ES101 Lecture Notes - Lecture 21: Worst-Case Scenario Series, Aral Sea, Societal Collapse
Midterm: Oct 19 - 20%
Final exam: 40%
Labs: 40%
Week 1, Lecture 1: Our Oceans, Our Future
● 10% of global human pop lives within 10m of sea level
● 15% of global urban pop lives within 10m of sea level
● Oceans have become human garbage dumps (eg. rio de janeiro flushing toilets to
ocean)
● Ocean dead zones:
○ large rivers deliver heavy nutrient loads to ocean, creates anoxic water
conditions killing fish and benthic organisms → oxygen sucked out of water from
bacteria, fish etc suffocate
● Oil spills:
○ usually associated with disasters, but the biggest source are parking lots
■ Storm drains: 1.364 bill litres per year
■ Deliberate spills from shipping: 518 mill litres per year
■ Accidental spills from shipping: 140 mill litres per year (est from 2002)
● Shoreline modification:
○ natural shoreline vegetation (mangroves) and habitat being steadily removed and
converted by people (beach resorts etc)
● Overfishing:
○ over 70% of global fish stocks are being fully exploited (taking as much as we
can without harming population over long term) or overexploited (fish can’t
reproduce fast enough)
● Climate change impacts:
○ sea surface temps warming
○ oceans becoming more acidic (creatures that have shells, bad for them)
○ coral reefs dying (water too warm/acidic/too much pollution = photosynthesis
stops)
● Human pressure on coastal zones:
○ Shoreline modification
○ Garbage, nutrients, chemicals, oil spills
○ Overfishing
○ Atmospheric carbon concentrations are altering ocean chemistry
○ Global warming altering sea temps
● Why worry?
○ Transition zone between ecosystems
○ Extremely sensitive environments with high levels of biodiversity
○ So many of us live there and our health and well being is dependent on them
○ eg. human systems and coastal zone ecological systems are fundamentally
linked
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