In this article, planetary astrobiogist David Grinspoon, senior scientist at the Planetary Science Institute and adjunct professor of astrophysical and planetary science at University of Colorado, focuses on our growing knowledge of what we are doing to this world. He says âwe have entered a new epoch of Earth history, one in which the net activity of humans has become an agent of global change as powerful as the great forces of nature that shape continents and propel the evolution of species.â
