Land Use and Geo-Engineering - Introduction to Carbon Capture and Sequestration - page 537

Table 11.4.1 Albedo coeffi cients of surfaces on the earth

Surface Albedo coeffi cient

Ocean 0.1

Land Surface 0.2-0.3

Ice and snow 0.6-0.8

Average 0.15

The albedo coefficient is defined as the ratio of reflected radiation from the surface to incident
radiation upon it. Data from [11.16] .

the mean surface albedo of the planet from 0.15 to about 0.17. This does
not look like a large change, but because most of the surface of the earth
is ocean, for which it is impractical to change its refl ectivity, the net
change on “usable” surface would therefore be much larger. The required
increase over the land area would be on average 8%. In practice, this is
further limited in that only on a small percentage of the total land surface
can one effectively modify its characteristics (see Question 11.4.1 ).

We emphasize that changing the amount of sunlight reaching the
earth's surface does not resolve the underlying cause of global warming;
it only mitigates the negative effects of increasing global temperatures.
This also implies that as soon as we stop applying any solar radiation
management techniques, the temperature would quite rapidly increase if
we do not control CO 2 emissions.

Question 11.4.1 10% of the surface

Estimate what the albedo coeffi cient needs to be to compensate for the
4 W/m 2 of radiative forces, if 10% of the total land surface can be modifi ed.