AP Environmental Science Unit 9 Review – Global Change | RevisionDojo

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Meta Title: AP Environmental Science Unit 9 Review – Global Change | RevisionDojo
Meta Description: Learn APES Unit 9 on global climate change, ozone depletion, invasive species, and sustainability. Key terms, AP Environmental Science FRQ tips, and exam strategies included.

AP Environmental Science Unit 9 Review – Global Change

Unit 9: Global Change focuses on how human activities alter Earth’s systems on a large scale. On the APES exam, you’ll see climate-related FRQs, cause-and-effect chains, and global policy references.

This RevisionDojo review breaks down the essential knowledge for both MCQs and FRQs.

🌍 Key Topics in Unit 9

  • Climate change and greenhouse gases
  • Ozone depletion and CFCs
  • Ocean acidification
  • Invasive species
  • Endangered species and biodiversity loss
  • Overfishing and resource depletion
  • Global treaties and policies
  • Sustainability strategies

☁ Greenhouse Gases & Climate Change

Main GHGs: CO₂, CH₄ (methane), N₂O, CFCs

  • Sources: Fossil fuel combustion, agriculture, industrial processes
  • Impacts: Sea level rise, glacial melt, extreme weather, ecosystem shifts

Solutions:

  • Renewable energy transition
  • Energy efficiency
  • Carbon sequestration

🌀 Ozone Depletion

  • Cause: CFCs & halons → release chlorine atoms → destroy stratospheric ozone
  • Impacts: More UV radiation → skin cancer, cataracts, ecosystem harm
  • Solution: Montreal Protocol (1987) → phased out CFCs

🌊 Ocean Acidification

  • CO₂ dissolves in seawater → forms carbonic acid → lowers pH
  • Impacts: Coral bleaching, shellfish decline, food chain disruptions

🌱 Invasive Species

  • Definition: Non-native species that outcompete native species
  • Examples: Zebra mussels, cane toads, kudzu
  • Control: Prevention, mechanical removal, biological control

🐟 Overfishing & Resource Depletion

  • Causes: Technological advances, weak regulation
  • Impacts: Population collapse, food web disruption
  • Solutions: Catch limits, marine protected areas, sustainable seafood

📜 Key Global Policies

  • Montreal Protocol – Ozone protection
  • Kyoto Protocol – GHG reduction targets
  • Paris Agreement – Global climate commitment
  • CITES – Regulates trade in endangered species

🌱 Sustainability Strategies

  • Reduce carbon footprint
  • Protect biodiversity hotspots
  • Promote circular economy principles
  • Support sustainable agriculture

🧠 APES Exam Tips for Unit 9

  • Always connect human activity → environmental impact → societal impact → solution.
  • Be ready to cite specific international treaties and explain their purpose.
  • Practice FRQs involving data interpretation for climate and biodiversity trends.

💡 FAQ – Unit 9: Global Change

Q: What’s the most effective treaty for ozone protection?
A: The Montreal Protocol.

Q: How does ocean acidification relate to CO₂ emissions?
A: More CO₂ in the air dissolves in oceans, lowering pH and harming marine life.

Q: Why are invasive species so damaging?
A: They often lack natural predators and outcompete native species for resources.

Final Word from RevisionDojo:
Unit 9 tests your ability to link global environmental issues with actionable solutions. Use real-world examples in FRQs to show depth in your answers.

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