The Long-Time Story of Planet Earth

 I apologize for the long silence on this blog in May. I have been sick, much of it caused by well-meaning  but misguided drugs. Now that they are out of my system, I'm feeling good again, thank heavens! And I've had a lot of time to ponder what's going on in the world. One source of inspiration while I was recuperating is the PBS Nova series on Ancient Earth. Watching one episode after another, my mind has felt blasted into a totally new paradigm. I highly recommend these consciousness-raising programs. Here in the 21 century (on our continent at least) most of us are so busy with our daily responsibilities that we have little time to look at the big picture. And until recently, we didn't even know all that much about the early beginnings of the planet that is our home. On present-day earth, human impact is vast. In fact, it is hard to find areas where we have not totally changed the environment. Just like any other species, we do what we can to make our lives comfortable and safe. But unlike other species, our intrepid intelligence as well as our opposable thumbs have meant that we've become masters at manipulating our surroundings. It is easy to believe that "man" is the king, the ruler of all. Looking around it would seem that the whole world has been patterned to fill the needs of this one species. 

Many of you have probably already studied earth's evolution, but I'm going to go through some major shifts in the past, just to remind us of what came before the tiny span of humans on earth. (The time period we have been here is like the blink of an eye compared to the rest of earth's history.) What's called the Hadea eon was near the beginning of our planet, 4.5 billion years ago. There was no atmosphere. It was a hellish world (hence its name), hot, constantly being bombarded by meteors, just a ball of rock collected from the rest of the solar system. The earth had gone through many different phases since then, each lasting millions of years, before planetary changes paved the way for our ancient ancestors (the first mammals) to appear. Powerful geological events and changes in air composition plus more bombardment from space has made the climate and very nature of the planet change many times. The Late Cretaceous period, about 66 million years ago, is when there was an opening for an interesting collection of new species to evolve. The age of the dinosaurs (160 million years ago) had just finished with a blaze. The asteroid that struck earth was the equivalent of 10 billion nuclear bombs, quite enough to have a huge impact. And besides the clouds of debris and dust that covered the planet for years, the mineral anhydrate vaporized and filled the atmosphere. No light got through to the earth. Photosynthesis stopped in this global winter and 75% of all life died, including the dinosaurs.

But as we see again and again, some forms of life are able to survive even during a mass extinction. After a decade of cold and dark, the remains of at least one tiny furry life form has been found in the rock record following the age of dinosaurs (an early mammal ancestor of ours).  During this period, with new warmth from volcanic action on the seafloor, the climate again became a place for life to thrive, at least for awhile. Eventually the temperature rose past the tipping point, and much of the earth was devastated with violent storms, hurricanes, droughts, and deep sea extinction. However, there were places on earth where tropical forests flourished. Flowering plants developed into fruit-bearing trees and shrubs, and this fruit was a wonderful food source for a wide variety of mammals in that lush climate. The little 2-inch climber mammal who lived 56 million years ago found a good life in the tree canopy. And over time, these early tree-dwelling mammals evolved and spread. It was the Golden Age of Primates. Our ancient relatives had big eyes in order to find fruit hiding among the leaves, hands to clasp branches, and were able to lead their entire lives in the tree tops. Some of them looked similar to today's howler monkeys. And these primates thrived for 20 million years. When you think of it, this is an awfully long time!

Of course, as we've come to anticipate by now, the climate was bound to change eventually. At the end of the Golden Age of Primates, the temperature started cooling. This was probably due to the movement of techtonic plates which reformed land masses and released new chemicals into the air. Mountains rose up and blocked the rains from some areas. Tropical rain forests shrank. Grasslands appeared. Old habitats disappeared, and our ancestors had a much harder time in this new environment. After all, until now, they had been mostly tree dwellers, swinging from branch to branch. But now they were faced with getting across large areas with no trees in order to find food. So they started experimenting with standing upright! Walking. 3.5 million years ago we find the first evidence that primate skeletons are beginning to have leg placement and joints that can accommodate walking as well as climbing. This was a huge leap, taking primates to more distant places. And soon to follow, they began to find ways to hunt. And then to make and use primitive tools. 

During the Pleistocene epic, 300,000 years ago (do you notice we're no longer talking about millions?), human-like species were thriving on earth. But then came another climate change: the ice age. By 60,000 years ago, 25% of land was covered with ice, oceans had dropped hundreds of feet, and early humans  often lived in communities sheltered in caves. We can still see examples of impressive cave art from 25,000 years ago helping us to understand the lives of these people. They worked together, cooperated, and learned that together they could find ways of living well in changing circumstances.

The next climate change was probably fueled by a slight change in the earth's orbit around the sun, causing much of the ice to melt. By now our ancestors were walking, making tools, and hunting. And by 11,000 years ago, they had figured out how to sow seeds from plants they liked to eat. They began to be farmers! This was the beginning of the need to somewhat control the landscape. And this ushered in the Anthropocene Era. At that point, there was still much evolution to occur before humans got to our present state of development. But looking back this far at the history of our home planet, and the very recent arrival of our species to the mix, gives us a perspective we need for today's environmental crisis. In a comparatively tiny window of time, humans had altered the planet so that it would be unrecognizable to our ancestors. One half of the earth is now used for farming. Cities and urban areas cover much of the other half. It is easy to forget that, in fact, there is more to our world than billions of people and the raw materials to keep them happy. We have taken over to such an extent that we are often blind to the ecological niches that surround us.

I have to say that watching these episodes of "Ancient Earth" has made me feel more relaxed about the worrisome things happening in our world today. That might sound strange. For those of us who are aware of the ecological crisis we're in, surely it is a time to be worried! But the long view has given me hope for the planet, if not for us. After all, time after time, extinctions have happened and yet afterwards there has always been some form of life that endured. And with each re-establishment of the living world, new species evolved, new life forms flourished. I am less worried that we are going to destroy the earth. But we are certainly on the way to another extinction. Compared to the countdown toward former extinctions, we are putting greenhouse gases into the air 10 times as fast. The chances of our own species continuing to exist looks pretty small, taking into account the speed we are driving toward a tipping point. A few years ago, it seemed that if we drastically changed our habits, we might save our hospitable environment. But it looks more doubtful now.

So how do we deal with this story, this uncertain future? Here's how I am dealing with it. I continue to live as sustainably as I can, planting trees, taking care of the land, using as few fossil fuels as I can, doing the things we know are small but helpful. But my most important mind shift has been an appreciation of what we still have, an earth that is resilient, beautiful, creative, astonishing in its variety, intelligent, and balancing. I realize that even though our species has inadvertently hurt the whole, hurt the systems that keep the planet healthy, this Earth will inevitably triumph in the end. Our species may not survive as long as many species have been able to thrive on earth. But we have been ever so fortunate to have had thousands of years to enjoy and live on this amazing planet. Compared to all the planets we know of, this is the shining example of the one flourishing with life and vitality. We can still learn, enjoy, and live in its shelter. We can still realize what a treasure we have in this unique planet-scape. So I am grateful to be here for as long as I can. And the future will evolve as it always has, with the dramatic changes that cause life to decline and then to rise again. It will be a continuing story. And perhaps more than any other species so far, we humans have the ability to look back and look ahead, to have a wide perspective and to gather knowledge as we live our lives. If any of us survive the next extinction, we might have learned enough to be better caretakers of whatever world we find ourselves in.