TORONTO – A tiny lake created by a sinkhole lake in Canada’s Golden Horseshoe that runs from Toronto to Niagara on the western shores of Lake Ontario may hold the ideal condition to mark the beginning of the Earth’s newest Epoch: The Anthropocene, a proposed geological epoch dating from the commencement of significant human impact.
The modest 95-foot (29m) lake may have all the distinct historical environmental markers to pinpoint the beginning of the epoch. Scientists believe they can pinpoint the exact start of the Anthropocene epoch by verifying the “golden spike” in the lake’s sediment. The “golden spike” refers to the point where humanity’s impact is visible in the environment.
Previous research from 2015 published in the prestigious scientific journal Nature described how sediments can pinpoint human-driven environmental changes. Prof Mark Maslin, from University College London, a co-author of the paper, said: “We look for these golden spikes – a real point in time when you can show in a record when the whole Earth has changed.” He added, “If you look back through the entire, wonderful geological timescale, we have defined almost every boundary in that way.”
Crawford Lake Conservation Area Ontario, Canada [Photo Credit: Laslovarga CCA-SA 3.0]
Dr. Simon Lewis, the study’s co-author added “Maize from Central America was grown in southern Europe and Africa and China. Potatoes from South America were grown in the UK, and all the way through Europe to China. Species went the other way: wheat came to North America and sugar came to South America – a real mixing of species around the world.” The event is referred to as the Columbian Exchange, where swaps of species, cultures, and germs were conducted between the new and old world.
“We saw these species jump continents, which is a geologically unprecedented impact, setting Earth off on a new evolutionary trajectory,” said Lewis.
But there have been questions about when to mark the beginning of the Anthropocene. Previous research suggests some point between 1610 and 1964. Lake Crawford appears to hold answers to give a precise date.
“The sediments found at the bottom of Crawford Lake provide an exquisite record of recent environmental change over the last millennia,” says Dr. Simon Turner, secretary of the Anthropocene Working Group from University College London.
The lake hosts annual sediments showing obvious spikes due to the enormous impact of humanity on the planet from 1950 onwards, including the presence of plutonium from hydrogen bomb tests to the minuscule particles that have poured on Earth from human use of fossil fuels. If the site is approved by the Anthropocene Working Group (AWG) scientists who oversee the geological timescale, the official declaration of the Anthropocene as a new geological epoch will come in August 2024.
The Anthropocene Working Group (AWG) is a scientific working group established by the International Commission on Stratigraphy (ICS) in 2009. The AWG is composed of an international group of scientists from various disciplines, including geology, climatology, biology, archaeology, and anthropology. These experts study the evidence in layers of sediments, ice cores, and other geological records, to determine whether there is a distinct boundary in the Earth’s rock layers that marks the beginning of the Anthropocene. Its primary objective is to assess and evaluate whether the Earth has entered a new geological epoch, the Anthropocene.
“The presence of plutonium gives us a stark indicator of when humanity became such a dominant force that it could leave a unique global ‘fingerprint’ on our planet,” says Professor Andrew Cundy from the University of Southampton, another member of the AWG. Cundy added “In nature, plutonium is only present in trace amounts. But in the early-1950s, when the first hydrogen bomb tests took place, we see an unprecedented increase and then [a] spike in the levels of plutonium in core samples from around the world. We then see a decline in plutonium from the mid-1960s onwards when the Nuclear Test-Ban Treaty came into effect.”
But there is more than plutonium. There is an acceleration of microplastic pollution, increases in ash and soot from coal-fired power plants, and intense concentrations of fertilizers in the soil. They are all part of the ‘The Great Acceleration’ – a surge in human activity from transport to energy use that started in the mid-20th century.
To be clear, there is substantial evidence and scientific consensus that we are in the Anthropocene epoch. The “epoch of humans” first proposed in 2002 by chemistry Nobel Laureate Paul Crutzen is widely accepted by scientists as reality.
The question is when did the epoch begin? That is the ultimate goal of the AWG’s work: to propose a formal definition and boundary for the Anthropocene epoch, which will then be subject to review and approval by the International Union of Geological Sciences (IUGS) and other relevant scientific bodies. The recognition of the start of the Anthropocene as a geological epoch would signify the profound and lasting impact of human activities on Earth’s systems and provide a framework for understanding and addressing the challenges posed by these changes.
Lake Crawford’s deep and cool waters along with its modest size may be able to annotate when the layers of sediments show the explosive effects of human activity that changed the planet. “It is this ability to precisely record and store this information as a geological archive that can be matched to historical global environmental changes which make sites such as Crawford Lake so important,” explained Crawford.
If the date for the beginning of the Anthropocene is established, it marks the Holocene epoch that has spanned the previous 11,7000 years.
Prof Jürgen Renn, director of the Max Planck Institute for the History of Science, in Berlin, Germany, said: “The Anthropocene concept has now received a firm anchoring in a very precise stratigraphic definition, [giving] a reference point for scientific discussions.
“It also creates a bridge between the natural sciences and the humanities, because it’s about the humans,” Renn said. “We are looking at something that is shaping our fate as humanity, so it’s very important to have a common reference point.”
Official ratification of the Lake Crawford site and the Anthropocene epoch will require a review of the evidence by geological authorities and then a voting process involving scientific organizations like the International Union of Geological Sciences (IUGS) representing over a million geoscientists.
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