Reading time: 3 – 4 minutes

I just finished Carl Sagan’s “Shadows of Forgotten Ancestors” last night.  Great read.  It is the story of evolution starting from before the planet Earth formed until roughly the present day.  Sagan makes a lot of interesting points in the book around why we are the way we are and what the future may hold.  I don’t have to say much more because anyone who has read any of Sagan’s work before knows he was a gifted author and top notch scientist.

Anyhow, Sagan makes a point about the environment and life’s effect on it that I thought was worthy of some thought.  It turns out that the very first microorganisms on Earth, those that emerged before we even had any oxygen in our atmosphere, “breathed” carbon dioxide and “exhaled” oxygen.

Since the growth of these bacteria were relatively uninhibited, due to lack of predators and other factors like an abundant supply of food, they spread like wildfire.  As their numbers increased so did the amount of oxygen in our atmosphere.  In fact, it increased so much that a lot of the microorganisms likely died and new microorganisms, ones that could process oxygen, rose up to take their place and restore a balance (of course this is a massive oversimplification).

The first life on this planet, while making the planet much more hospitable for future life, actually polluted the planet so badly that a lot of the first life on the planet perished.  Pretty interesting realization. Looks like we’re not the first life to pollute the planet to the point where we are in danger of changing the environment so severely that we can’t survive on it.

The changing of our environment is best summed up by a passage from “Shadows of Forgotten Ancestors”:

By 3 billion years ago, life had changed the color of the inland seas; by 2 billion years ago, the gross composition of the atmosphere [what I was referring to in this post]; by 1 billion years ago, the weather and the climate; by a third of a billion years ago, the geology of the soil; and in the past few hundred million years the close-up appearance of the planet. These profound changes, all brought about by forms of life we tend to consider “primitive,” and of course by processes we describe as natural, mock the concerns of those who hold that humans, through their technology, have now achieved “the end of Nature.” We are rendering many species extinct; we may even succeed in destroying ourselves. But this is nothing new for the Earth. Humans would then be just the latest in a long series of upstart species that arrive on-stage, make some alterations in the scenery, kill off some of the cast, and then themselves exit stage-left forever. New players appear in the next act.  The Earth abides. It has seen all this before.

The good news is that humans have evolved to have significant intelligence.  Higher intelligence, given that is was selected for in the evolutionary process, has to be helpful for something (most likely a lot of things) and climate change is one of those things.  Climate change could wipe us out but we have the ability to understand it, to consciously change our course and to work together to engineer better solutions that serve our needs and that keep our planet healthy.