🌍 Greenhouse Effect: Complete AP Exam Guide
⚡ TL;DR (Too Long; Didn’t Read)
- Natural process where greenhouse gases trap heat in Earth’s atmosphere
- Key gases: CO₂, CH₄, H₂O vapor, N₂O – absorb infrared radiation
- Without it, Earth would be -18°C; with it, average is 15°C
- Enhanced greenhouse effect from human activities causes global warming
- Critical for AP Exam: understand mechanism, gases, and human impact
📋 AP Exam Pattern
| Aspect | Details |
|---|---|
| Topic Weight | 6-8% of AP Environmental Science Exam |
| Question Types | MCQ, FRQ (Free Response), Data Analysis |
| Typical Points | 4-10 points in FRQ section |
| Difficulty | Medium to High |
| Common Connections | Climate change, carbon cycle, energy balance |
📚 Syllabus Breakdown
- Greenhouse effect mechanism – High weightage (30%)
- Greenhouse gases and sources – High weightage (25%)
- Natural vs. enhanced greenhouse effect – Medium weightage (20%)
- Global warming potential (GWP) – Medium weightage (15%)
- Mitigation strategies – Medium weightage (10%)
📖 Concept Explanation
🔬 What is the Greenhouse Effect?
The greenhouse effect is a natural atmospheric process where certain gases trap heat radiated from Earth’s surface, warming the planet to temperatures that support life. Named after greenhouses that trap heat for plants, this phenomenon is essential for maintaining Earth’s habitable temperature.
🌡️ The Mechanism: How It Works
Step-by-step process:
- Solar radiation reaches Earth – The Sun emits shortwave radiation (visible light, UV) that passes through the atmosphere
- Earth absorbs and heats up – About 50% of solar radiation is absorbed by Earth’s surface, warming land and oceans
- Earth re-radiates heat – The warmed surface emits longwave infrared radiation (heat) back toward space
- Greenhouse gases absorb infrared – GHGs in the atmosphere absorb this infrared radiation instead of letting it escape
- Heat is re-emitted in all directions – The absorbed energy is re-radiated, with some going back to Earth’s surface
- Surface temperature increases – This trapped heat warms the lower atmosphere and Earth’s surface
🧪 Greenhouse Gases (GHGs)
| Gas | Chemical Formula | Atmospheric % | GWP (100-year) | Main Sources |
|---|---|---|---|---|
| Water Vapor | H₂O | 0-4% (variable) | N/A | Evaporation, transpiration |
| Carbon Dioxide | CO₂ | 0.04% (420 ppm) | 1 (baseline) | Fossil fuels, deforestation, respiration |
| Methane | CH₄ | 0.00018% (1.9 ppm) | 28-36 | Agriculture, landfills, natural gas |
| Nitrous Oxide | N₂O | 0.00003% (0.3 ppm) | 265-298 | Fertilizers, industrial processes |
| Ozone | O₃ | Variable | N/A | Photochemical reactions |
| CFCs | Various | Trace | 4,750-14,400 | Refrigerants (now banned) |
- CO₂ is most abundant human-caused GHG (responsible for ~75% of warming)
- CH₄ has higher GWP but shorter atmospheric lifetime (~12 years vs. 100+ for CO₂)
- Water vapor is the most abundant GHG but not directly controlled by humans
- Know GWP concept: compares warming potential relative to CO₂
🌍 Natural vs. Enhanced Greenhouse Effect
🌱 Natural Greenhouse Effect
- Exists for billions of years – Essential for life on Earth
- Without it: Earth’s average temperature would be -18°C (0°F)
- With it: Earth’s average temperature is 15°C (59°F)
- Temperature increase: +33°C due to natural GHGs
- Balanced system: Carbon cycle naturally regulates CO₂ levels
🏭 Enhanced Greenhouse Effect
- Human activities increase GHG concentrations since Industrial Revolution (~1750)
- CO₂ levels: Rose from 280 ppm (pre-industrial) to 420 ppm (2024)
- Result: More heat trapped = global temperature rise
- Observed warming: ~1.1°C increase since 1880
- Consequences: Climate change, sea level rise, extreme weather
✅ Marking Scheme Knowledge
For 4-point FRQ on Greenhouse Effect:
Question example: “Describe the greenhouse effect and explain how human activities have enhanced it.”
Marking points:
- Point 1 (1 mark): Identify that greenhouse gases trap infrared radiation/heat in the atmosphere
- Point 2 (1 mark): Explain the mechanism – Earth emits longwave radiation that GHGs absorb and re-radiate
- Point 3 (1 mark): Identify specific human activity (fossil fuel combustion, deforestation, agriculture)
- Point 4 (1 mark): Connect human activity to increased GHG concentrations and enhanced warming
What AP Examiners Look For:
- ✅ Specific gas names (CO₂, CH₄, N₂O) – not just “greenhouse gases”
- ✅ Correct terminology: “infrared radiation” or “longwave radiation”
- ✅ Distinction between natural and enhanced greenhouse effect
- ✅ Quantitative data when possible (e.g., CO₂ at 420 ppm)
- ✅ Cause-and-effect relationships clearly stated
📝 Previous Year AP Questions
2022 AP Exam – 6 marks:
Question: “Explain how the greenhouse effect warms Earth’s atmosphere. Identify TWO greenhouse gases and describe ONE human activity that contributes to increased atmospheric concentrations of each gas.”
Model Answer:
(a) Mechanism (2 marks):
- Greenhouse gases in the atmosphere absorb infrared/longwave radiation emitted by Earth’s surface (1 mark)
- These gases re-radiate the energy in all directions, including back toward Earth’s surface, which increases atmospheric temperature (1 mark)
(b) Gas 1 – Carbon dioxide (2 marks):
- CO₂ is a greenhouse gas (1 mark)
- Burning fossil fuels (coal, oil, natural gas) for energy releases CO₂ into the atmosphere (1 mark)
(c) Gas 2 – Methane (2 marks):
- CH₄ is a greenhouse gas (1 mark)
- Livestock farming (cattle) produces methane through enteric fermentation/digestion (1 mark)
2020 AP Exam – 4 marks:
Question: “Describe the role of carbon dioxide in the greenhouse effect.”
Model Answer:
- CO₂ molecules absorb infrared radiation emitted from Earth’s surface (1 mark)
- The absorbed energy causes CO₂ molecules to vibrate and re-emit infrared radiation (1 mark)
- Some of this re-emitted radiation travels back toward Earth’s surface, warming it (1 mark)
- Increased CO₂ concentrations from human activities enhance this warming effect (1 mark)
⭐ Must-Know Points for AP Exam
- Radiation types matter – Shortwave (visible) from Sun passes through; longwave (infrared) from Earth gets trapped
- CO₂ is the primary concern – Most abundant human-caused GHG, long atmospheric lifetime (100+ years)
- Positive feedback loops – Warming causes more water vapor (a GHG), which causes more warming
- Albedo effect connection – Melting ice reduces Earth’s reflectivity, absorbing more heat
- Ocean acidification link – Oceans absorb ~30% of CO₂, forming carbonic acid
- Methane’s dual role – Powerful GHG (28x CO₂) but shorter lifetime; from agriculture and fossil fuels
- Deforestation impact – Removes CO₂ sinks (trees) AND releases stored carbon
- Global Warming Potential (GWP) – Standardized measure comparing gases to CO₂ over 100 years
- Residence time varies – CH₄ (~12 years), CO₂ (100-300 years), N₂O (~114 years)
- Mitigation strategies – Renewable energy, reforestation, carbon capture, reducing meat consumption
⚠️ Common AP Exam Mistakes
Mistake 1: Confusing ozone depletion with greenhouse effect
Why you lose marks: These are separate issues. Ozone layer protects from UV; greenhouse effect involves heat trapping.
Correct approach: Greenhouse effect = GHGs trap infrared radiation. Ozone depletion = CFCs destroy O₃ in stratosphere.
Mistake 2: Saying “greenhouse gases trap heat”
Why you lose marks: Imprecise terminology – they don’t trap heat directly.
Correct approach: Say “greenhouse gases absorb and re-emit infrared radiation” or “trap longwave radiation.”
Mistake 3: Not distinguishing natural from enhanced
Why you lose marks: Question may specifically ask about human impact.
Correct approach: Always clarify – “natural greenhouse effect maintains habitable temperature; enhanced effect from human activities causes warming.”
Mistake 4: Forgetting to name specific gases
Why you lose marks: “Greenhouse gases” alone is too vague for full credit.
Correct approach: Always name specific gases: CO₂, CH₄, N₂O, H₂O vapor.
Mistake 5: Incorrect GWP values or comparisons
Why you lose marks: Data accuracy matters on AP exam.
Correct approach: Memorize key GWP values – CH₄ is ~28-36x CO₂, N₂O is ~265-298x CO₂.
⏱️ Time Management Strategy
For 4-mark FRQ question:
- Reading: 1 minute – Identify what’s being asked (mechanism, gases, impacts?)
- Planning: 1 minute – Outline 4 key points to cover
- Writing: 6 minutes – Write clear, concise answers with specific examples
- Review: 1 minute – Check you’ve addressed all parts, used correct terminology
Total time: ~9 minutes for 4-mark question
💡 AP Exam Tips
Before exam:
- Memorize the 4 main GHGs and their sources (CO₂, CH₄, N₂O, H₂O)
- Practice drawing and labeling greenhouse effect diagrams
- Review past FRQs on College Board website
- Understand carbon cycle connections
- Know current CO₂ concentration (~420 ppm)
During exam:
- Read question carefully – are they asking about natural or enhanced effect?
- Use specific terminology: “infrared radiation,” not just “heat”
- For FRQs, make sure each point is distinct (don’t repeat same idea)
- Include units when giving data (ppm, °C, GWP values)
- Connect to other topics when relevant (carbon cycle, climate change)
- If asked for examples, give SPECIFIC ones (coal combustion, not just “burning fuel”)
💪 Practice Questions
Question 1 (4 marks – 9 minutes):
Explain how the greenhouse effect maintains Earth’s temperature. Identify TWO greenhouse gases and describe ONE human activity that increases atmospheric concentration of each.
Marking scheme:
- Mechanism explanation (1 mark) – GHGs absorb infrared radiation from Earth
- Re-radiation explanation (1 mark) – Energy re-emitted back to surface, warming it
- Gas 1 + human activity (1 mark) – e.g., CO₂ from fossil fuel combustion
- Gas 2 + human activity (1 mark) – e.g., CH₄ from rice paddies/livestock
Question 2 (6 marks – 13 minutes):
(a) Describe the difference between the natural greenhouse effect and the enhanced greenhouse effect. (2 marks)
(b) Explain why methane has a higher global warming potential than carbon dioxide. (2 marks)
(c) Propose TWO strategies to reduce greenhouse gas emissions. (2 marks)
Hint for (a): Natural = maintains 15°C vs. -18°C; Enhanced = human activities increase GHG concentrations above natural levels
Hint for (b): CH₄ absorbs more infrared per molecule; has GWP of 28-36 over 100 years
Hint for (c): Renewable energy (solar/wind), reforestation, carbon capture, reduce meat consumption, improve energy efficiency
Question 3 (3 marks – 7 minutes):
A student claims that “the greenhouse effect is bad for the environment.” Evaluate this claim.
Marking scheme:
- Identify that natural greenhouse effect is essential (1 mark)
- Explain it maintains habitable temperature/supports life (1 mark)
- Clarify that enhanced greenhouse effect from human activities is problematic (1 mark)
🔥 Last-Minute Revision Points
- ⚡ Mechanism: Sun → shortwave in → Earth absorbs → longwave out → GHGs absorb → re-radiate → warming
- ⚡ Main GHGs: H₂O (most abundant), CO₂ (main human-caused), CH₄ (high GWP), N₂O (agriculture)
- ⚡ CO₂ sources: Fossil fuels (75%), deforestation (25%)
- ⚡ CH₄ sources: Agriculture (40%), fossil fuels (35%), landfills (15%)
- ⚡ Key numbers: CO₂ = 420 ppm (up from 280), CH₄ GWP = 28-36, N₂O GWP = 265-298
- ⚡ Temperature: Without GHE = -18°C; With natural GHE = 15°C; Current warming = +1.1°C
- ⚡ Feedback loop: Warming → more H₂O vapor → more warming (positive feedback)
- ⚡ Mitigation: Renewable energy, reforestation, carbon pricing, energy efficiency
- ⚡ Not greenhouse effect: Ozone depletion (separate issue with CFCs)
- ⚡ Exam language: Say “infrared radiation” not “heat”; “absorb and re-emit” not “trap”
🤔 People Also Ask
❓ What would happen if there were no greenhouse effect?
Without the greenhouse effect, Earth’s average temperature would plummet to about -18°C (0°F), making it uninhabitable for most life forms. The planet would be frozen, similar to Mars. The natural greenhouse effect is essential because it traps enough heat to maintain our current average temperature of 15°C (59°F), creating conditions suitable for liquid water and life as we know it.
❓ Why is CO₂ considered the most important greenhouse gas?
While CO₂ isn’t the most powerful greenhouse gas per molecule, it’s the most important because of its abundance and longevity. Human activities have increased atmospheric CO₂ by 50% since pre-industrial times, and it remains in the atmosphere for 100-300 years. CO₂ is responsible for about 75% of human-caused global warming, making it the primary target for climate mitigation efforts.
❓ How does deforestation contribute to the greenhouse effect?
Deforestation contributes to the greenhouse effect in two ways: First, when trees are cut and burned or left to decompose, they release stored carbon dioxide back into the atmosphere. Second, removing forests eliminates important carbon sinks that absorb CO₂ through photosynthesis. Tropical deforestation alone accounts for about 10-15% of global greenhouse gas emissions, making forest conservation crucial for climate action.
❓ What is the difference between global warming and the greenhouse effect?
The greenhouse effect is the natural mechanism by which greenhouse gases trap heat in Earth’s atmosphere, maintaining habitable temperatures. Global warming refers to the observed increase in Earth’s average temperature over recent decades, caused by the enhanced greenhouse effect from human activities. Think of it this way: the greenhouse effect is the process, while global warming is the result of intensifying that process through increased GHG emissions.
❓ Can the greenhouse effect be reversed?
The natural greenhouse effect cannot and should not be reversed as it’s essential for life. However, the enhanced greenhouse effect can be slowed and partially reversed through aggressive mitigation strategies: transitioning to renewable energy, reforestation, carbon capture technologies, and reducing emissions. Even with immediate action, CO₂’s long atmospheric lifetime means some warming is already locked in, but we can prevent the worst future scenarios.
❓ Why is methane worse than CO₂ for global warming?
Methane is a more potent greenhouse gas than CO₂ on a per-molecule basis, with a Global Warming Potential (GWP) of 28-36 over 100 years. This means one ton of methane traps 28-36 times more heat than one ton of CO₂ over a century. However, methane has a shorter atmospheric lifetime (~12 years vs. 100+ for CO₂), so reducing methane emissions can provide faster climate benefits. Both gases require urgent attention.
❓ How do scientists measure greenhouse gas concentrations?
Scientists measure GHG concentrations using several methods: Direct atmospheric sampling at monitoring stations like Mauna Loa Observatory in Hawaii, satellite observations that detect infrared absorption patterns, and ice core analysis that reveals historical concentrations. Concentrations are expressed in parts per million (ppm) for CO₂ or parts per billion (ppb) for trace gases. These measurements show CO₂ has risen from 280 ppm (pre-industrial) to 420 ppm today.
❓ What role does water vapor play in the greenhouse effect?
Water vapor is actually the most abundant greenhouse gas, responsible for about 60% of the natural greenhouse effect. However, it’s not directly controlled by human activities. Instead, water vapor acts as a feedback mechanism: as CO₂ and other GHGs warm the atmosphere, more water evaporates from oceans, increasing water vapor concentrations, which causes additional warming. This positive feedback loop amplifies the warming effect of human-caused GHG emissions.
🎴 Flashcards: Greenhouse Effect
📚 Flashcard Set Information
- Total Cards: 20
- Topic: Greenhouse Effect – AP Environmental Science
- Difficulty: Medium to High
- Study Time: 25-30 minutes
💡 How to Use
- Read the FRONT (question/term)
- Try to recall the answer
- Check the BACK (answer/definition)
- Mark cards you got wrong
- Review wrong cards again
- Repeat until you get all cards correct
What is the greenhouse effect?
A natural atmospheric process where greenhouse gases absorb and re-emit infrared radiation from Earth’s surface, trapping heat and warming the planet to habitable temperatures.
Additional Info:
- Without it: Earth would be -18°C
- With it: Earth is 15°C average
- Essential for life
Name the four main greenhouse gases
1. Water vapor (H₂O) – most abundant
2. Carbon dioxide (CO₂) – main human-caused
3. Methane (CH₄) – high GWP
4. Nitrous oxide (N₂O) – from agriculture
Memory aid: “Water Carries Many Nutrients” (H₂O, CO₂, CH₄, N₂O)
What is Global Warming Potential (GWP)?
A measure that compares the warming potential of a greenhouse gas to carbon dioxide over a specific time period (usually 100 years). CO₂ has a GWP of 1 (baseline).
Examples:
- CH₄: GWP = 28-36 (28-36x stronger than CO₂)
- N₂O: GWP = 265-298
Explain the mechanism of the greenhouse effect in 3 steps
Step 1: Sun’s shortwave radiation reaches Earth and is absorbed by surface
Step 2: Warmed Earth emits longwave infrared radiation back toward space
Step 3: Greenhouse gases absorb this infrared and re-radiate it in all directions, including back to Earth, causing warming
Key point: Shortwave passes through, longwave gets trapped
What is the current atmospheric CO₂ concentration?
Approximately 420 ppm (parts per million) as of 2024
Context:
- Pre-industrial (1750): 280 ppm
- Increase: 50% rise due to human activities
- Rate: Fastest increase in 800,000 years
What is the difference between natural and enhanced greenhouse effect?
Natural: Maintains Earth at habitable 15°C; has existed for billions of years; balanced by natural carbon cycle
Enhanced: Increased GHG concentrations from human activities (fossil fuels, deforestation); causes additional warming beyond natural levels; leads to climate change
List 3 human activities that increase CO₂ emissions
1. Burning fossil fuels – coal, oil, natural gas for energy/transportation
2. Deforestation – removes CO₂ sinks and releases stored carbon
3. Industrial processes – cement production, manufacturing
Contribution: Fossil fuels account for ~75% of CO₂ emissions
What are the main sources of methane (CH₄)?
1. Agriculture (40%) – livestock (enteric fermentation), rice paddies
2. Fossil fuels (35%) – natural gas leaks, coal mining
3. Landfills (15%) – decomposition of organic waste
4. Wetlands (10%) – natural source
Note: Cattle produce CH₄ through digestion (burps, not just flatulence!)
Why is water vapor not directly controlled by humans?
Water vapor concentration is determined by temperature and evaporation rates, not direct human emissions. It acts as a feedback mechanism: warming from CO₂ increases evaporation → more water vapor → more warming (positive feedback loop).
Key point: We control CO₂/CH₄; temperature controls H₂O vapor
What is the atmospheric lifetime of CO₂ vs. CH₄?
CO₂: 100-300 years (very long-lived)
CH₄: ~12 years (shorter-lived)
Implication: Reducing CH₄ emissions provides faster climate benefits, but CO₂ reduction is crucial for long-term stabilization
Describe one positive feedback loop related to greenhouse effect
Water vapor feedback:
- Warming increases evaporation from oceans
- More water vapor in atmosphere (H₂O is a GHG)
- Additional heat trapped
- More warming occurs
- Cycle continues
What percentage of Earth’s warming is caused by CO₂?
Approximately 75% of human-caused global warming is due to CO₂ emissions
Breakdown:
- CO₂: 75%
- CH₄: 17%
- N₂O: 6%
- Other gases: 2%
Name 3 mitigation strategies for greenhouse gas emissions
1. Renewable energy – solar, wind, hydroelectric to replace fossil fuels
2. Reforestation – planting trees to absorb CO₂
3. Energy efficiency – LED bulbs, insulation, efficient appliances
Others: Carbon capture, carbon pricing, reduce meat consumption, public transit
What type of radiation does the Sun emit vs. Earth?
Sun emits: Shortwave radiation (visible light, UV) – high energy
Earth emits: Longwave radiation (infrared) – lower energy, heat
Critical concept: GHGs are transparent to shortwave but absorb longwave – this is why greenhouse effect works!
How much has Earth’s temperature increased since 1880?
Approximately 1.1°C (2°F) increase in global average temperature
Context:
- Most warming occurred after 1980
- Last decade was warmest on record
- Paris Agreement goal: limit to 1.5-2°C total
What is the primary source of nitrous oxide (N₂O)?
Agriculture – specifically synthetic nitrogen fertilizers used in farming
Other sources:
- Livestock manure
- Industrial processes
- Fossil fuel combustion
- Wastewater treatment
Explain how deforestation contributes to greenhouse effect (2 ways)
Way 1: Removes carbon sinks – trees absorb CO₂ through photosynthesis; cutting them eliminates this absorption
Way 2: Releases stored carbon – when trees are burned or decompose, they release CO₂ back into atmosphere
Impact: Deforestation accounts for ~10-15% of global GHG emissions
What is the relationship between greenhouse effect and ozone depletion?
They are SEPARATE issues!
Greenhouse effect: GHGs trap infrared radiation in troposphere, causing warming
Ozone depletion: CFCs destroy O₃ in stratosphere, allowing more UV radiation to reach Earth
AP Exam warning: Don’t confuse these – common mistake!
Why does methane have a higher GWP than CO₂?
Methane molecules are more efficient at absorbing infrared radiation per molecule than CO₂. One CH₄ molecule traps 28-36 times more heat than one CO₂ molecule over 100 years.
However: CH₄ breaks down faster (~12 years) while CO₂ persists for centuries, so both gases require attention
What percentage of solar radiation is absorbed by Earth’s surface?
Approximately 50% of incoming solar radiation is absorbed by Earth’s surface
What happens to the rest:
- ~30% reflected back to space (by clouds, ice, atmosphere)
- ~20% absorbed by atmosphere
⚡ Quick Review Sheet
All key answers at a glance:
| Card # | Question | Quick Answer |
|---|---|---|
| 1 | What is greenhouse effect? | GHGs trap infrared radiation, warming Earth |
| 2 | Main GHGs? | H₂O, CO₂, CH₄, N₂O |
| 3 | What is GWP? | Warming potential vs. CO₂ over 100 years |
| 4 | Mechanism? | Shortwave in → longwave out → GHGs trap |
| 5 | Current CO₂? | 420 ppm (up from 280 ppm) |
| 6 | Natural vs. enhanced? | Natural = habitable; Enhanced = human-caused warming |
| 7 | CO₂ sources? | Fossil fuels, deforestation, industry |
| 8 | CH₄ sources? | Agriculture (40%), fossil fuels (35%), landfills |
| 9 | Why not control H₂O? | Feedback mechanism – controlled by temperature |
| 10 | Atmospheric lifetime? | CO₂: 100-300 years; CH₄: 12 years |
| 11 | Positive feedback? | Warming → more H₂O vapor → more warming |
| 12 | CO₂ warming %? | 75% of human-caused warming |
| 13 | Mitigation? | Renewables, reforestation, efficiency |
| 14 | Radiation types? | Sun: shortwave; Earth: longwave (infrared) |
| 15 | Temperature increase? | 1.1°C since 1880 |
| 16 | N₂O source? | Agriculture – nitrogen fertilizers |
| 17 | Deforestation impact? | Removes sinks + releases stored carbon |
| 18 | Ozone vs. greenhouse? | SEPARATE issues – don’t confuse! |
| 19 | Why CH₄ higher GWP? | More efficient at trapping heat per molecule |
| 20 | Solar absorption? | 50% absorbed by Earth’s surface |
📖 Study Tips
Spaced Repetition Schedule
- Day 1: Study all 20 cards
- Day 2: Review all cards
- Day 4: Review cards you got wrong
- Day 7: Review all cards
- Day 14: Final review before AP exam
Active Recall Techniques
- Cover the back – Try to recall before looking
- Explain out loud – Teach the concept to yourself or a study partner
- Write it down – Write the answer before checking
- Mix the order – Don’t study in the same sequence every time
Difficulty Marking
- ✅ Easy: Got it right immediately
- ⚠️ Medium: Got it right after thinking
- ❌ Hard: Got it wrong or couldn’t recall
Focus extra time on ❌ and ⚠️ cards
🎴 Flashcards: Greenhouse Effect (Click to Flip!)
💡 How to Use: Click on any card to flip it and see the answer!
What is the greenhouse effect?
✅ Answer:
A natural atmospheric process where greenhouse gases absorb and re-emit infrared radiation from Earth's surface, trapping heat and warming the planet to habitable temperatures.
📌 Key Points:
- Without it: Earth would be -18°C
- With it: Earth is 15°C average
- Essential for life
👆 Click card to flip
Name the four main greenhouse gases
✅ Answer:
- Water vapor (H₂O) - most abundant
- Carbon dioxide (CO₂) - main human-caused
- Methane (CH₄) - high GWP
- Nitrous oxide (N₂O) - from agriculture
💡 Memory aid: "Water Carries Many Nutrients"
👆 Click card to flip
Explain how deforestation contributes to greenhouse effect (2 ways)
✅ Answer:
Way 1: Removes carbon sinks - trees absorb CO₂ through photosynthesis; cutting them eliminates this absorption
Way 2: Releases stored carbon - when trees are burned or decompose, they release CO₂ back into atmosphere
📊 Impact: Deforestation accounts for ~10-15% of global GHG emissions
👆 Click card to flip
What is the relationship between greenhouse effect and ozone depletion?
✅ Answer:
They are SEPARATE issues!
Greenhouse effect: GHGs trap infrared radiation in troposphere, causing warming
Ozone depletion: CFCs destroy O₃ in stratosphere, allowing more UV radiation to reach Earth
⚠️ AP Exam warning: Don't confuse these - common mistake!
👆 Click card to flip