Sahara Desert Expansion and the Great Green Wall

The Sahara Desert, the world's largest non-polar desert, has been expanding by about 11,000 square kilometers annually for over 70 years, a trend expected to continue into the 2050s. This expansion is linked to the drying of the Sahel rainfall belt, a phenomenon driven by rising temperatures and altered precipitation patterns since the 1950s, exacerbated by severe droughts in the 1980s. The desert's growth negatively impacts African agriculture. However, the Great Green Wall initiative aims to reverse this trend by regreening the Sahel using traditional water-smart methods, potentially slowing the Sahara's expansion and enhancing food and water security for millions.

How much area has the Sahara Desert been expanding annually?

• 5,000 square km

• 11,000 square km

• 20,000 square km

• 15,000 square km

What is the primary factor contributing to the Sahara's expansion?

• Rising sea levels

• Deforestation

• Increased agricultural activities

• Drying of the Sahel rainfall belt

When did the changes in precipitation patterns that affect the Sahara begin?

• 1950s

• 1970s

• 1980s

• 2000s

What is the goal of the Great Green Wall initiative?

• To build a wall to stop desert expansion

• To regreen the Sahel with water-smart methods

• To relocate affected populations

• To increase rainfall in the Sahara

Which method is used in the Great Green Wall initiative to direct rainfall?

• Terracing

• Crescent-shaped ditches

• Rainwater harvesting tanks

• Irrigation canals