Geography: Ecosystems, Deforestation, and Desertification

• Geography analyses the Earth’s physical environment and human populations.

Ecosystem

• An ecosystem is where animals and plants live interlinked in balance with their environment.
• Unless external factors influence it, it does not change.

Destruction of rainforests

• Mining
• Population growth
• Agriculture (land cleared for consumer goods)
• Logging (trees cut down)
• Plantations
• Road building

Desertification

• Desertification is the process of land degradation that turns land into the desert.
• It occurs mainly in arid and semi-arid lands where rainfall is unreliable or because of human activity.
• Regions at serious risk of desertification:
  • The Sahel Region (Africa)
  • Southern Africa
  • China
  • India
  • Australia
  • Argentina
  • Drylands in Brazil
  • Mexico
  • North America
• Main Causes Include:
  • Climate change
  • A decrease in rainfall
  • Effects of global warming
  • High birth rates and immigration leading to overcultivation, soil erosion, and deforestation
  • People seeking fuelwood
  • Overgrazing in the Sahel
• When drought hit, too many animals stripped away grass
• Overgrazing near water sources worsened the problem, turning land into the desert.
• These events increase the vulnerability of local people to drought, food shortages, and the longer-term risk to their traditional way of life.

Tropical Cyclones

• Primarily form in tropical and subtropical regions with warm ocean waters.
• Other names for Tropical Cyclones include:
  • Hurricanes in North and Central America
  • Typhoons in the Northwest Pacific Ocean near China and Japan.
  • Cyclones in the Indian Ocean and Australia
  • Willy-Willy in Australia
• Cyclones require warm sea surface temperatures of at least 80°F(27°C).
• Regions include:
  • The Caribbean
  • Parts of Asia (notably the Philippines and Japan)
  • Australia
  • Coastlines of North America and South America
• Tropical cyclone activity is influenced by seasons, typically escalating during warmer months.
  • The Atlantic hurricane season runs from June to November.
• Characteristics:
  • A calm center called the eye
  • The eyewall surrounds the eye with strong winds and heavy rainfall
• Tropical Cyclones are categorized using the Saffir-Simpson Hurricane Wind Scale
  • Ranges from Category 1 (sustained winds of 74-95mph) to Category 5 (sustained winds over 157mph).
  • The higher the category, the greater the potential damage.
• Wind speed is fierce, often exceeding 74mph, and heavy rainfall accompanies it, leading to flooding and other hazards.
• Cyclones typically travel westward and may veer towards the poles influenced by prevailing wind patterns.
  • Including the Coriolis effect, helps them to gain strength through rotation.
• Storm surges elevate sea levels, causing flooding during landfall.
• High winds can destroy buildings, uproot trees, and cause widespread destruction.
• Heavy Rainfall leads to rivers overflowing, often causing flash floods and mudslides.