Notes on Global Geophysical Catastrophes and Climate Change

Climate Change and Global Geophysical Catastrophes

Lecture Overview
  • Topic: Global Geophysical Catastrophes
  • Film to watch: Remaining half of "Merchants of Doubt"
I. Continental Drift to Plate Tectonics
  • Recap of fundamental concepts from previous session.
  • Introduced by:
    • Frederick Vine, Drummond Matthews, Lawrence Morley (1963).
  • Discovery of sea floor spreading reveals rich interconnections between science and military endeavors during the Cold War.
II. Ice Ages
  • Discussion on simultaneous global warming and local cooling.
  • Critics of anthropogenic climate change exploit this contrast.
  • Core concept: Croll-Milankovitch cycles, explaining the astronomical theory of Ice Ages.
    • Relevant links and resources provided (but have access issues).
    • Recommended readings: McGuire text, especially pages 50 and 54.
Global Conveyor Belt
  • Mechanism: Warm, salty waters of Gulf Stream flow northward, cool, increase in density, and sink.
  • Potential impact of freshwater melt from ice on this system discussed.
    • Reference: McGuire (pp. 61-63).
III. Super Eruptions, Waves, Quakes
  • Discusses natural disasters including super eruptions, tsunamis, and earthquakes.
  • Focus on Volcanic Explosivity Index (VEI) as a way to quantify eruptions.
  • Important to consider the socio-economic impacts of these events (as articulated by McGuire).
IV. Asteroid and Comet Impacts
  • Concept of “threat from space” with a nearly 100% probability of occurrence over geological timescales.
  • Key question: Timing of such events, especially in relation to large-scale geological models like the Shiva Hypothesis (operates on a 30 million year cycle).
Oort Cloud and Notable Events
  • Definition and importance of the Oort Cloud, especially concerning cometary impacts.
  • The Tunguska event as a case study:
    • Comprehensive analysis can be found on pages 97-100, 109 of the text.
    • Caution advised about unreliable web sources; McGuire’s account is recommended for factual accuracy.
Conclusion
  • Engaging query about the balance between geophysics as a scientific discipline and its implications for the social world.
  • Encourages critical thinking on the interconnectedness of natural phenomena and human society.