The green area was taking in CO 2 and putting out oxygen. Only during the day, granted, but I’d bred it to go into a deep dormancy at night, so it used up virtually no oxygen. The green could double in size every year, given enough available space, and I’d been careful to give the individual plantings enough room to grow. I would continue to start new plantings as well, so within ten years I expected to have half the global land surface covered. And within a decade after that, I should have an oxygen level that humans could tolerate.