Evolution is a constant in the human experience, although we interpret it in different manners. To some, particularly scientists, evolution is an accidental progression that yielded the cosmos, our planet and life. To others, it is a process created by a supreme being as part of a master plan. Regardless of our beliefs, life in the universe evolves with new stars being born, galaxies forming, and life on planet Earth in a continuing state of flux.
According to scientific studies, the evolution of the universe started with the Big Bang 13.8 billion years ago and will continue for an indefinite period of time. We humans are as much a part of this cosmic evolution as any galaxy or star. Even with the increasing sophistication of scientific methods and tools, we cannot predict where evolution will take us. It is not clear if our degree of evolution on Earth is the most evolved in the universe and if it can continue further. What is certain is that we as a species are changing and that to a large degree, we have control of what happens to life on Earth.
There is significant debate about the sustainability of our civilized world. Driven by scientific evidence, some adhere to the notion that Earth is a planet in peril. Others deny this notion and assert that life will continue its course and that humans do not need to worry. Climate change has been identified as one of the threats to sustainability.
Our history is plagued with end-of-the-world scenarios. Our documented doomsday prophecies date as far back as 634 BCE, when many Romans believed that the city would be destroyed in the 120th anniversary of its founding. Recent predictions about the end of the world were associated with the Mayan calendar that pointed at the year 2012 as the end of times. I mention these past scenarios because I worry that our current scientific predictions about climate change, water scarcity, and other modern complications may simply be more sophisticated “end-of-the-world” predictions backed by scientific observations that may be based on narrow perspectives.
In my mind, we should not embrace a planetary sustainability consciousness only because of the possibility of a large impact to life in our planet. We should do so because we understand the enormity of evolution itself and that at this point in our development we have influence in what happens next to our species, other species on Earth, and perhaps the planet itself.
To gain a deeper appreciation for where we are in our planet’s evolution, it is important to understand climate changes and levels of carbon dioxide. Both of these conditions significantly affect life. Climate change has been part of our planet’s history. There have been five major ice ages in the 4.7 billion years since the formation of Earth. We are currently in the Quaternary glaciation that started 2.58 million years ago. Within each ice age, we experience cycles of glaciation with ice sheets advancing and retreating on 40,000- and 100,000-year time scales called glacial and interglacial periods.
Earth is currently in an interglacial period. The last glacial period ended about 10,000 years ago. All that remains of the continental ice sheets are Greenland and Antarctic and smaller glaciers such as the ones on Baffin Island. Population development greatly advanced in the last 10,000 years from an estimated 1 million inhabitants to our current level of approximately 7 billion humans. This growth was made possible by many technological advances, but having a warmer planet was a significant condition.
The figure above from Nasif Nahle’s Cycles of Global Climate Change (and which can be viewed more closely at that site) shows three superimposed graphs of the amount of flooding, the fluctuation in temperature, and the concentration of carbon dioxide in our planet’s atmosphere across eras from the Precambrian to the current Cenozoic. In this figure, we can graphically appreciate that in our current epoch (Holocene), we have the greatest amount of inhabitable landmass, the least amount of temperature fluctuation, and the least concentration of carbon dioxide. These three conditions have not previously occurred in the history of Earth. We are living in a unique period of geological wonder. This alone makes our current life conditions miraculous regardless of any cosmological belief. Whether God architected the life conditions we now enjoy or had nothing to do with them, we live in very special times that have taken 4.7 billion years to reach.
From the information in the figure above, we can discern that the dilemma of our times may be not so much temperature or carbon dioxide because both have widely varied and have previously been at levels much higher that those presently claimed to be unsustainable. I believe the dilemma we face has do to with providing dignified living conditions to our large population, a harmonious coexistence with the other species, and maintaining our natural environment with as much life-sustaining capability as possible for as long as we can. After all, we know from the earth sciences that at some point life conditions will drastically change as we return to another ice age.
I do not believe we have the power to determine cosmic evolution, including what happens to our planet in the long run. Our own sun—a star—will cease to exist in approximately 6 billion years. This seems like an eternity to worry about in anyone’s lifetime. However, I go back to how precious life is in the present moment considering all that had to take place since the Big Bang for us to enjoy a cup of coffee at Starbucks. What is sad about our human condition is that not everyone can enjoy that cup of coffee; and this is where the opportunity lies. We can consciously evolve as a species taking care of all humans, other species, and our home planet.