Summarising follows note-making. The purpose of note-making is usually | Class 11 English Notes

Practice Passage: Green Sahara

The passage titled 'Green Sahara' describes the Sahara Desert's climatic history and geological features. The Sahara is the world's largest desert, characterized by extremely low humidity and rare rainfall, sometimes once a century. Despite this, vast underground aquifers of fossil water exist beneath it, some possibly a million years old. Around 6,000 years ago, the Sahara was green and supported water-dependent animals like hippopotamuses, as evidenced by prehistoric rock art. This greener phase was due to the migration of the paleo-monsoon, influenced by Earth's axial tilt, wobble, and orbital changes, which periodically shift monsoon patterns north and south. When the Northern Hemisphere tilts sharply towards the sun and Earth is closest to it during summer, the African monsoon shifts north, bringing rains to the Sahara as it did 10,000 years ago. About 5,000 years ago, the monsoon shifted southward, causing the Sahara to dry and prompting prehistoric inhabitants to migrate, possibly towards the Nile Valley where Egyptian civilization flourished. The drying caused a feedback loop reducing vegetation and soil water retention, leading to the Sahara's current arid state by 4,000 years ago. The passage ends by noting uncertainty about how human-driven climate change may affect the Sahara's future and mentions that fossil water is still pumped for drinking in Egypt. This passage provides rich material for practicing summarising skills.

📊 Diagram: No diagrams provided; a map showing Sahara with monsoon migration zones and timeline of climatic changes would aid understanding.

🧪 Activity: Read the passage carefully, underline important words, and prepare notes for summarising.

🔗 Connection: Leads to the next section where students write notes and summaries from this passage.