A recent paper by Colin Waters (British Geological Survey) and others in Science provides one of the most comprehensive lists to date as to how humans are making their signature within the geologic record. The authors suggest that humans have altered the planet so much that we end the current geologic epoch - the Holocene, and start a new one, known as the Anthropocene.
This is not a new conversation. The debate in the geologic world over ending the Holocene and starting the Anthropocene has been around for a while. There is also a huge debate over determining when exactly to end the Holocene. Some people have suggested 1492, when Columbus arrived in the Bahamas; others suggested the start of the industrial revolution in the 1800s. Perhaps the most precise suggested date and time to end the Holocene is when the United States tested the first atomic bomb in Alamogordo, New Mexico, on July 16, 1945, at 5:30 am.
Waters and his team of authors compiled results including atmospheric concentration of Carbon-14, Plutonium, Methane, and Carbon dioxide; production of concrete, aluminum, synthetic fibers, and plastic; black carbon; nitrate in ice cores; temperature anomalies; sedimentation rates; and extinction rates. They conclude that all these lines of evidence demonstrate how humans have a distinct fingerprint in the geologic record. In addition, the proposed Anthropocene deposits are distinguishable from Holocene aged deposits.
OK, here's where I found a lot of news articles screwing up the story, and quite frankly I am really disappointed in the media coverage of this story. The Anthropocene has not officially been accepted as a new epoch. The International Commission on Stratigraphy is the group that officially makes decisions on geologic time. Technically, we're still in the Holocene until they decide on the fate of the term Anthropocene. The commission still needs to determine when to start the Anthropocene. Colin Waters's article proposed that the start of the atomic age be used to mark the beginning of the Anthropocene, somewhere between 1945 and 1964. Finally Waters and his team of authors state that the Anthropocene may end up as an informal time period, much like the Precambrian or Tertiary.
So in conclusion, let's get a few facts straight:
- Have humans severely altered the Earth? Yes.
- Are we in a new geologic epoch? Not yet officially.
- When would the Anthropocene begin? Not determined yet, but the start of the atomic age is a good candidate.