2023-07-13 20:31:25
Some geologists have proposed that we live in a new geological era, the Anthropocene, and Crawford Lake, in Canada, has been chosen this week to study whether we really are already in that period.
The Anthropocene proposes that human activity has become a dominant influence on the planet’s climate and environmentespecially since the middle of the 20th century.
The International Commission on Stratigraphy (ICS) held in Lille (France) agreed to select Crawford Lake as a Global Boundary Stratrotype Point (GSSP) for the Anthropocene, considering it the place that best represents the beginnings of what could be a new geological epoch.
This lake will thus be the so-called “golden nail”, an internationally agreed reference point to show the beginning of a new geological period or epoch in layers of rock that have been accumulating.
Some scientific currents consider that the Holocene, the time in which we live and during which the climate has been unusually stablehas already given way to the Anthropocene.
WHAT IS THE ANTHROPOCENE?
That term was coined by Paul Crutzen and Eugene Stoermer in 2000 to denote the current geologic time interval, in which many conditions and processes on Earth are profoundly altered by human impact.
Adaptation, change, extinction, ecosystem, evolution, diversity, footprint, are some of the words that come up with this idea.
At the beginning of this century, it was when the hypothesis of a new biological era was published in the bulletin of the International Geosphere-Biosphere Program (IGBP for its acronym in English). The word Anthropocene contained a large number of concepts about the new rhythm of the planet. Anthropocene was used to designate the impacts of climate and biodiversity, the rapid accumulation of greenhouse gases, and the excessive consumption of natural resources.
The term was created in the early 1980s by American biologist Eugene F. Stoermerbut who popularized it was Dutchman Paul Crutzen, Nobel Prize in Chemistry, who used it to define a time when the activities of humanity began to cause dizzying biological and geophysical changes on a global scale. Both are authors of that text published in May 2000, where the concept of the Anthropocene synthesized man’s footprint on Earth as a geological force capable of accelerating natural processes since the end of the 18th century, marking a new era.
After the formal appearance of the concept, the scientific community began to investigate the scientific evidence and established the Anthropocene Working Group, which has examined possible markers and periodizations of the new era, while researchers from other disciplines have also identified it as a cultural concept. The geological and cultural term that accounts for the transformation of the planet and environmental challenges.
DISAGREEMENT AND FINDINGS
But there is disagreement in the scientific community about When did the Anthropocene begin, how is it evidenced, and if human influence has been substantial enough to constitute a new geological era?which typically span millions of years.
The ICS will evaluate the evidence obtained in Crawford Lake (Canada) and 12 other secondary sites to decide if we are in a new geological era.
Sediments found at the bottom of Crawford Lake “provide an exquisite record of recent environmental changes over the past millennia,” according to Simon Turner of the Anthropocene Working Group, cited by the University of Southampton (United Kingdom).
Seasonal changes in water chemistry and ecology have created annual layers there that can be sampled for multiple markers of historical human activity.
A GSSP is used to correlate similar environmental changes observed at other sites around the worldso it is essential to have a solid and reproducible record in this type of locality.
The team has collected sections of core samples from various environments around the world, from coral reefs to ice sheets, which were sent for analysis to the University of Southamptonwhere to detect a key marker of human influence on the environment: the presence of plutonium.
The presence of this material “gives us a clear indicator of when humanity became such a dominant force that it was able to leave a unique global ‘fingerprint’ on our planet,” explained Andrew Cundy, a member of the Anthropocene Working Group.
In nature, plutonium is only present in trace amounts, but in the early 1950s, when the first hydrogen bomb tests were carried out, there was an unprecedented increase in plutonium levels in core samples from around the world.
There is disagreement in the scientific community about when the Anthropocene began, how it is evidenced, and whether human influence has been substantial enough to constitute a new geological era.
Starting in the mid-1960s, when the Nuclear Test Ban Treaty came into force, there was a decline, the expert described.
Other geological indicators of human activity are high levels of ash from coal-fired power plants, high concentrations of heavy metals such as lead, and the presence of fibers and plastic fragments.
All this coincides with the so-called “Great Acceleration”a dramatic increase in human activities, from transportation to energy use, that began in the mid-20th century and continues today.
The Anthropocene Working Group indicates in its documents that the phenomena associated with it include an order-of-magnitude increase in erosion and sediment transport associated with urbanization and agriculture.
In addition to marked and abrupt anthropogenic disturbances of the cycles of elements such as carbon, nitrogen or phosphorus, together with environmental changes generated by these disturbancessuch as global warming, sea level rise, ocean acidification, and the spread of ocean “dead zones.”
Many of these changes “will persist for millennia or more, and are altering the trajectory of the Earth System, some with permanent effects.”which are being reflected in “a distinctive body of geological strata now accreting, with the potential to be preserved in the distant future,” according to the working group documents.
The evidence of the deposits will now be submitted to the ICS, that next year it will decide whether to ratify the Anthropocene as a new geological epoch.
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