Flying over somewhere is not the same as walking it, or even passing through it on a train. There is nothing we can do that will kill all life on Earth. We are

Flying over somewhere is not the same as walking it, or even passing through it on a train. There is nothing we can do that will kill all life on Earth. We are simply not that powerful. As a race, we've been through Ice Ages that have seen most of the world covered in ice, and a narrow strip of habitable land around the equator. We survived all that with no technology to help us. Twice. We'll cope.