₦airaland Forum

a.

Satellite information has revealed that the average albedo of the Earth’s surface is 0.32. Briefly describe what is conveyed by this measurement of albedo, and how albedo might affect the temperature experienced on Earth’s surface.

(5 marks)
b.

Imagine a situation where Earth’s atmosphere begins to trap more of the incoming solar radiation (e.g. this could occur through an increase of ‘greenhouse’ gases such as CO2). Explain what effect this would have on the temperatures experienced at Earth’s surface, then, with reference to the different types of surfaces listed in Table 1, complete the eight blank entries.

(9 marks)

Table 1
Surface type Albedo Nature of the change Effect on total area of surface Effect on Earth’s albedo

Ocean surface 3% less sea ice covering increase
Conifer forests (summer) 9% longer growing season increase
Grassy fields 25% decrease
Sea ice 40% decrease decrease
Desert sand 40% expanding desert increase
Fresh snow 85% decrease

c.

Briefly outline how the Earth’s overall (i.e. average) albedo might respond to such a rise in CO2 (e.g. over a period greater than 100 years) and, with the aid of a simple diagram, state whether this response would represent a positive or a negative feedback loop.

(6 marks)