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
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
Atmosphere A thin layer of air lying directly above the lands and oceans
Atmosphere A 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 Soil erosion: - Soil not having enough time to rebound - Farmers not efficiently/properly using soil (increased demand) - Livestock destroying vegetation
The Land – Soil Erosion
Approx km 2 of cropland lost to soil erosion each year
Next Class - Continue Unit 10 (Human Environment)