Post on 03-Jan-2016
WORLD GEOGRAPHY
December 9, 2014
Today
Unit 10 (Human Environment)
Unit 10: Human Environment
Key aspects:
- How the Earth’s environment has changed over time
- How humans have impacted Earth’s environment
- Major factors contributing to environmental change today
- How humans are responding to environmental change
How Earth’s Environment has changed
Plate Tectonics
Division of the Earth’s crust into plates, which are in motion
Recent earthquakes and volcanic eruptions
Mount Toba, Indonesia
Volcanic Eruptions
1 billion years ago- Mass depletions: Loss of diversity from failure of new species to appear
- Mass extinctions: 3 over last half-billion years
Fragmentation of Pangaea- 160–180 million years ago
- Pacific Ring of Fire as last remnant of these eruptions
Pangea (“super continent”)
Pacific Ring of Fire
Glaciations
Pleistocene (less than 2 million years ago) marked by:
- Glaciations: Permanent ice stable and growing
- Interglaciation: Warming spell in which ice recedes
Glaciations
Emergence of humans (homo sapiens) during interglacial between 120,000 and 100,000 years ago
Most recent glaciation: Wisconsin Glaciation
Wisconsin Glaciation
Recent Glacial History
Holocene: Interglaciation that began 18,000 years ago.
“Little Ice Age”
- A minor glaciation that began in the early 1300s
- Growing glaciers
- Effects on agricultural production
- Abandonment of Greenland and Iceland by Europeans
- Abandonment of Chung Ho’s voyages
- Black Death (bubonic plague)
Warming Phase
Eruption of Tambora (1815) on Sumatra (Indonesia)
- Local pollution of land and water by ash and acid
- Ash and dust in atmosphere
- Cooling of temperatures worldwide: “Year without summer” (1816)
- Food shortages
Warming since about 1850
Human Impact on the Environment
Altering ecosystems
- All humans (over time) altering environments
- Impact greater with growth in population
Environmental stress
- Cutting forests, emitting pollutants, spilling oil
- Burying toxic waste, dumping garbage in oceans
Water
A renewable resource (replenished as used)
Water shortages: Depletion of water in aquifers (porous, water-holding rocks) at a rapid rate
Causes of shortages
- Growing population
- Large population concentrations near small supplies
- Agricultural and industrial use
Hydrological Cycle
Precipitation Distribution
Desalination plants
The Dying Aral Sea
Effects of climatic cycles and human interference
The Dying Aral Sea
http://www.youtube.com/watch?v=cbSkRS8Ih7o
Water & Israeli-Palestinian Relations
Israel’s major water resources
- Jordan River
- Aquifer under West Bank
30 percent of flow to Sea of Galilee from Golan Heights
AtmosphereA thin layer of air lying directly above the lands and oceans
AtmosphereA thin layer of air lying directly above the lands and oceans
Natural impacts (volcanic eruptions)
Human impacts
- Global warming
- Acid rain
The Land
Deforestation:
- Effect on oxygen cycle
- Biodiversity and habitats
- Pollution
The Land - Deforestation
The Land - Deforestation
The Land - Deforestation
The Land - Deforestation
The Land
Soil erosion:
- Soil not having enough time to rebound
- Farmers not efficiently/properly using soil (increased demand)
- Livestock destroying vegetation
The Land – Soil Erosion
The Land – Soil Erosion
Approx. 9600 km2 of cropland lost to soil erosion each year
Next Class
- Continue Unit 10 (Human Environment)