Tài liệu The Influence of Human Activity on the Environment ppt

Burning fossil fuels in cars and power stations produces carbon dioxide, sulphur dioxide and other greenhouse gases • carbon dioxide traps heat in the atmosphere and causes the tempera

The Influence of Human Activity on the

Environment

Improvements in agriculture health and medicine have produced a dramatic rise in the human population

This increase in population size leads to an increase in pollution and higher demand for the world’s resources

Humans are using up the earth’s resources, including fossil fuels.

Burning fossil fuels in cars and power stations produces carbon dioxide, sulphur dioxide and other greenhouse

gases

• carbon dioxide traps heat in

the atmosphere and causes

the temperature of the

earth to rise.

• This leads to disruption of

the weather patterns eg

drought, floods

• Some weeds may thrive on

the extra carbon dioxide

while other plants are killed

Sulphur dioxide will dissolve in rain producing Acid Rain

• Acid rain damages trees and pollutes rivers and lakes

Acid rain causes erosion of buildings

and statues particularly if they are made of limestone

• In may countries people

are chopping down

forests to provide

timber or space for

agriculture for the

growing population

This causes several problems

1 Burning the timber increases the level of

carbon dioxide in the air

2 Less trees means less carbon dioxide

absorbed for photosynthesis

3 Soil is eroded as it is exposed to the wind

and rain

4 Less water is transpired into the atmosphere

5 Many animal and plant habitats are

destroyed causing extinction of species

Intensive Farming

• Farming has become more intensive to provide

a higher % yield from land

• Many people regard intensive farming of

animals to be cruel

• In order to produce more food from the land farmers have to use more fertilisers and

pesticides

Problems with Fertilisers

• Fertilisers enable farmers to grow more food

as they are replacing the nutrients removed from the soil by plants

• However, if too much fertiliser is added and

it then rains, the fertiliser finds its way into rivers and lakes

• This causes the water plants to grow and as there is competition for light, some will die

• Bacteria decay the dead plants and in so doing

use up oxygen from the water

• This means the fish

suffocate and die

• This process is called Eutrophication

• Raw sewage pumped into rivers has the same

effect

• Pesticides kill insects that will damage crops

• They also kill harmless insects or can get washed into rivers and pollute the water

• They may even end up in the food chain

In the 1960s, DDT in the food chain threatened bird populations.

Many birds of prey came close to extinction

What can we Do?

Organic Farming?

• This produces less food

and is more expensive

but it does not produce

the pollution problems

of intensive farming

Use farmyard manure as a fertiliser and set

aside land for growth of wild plants

Biological Control of Pests

• This means using natural

predators to eat pests

instead of pesticides

• It does not have

harmful effects

Develop alternative energy sources

• Conserve our rapidly

diminishing fossil fuel

reserves by using solar

power or wind power

Benefits of conserving endangered species

• WHAT ELSE?????????

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