3. Life on Earth - It's fragile

Our power to save a planet.

How can few billion of us change our environment so drastically?


Our living space seems nearly infinite – That moon mission shot of our blue planet conjures up a cloudy sphere sailing resolutely through space with some specks of life riding along – fleas on an elephant.


But – the livable fraction of our planet is actually small: a thin skin on that 8000-mile-diameter globe.


Most of the planet is very unfriendly molten material, crusted with an apple peel of hard rock. On that peel, we subsist on a dusting of farmable soil and a couple of miles of ocean depth. We inhale from a mile of so of atmosphere. The actual living volume we inhabit on earth is a thin, green envelope.


We can threaten that bit of real estate very quickly when we put our industrial minds to it.


That envelope is livable only through a set of unlikely coincidences: our tilted orbit the right distance from a mid-size and stable star, enough water, carbon, oxygen and other starstuff to support life, a large moon refreshing the tidal pools where microlife first sheltered. A series of very unlikely events over billions of years evolved that life, and life itself transformed the atmosphere into something livable. I’ve seen calculations that our situation might be unique in the universe; there may be good reason that our telescopes don’t see anyone staring back!


Life here has been lucky for a long time – It’s up to us to quickly fix what we’re breaking and extend that lucky streak.