David Attenborough Explains Desertification

Summary

The Sahara, the largest desert on Earth, is an extreme environment, with temperatures soaring to 58°C (137°F) by day and freezing cold at night. However, it wasn't always this hostile. Thousands of years ago, the region supported abundant wildlife and even herds of cattle, as evidenced by rock paintings of antelope, giraffes, and wild goats. As the climate changed and the rains shifted away from Africa, the Sahara dried up. The last remnants of this ancient world, like a 3,000-year-old cypress tree, continue to survive by tapping into underground water, highlighting the desert's relatively recent transformation.

Takeaways

• 🌍 The Sahara Desert is the largest desert on Earth, stretching across 3.5 million square miles of Africa.
• ❄️ The Sahara experiences extreme temperatures, with nighttime cold so severe it can freeze, and daytime heat reaching 58°C (137°F).
• 🌡️ The Sahara's intense heat causes it to lose most of its moisture, making it one of the harshest environments on Earth.
• 🦌 Evidence suggests the Sahara wasn't always a desert, as ancient rock paintings depict wild animals like antelope and giraffes, indicating a more hospitable environment.
• 🦓 Ancient humans or their ancestors, likely nomadic herders, created rock art around 5000 years ago, showing animals like wild goats and antelopes.
• 🌱 The Sahara once had enough vegetation to support not just wild animals but herds of cattle, suggesting it was once a much greener region.
• 🖼️ Ancient portraits left by the artists, possibly ancestors of current nomads, offer a glimpse into their lives and the environment at the time.
• 🌲 The Cypress trees in the Sahara are some of the oldest living plants, with one estimated to be 2,000-3,000 years old, surviving through deep roots tapping underground water.
• 💧 The drying out of the Sahara correlates with global climate changes at the end of the last ice age, as the belt of rains that once fell over Africa shifted northwards into Europe.
• 🌍 The Sahara's transformation into a desert is part of a larger global pattern, where many of the world's great deserts formed during this period of climate shift.

Q & A

What makes the Sahara one of the harshest environments on Earth?

The Sahara is extremely harsh due to its extreme temperatures, which can reach 58°C (137°F) during the day, and its lack of moisture, making it nearly impossible for most life to survive.

How did the Sahara change over time?

The Sahara was not always a desert. Thousands of years ago, it had abundant vegetation and wildlife. However, climate changes at the end of the last Ice Age led to the region drying out, transforming it into the desert we know today.

What evidence do we have of the Sahara's greener past?

Evidence includes rock paintings depicting wild animals like antelope, giraffes, and wild goats, suggesting that there was once sufficient vegetation to support these creatures and herds of cattle.

What animals were depicted in the rock paintings of the Sahara?

The rock paintings depict various animals, including antelope (likely sable), giraffes, wild goats, and possibly other species that once roamed the region.

Why can't the antelope species shown in the paintings survive in the Sahara today?

The antelope species, such as the sable, cannot survive in the Sahara today due to the lack of vegetation and water, making it impossible to sustain them.

How old are the rock paintings in the Sahara?

The rock paintings are believed to have been made around 5,000 years ago, offering a glimpse into the region's past before it became the desert it is now.

Who might have created the rock paintings in the Sahara?

The rock paintings may have been created by the ancestors of modern nomads, who still live near the Sahara and tend to herds of cattle similar to those depicted in the paintings.

What role did the Cypress tree play in the changing environment of the Sahara?

The ancient Cypress tree, which may be between 2,000 and 3,000 years old, symbolizes the environmental shift. It survives by tapping into underground water, though no new seedlings are growing due to the dry conditions.

Why does the Cypress tree still survive in the Sahara despite the harsh conditions?

The Cypress tree survives by sending its roots deep into the ground to access underground water, as the surface environment has become too dry for new growth.

What global climate event contributed to the Sahara's transformation into a desert?

The retreat of glaciers at the end of the last Ice Age caused a shift in the global climate, with rains that once fell over the Sahara moving northward into Europe, leading to the desertification of the region.