CCA Climate Science & GHG Fundamentals 1 — Questions and Answers
Question 1: Which greenhouse gas has the highest global warming potential (GWP) over a 100-year timeframe among those covered by the Kyoto Protocol?
- Sulfur hexafluoride (SF6) (Correct answer)
- Carbon dioxide (CO2)
- Methane (CH4)
- Nitrous oxide (N2O)
Correct answer: Sulfur hexafluoride (SF6)
SF6 has a 100-year GWP of approximately 23,500, making it the most potent greenhouse gas covered under the Kyoto Protocol.
Question 2: What does the term 'CO2 equivalent (CO2e)' allow carbon auditors to do?
- Express emissions from different GHGs on a common scale based on their warming potential (Correct answer)
- Convert metric tons to short tons for US reporting
- Calculate the financial value of carbon credits
- Standardize energy consumption across fuel types
Correct answer: Express emissions from different GHGs on a common scale based on their warming potential
CO2e converts the warming impact of various greenhouse gases into the equivalent amount of CO2 that would cause the same warming, enabling a unified measurement.
Question 3: According to the IPCC, what is the primary driver of observed climate change since the mid-20th century?
- Human-caused greenhouse gas emissions (Correct answer)
- Natural solar variability
- Volcanic activity
- Changes in Earth's orbital cycles
Correct answer: Human-caused greenhouse gas emissions
The IPCC's Sixth Assessment Report concludes with high confidence that human-caused GHG emissions are the dominant cause of observed global warming since the mid-20th century.
Question 4: The '1.5°C target' referenced in the Paris Agreement refers to limiting global average temperature rise above:
- Pre-industrial levels (Correct answer)
- 1990 baseline temperatures
- Year 2000 temperatures
- The current global average temperature
Correct answer: Pre-industrial levels
The Paris Agreement aims to limit global average temperature increase to 1.5°C above pre-industrial levels to avoid the most severe climate impacts.
Question 5: Which of the following is a short-lived climate pollutant (SLCP) with a 100-year GWP approximately 28 times that of CO2?
- Methane (CH4) (Correct answer)
- Nitrous oxide (N2O)
- Hydrofluorocarbons (HFCs)
- Carbon monoxide (CO)
Correct answer: Methane (CH4)
Methane has a 100-year GWP of approximately 28–34 (AR6), making it a potent but relatively short-lived climate forcer compared to CO2.
Question 6: What is the significance of the atmospheric concentration of CO2 reaching 420 ppm (parts per million)?
- It represents the highest CO2 levels in at least 800,000 years of ice core records (Correct answer)
- It is the safe upper limit established by the Paris Agreement
- It marks the threshold for mandatory carbon reporting in the US
- It is the target concentration for net-zero emissions
Correct answer: It represents the highest CO2 levels in at least 800,000 years of ice core records
Current CO2 concentrations around 420 ppm are the highest measured in ice core records spanning 800,000 years, reflecting the scale of human industrial emissions.
CCA Climate Science & GHG Fundamentals 1
Which greenhouse gas has the highest global warming potential (GWP) over a 100-year timeframe among those covered by the Kyoto Protocol?