CAP Environmental Impact 3 — Questions and Answers
Question 1: Under the IPCC framework, which sector is the largest contributor to global anthropogenic greenhouse gas emissions?
- Agriculture, Forestry and Land Use (AFOLU)
- Industry (including manufacturing)
- Energy supply (electricity and heat production) (Correct answer)
- Transport
Correct answer: Energy supply (electricity and heat production)
Energy supply — primarily electricity and heat generation from fossil fuels — is the single largest sectoral source of global GHG emissions, accounting for roughly 34% of total emissions.
Question 2: What is 'additionality' in the context of carbon offset projects?
- The additional cost of implementing carbon reduction measures
- The requirement that emission reductions would not have occurred without the offset project (Correct answer)
- Adding new carbon sinks to an existing project boundary
- The incremental GWP of newly regulated gases
Correct answer: The requirement that emission reductions would not have occurred without the offset project
Additionality requires that carbon offset projects deliver emission reductions that are genuinely additional to what would have happened under a business-as-usual scenario.
Question 3: Ocean acidification is a secondary environmental consequence of rising CO₂ levels primarily because:
- CO₂ reacts with seawater to form carbonic acid, lowering pH (Correct answer)
- Warmer oceans absorb less oxygen, increasing acidity
- Methane from ocean floors neutralizes alkaline minerals
- Increased UV radiation accelerates chemical reactions in surface water
Correct answer: CO₂ reacts with seawater to form carbonic acid, lowering pH
When CO₂ dissolves in seawater it forms carbonic acid (H₂CO₃), which dissociates to release hydrogen ions, lowering ocean pH — a process called ocean acidification.
Question 4: In a carbon audit, 'materiality threshold' determines:
- The minimum GWP required for a gas to be included in reporting
- The percentage below which an emission source may be excluded without significant impact on total accuracy (Correct answer)
- The legal limit for carbon emissions in a regulated sector
- The conversion factor between metric tons and short tons of CO₂e
Correct answer: The percentage below which an emission source may be excluded without significant impact on total accuracy
A materiality threshold allows auditors to exclude minor emission sources whose omission would not materially affect the reported total, improving audit efficiency without sacrificing accuracy.
Question 5: Which environmental impact is directly worsened by black carbon (soot) emissions from incomplete combustion?
- Stratospheric ozone depletion
- Glacial and sea ice albedo reduction (Correct answer)
- Ocean de-oxygenation
- Soil nitrogen saturation
Correct answer: Glacial and sea ice albedo reduction
Black carbon particles deposited on snow and ice darken their surface, reducing albedo (reflectivity) and accelerating melting — a significant regional climate feedback.
Question 6: A carbon auditor reviewing a landfill site should account for which primary GHG generated by decomposing organic waste?
- Carbon dioxide only
- Methane and carbon dioxide (Correct answer)
- Nitrous oxide and methane
- Hydrofluorocarbons and CO₂
Correct answer: Methane and carbon dioxide
Anaerobic decomposition of organic matter in landfills produces landfill gas, which is approximately 50% methane and 50% CO₂, both significant GHGs that must be inventoried.
Question 7: The 'carbon budget' concept, as used by the IPCC, refers to:
- A company's annual spending allocation for carbon reduction projects
- The cumulative amount of CO₂ emissions permitted to limit warming to a specific temperature target (Correct answer)
- The ratio of carbon sequestration capacity to annual emissions
- A government's tax revenue from carbon pricing mechanisms
Correct answer: The cumulative amount of CO₂ emissions permitted to limit warming to a specific temperature target
A carbon budget defines the total cumulative CO₂ emissions humanity can release while still having a reasonable probability of staying within a given temperature limit, such as 1.5°C.
CAP Environmental Impact 3
Under the IPCC framework, which sector is the largest contributor to global anthropogenic greenhouse gas emissions?