Earth System Perspectives Inspired by Carl Sagan

Abstract:

Although Carl Sagan was an astronomer, his study of the origin and distribution of life in planetary systems resulted in three major Earth Science contributions: Identifying Venus’ runaway greenhouse effect in 1962; alerting the world in 1983 that the use of nuclear weapons would inject a massive volume of aerosols into the stratosphere, plunging the Earth into “nuclear winter”; and in 1990, obtaining the Voyager-1 image of Earth from beyond the orbit of Neptune that shows our planet to be a ’Pale Blue Dot’, that Sagan described as “it’s here, it’s home, it’s us”.

Carl Sagan’s ’Pale Blue Dot’ image puts our Planet in perspective with respect to our and nearby solar systems: there’s nowhere for all of Earth’s lifeforms to go. My presentation will also elaborate the contribution satellite geophysical observations have made to understanding the Earth System, making our planet well-understood in the planetary realm with respect to biogeochemistry and physical processes. I will stress the importance of protecting the ‘Pale Blue Dot’, the only home we have known. We are deeply indebted to Carl Sagan for his tremendous contribution for all Earth’s species, and for searing this understanding of the ‘Pale Blue Dot’ into our psyche. “This is where we make our stand”.