9.5 pt 2 - Global Climate Change

Question 1

Impact on Marine Ecosystems

Answer 1

• Altered range of marine ecosystems: some new marine habitats will be formed by rising sea level flooding coastline
  - Some areas of ocean will become too deep to receive sunlight & photic zone will shift up, further from ocean floor
• Altered ranges for organisms: warm water holds less O2, so many fish populations have declined, or migrated to cooler waters

Question 2

Impact on Ocean Circulation

Answer 2

Suppression of thermohaline circulation: global ocean current that redistributes heat from the equator, salt, and nutrients by mixing ocean waters could slow or stop altogether
- Ice melt from Greenland ➡️ especially cold, fresh water buildup in north Atlantic
- Freshwater is less dense than salt, preventing it from sinking
- This cold north atlantic slows warmer Gulf Stream waters, cooling Europe & slowing global thermohaline circulation

Question 3

Unequal Global Warming

Answer 3

Polar regions of earth are warming faster than other regions (polar amplification)
- Especially the arctic (N pole) because there is more land & less water to absorb heat
- Melting sea ice = more exposed ocean water, which absorbs more sunlight than ice & snow, leading to more ice melting (positive feedback loop)
- Distribution of tropical heat to poles by thermohaline circulation also warms poles

Melting of Permafrost - permanently frozen tundra soils that begin to thaw & release methane & CO2 from anaerobic decomposition
- Air pollution adds soot & other PM to atmosphere, distributed to poles by atmospheric circulation
- Darker, soot/PM covered ice absorbs even more heat due to lower albedo

Question 4

Impact on Polar Ecosystems

Answer 4

Arctic sea ice loss = habitat loss
- Seals use it for resting and find holes for breathing
- Algae grow on ice, forming base of arctic food web
- Polar bears use ice for hunting seals at breathing holes