5/8/2017

1

Human Impact on Resources

Chapter 26

Main Idea • More demands are

placed on natural

resources as the human

population increases.

Resources and Organisms

• Like all organisms,

humans need natural

resources to grow,

reproduce, and maintain

life.

Resources and Organisms • What resources do humans

require?

• Air

• Food

• Water

• Shelter

5/8/2017

2

Resources and Organisms

• Humans have an

unequaled capacity to

modify their

environments.

Resources and Organisms • Humans can live in every

terrestrial environment on Earth.

• We also have the greatest impact on Earth’s natural resources.

Human Impact on Land Resources

• Mining

• Reclamation

• Deforestation

• Urban Development

• Agriculture

Mining • Mining can have a significant impact

on Earth’s surface.

• Modern societies require large amounts of land resources: iron,

aluminum, copper, sand, gravel,

limestone, ect…

• Groundwater can become polluted,

natural habitats are destroyed, and air

quality suffers.

5/8/2017

3

Limestone Mining Reclamation

• US has legislation in place

requiring mining companies to

restore the land to its original

condition after mining operations

are complete.

• It is extremely difficult to restore

land to its original contours and

vegetation

Deforestation

5/8/2017

4

Deforestation Urban Development

Landfills Agriculture

5/8/2017

5

Pesticides/Insecticides Bioremediation

Human Impact on Air Resources

What types of human

activities may have an

effect on Earth’s

atmosphere?

Global Warming

• An increase in

greenhouse gas (CO2)

• Burning of fossil fuels

5/8/2017

6

Photochemical Smog • Yellow/brown haze near

densely populated areas.

• Caused by car exhaust and sunlight.

• Forms ground level ozone.

Ozone Depletion • Ozone absorbs and filters out

harmful UV radiation from the

sun.

• Chlorofluorocarbons (CFCs) destroy ozone in the upper atmosphere.

5/8/2017

7

Acid Precipitation • Precipitation with a pH of less than

5.0

• pH is a measure of acidity from a

scale of 0-14

• It forms when sulfur dioxide and

nitrogen oxides combine with

atmospheric moisture to produce

sulfuric acid (Battery Acid).

Water Resources Water conservation

• 20-30% of the water taken from public water supplies is lost through leaky toilets, bathtubs, and faucets.

5/8/2017

8

Water Resources • What happens when

there is not enough water

to go around?

• There are 2 options

Water Resources • Decrease demand

• Develop new supplies.

Water Resources • How could we decrease the

demand for water?

• Efficient irrigation systems for crops

• Recycling wastewater.

• Other conservation practices.

Think: • How many gallons of water

do you think you use on every day?

• 123 gal • What would you have to do

to cut your water use by half?

5/8/2017

9

Pollution

• There are two main types

of water pollution:

oPoint Source

oNonpoint Source

Water Pollution • Point sources

originate from a single point of origin, such as a sewage-treatment plant or an industrial site

Water Pollution

• Nonpoint

sources are

generated

from a

widespread

area.

Groundwater Pollution • Leaking chemical-storage

barrels, underground gasoline storage tanks, landfills, road salts, nitrates from fertilizers, sewage from septic systems, ect. Can seep into the ground and pollute groundwater supplies.

5/8/2017

10

Pollution in Oceans

• 50% of the US population

lives near coastlines.

• Pollutants from cities end

up in nearshore regions.

Reducing Water Pollution Two Major laws have been passed in the US to combat

water pollution:

• The Safe Drinking Water Act (1974)

• The Clean Water Act (1977)

Population Growth • Exponential

growth: Populations

begin to grow faster as they increase in

size.

Population Growth • The number of organisms that

any given environment can

support is its carrying capacity = K

5/8/2017

11

Population Growth • Are there limits to population

growth?

• Food availability

• Water

• Shelter

• Land/Space

Estimates of Population Size

• Modern estimates for human carrying capacity have ranged from 1 or 2

billion people living in prosperity, to 33

billion people fed on minimum rations and using all suitable land for high-

intensity food production. Many

scientists now believe that the human carrying capacity of Earth may be

approximately 12 billion.