| Online: | |
| Visits: | |
| Stories: |
When did the Age of Man begin?
Eric Hopton for redOrbit.com – Your Universe Online
This, we are told, is the Anthropocene, the Age of Man. But just what does that mean and when did the current age begin? So far, scientists can’t agree on the answer to either question and there is as yet no formal recognition by the International Commission on Stratigraphy (ICS) which enshrines these epochs in the Geological Time Scale. New research suggests the arrival of Europeans in the Americas as a potential start date.
A few dates have been thrown around for the start of the Anthropocene and international Anthropocene Working Group (AWG) is weighing up the evidence. The AWG will announce its decision in 2016.
[STORY: Prehistoric mammals shaped their ecosystem]
Geologists divide time into epochs which are signified by marked shifts in the state of the Earth. The concept of the Anthropocene age reflects recent major global environmental changes resulting from human domination of the planet. According to the AWG, two proposed dates “do appear to conform to the criteria to mark the beginning of the Anthropocene: 1610 and 1964.”
What the heck is the Anthropocene?
The term ‘Anthropocene’ was originally invented in 2000 by Nobel Laureate Paul Crutzen, a leading researcher in diatoms. Crutzen discovered that many geologically significant conditions and processes, including erosion and sediment transport, were profoundly changed by human activities. Those activities included colonization, agriculture, urbanization, and global warming, and these led to chemical changes in the atmosphere, oceans, and soils. This all added up to alterations to the environment: global warming, ocean acidification, and increasing numbers and spread of oceanic ‘dead zones’. The ‘biosphere’, claimed Crutzen and Stoermer, was changed forever by mankind.
[STORY: Anthropocene continues to instigate scientific debate]
The AWG will aim to establish the Anthropocene as a formal geological epoch, at the same hierarchical level as the Pleistocene and Holocene epochs. This will signify the end of the Holocene, the currently recognized epoch which began over 11,500 years ago when the last Ice Age ended. Alternatively, they may classify the Anthropocene at a lower hierarchical level as a subdivision of a continuing Holocene epoch.
To be accepted as a formally recognized epoch, the Anthropocene would need to provide a sufficiently significant, large, clear, and distinctive ‘geological signal’ in strata now being formed. The term has to meet another criteria – it must be useful as a formal term to the scientific community at large.
Date debate
The findings of a new study which have been published in the journal Nature, suggest that the Anthropocene began in 1610 when the arrival of Europeans to the Americas resulted in major changes to the planet. When Columbus arrived in America, he set in motion a monumental exchange of people, crops, and diseases between continents that would change the face of the Earth. Was this the ‘golden Spike’ of the Anthropocene?
[STORY: The age of cyborgs is coming]
Prof Mark Maslin, from University College London, who co-authored the paper, told the BBC “We look for these golden spikes – a real point in time when you can show in a record when the whole Earth has changed. If you look back through the entire, wonderful geological timescale, we have defined almost every boundary in that way.”
The pollen record confirms these changes but the work by Maslin and his co-author Simon L. Lewis, pinpoints another golden spike – the introduction of deadly diseases to the Americas and beyond.
“Around 50 million people (in the Americas) died, and most of those people were farmers,” said Dr. Lewis. As deserted farmland returned to its more natural state, the increase in vegetation reduced global atmospheric carbon dioxide levels which are reflected in ice core records. The lowest levels of ice-core CO2 are from around 1610, making that another good candidate as a Golden Spike.
[STORY: Where penguins hid during the last Ice Age]
The proponents of the Nuclear Age as a starting point for the Anthropocene have some backing too as atomic bomb and nuclear weapons testing in the 20th Century have left a permanent marker. During testing between the 1940’s and 1960’s there was a clear spike in atmospheric radioactive carbon levels. There was a major fall in levels after tests were banned in 1964.
To be formally recognized, the date would be defined by one of two methods. It might be decided with reference to a particular point within a stratal section, a ‘Golden Spike’, or l Stratigraphic Section and Point (GSSP). Alternatively, it could be a designated time boundary, a Global Standard Stratigraphic Age (GSSA). If a formal date is agreed on, the new ‘official’ Anthropocene Epoch would represent the massive impact of human activity on the environment.
—–
Follow redOrbit on Twitter, Facebook, Google+, Instagram and Pinterest.
redOrbit.com
offers Science, Space, Technology, Health news, videos, images and
reference information. For the latest science news, space news,
technology news, health news visit redOrbit.com frequently. Learn
something new every day.”
Source: http://www.redorbit.com/news/science/1113351306/when-did-the-age-of-man-begin-031215/
