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)