HUMAN-ENVIRONMENT INTERACTION: PATTERNS &

PROCESSES of CHANGE

The Human Impact

• Alteration of ecosystems– Environmental destruction began early– Increase in human modification over the last

500 years

Ecosystem

• Self-sustaining units consisting of all organisms (biota) and physical features existing together in a particular area

• Everything interconnected– Even slight changes can bring dire

consequences

• Each organism has a niche and plays a specific role in the Theatre of Energy

Ecosystems

• Environment: the totality of things that in any way can affect an organism– A mosaic of terrestrial features, weather &

climate, landforms, and biota

A Mosaic

Ecosystems

• Ecology: study of how organisms interact with each other and their environment

• Where does the interaction happen?– The Biosphere

The Human Impact

• Environmental stress– Obvious actions

• Cutting of trees • Atmospheric & oceanic pollutants• Other examples???

– Less obvious actions• Toxic waste burial• Ocean garbage dumps• Agricultural pesticides• Other examples???

Water

• A renewable resource– Not distributed evenly across the globe– Distribution is sustained through the

hydrologic cycle– Where precipitation goes

• Much is lost through runoff and evaporation• Some seeps downward into porous water-holding

rocks called aquifers• Aquifers hold about 50 times as much water as

falls on the United States each year

Ocean and Freshwater Distribution

Water Withdrawal by Sector

Global Water Scarcity

• Diversion of water from streams feeding the Aral Sea for irrigation

• Chemical pesticide use caused pollution of groundwater• Aral Sea is drying up:

Kazakhstan and Uzbekistan

The Atmosphere

• What it does– Oxygen and temperate climates– “Natural” UV-protectant– Helps with hydrologic cycle– Self-cleaning

• Human influences?

The Atmosphere

• Global warming– Estimates of global warming have been

lessened• Earth might warm 3.5ºF to 5.5ºF over the next 50

years

– Little consensus on the extent of greenhouse warming

– Key greenhouse gases have been increasing about 2 percent per decade

– Past evidence?

The Atmosphere• Acid rain

– Does great harm over time to some ecosystems– Mostly in industrial regions with good wind flow

Acid Rain Destroys Quickly

The Land

• Desertification– Natural, but anthropogenic factors enhancing

process• E.g., the Sahara

Deforestation• Increasing human population taxing forests

– Taiga forests play key role (NOT just the Amazon)

– Tropical Rainforests still important...

Soil Erosion

The “quiet crisis”– Anthropogenic

factors can lead to increased soil erosion

– Possibly > 25 billion TONS per year

– Better education needed

– Renewable and recoverable

CONFRONTING ANTHROPOGENIC

ENVIRONMENTAL CHANGE

• Greeks and Romans to Spanish invaders

• E.g., Florida Everglades

• Anthropogenic factors are increasing!

• Geography’s role– “Man's Role in Changing the Face of the

Earth”, 1955– “The Earth as Transformed by Human Action”– Myriad temporal & spatial scale connections

Natural & Anthropogenic Changes

UnderstandingEnvironmental Change

• Global changes

• Population

UnderstandingEnvironmental Change

• Patterns of consumption– Exceptional resource usage– Urban areas have global access– Periphery countries greatly affect environment– Water demand– Consumption tied to technology

UnderstandingEnvironmental Change

• Technology– Resource extraction– Fossil fuels pollution– Hazardous and toxic byproducts– Open pit mines

Understanding Environmental Change

• Transportation– Internal combustion engine– Near-open access to remote areas– Oil spills & species distribution– Facilitates global transport of goods and foods

UnderstandingEnvironmental Change

• Energy– Tertiary, quaternary, and quinary economic

activities– Many LDCs increasing fossil-fuel development– 1999’s energy consumption vs. 1971’s

Resource

• Video: David Fronander, biogeographer– Discusses Humans in Nature

Discussion Questions

• While global temperatures are increasing, this is nothing new, according to past climate records. So why should we be worried if it’s all part of a cycle?

• Are the Earth’s processes interconnected?