by Igor MOKHOV, Corresponding Member of the Russian Academy of Sciences, RAS Institute of Physics of the Atmosphere named after A. Obukhov (IFA) Changes of the climate-current and coming-are one of the major problems of our time which requires a comprehensive approach. That includes taking into account the impact of human activities. Studies of key problems involved are conducted by our Institute scientists in close cooperation with specialists from other research organizations of this country and foreign colleagues. Pages. 62 Air temperature near the surface of the Earth during the past century was rising much faster than during the past 2000 years (according to paleoreconstructions). Naturally enough, one cannot disregard an important role in this process of natural climate variations caused by changes in solar radiation and volcanic activities. For example, the warming in the first half of the 20th century can be explained by exactly such reasons, but according to calculations in these past few decades the main role belonged to anthropogenic factors, including the central one-mounting levels in the atmosphere of hothouse gases, above all of carbon dioxide. As compared with what we call the "pre-industrial time", its level increased by one third. Man's intrusion into the "weather laboratory" of nature is demonstrated by temperature difference in different strata of the atmosphere. With growing intensity of solar radiation the temperature is increased not only of the lower layers, but also of the stratosphere and mesosphere. And with the growing hothouse effect the latter are cooling down and it becomes warmer only in the troposphere (up to 8 - 16 km from the Earth surface). This is exactly what happens now and the gas "envelope" of our planet is cooling down mostly near the menopause (at altitudes of some 80 - 90 km). An important characteristic of climate changes are their rates, which are especially significant in high latitudes (Siberia, North America, An ... Read more