In 1938, Kirill Kondratyev entered Physics Department of the Leningrad State University. In 1941, he was drafted to the Red Army. In 1944, he was wounded and returned to Leningrad where he continued his studies. Kirill Kondratyev held progressively responsible posts at the Leningrad State University: from Assistant to Physics Department to Rector of the University.
In 1960–70s, Kirill Kondratyev made a significant contribution to the emerging satellite meteorology, environmental research using manned orbital stations, sub-satellite and air atmospheric radiation research as well as to the preparation of integrated national and international experiments.
In 1960-70s, Kirill Kondratyev participated in developing and implementing scientific programmes for manned spacecrafts Soyuz and Salut. Results obtained jointly with cosmonauts gave the start to global research of atmosphere and natural resources of the Earth. Particularly, this research resulted in discovering vertical ray structure of the diurnal radiation in the upper atmosphere of the Earth, which brought the research team the USSR State Award.
In 1980s, Kirill Kondratyev also studied optical properties of natural waters, phytoplankton, suspended dissolved organic matters, and developed remote limnologic research methods. He was among the founders of the International Center for Environmental Research and Remote Sensing n.a. Nansen.
He has significantly contributed to global environmental problems research. Kirill Kondratyev co—authored 1,200 articles and 118 papers. Many of his books were translated into foreign languages.
Kirill Kondratyev believed that besides the third world war natural and anthropogenic disasters were among the greatest threats to the humankind, thus rendering environmental safety issues utmost importance.
His achievements are recognized by the global society: he was elected Honorary Member of the Deutsche Akademie der Naturforscher Leopoldina (German National Academy of Sciences), Member of the American Academy of Arts and Sciences, American Meteorological Society, Member of the Royal Meteorological Society (UK), etc. He also was Honorary Doctor with a number of European universities.
Kirill Kondratyev received state awards of the USSR.