🌿Archaeology of Environmental Change Unit 10 – Anthropocene: Environmental Archaeology

What's the Anthropocene?

• Proposed geological epoch defined by significant human impact on Earth's geology and ecosystems
• Term coined by Paul Crutzen and Eugene Stoermer in 2000
• Anthropocene Working Group (AWG) formed in 2009 to investigate the Anthropocene as a potential addition to the Geological Time Scale
• Debate centers around whether human activities have had a sufficient impact on Earth's systems to warrant a new geological epoch
• Proponents argue that human activities have left measurable changes in the geological record (increased carbon dioxide levels, nuclear fallout, plastic pollution)
• Critics argue that the Anthropocene is not yet a formally defined geological unit and that human impact is not significant enough to warrant a new epoch
• Some suggest the Anthropocene began with the Industrial Revolution in the late 18th century, while others propose the Great Acceleration of the mid-20th century as the starting point

Key Concepts and Debates

• Anthropocene as a concept highlights the significant impact of human activities on Earth's systems
• Debates surrounding the Anthropocene include its starting point, whether it should be formally recognized as a geological epoch, and its implications for environmental policy and management
• The Great Acceleration refers to the rapid increase in human population, resource consumption, and technological advancements since the mid-20th century
• Planetary boundaries concept introduced by Johan Rockström and colleagues in 2009 to define safe operating limits for human activities to maintain Earth's stability
• Anthropogenic biomes (anthromes) concept proposed by Erle Ellis and colleagues to describe human-modified ecosystems that now cover most of Earth's land surface
• Debates also include the role of capitalism, colonialism, and inequality in shaping the Anthropocene and its impacts on different communities and regions

Timeline and Markers

• Proposed start dates for the Anthropocene include the onset of agriculture (~12,000 years ago), the Industrial Revolution (late 18th century), the Great Acceleration (mid-20th century), and the first nuclear bomb test (1945)
• Geological markers of the Anthropocene include increased carbon dioxide levels, changes in sediment composition (plastics, concrete), and the presence of radionuclides from nuclear testing
• Other markers include changes in biodiversity (extinctions, invasive species), alterations in biogeochemical cycles (nitrogen, phosphorus), and the spread of novel materials (plastics, aluminum)
  • Extinctions: Passenger pigeon, Tasmanian tiger, Golden toad
  • Invasive species: Kudzu vine, Asian carp, European starling
• The Anthropocene Working Group has proposed the mid-20th century as the starting point for the Anthropocene, with the first nuclear bomb test in 1945 as a potential golden spike (global marker)

Human Impact on the Environment

• Anthropogenic climate change driven by greenhouse gas emissions from fossil fuel combustion, deforestation, and agricultural practices
• Land use changes, including deforestation, urbanization, and the expansion of agriculture, have altered ecosystems and biodiversity
  • Amazon rainforest deforestation for cattle ranching and soybean cultivation
  • Urbanization leading to habitat fragmentation and loss of green spaces
• Pollution from industrial activities, agriculture, and waste disposal has contaminated air, water, and soil
  • Great Pacific Garbage Patch, a collection of marine debris in the North Pacific Ocean
  • Acid rain caused by sulfur dioxide and nitrogen oxide emissions from fossil fuel combustion
• Overexploitation of natural resources, such as overfishing, has led to the collapse of many fish stocks and marine ecosystems
• Introduction of invasive species through human activities (trade, travel) has disrupted native ecosystems and caused extinctions

Archaeological Evidence

• Stratigraphic records show changes in sediment composition, such as the presence of plastics, concrete, and other novel materials
• Fossil records reveal extinctions and changes in species distributions, often linked to human activities (overhunting, habitat destruction)
  • Extinction of megafauna (mammoths, giant sloths) following human expansion into new regions
  • Changes in plant species composition due to agricultural practices and land use changes
• Artifacts and structures provide evidence of human technology and resource use over time
  • Stone tools, pottery, and metal objects reflect changes in human technology and resource exploitation
  • Ancient agricultural terraces, irrigation systems, and urban centers demonstrate human modification of landscapes
• Paleoclimatic and paleoecological records (ice cores, tree rings, pollen) show changes in climate and ecosystems that can be linked to human activities
• Geochemical signatures, such as increased lead concentrations from mining and industrial activities, are preserved in sediments and ice cores

Case Studies

• The Maya collapse (9th-10th centuries CE) has been linked to a combination of environmental stress (drought, deforestation) and sociopolitical factors
  • Deforestation for agriculture and construction led to soil erosion and reduced water retention
  • Drought and resource scarcity contributed to social unrest and the abandonment of cities
• The Dust Bowl (1930s) in the United States resulted from a combination of drought and unsustainable agricultural practices
  • Overplowing and removal of native vegetation led to severe soil erosion and dust storms
  • The event led to the displacement of millions of people and significant economic losses
• The Aral Sea disaster (1960s-present) in Central Asia was caused by the diversion of rivers for irrigation, leading to the shrinking of the sea and ecological collapse
  • Increased salinity and pollution have caused the collapse of fish populations and health problems for local communities
  • The event has been described as one of the world's worst environmental disasters

Methods and Techniques

• Stratigraphy and sedimentology to identify changes in sediment composition and depositional environments related to human activities
• Paleoecology and paleoclimatology to reconstruct past environments and climates using proxies such as pollen, diatoms, and stable isotopes
  • Pollen analysis can reveal changes in vegetation composition and land use over time
  • Stable isotope analysis of tree rings can provide information on past climate conditions
• Geochemical analysis to detect anthropogenic pollutants and trace the sources and pathways of contamination
  • Lead isotope analysis can identify the sources of lead pollution in sediments and soils
  • Analysis of persistent organic pollutants (POPs) can trace the spread and accumulation of these compounds in the environment
• Remote sensing and GIS to map and monitor land use changes, urbanization, and other human impacts on the environment
• Archaeological excavation and artifact analysis to study human technology, resource use, and social organization in the past

Future Implications

• The Anthropocene concept highlights the need for sustainable management of Earth's resources and ecosystems to ensure the well-being of current and future generations
• Understanding the drivers and consequences of human impact on the environment can inform policy decisions and management strategies
  • Developing sustainable agricultural practices to reduce soil erosion, water pollution, and biodiversity loss
  • Promoting renewable energy and energy efficiency to mitigate climate change and reduce air pollution
• The study of past human-environment interactions can provide insights into the resilience and vulnerability of societies to environmental change
  • Identifying successful adaptations to past climate changes can inform current and future adaptation strategies
  • Understanding the factors that contributed to the collapse of past societies can help prevent similar outcomes in the future
• The Anthropocene emphasizes the interconnectedness of human and natural systems and the need for interdisciplinary approaches to address environmental challenges
• Recognizing the uneven distribution of the causes and consequences of the Anthropocene across regions and communities is crucial for developing equitable and just solutions