Vladimir Valentinovich Alexandrov (Russian: Владимир Валентинович Александров; born 1938; disappeared 1985) was a Soviet/Russian physicist who created a mathematical model for the nuclear winter theory. He disappeared while at the Second International Conference of Nuclear Free Zones Local Authorities in Cordoba, Spain on March 31 and his ultimate fate remains unknown, though speculation continues. One of his last papers was Man and Biosphere published in 1985; it is said to have charted the moving trend in the science of nuclear winter. It was co-authored with Nikita Moiseyev and A. M. Tarko.The last moments of his life are shrouded in contradiction. When questioned by journalists in 1986, his acquaintances in Madrid gave differing accounts of how much he resisted when being driven towards the Soviet embassy.In 2016 Andrew Revkin argued, "He's almost assuredly dead. ...This wasn't just, you know, thumb-sucking climate science. It was in the middle of a war—a long Cold War—and there were bodies."