Humankind's impact on the earth's natural ecosystems has ushered in a new geologic time period: the Anthropocene. From the Industrial Revolution to the present and beyond, the Anthropocene reflects detrimental changes in nature brought about by human progress.
In 2000, Dutch chemist Paul Crutzen coined the term "Anthropocene" to provide a name for the period of time in human existence that has had the greatest impact on our planet. ("Anthropo" means human, and "cene" is the common suffix used for geologic epochs.) The word reflects the changes that have occurred in the earth's atmosphere, biosphere, and water and soil systems because of human activity, particularly since the Industrial Revolution.
The Beginnings of the Anthropocene
With the advent of the Industrial Revolution in the late eighteenth century, human beings made unprecedented progress in the development of machinery. In turn, machine use transformed industry in terms of speed, efficiency, and production level—in everything from agriculture and manufacturing to mining and transportation. For these reasons, Crutzen and many other scientists argue that the Anthropocene started during this period of rapid technological growth, when human progress began having a negative global impact on the natural environment.
Other scientists take the beginning of the Anthropocene back much further to the rise of farming and great increase in human population some 8,000 years ago. Massive land clearing, soil erosion, and changes in greenhouse gases accompanied human movements during this time—enough to warrant some claims that this was the actual birth of earth's "human epoch."
While there is debate on whether the Anthropocene began many centuries ago or a couple of centuries ago, few would deny that it did begin and that we are well into it in the twenty-first century.
Physical Evidence for the Anthropocene Epoch
Physical changes in the earth's natural systems must be measurable in order to work as evidence that the world has entered a new epoch. One of the most discussed measurable changes over the past several decades is the rise of greenhouse gases such as carbon dioxide and methane, which actually began during the Industrial Revolution. The increase in greenhouse gases has resulted in global warming, which in turn causes an increase in sea levels.
In an article for National Geographic, writer Elizabeth Kolbert states that:
"[The gases'] warming effects could easily push global temperatures to levels that have not been seen for millions of years. Some plants and animals are already shifting their ranges toward the Poles, and those shifts will leave traces in the fossil record. Some species will not survive the warming at all. Meanwhile rising temperatures could eventually raise sea levels 20 feet or more."
Other evidence that we are in the Anthropocene is the obvious soil erosion occurring globally due to land clearing or deforestation. Massive agricultural tilling also contributes to the erosion.
Still other evidence is in the extinction of various animal and plant species caused by destruction of natural habitats. According to Kolbert, "Loss of forest habitat is a major cause of extinctions, which are now happening at a rate hundreds or even thousands of times higher than during most of the past half billion years. If current trends continue, the rate may soon be tens of thousands of times higher."
The Anthropocene: Official or Unofficial, It's Here
Members of the International Commission on Stratigraphy, a part of the International Union of Geological Sciences, is now debating whether to adopt the Anthropocene as an official epoch in the geologic timescale. The proceedings will undoubtedly take years. In the meantime, evidence that the epoch has already declared itself official will likely continue to grow.
"Anthropocene," Encyclopedia of Earth, Sept. 10, 2008, http://www.eoearth.org/article/Anthropocene
Kolbert, Elizabeth, "Anthropocene: Age of Man," National Geographic, March 2011, http://ngm.nationalgeographic.com/2011/03/age-of-man/kolbert-text