Public Health 416: The Atmosphere and Global Climate Change - Part 2

Overview

• Continuation of Topic 7 focusing on recent trends and evidence of climate change
• Discussion on impacts of climate change on human health
• Strategies for mitigating and adapting to climate change

Current Trends in Climate Change

• Greenhouse Gases:

  • Recent trends show increasing concentrations of CO2, nitrous oxide, and methane
  • CFCs levels are stabilizing due to regulatory bans
  • CO2 measurements by Charles Keeling (Keeling Curve) show seasonal variations and a long-term increase
  • Ice cores used to measure historical CO2 levels

• Global Warming:

  • Defined as the rise in Earth's average surface temperature
  • Temperature anomaly increases observed since the Industrial Revolution
  • The average global temperature has risen by approximately 0.74°C (1.3°F) in the past century

• Greenhouse Gas Emissions:

  • Fossil fuels as primary source of CO2
  • Major emitters: China, USA, India
  • Human activities contributing to increased emissions

Evidence and Impacts of Climate Change

• Climate Change Indicators:

  • Surface air temperature rise
  • Rising ocean temperatures and sea levels
  • Melting glaciers and ice caps
  • Ocean acidification due to increased CO2 concentrations

• Human Health Impacts:

  • Extreme heat events, air quality deterioration, increases in vector-borne diseases
  • Displacement due to rising sea levels
  • Disparities in impact: poorer populations more vulnerable

• Biodiversity and Ecosystems:

  • Habitat loss for amphibians, coral reefs bleaching
  • Potential extinction of species in biodiversity hotspots

Responses to Climate Change

• Mitigation:

  • Reduce greenhouse gas emissions, stabilize atmospheric concentrations
  • Strategies include decarbonization, cap-and-trade, carbon taxation

• Adaptation:

  • Adjust societal practices in anticipation of climate impacts
  • Coastal protection, crop adjustments, infrastructure investment

• International Efforts:

  • Kyoto Protocol and Copenhagen Accord for emission reductions
  • Challenges in achieving global cooperation, particularly from major emitters

The Ozone Hole

• Ozone Depletion:

  • Significant decrease in stratospheric ozone observed since the 1970s
  • CFCs identified as a major cause of ozone breakdown

• International Response:

  • Montreal Protocol successfully reduced CFC use
  • Slow recovery of the ozone layer projected by 2070

Closing

• Encourage review of lecture slides and required reading
• Complete the quiz related to this lecture

Note: Detailed understanding of cap-and-trade systems and carbon footprint calculation is recommended.