Environmental Challenges and Human Impact

Overview of Environmental Challenges

  • This lecture continues the exploration of environmental issues, including the examination of various environmental challenges and human impacts on ecosystems.

1. Holocene Epoch or Anthropocene Age

  • The current period is referred to as the Holocene Epoch or Anthropocene, marking the last 11,700 years in Earth's history.

  • The shift in how humans perceive nature, from stewardship to a mindset of domination due to western colonial influences.

2. Impact of Overpopulation

  • Larger human populations correlate with greater environmental impacts:
      - Increased resource demand
      - Higher waste generation

3. Water Resources

  • Availability of water:
      - Earth's water is predominantly saltwater (97.5%)
      - Only 2.5% is fresh water, of which:
        - 68.7% is locked in glaciers and permanent snow cover
        - 30.1% is groundwater (in soil)
        - Only 0.3% is readily accessible surface freshwater.

4. Soil as a Nonrenewable Resource

  • Fertile soil is considered a nonrenewable resource due to vulnerability caused by human activities.

  • Activities leading to soil degradation include:
      - Mining and quarrying: Disturbance of the soil layer.
      - Logging and deforestation: Removing trees that anchor soil, leading to erosion.
      - Urbanization: Infrastructure development disturbs soil profile, increasing erosion.
      - Agriculture: Crops often have shallower root systems compared to trees, leading to lesser soil retention capacity.

5. Overgrazing

  • Overgrazing diminishes plant cover, contributing to soil erosion:
      - Particularly from livestock and unchecked invasive species.
      - Example: Rabbit overpopulation in Australia, introduced by British colonizers for hunting. Lack of natural predators has allowed their population to spike, damaging the ecosystem.

  • Solutions attempted include the establishment of the rabbit proof fence in Australia.

6. Air Pollution and Its Consequences

  • Major sources of air pollution include:
      - Vehicle emissions (cars, motorcycles, trains, airplanes, etc.)
      - Industrial emissions from factories.

  • Effects of air pollution:
      - Increased risk of respiratory diseases.
      - Higher risk of cardiovascular diseases.

7. Global Warming and Climate Change

  • Linked to increased emissions of greenhouse gases, particularly carbon dioxide, due to reliance on fossil fuels since the Industrial Revolution.

  • Evidence includes
      - Average surface temperatures rising over the years, with most recent years breaking previous records for heat.
      - Effects on Arctic sea ice, which shrinks significantly over time, affecting polar bear migrations.

8. Impacts of Global Warming

  • Melting of land ice, notably Greenland, significantly contributes to rising sea levels due to increased water volume in oceans.

  • Coral bleaching is exacerbated by global warming, resulting from coral/algae symbiotic relationships breaking under stress:
      - Algae provide color and health to corals; loss leads to white, bleached coral structures.

  • Climate change leads to increased severity in typhoons, often recorded as the strongest typhoons to date.

9. Difference Between Climate Change and Ozone Depletion

  • Ozone Depletion:
      - Caused by man-made chemicals, primarily chlorofluorocarbons (CFCs), which deplete the ozone layer.
      - The ozone hole forms primarily over Antarctica every spring.

  • Historical context:
      - Satellite imagery revealed ozone hole size changes, highlighted by earlier sizes in square kilometers:
        - 1980: 3,270,000 km²
        - 2014: Down to 24,100,000 km² due to ban on CFCs.

  • Ozone layer responsibilities include blocking UV radiation, particularly UVC, while less effectively shielding UVB and UVA.

  • Increased UV exposure due to depletion contributes to health risks, including skin cancer.

10. Waste Generation and Management

  • Solid waste problem exemplified by the daily waste production:
      - In Metro Manila (2016): 9,212 tons of waste daily, expected to increase in subsequent years.

  • Key issues with waste management include:
      - Improper disposal due to lack of systems and discipline among citizens and officials.
      - Debate surrounding incineration vs. landfilling of waste, including pros/cons:
        - Landfilling: Doesn’t emit harmful gases, but produces leachate and emits odor.
        - Incineration: Reduces waste volume by 90%, but can produce harmful emissions and has been made illegal in The Philippines.

11. Pollution

  • Defined as having an excess of something in the improper place or time, often arising from increased economic activity.

  • Further exacerbated by population growth leading to more waste and pollution.

12. Conclusion and Reflection

  • Reflection on how science and society can collaboratively tackle environmental issues:
      - Balance between technological solutions and humane approaches to environmental problems.
      - Acknowledge that some technologies can create issues (e.g., CFCs).

  • Importance of governance and community engagement in environmental resource management.

  • An open-ended reflection for addressing how environmental challenges can be met with adaptable and responsible solutions.