Environmental Change

Unit 1: Anthropocene

What is the anthropocene?

A new epoch when human activities have “become so profound and pervasive that they rival, or exceed the great forces of Native in influencing the functioning of the Earth Systems” - Steffen

  • “Anthro” - human “cene” - epoch

  • New “age of man” where humans have begun to significantly alter dynamic processes of the enviroment

    • Biosphere

    • Hydrosphere

    • Atmosphere

    • Lithosphere

    • Cryosphere

When did it start?

How do we measure geologic time?

Eons

  • Eras

    • Periods

      • Epochs

How long have humans benn around

  • Currently in the Cenozoic Era

  • Quaternary Period began 2.6 million
    years ago

  • Within the boundaries of geologic time,Humans are relatively new

  • Humans did not show up until the Quaternary Period

    • Pleistocene Epoch

    • Holocene Epoch

    • Start date of Anthropocene Epoch

How is a new Era determined?

  • Global Boundary Stratotype Section (GSSP) using:

    • Primary markers (e.g. datum of fossil species)

    • Secondary markers (e.g. chemical markers)

    • Well preserved geologic sections and key events

Human Colonization

  • Most recognizable human was Homo habilis which evolved around 2.5-2.8 million years ago

Animal Domestication

  • They no longer had to follow animal migration routes

Crop Domestication

  • By obtaining agricultural practices and animal domestication allow humans to establish permanent homes

    • Increasing population densities leading to towns then cities

  • Plant breeding allowed them to culturally advance

Stages of Social and Economic Development

  • Agricultural Revolution

    • ~11k - 3k BP

    • Animal domestication

    • Crop domestication

  • Early Globalization

    • 1492-1800

  • Industrial Revolution/Great Acceleration

    • 1750

  • Nuclear Weaponization

    • 1945

  • Persistent industrial chemicals

    • ~1950

Measuring Change

  • Ice Cores

  • Fossil crop pollen

  • Temperature

  • Atmospheric Carbon Dioxide

  • Methane (ppb)

  • Radioactive isotopes

  • Persistent Industrial Chemicals

Five Major Earth Systems

  • Biosphere - Life

  • Hydrosphere - Water

  • Atmosphere - Air

  • Lithosphere - Land

  • Cryosphere - Ice

What drives change in Natural Systems?

  • Feedback loops

    • involves couples systems that collectively act to accelerate or decelerate and initial change →can be positive or negative

    • ex: el nino (warm phase)

      • surface ocean temperatures increase and can lead to a change in atmospheric wind pressure increasing surface water temperature

  • Perturbations

    • a change in earth’s energy balance or climate systems

  • Forcing

    • an imposed perturbation. A positive forcing warm’s the earth, such as a solarflare, a negative forcing can cool the earth, such as an increase in particles in the atmosphere from a meteor impact that reduces the energy that reaches earth.

  • Teleconnections

    • an understanding of climactic relationships that span great distances
      (across non-contiguous regions) that can provide predictability of climate systems during various timeframes

Human affect natural systems

  • Anthropogenic climate forcing has resulted in a warming climate through fossil fuel burning, and alterations of earth's surface from various changes in land use, such as the conversion of forests into agricultural plots, to name a few.

Human Environmental System Framework

Coupled Human

  • Human systems, such as economic structures, have become linked to natural systems, such as hydrologic processes, to such as extent that they must be treated as a coupled systems instead of isolated ones. This framework is also know as the Coupled Human and Nature Systems (CHANS)

    • It is a two-way relationship – humans have an impact on the environment and the environment impacts humans

Socio-Ecological

  • a conceptual model to assess how sustainable socioecological systems
    (SES) are.

    • Modern environmental issues often arise from complex interaction between social and ecological components. This allows for a common approach to analyze these systems, such as:

      • fisheries

      • groundwater ecology

      • freshwater ecosystems

How do we measure change?

  • Environmental change can be measured through

    • Deforestation

    • Local ecology

    • Types of land use

    • Change in temp. over time

      • Proxy data: tree rings, peat cores, and ice cores

      • Direct measurement: river flow, precipitation, temperature change

What is Proxy data?

  • Tree Rings

    • The tree core widths tell you fire, drought, and age activity

  • Peat Cores

    • you can measure paleoclimatology and carbon cycling

    • can help determine the temp of the climate and when

  • Surface and Deep Sea Corals

    • measure paleoclimatology and change in ocean temperature

Direct Measurement of Change

  • Measuring River flow

    • land cover change

    • how much is the river bending/eroding at the menders

  • Measuring Climate change

    • improving model accuracy

    • accurately predicting climate change over time

what are others saying?

how are they discussing it?

why are we discussing it?