Climate System Components Questions and Answers

Answer: C

The blackbody response is what stabilises the system, and cloud feedback remains the largest uncertainty in climate sensitivity. Adding the feedbacks together gives the overall response. Cloud remains the largest uncertainty.

Answer: D

Both are true and the reason gives the mechanism, and without it any positive feedback would carry the system away without limit. It is the term against which all the other feedbacks are measured when a climate sensitivity is estimated.

Answer: A

Correct answer: 1 and 2 only

Statements 1 and 2 are correct: warmer air holds more water vapour, which is itself a greenhouse gas, roughly doubling the direct effect of carbon dioxide; and the increase in emitted radiation with temperature is the negative feedback that stabilises the whole system. Statement 3 overstates the case - cloud feedback remains the largest single uncertainty in climate sensitivity, and the best estimates place it as positive.

Answer: B

Correct answer: False

Runaway requires the total feedback to exceed the stabilising blackbody response, and it does not. The Planck response is strongly negative - radiation rises as the fourth power of temperature - so a positive feedback amplifies the response to a forcing and reaches a new equilibrium rather than diverging. The amplification factor is finite: the water vapour feedback roughly doubles the direct warming and stops there.

Answer: C

The magnetosphere is a magnetic phenomenon and plays no part in the energy and matter exchanges that define the climate system. The other three are three of the five recognised components. Energy and matter exchange is the test.

Answer: D

Correct answer: sea ice, glaciers, snow and permafrost

The cryosphere is water in its frozen forms, wherever it occurs: sea ice, ice shelves and ice sheets, glaciers, seasonal snow cover, lake and river ice, and frozen ground. It matters out of proportion to its mass because of albedo - fresh snow reflects most of the sunlight falling on it, so losing it is strongly self-reinforcing.

Answer: A

Both are true and the reason gives both mechanisms, and the loss of Arctic sea ice is one of the clearest signals of change in the whole system. Albedo is where most of its influence lies. Its mass is a small part of the system.

Answer: B

Correct answer: about 71 per cent

Just over seventy per cent of the surface is ocean, and that dominance drives much of the system: the ocean holds vastly more heat than the atmosphere, absorbs the bulk of the energy imbalance and most of the added carbon dioxide, and supplies the water vapour on which the greenhouse effect and the hydrological cycle depend.

Answer: C

The first two are correct. The third is quite wrong, since the ocean is precisely what sets the decadal timescale of much climate variability, El Nino among them. Its heat capacity dwarfs the air. Ocean heat content is the better measure of warming.

Answer: D

The ice sheet responds over thousands of years, while the other three all adjust within a season or two. Timescale is what determines which components must be treated as fixed in a given problem. Ice sheets are the slowest of all.