If you could squeeze the Earth's atmosphere into a ball of similar density it would be more or less of size of the middle sphere (all the oceans only weigh 270

If you could squeeze the Earth's atmosphere into a ball of similar density it would be more or less of size of the middle sphere (all the oceans only weigh 270 times as much as the atmosphere [1]). So there you have it: the key ingredients all life depends on are but a tiny boundary layer of water and air, stretched thinly between solid rock and the hostile emptiness of outer space. The grand challenge of our sustainability is, indeed, how much can we (humans) perturb this extraordinary complex boundary layer without inducing runaway dynamics that we (or rather, future generations of us) will not particularly like. [1] https://www.sciencefocus.com/science/how-much-does-earths-atmosphere-weigh https://www.sciencefocus.com/science/how-much-does-earths-at...