Alien Atmospheres and the Making of Earth’s Environmental Sciences

Studying other planets depends heavily on what we know about our own.  Research in the field of exoplanet astronomy, which has grown significantly since the detection in 1995 of a planet around another sun-like star, refers to planets as “Earth-like” or being “windy.”  Alien worlds are often made familiar by comparing them to our own.  How, then, did we come to know our own planet, particularly the complex structure that is our atmosphere?  This paper demonstrates that some of the first Global Circulation Models, simulations of key interest to historians of technology, were in fact modeled from what scientists knew about the atmospheres of Venus and Mars.  Between 1962 and 1989, while the environmental movement was experiencing its first period of growth, NASA's Goddard Institute for Space Studies (GISS) pointed its instrumentation not away from the Earth, but back toward it.  Scientists at GISS, including its vocal director, climate change advocate James Hansen, tweaked models they had developed for the atmospheres of other planets in the Solar System to create one of the first mathematical pictures of Earth's atmospheric and climatological future.  This paper will explore the history of atmospheric modeling from the 1960s to today and analyze how lessons from outer space have been applied on Earth and vice versa.  The “environment,” I will show, is something that is scientifically created in conversation with processes that occur on other planets.