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B: There are THREE proposed origins of the ‘Anthropocene’ – 1. the advent…
B: There are THREE proposed origins of the ‘Anthropocene’ – 1. the advent of farming c. 7000BP, 2. the Industrial Revolution c. 1750, and 3. the Great Acceleration c.1950. Which one is the most likely?
- The advent of farming (~7000 BP)
Key characteristics
Ecological impact
Deforestation: the clearing of land for agriculture began significantly altering ecosystems, reducing biodiversity and driving species extinction.
Domestication of species: Both plants (e.g. wheat, rice maize) and animals (e.g. cattle, sheep) became key to human survival. These species altered natural selection processes and biogeochemical cycles
Methane emissions: early rice paddies and livestock released methane into the atmosphere, contributing to greenhouse gas levels
Geological evidence
Sediment records: changes in sediment composition and pollen reflect widespread deforestation and land use change
Greenhouse gases: Ice core data show slight increases in CO2 and CH4 concentrations associated with early agriculture, termed "Ruddiman hypothesis"
Strengths
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marked the transition from hunter gatherer societies to agrarian civilisations, altering human culture permanently
Weaknesses
Changes were gradual and mostly regional, without immediate or dramatic global impact
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- the great acceleration (~1950 CE)
Key characteristics:
Ecological impact:
Exponential growth: the post World war ll era saw unprecedented increased in population, industrial output, and resource consumption
Nuclear fallout: Radioactive from nuclear bomb testing (e.g. cerium-137, plutonium-239) became globally distributed and form a clear stratigraphic marker
Plastic pollution: microplastics began accumulating in marine and terrestrial sediments, creating a durable geological marker
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Geological evidence:
Nuclear fallout layer: fallout from nuclear tests (1945-1980s) left distinct isotopic signatures detectable in sediments and ice cores worldwide
Microplastics and inudstrial materials: these materials are novel and pervasive in modern strata, serving as clear indicators of human impact
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Strengths:
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provides distinct, global, and durable markers in the geological record, such as radionuclides and plastics
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Weaknesses:
A relatively short timeframe compared to earlier origins, potentially seen as more a continuation of Industrial Revolution impacts
- The Industrial Revolution (~1750 CE)
Key characteristics
Ecological impacts:
Fossile fuel combustion: the large scale use of coal and later oil and gas drastically increased atmospheric CO2 levels, initiating long term climate change
Urbanisation: cities expanded, altering local ecosystems and creating urban head island
Deforestation and resource extraction: industrialisation accelerated the clearing of forests and mining of resources
Geological evidence:
Atmospheric markers: ice cores from the mid 18th century show a sharp rise in CO2 and methane levels, marking the onset of the anthropocene
soot layers: sediments from this time contain soot particles from coal burning, providing a clear and traceable layer in the geological record
Strengths:
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the impacts are observable globally, as industrialisation spread across continents
weaknesses:
While impactful, the changes were uneven and regional for much of the 18th and 19th centuries, limiting their immediate global influence
geologically, markers like soot may not be as universal as those from the Great Acceleration