The Growing Desert

How desertification is affecting the continent of Africa

DesertificationO Drought causes grasses to thin out in

the Sahel. The bare dirt turns to dust. This process is called desertification.

O Humans add to this natural process and we will discuss how in the following slides.

OverplantingO Farmers overwork the land because

they cannot get enough food from one crop, so they plant multiple times in one season.

O This practice strips the land of all nutrients and eventually nothing will grow.

OvergrazingO Animals eat the scattered clumps of

grass. Since there is so little of it they eat it down to the ground.

O The animals hooves then pulverize the root systems and the grass dies.

Water WellsO Extra water allows the communities

to grow larger.O Desert biomes cannot support large

animal, plant and human populations.

O Think: What effect does our large population have on the amount of available water?

DeforestationO Tree roots keep the soil in place. O However, wood is the main source of

fuel in this region and tree are cut down.

Quick FactsO In 1880, only 9.4% of the land on

Earth was desert.O In 1950, that percentage increased

to 23.3%.O In Nigeria, the Sahara spread 60

miles in less than 20 years.

Sandstorm in Phoenix, AZ, 2011