Central Idea

• AWG’s Proposal: The Anthropocene Working Group (AWG) proposes a new geological epoch called the Anthropocene.
• Reference Point: The unique reference point for the Anthropocene is Crawford Lake near Toronto in Canada’s Ontario Province.

Understanding the Anthropocene Epoch

• Coined Term: The Anthropocene epoch was first coined by Nobel Prize-winning chemist Paul Crutzen and biology professor Eugene Stoermer in 2000.
• Human Impact: The Anthropocene represents the geological time interval characterized by radical changes in the Earth’s ecosystem due to human impact, particularly since the onset of the Industrial Revolution.
• Environmental Changes: Numerous phenomena associated with the Anthropocene include global warming, sea-level rise, ocean acidification, mass-scale soil erosion, deadly heat waves, and environmental deterioration.
• Geological Strata: The AWG’s website states that these changes are reflected in a distinctive body of geological strata, with the potential to be preserved into the far future.

Evidence from Crawford Lake

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• Selected Site: Crawford Lake in Canada’s Ontario Province was chosen by geologists for examination over 11 other potential sites.
• Preserved Sediments: The lake’s layers of sediment have preserved the annual impact of human activities on the Earth’s soil, atmosphere, and biology.
• Shift in Mid-20th Century: The analysis of Crawford Lake’s bottom sediments reveals a clear shift from the mid-20th century, surpassing the bounds of the previous Holocene epoch.
• Captured Fallout: Over the years, the lake’s sediments have captured the fallouts of large-scale burning of fossil fuels, explosion of nuclear weapons, and dumping of plastic and fertilizers on land and in water bodies.

Debate and Disagreements

• Scientific Community Disagreements: Not all geologists agree on the reality of the Anthropocene epoch.
• Debate Points: Disagreements revolve around the precise start of the epoch, whether it has already begun, and the sufficiency of evidence to prove its advent.

The Geological Time Scale

• Divisions and Categories: The Earth’s geological time scale is divided into five broad categories: eons, eras, periods, epochs, and ages.
• Fossil-Based Boundaries: Boundaries on the geological time scale correspond to the origination or extinction of specific types of fossils.
• Current Classification: Currently, we are in the Phanerozoic eon, Cenozoic era, Quaternary period, Holocene epoch, and Meghalayan age.

AWG’s Findings and Next Steps

• Selection of Crawford Lake: Crawford Lake was chosen due to its preserved sediment layers that provide an annual record of human impact.
• Overwhelming Effects: Distinct and multiple signals in the lake’s sediments starting around 1950 demonstrate that the effects of human activity overwhelm the Earth system.
• Unique Global ‘Fingerprint’: The presence of plutonium resulting from nuclear weapon detonations serves as a stark indicator of humanity’s dominant influence on the planet.
• Approval Process: The AWG plans to present a proposal to the Subcommission on Quaternary Stratigraphy (SQS) and the International Commission on Stratigraphy (ICS) for approval.
• Final Approval: The final approval is expected to be granted at the 37th International Geological Congress in Busan, South Korea, next year.

Conclusion

• Compelling Evidence: Geologists’ examination of Crawford Lake provides compelling evidence for the existence of the Anthropocene epoch.
• Challenging Conventional Timeline: The proposal for the Anthropocene epoch challenges the conventional understanding of the Earth’s official geological timeline.
• Future Determination: Further discussions and approvals by international geological bodies will determine the recognition and acceptance of the Anthropocene epoch.

Back2Basics: Geological Time Scale

• The Geological Time Scale is a system used by geologists and palaeontologists to divide Earth’s history into distinct time intervals based on significant geological and biological events.
• It provides a framework for organizing and understanding the vast expanse of time since the formation of the Earth, approximately 4.6 billion years ago, up to the present day.
• The Scale is divided into several hierarchical units, including eons, eras, periods, epochs, and ages.

Here is a simplified overview of the major divisions:

(1) Eon: The largest division of time on the Geological Time Scale. The history of Earth is typically divided into four eons:

• Hadean Eon: Represents the earliest stage of Earth’s history, from its formation to around 4 billion years ago.
• Archean Eon: Covers the period from around 4 billion to 2.5 billion years ago. It includes the formation of the Earth’s crust, the emergence of life, and the development of the first continents.
• Proterozoic Eon: Encompasses the time between 2.5 billion and 541 million years ago. It includes significant evolutionary developments, such as the emergence of complex multicellular life.
• Phanerozoic Eon: The current eon, spanning from 541 million years ago to the present. It is further divided into eras.

(2) Era: The second-largest division of time, encompassing longer periods of geological history within an eon. The Phanerozoic Eon is divided into three eras:

• Paleozoic Era: Covers the time from 541 million to 252 million years ago. It is known for the diversification of life, including the appearance of complex marine organisms, fish, insects, and the first terrestrial plants.
• Mesozoic Era: Spans from 252 million to 66 million years ago. It is often referred to as the “Age of Reptiles” and includes the dominance of dinosaurs, as well as the rise of mammals and birds.
• Cenozoic Era: Extends from 66 million years ago to the present. It is sometimes called the “Age of Mammals” and includes the diversification and proliferation of mammals, the appearance of humans, and the development of modern ecosystems.

(3) Period: A subdivision of an era, representing a distinct interval of time characterized by specific geological and biological events. For example:

• The Paleozoic Era is divided into periods such as the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian.
• The Mesozoic Era is divided into periods including the Triassic, Jurassic, and Cretaceous.
• The Cenozoic Era is divided into periods such as the Paleogene, Neogene, and Quaternary.

(4) Epoch: A smaller subdivision of a period, representing a shorter interval of time. Epochs are defined by more localized geological and biological changes.

(5) Age: The smallest division of time on the Geological Time Scale. Ages represent relatively brief periods, often defined by specific fossil or rock layers.

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