CAP Climate Science & Atmospheric Systems 3 — Questions and Answers
Question 1: Which of the following gases has the highest 100-year Global Warming Potential (GWP100) among common industrial refrigerants?
- Carbon dioxide (CO₂)
- Methane (CH₄)
- Sulfur hexafluoride (SF₆) (Correct answer)
- Nitrous oxide (N₂O)
Correct answer: Sulfur hexafluoride (SF₆)
Sulfur hexafluoride (SF₆) has a GWP100 of approximately 23,500, making it one of the most potent greenhouse gases used in electrical switchgear.
Question 2: What climate phenomenon is characterized by anomalous warming of sea surface temperatures in the central and eastern tropical Pacific Ocean?
- La Niña
- El Niño (Correct answer)
- Indian Ocean Dipole
- Atlantic Multidecadal Oscillation
Correct answer: El Niño
El Niño is the warm phase of the El Niño–Southern Oscillation (ENSO), during which warmer-than-average sea surface temperatures in the tropical Pacific alter global weather patterns.
Question 3: The carbon cycle's 'biological pump' refers to which process?
- Volcanic outgassing of CO₂ from the mantle
- Photosynthesis by land plants sequestering atmospheric carbon
- Ocean phytoplankton fixing CO₂ that sinks as organic matter (Correct answer)
- Carbonate rock weathering releasing CO₂
Correct answer: Ocean phytoplankton fixing CO₂ that sinks as organic matter
The biological pump describes the process by which marine phytoplankton absorb CO₂ through photosynthesis, and when they die, transport organic carbon to the deep ocean.
Question 4: According to the IPCC AR6, which scenario (SSP) projects the highest warming by 2100?
- SSP1-1.9
- SSP2-4.5
- SSP3-7.0
- SSP5-8.5 (Correct answer)
Correct answer: SSP5-8.5
SSP5-8.5 represents a fossil-fuel intensive development pathway with the highest greenhouse gas emissions, projecting up to 4.4°C of warming above pre-industrial levels by 2100.
Question 5: What is the approximate atmospheric lifetime of CO₂ that is most relevant for long-term climate commitments?
- 12 years
- 50–100 years
- Centuries to millennia (Correct answer)
- 10,000+ years
Correct answer: Centuries to millennia
While the 'effective' atmospheric lifetime of CO₂ is often cited as 50–100 years for policy purposes, about 20% of emitted CO₂ remains in the atmosphere for thousands of years.
Question 6: Which Earth system tipping point could irreversibly destabilize the West Antarctic Ice Sheet, contributing multiple meters of sea level rise?
- Permafrost thaw release of methane
- Loss of Arctic summer sea ice
- Marine ice sheet instability (MISI) (Correct answer)
- Dieback of the Amazon rainforest
Correct answer: Marine ice sheet instability (MISI)
Marine Ice Sheet Instability (MISI) is a self-reinforcing feedback where warm ocean water melts the base of marine-based ice sheets, potentially causing irreversible collapse.
Question 7: In atmospheric science, what does a 'temperature inversion' describe?
- The cooling of the stratosphere as the troposphere warms
- A layer where temperature increases with altitude rather than decreasing (Correct answer)
- The reversal of trade winds during El Niño
- The seasonal flip in polar vortex direction
Correct answer: A layer where temperature increases with altitude rather than decreasing
A temperature inversion is an atmospheric condition where a layer of warm air traps cooler air below it, reversing the typical decrease of temperature with altitude.
CAP Climate Science & Atmospheric Systems 3
Which of the following gases has the highest 100-year Global Warming Potential (GWP100) among common industrial refrigerants?