Climate Science & Atmospheric Systems Flashcards

What is 'carbon budget' in the context of the Paris Agreement's 1.5°C target?

Answer: The cumulative amount of CO₂ that can still be emitted while limiting warming to a given level

A carbon budget is the maximum cumulative amount of CO₂ emissions consistent with limiting global average temperature rise to a specific level, such as 1.5°C.

Which atmospheric circulation system creates the persistent dry zones at approximately 30° latitude north and south, affecting desert distribution?

Answer: Hadley cells

Hadley cells drive air upward at the equator (creating tropical rainfall) and downward at approximately 30° latitude, creating subtropical high-pressure zones where major deserts form.

The Paleocene-Eocene Thermal Maximum (PETM) about 56 million years ago is studied by carbon auditors primarily because it demonstrates:

Answer: The effects of rapid large-scale carbon release on global temperature

The PETM, during which ~3,000–7,000 GtC was released and temperatures rose 5–8°C, serves as a geological analogue for understanding the consequences of rapid carbon release.

Which concept describes the long-term warming already 'locked in' due to past greenhouse gas emissions, even if all emissions stopped today?

Answer: Committed warming (warming in the pipeline)

Committed warming refers to the additional temperature rise that will occur due to the thermal inertia of the oceans absorbing heat from existing atmospheric GHG concentrations, regardless of future emissions.

In carbon auditing, which metric best captures the near-term climate impact of methane emissions compared to CO₂?

Answer: GWP20 (20-year Global Warming Potential)

GWP20 reflects methane's much higher near-term warming potency (~80× CO₂ over 20 years) and is increasingly used when assessing near-term climate targets.

What role does stratospheric aerosol injection (SAI), a proposed solar geoengineering approach, play in climate management?

Answer: Reflects incoming solar radiation to reduce surface temperatures without addressing CO₂

SAI would inject reflective particles (e.g., sulfur dioxide) into the stratosphere to scatter incoming sunlight, reducing surface temperatures but not addressing the root cause of rising CO₂.

Which feedback is considered the most important amplifying feedback in the climate system, approximately doubling the warming from CO₂ alone?

Answer: Water vapor feedback

Water vapor feedback is the dominant amplifying feedback: as CO₂ warms the atmosphere, evaporation increases atmospheric water vapor (itself a greenhouse gas), roughly doubling the initial warming.