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Week 9 Lecture 2

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  • Historical atmospheric CO2 trends
    Atmospheric carbon-dioxide levels have varied over geologic history but have increased rapidly since the Industrial Revolution, reaching unprecedented levels.
  • Link between CO2 and global temperature
    There is a tight correlation between rising atmospheric carbon-dioxide and increasing global temperatures.
  • Consequences of warming terrestrial environments
    Warming leads to emergent diseases, shifts in species distributions, more extreme hurricanes, flooding, droughts, forest fires, and heat waves.
  • Effect of warming on locust populations
    Wet years and warm winters increase locust populations, causing swarms that devastate vegetation and crops.
  • Net primary productivity (NPP) changes with warming
    NPP changes globally; northern latitudes show negative NPP due to permafrost melt releasing carbon, while some tropics show decreased NPP due to heat stress.
  • Predicted spread of tropical diseases
    Warming temperatures may expand tropical diseases like malaria into northern latitudes, increasing their geographic range.
  • Ocean warming trends
    Oceans have warmed alongside the atmosphere since 1940, with models predicting continued temperature increases.
  • Predicted ocean temperature increase by 2100
    Models predict an average global ocean temperature rise of about 4°C (7°F) this century.
  • Consequences of ocean warming
    Ocean warming causes species distribution shifts, coral bleaching, polar ice melt, sea level rise, emergent marine diseases, and altered ocean currents.
  • Sockeye salmon distribution shifts
    Warming allows sockeye salmon to expand their range northward year-round, reducing seasonal migration.
  • Coral bleaching mechanism
    Heat stress causes corals to expel symbiotic zooxanthellae, leading to bleaching and coral death.
  • Coral bleaching trends and predictions
    Bleaching events have increased since 1990 and are predicted to become more frequent and severe through 2100.
  • Melting polar ice caps impact
    Arctic ice volume has decreased 15-20% over 30 years, with continued melting predicted under all climate scenarios.
  • Ecological effects of melting Arctic ice
    Reduced habitat for polar bears, shifts in fish distributions, and fishery collapses due to temperature fluctuations.
  • Southern hemisphere melting effects
    Decline in Antarctic krill reduces food for marine species like penguins, causing population declines.
  • Sea level rise causes
    Sea level rises due to glacier and polar ice melt plus thermal expansion of warming seawater.
  • Predicted sea level rise by 2100
    Models predict sea level rise between 0.1 to 0.9 meters by 2100.
  • Impacts of sea level rise on coastal areas
    Low-lying areas like the Florida Keys and Miami are at risk of flooding and submersion with rising sea levels.
  • Climate refugees
    Rising sea levels and storms displace millions, creating internal refugees who move to higher elevations within their countries.
  • Ocean acidification process
    Increased CO2 dissolves in oceans forming carbonic acid, lowering pH and reducing carbonate availability needed for marine calcifiers.
  • Effects of ocean acidification on coral calcification
    Coral calcification rates have declined sharply since 1900 and may decrease up to 30% by 2100 due to acidification.
  • Behavioral effects of ocean acidification on fish
    Fish raised in acidic water show riskier behavior, spending more time near predators.
  • Acidification effects on fish sensory abilities
    Fish exposed to higher acidity require louder reef sounds to detect habitat, reducing their ability to find suitable settlement areas.
  • Importance of ecological data in climate change
    Ecological research now focuses on understanding and mitigating climate change impacts rather than just explaining natural processes.