrations of carbon dioxide and particles put into the atmosphere by human activities are playing an important role in causing changes in climate. Theoretical analysis have shown that small changes in the cloud cover of the earth can have important effects on the air temperature near the ground. Atmosphere pollution might be affecting climate by causing changes in the cloud cover.