Why did the dinosaurs go extinct? It was probably caused by a super-sized asteroid hitting Planet Earth right in the middle of the Yucatan Peninsula. The resulting debris of fine dust in the atmosphere shut out the sun for many, many years. Dinosaurs’ dinners withered and died, as did three-quarters of all species on the Earth and in the oceans. That happened about 66 million years ago. Scientists call that the Cretaceous-Tertiary Mass Extinction (or K-T Extinction).
Since this planet came into existence about four and a half billion years ago, there have been five mass extinctions. All of them have occurred due to a cataclysmic natural event. The sixth extinction is happening right now and is being caused by us. Scientists have dubbed it “The Anthropocene.”
The Anthropocene de- fines Earth’s most recent period as “being influenced by humans. “Overwhelming scientific evidence shows that the Earth’s atmosphere, geology, hydrology, and biosphere are being altered by humans and have been for thousands of years. We are destroying the planet, and the cumulative effects of our actions are leading to the sixth extinction.
We are unlike any other living organism – we consume everything on the planet. Other creatures simply eat, mate, and die. They do not mine minerals, suck oil out of the Earth, impose agriculture on much of the Earth’s surface, or poison the oceans. We do.
Homo Erectus appeared almost two million years ago and a hundred thousand years ago got the wanderlust and left Africa to explore the world. Everywhere humans went, they killed things. By 9000 BCE, the megafauna, like mammoths and saber-toothed tigers, had been decimated in the Americas and Australia. At about the same time, agriculture was started in Mesopotamia, South America, and North China. We began to alter the courses of rivers, cut down forests, and destroy the natural habitats of many animals and birds. At about the same time, we started to tame and domesticate dogs, goats, and sheep.
2000 years ago the Earth’s soils began showing signs of degradation, because of our use of natural phosphorus as a fertilizer.
The explosion of colonization by European powers around five hundred years ago brought a global mixing of plants, animals, and diseases. Europeans got sugar, cotton, and tobacco, while Native Americans got smallpox.
The carnage in the America’s brought total agricultural acres down, and forests started to regrow. This reduction in the world population caused the only dip in carbon dioxide levels in the last 11,000 years. We started to get smarter and smarter. In the middle of the sixteenth century, we developed new and more reliable ways of looking at science, including physics, astronomy, biology, and chemistry. We started mining coal.
The Anthropocene is said to have started in the late 18th century. Present-day analyses of air trapped in polar ice show the beginning of growing global concentrations of carbon dioxide. That just happens to coincide with the time of James Watt’s invention, in 1784, of the steam engine used for locomotives.
Twenty years later, in 1804, the number of homo sapiens (”Wise People”) passed one billion. Now we are over seven and climbing towards eleven by the end of the century.
Perhaps nothing has been as destructive to our health and our planet as the mining of hydrocarbons. The first modern oil well hit pay dirt on Saturday, August 27, 1859, in Pennsylvania, and the world changed. But fifty years later it changed again. A couple of German chemists invented the Haber-Bosch process that produced nitrogen artificially and allowed even more intensive farming practices. It is estimated that this process allows the world to feed two billion more people.
The Great Acceleration happened during my lifetime. The last sixty years have seen a profound transformation of our relationship with the natural world. Our drive for new things to consume has resulted in the proliferation of plastics and persistent organic pollutants. POP’s are organic chemical substances that are carbon-based and toxic to both humans and wildlife. These actions will leave their marks for hundreds or thousands of years.
By 2014 the level of carbon dioxide in the atmosphere exceeded 400 parts per million. The last time levels were this high was between 800,000 and 15,000,000 years ago. Then the sea levels and the temperatures were much higher than today. Where will ours be in a hundred years?
What do you see in your future? What will Puerto Vallarta look like in a hundred or a thousand years? Who knows? We may be smart enough to avoid the thunder clouds on the horizon, but I’m not holding my breath. Let’s hope that the Anthropocene, somehow, reverses itself, and our children and grandchildren enjoy their lives too.