Sahara and the Albedo Effect

Albedo is a measure of sun reflection in which a score of 100 would mean complete reflection off all incoming light, and a score of 0 corresponds to complete absorption of all incoming light.

As can be seen in the following diagram, snow and clouds have high albedo, while water and wet dirt have low albedo.

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When it comes to land features, deserts have higher albedo than savanna, crops and meadows, while forests have the very highest albedo.

Deforestation is in other words contributing to a higher albedo. The less forest we have, the more sunlight is reflected back into space.

From this fact alone, we can conclude that global warming can be countered by cutting down forests and planting crops instead.

Conversely, we can combat global cooling by planting forests.

What is interesting to note from a climate history perspective is that this is precisely what has been happening naturally through the ages.

During cold periods, Sahara and the Arabian Peninsula have turned lush and green, with large forests, lakes and savanna.

During warm periods, such as the one we are presently in, these areas turn to deserts.

The increase in albedo caused by growing ice sheets during glaciation periods has always been countered by a drop in albedo farther south. Conversely, the falling albedo caused by retreating ice sheets during warm periods have been countered by a rise in albedo farther south due to desertification.

It is this balancing of albedo effects that keep glaciation and deglaciation periods from spiraling out of control. Places like the Sahara and the Arabian Peninsula react naturally to counter the effects of ice sheets growing and shrinking.

Since we know that our planet is constantly re-balancing its temperature distribution through this mechanism, we have ways to detect and predict climate trends here on Earth.

If the large desert areas on our planet start greening, we know that the trend is towards a colder climate closer to the poles. An increase in the size and number of ice patches and glaciers farther north, is similarly indicative of better climate conditions in places like the Sahara.