Ellen Stofan is Chief Scientist of NASA, and a field geologist. In a fantastic interview with the Guardian, she explains why people who want to save the Earth must also look to space.
One of the common complaints about space programs, especially from environmentalists, is that it's a waste of resources to send things offworld when we still have so many problems to clean up here. Here's Stofan's response:
I always like to say just think you were a doctor with only one patient. You might understand how that person gets sick, how they get better, but you understand nothing about the progression of disease or how humans in general get ill. Now take an Earth scientist: you only have one planet to study. Our studies of other planets are really what we call comparative planetology. Think of the other planets as being simpler versions of the Earth where you've tweaked the physical conditions, maybe the composition, the density of the atmosphere. It allows us to rip apart the physics of some of these problems and give us a better comparison.
Read more at The Guardian