Geologists who define ages and epochs according to the rise and fall of organisms have come to realize that one particular species has dramatically altered the earth in ways that will be detectable well into the future. That species is us: Homo sapiens sapiens. As the name implies, higher-order thinking distinguishes us from the rest of our genus, and indeed from the rest of all life. It may be both our doing and our undoing.
A lot of that thinking has been directed at the extraction of resources that could be used both for energy and for useful products. Those resources, especially coal, petroleum, and natural gas, provided both concentrated energy and material -- plastic -- that could be used to manufacture almost literally anything.
The Anthropocene (human age) is so called because that process of extraction has fundamentally changed the Earth in ways that some humans have difficulty believing. The earth is indeed so vast -- comprising billions of cubic miles of material -- that it seems unlikely that a "mere" humans could affect it in any significant way.
The first step in understanding how this is possible is to think about the spatial scale of Earth's environments. I help to run an educational project called EarthView, in which we take a giant, inflatable globe to school gyms. We point out that on a 20-foot globe, almost everything that counts in the atmosphere, hydrosphere, and lithosphere -- indeed, the entire biosphere -- is within 1/5 of an inch of the surface. At the scale of an ordinary classroom, all of our resources are within the thickness of the paper covering it.
The second step in understanding how humans can significantly alter the planet is to think about the temporal (time) scale of human activity. Over a few millennia of civilization, humans have changed land-use patterns through hunting, fire, and agriculture. And in just a couple of centuries, we have extracted fossil fuels that have formed over a period of about 300,000,000 years. We use energy for our homes, factories, planes, trains and automobiles that was derived by photosynthesis when India was still attached to Antarctica.
About half of the oil, coal, and natural gas are formed from decayed layers of plants and animals that were growing during the carboniferous period and developed under heat and pressure ever since have been released into the atmosphere and oceans in just two centuries. In half a century, much of that has been turned into plastics that -- whether dutifully recycled or not -- have accumulated into Texas-sized sludge islands in the oceans.
|Anthropocene imagined. Image: Shutterstock by way of NPR.|
Note vertical exaggeration of the near-surface features.
The Earth has a diameter of 8,000 miles; almost all of our experience is
within a layer that is far less that 1 percent of that thickness.
To this end, the most recent edition of the Ted Radio Hour is dedicated to understanding the Anthropocene and considering our responsibilities. The discussion begins with a paleontologist's perspective on the evidence we are leaving future geologists, and then turns to several discussions of our impact on biodiversity, including the potential of landscape ecology to reduce further harm.
For more on the basics that drive the climate part of our epochal impact, see my earlier posts Frosty Denial and Early Warning. For beautifully written, nuanced discussion of the localized impacts of climate change throughout the world, please see my various blog posts referencing the works of Carl Safina and read his book The View from Lazy Point.