Sahara desert climate alters every 20,000 years

The video explores the Sahara Desert's historical climate changes, suggesting it once thrived with nature. Researchers analyzed marine sediments from West Africa, revealing a 20,000-year cycle of dry and wet periods. These changes are linked to Earth's axial shifts, affecting sunlight exposure and monsoon intensity, leading to alternating arid and green phases in the Sahara.

What evidence do researchers use to suggest the Sahara Desert was once lush?

• Analysis of marine sediments

• Satellite imagery

• Ancient maps

• Fossil records

How often does the Sahara's climate switch between dry and wet periods?

• Every 100,000 years

• Every 50,000 years

• Every 20,000 years

• Every 10,000 years

What is believed to cause the Sahara's climatic changes?

• Volcanic eruptions

• Ocean currents

• Human activity

• Changes in Earth's axis

What happens to the Sahara when Earth tilts to receive maximum sunlight?

• It becomes more arid

• It experiences more monsoon rains

• It remains unchanged

• It becomes colder

What is the result when the Earth's tilt reduces the amount of sunlight the Sahara receives?

• The Sahara experiences more snowfall

• The Sahara becomes more arid

• The Sahara becomes greener

• The Sahara's climate remains stable