Is it the Dawning of the Anthropocene Epoch?!
Science textbooks in every grade-school classroom will tell you that we are currently living in the Holocene geologic epoch…but this probably won’t be the case for very much longer. Many of the world’s leading scientists propose that the Earth has now entered a new geological period—the Anthropocene—in which human influence dominates the state of the planet.
Researcher Eugene Stoermer first proposed the idea that we might be in the Anthropocene epoch in the early 1980s,2 and journalist Andrew Revkin made the claim again in 1992.3 Throughout the eighties and nineties the idea was very controversial. Then in the year 2000, when a letter from the Nobel laureate Paul Crutzen and his colleague Eugene Stoermer appeared in the news bulletin of the International Geosphere-Biosphere Programme, the existence of the Anthropocene began to be more widely accepted.4 As the evidence linking human activities and climate change continues to grow, the Anthropocene’s reality is harder to challenge.
In 2008, a proposal was presented to the Stratigraphy Commission of the Geological Society of London to make the Anthropocene a formal unit of geological time. In the United Kingdom, steps are being taken by independent working groups of scientists from various geological societies to determine if the Anthropocene epoch will be formally accepted into the Geological Time Scale. In the United States, the Geological Society of America titled its 2011 annual meeting: Archean to Anthropocene: The past is the key to the future.5
Defining an Epoch
For the last 11,700 years, the earth has been characterized by an epoch that geologists call the Holocene. “Epoch” is a formal geologic term—they are relatively short time spans, though they can extend for tens of millions of years. “Period” is another geologic term used for longer time spans, such as the Ordovician and the Cretaceous. “Era” refers to extremely longest time spans, like the Mesozoic. Epoch changes are defined by changes preserved in sedimentary rocks. For example, the prevalence of one type of fossilized organism, or the disappearance of another, might be enough to justify a boundary shift.
Using the sedimentary rock test, scientists have proposed three different Anthropocene epoch start dates. The first proposed start date is about 8,000 years ago when agriculture was invented and large-scale deforestation began. Others propose that the boundary is around 1800. That was the year that human population hit one billion and carbon dioxide (CO2) started to significantly rise due to the burning of fossil fuels in the Industrial Revolution.8
The third start date option is around the end of the Second World War. Not only was this the time when humans started to build huge cities, with vast stretches of man-made materials—steel, glass, concrete, and brick—we also started to do things that will be preserved in the sediment record for far longer. The year 1945 was the dawn of the nuclear age, and sediments deposited worldwide that year contain a radioactive signature from the first atom bomb tests.9 Recently, there have also been significant changes in ocean chemistry as we release more carbon dioxide into the atmosphere. Rising ocean temperature and coral activity, which would also be noticeable in fossil records.10
Why Acceptance of the Anthropocene Epoch Reality is Important
Wherever we draw the final line, it is becoming more and more apparent that humans are fundamentally changing the chemistry of the Earth’s atmosphere and composition of the Earth’s biodiversity. Climate change is upon us. By acknowledging that we are in the Anthropocene, we are acknowledging that we are now in the driver’s seat. Unfortunately, we don’t really know how to operate the vehicle. So we’d better think about what we’re doing very carefully. As a recent article in The Economist summed it up:
[this] means more than rewriting some textbooks. It means thinking afresh about the relationship between people and their world and acting accordingly… this is one of those moments where a scientific realization, like Copernicus grasping that the Earth goes round the sun, could fundamentally change people’s view of things far beyond science.11
