Climate Change & Ocean Impacts – Quick Review Notes

Warmer Waters

• Rising ocean temperature ties directly to global warming.
• Consequences:
  • Coral bleaching → potential reef collapse.
  • Cold-water fish shift poleward/deeper → food-web disruption.
  • Loss of polar ice habitat for penguins, polar bears, walruses.
  • Temperature-driven changes in metabolism & reproduction; sex ratios skewed in sea turtles, some fish & shrimp.

Evidence of Warming

• Four independent records (NASA, Met Office, NOAA, JMA) analyze global data.
• All show closely matching trends: rapid warming since mid 20^{th} century.
• Current anomaly ≈ +0.5\,^{\circ}\text C above 1880–1900 mean.
• Minor methodological variations, but overall agreement is strong.

Chemical Changes

• Gas solubility ↓ as temperature ↑:
  • Warm surface water holds less O_2 → reduced deep-water oxygenation.
• More atmospheric CO2 → more oceanic CO2 → higher acidity.
  • Acidic water impairs gill oxygen uptake in marine animals.

Rising Sea Levels

• Ice melt elevates sea level.
• Impacts:
  • Coastal flooding disrupts turtle & bird nesting.
  • Mangrove ecosystems stressed by variable salinity & tides.
  • Increased water depth ↓ light to offshore plants/algae → lower photosynthesis → food-web effects.

Extreme Weather

• Warmer air–sea system amplifies severity & unpredictability of events.
  • Stronger hurricanes, storms, heavy rainfall & floods.
  • Direct damage to coral reefs and coastal habitats.