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Human Impact on the Environment

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There are approximately 6.9 billion people in the world and

over 80 million babies are born per year – that is almost

three babies per second!

Population growth

The human population is said to be growing exponentially.

This means that the larger the population, the faster it grows.


The biggest increase in population is in economically

developing nations, rather than economically developed

nations. Why do you think this is the case?

Exponential growth

An increase in average life expectancy is largely responsible

for the rapid increase in population. Why do people live longer

than they did hundreds of years ago?

better healthcare (hospitals, medicines, vaccines)

more and better food

cleaner water

better sanitation.


The changing population


More people use more resources


What are pollutants?



Air pollution

Human activity produces two main types of air pollutant:

particulates – These are tiny particles suspended in air

(e.g. smoke), which are usually produced by the

combustion of fossil fuels.

noxious gases – These include carbon dioxide (CO2),

sulfur dioxide (SO2) and nitrogen oxides (NOx)

Air pollution has become an

increasing problem due to

humans’ reliance on burning fossil fuels for energy. It has

serious implications for the

environment and human health.


Global warming and greenhouse gases

One of the greatest threats caused by air pollution is

global warming. Global warming is caused by a build-up

of greenhouses gases, which leads to an increase in the

Earth’s temperature.

A greenhouse gas is an atmospheric

gas that absorbs infrared light.

Key greenhouses gases include:

carbon dioxide (CO2)

methane (CH4)

water vapour (H2O)

nitrous oxide (N2O).


The greenhouse effect


The effects of global warming


Carbon dioxide levels

Burning fossil fuels, deforestation and

flooding land for the construction of

hydroelectric dams have all contributed

to rising levels of carbon dioxide.

Carbon dioxide is one of the most important greenhouse

gases because atmospheric concentrations have risen

dramatically over the past century. Why do you think this is?

How many examples of burning

fossil fuels can you think of?

Are there any alternatives?


Acid rain


What damages the ozone layer?

CFCs are used in fridges and freezers,

aerosol sprays and packaging materials such

as polystyrene. The production and use of

CFCs is now banned in many countries.

The ozone layer is a protective part of the atmosphere that

absorbs some of the Sun’s damaging ultraviolet (UV) rays. Damage to the ozone layer means that more UV rays reach

Earth, increasing the risk of skin cancer.

The ozone layer is damaged by chemicals

called chlorofluorocarbons (CFCs),

which contain the elements carbon,

hydrogen, chlorine and fluorine.



Water pollution

Fertilizers and sewage can easily be washed into rivers,

streams and lakes. The nutrients, phosphates and nitrates in

these substances cause eutrophication.

Sewage, industrial waste, oil, pesticides and fertilizers all

pollute water.

Eutrophication is the

accumulation of nutrients

in water, which causes

excessive algal growth.

This leads to a reduction

in oxygen levels and the

death of aquatic life.


Eutrophication


Eutrophication


Land pollution

Land and soil can be polluted by two main types of

substance:

solid waste – such as plastic,

metal, paper and other man-

made substances

chemicals – such as

herbicides and pesticides,

crude oil and waste from

industrial processes.

Land pollution often leads to

water pollution, as chemicals are

washed into rivers and lakes.


How much waste?

Every year, billions of tonnes of paper, plastics, synthetic

materials, metal and wood are thrown away.

On average, each UK

household produces

over 1 tonne of rubbish

each year.

How could you estimate

the amount of rubbish

you throw away

each year?



Who uses the most energy?

Over 10,000

5,001 to 10,000

2,501 to 5,000

1,001 to 2,500

501 to 1,000

0 to 500

kg of oil

equivalent

This map shows world energy consumption per capita.

Do countries that are more or less economically developed

use the most energy?


Who produces the most CO2 emissions?


Carbon footprints

This is the amount of greenhouse gases that person or

region gives off over a particular time (often over a year).

The volume of carbon that you are responsible for producing

is known as your carbon footprint.

If you take the bus to

school, check Facebook,

watch TV or switch on a

light, these will all leave a

carbon footprint.


How big is your carbon footprint?



Glossary


Anagrams


Multiple-choice quiz

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Human Impact on the Environment - todhigh.comtodhigh.com/.../03/Human_Impact_on_the_Environment.pdf · Human activity produces two main types of air pollutant: particulates –These