  Another partial solution of Fermi's famous paradox is proposed, based on our
increased understanding of geophysics, geo-engineering and climatology. It has
been claimed in the recent astrobiological literature (for instance, in the
recent controversial "rare Earth" theory of Ward and Brownlee), that geological
activity of a terrestrial planet is an important precondition for the emergence
of complex metazoan life forms. Technological civilizations arising on such
planets will be, at some point of their histories or another, tempted to embark
upon massive geo-engineering projects. If, for some reasons only very recently
understood, large-scale geo-engineering is in fact much more dangerous than
previously thought, the scenario in which at least some of the extraterrestrial
civilizations in the Milky Way self-destruct in this manner gains plausibility.
In addition, we speculate on possible reasons, both physical and
culturological, which could make such a threat even more pertinent on an
average Galactic terrestrial planet than on Earth.
