Climate Change Science & Modeling Flashcards

What is the primary mechanism by which aerosols cool the climate ('first indirect effect' or Twomey effect)?

Answer: Increasing cloud droplet number, making clouds more reflective

The Twomey effect (first indirect aerosol effect) occurs when aerosols act as cloud condensation nuclei, increasing cloud droplet number concentration and producing brighter, more reflective clouds.

In Earth's energy budget, what fraction of incoming solar radiation is approximately reflected back to space (Earth's albedo)?

Answer: About 30%

Earth's average planetary albedo is approximately 0.30 (30%), with clouds, ice, and land surfaces accounting for most of this reflection.

What does the term 'carbon cycle feedback' describe in climate modeling?

Answer: Changes in land and ocean carbon uptake that amplify or dampen warming

Carbon cycle feedbacks describe how warming affects ecosystem carbon uptake and release, such as reduced ocean CO₂ solubility and permafrost thaw releasing stored carbon, amplifying greenhouse warming.

Which phenomenon explains why polar regions warm roughly twice as fast as the global average?

Answer: Arctic amplification driven by multiple reinforcing feedbacks

Arctic amplification results from several feedbacks operating more strongly at high latitudes, especially the ice-albedo feedback, water vapor feedback, and changes in atmospheric circulation and ocean heat transport.

What is 'statistical downscaling' in climate modeling?

Answer: Using statistical relationships between large-scale climate patterns and local observations to derive local projections

Statistical downscaling uses empirical relationships between coarse-resolution model output and historical local observations to produce high-resolution regional climate projections.

The 'committed warming' or 'warming in the pipeline' concept means:

Answer: Future warming already guaranteed due to past emissions and thermal lag

Committed warming refers to additional warming that will occur even if greenhouse gas concentrations were stabilized today, due to the slow response of the ocean absorbing and releasing heat.

What is the main reason that cloud feedbacks represent the largest source of uncertainty in climate projections?

Answer: The net effect of cloud changes on radiation depends on unresolved microphysics, altitude, and coverage changes

Cloud feedbacks are uncertain because changes in cloud type (low vs. high), altitude, coverage, and optical properties have competing warming and cooling effects that current models represent with different net results.