Revision Notes. Human Effects on the Environment. Land use, pollution and sustainability.

Pollution

Waste may pollute:

• water with sewage, fertiliser or toxic chemicals;
• air - with smoke and gases such as sulfur dioxide;
• land - with toxic chemicals, such as pesticides and herbicides, which may be washed from land into water.  

Sulfur dioxide contributes to acid rain:

• It dissolves in the rain forming sulphuric acid.
• This damages the leaves and the roots of trees.
• Rivers and streams become acidic.
• Aquatic plants and animals may die.

The Greenhouse Effect

• Carbon dioxide and methane in the atmosphere absorb most of the energy radiated by the Earth.
• Some of this energy is reradiated back to the Earth and so keeps the Earth warmer than it would otherwise be.

Global Warming

Deforestation has:

• increased the release of carbon dioxide into the atmosphere (because of burning and the activities of microorganisms);
• reduced the rate at which carbon dioxide is removed from the atmosphere and ‘locked-up’ for many years as wood.

• Increases in the numbers of cattle and rice fields have increased the amount of methane released into the atmosphere.  
• These gases may be causing global warming by increasing the greenhouse effect.  

An increase in the Earth’s temperature of only a few degrees Celsius may cause:

• quite big changes in the Earth’s climate;
• a rise in sea level.

Sustainable Development

As the human population grows we will require more resources.

Sustainable development is about how we should ensure that we:

• Conserve natural resources
• Reduce the damage we make to the environment
• Maintain biodiversity

Planning is needed at local, regional and global levels to manage sustainability.

Examples:

• Local – conservations sites eg SSSIs – Sites of Special Scientific Interest
• Regional – maintenance of green-belts around large cities.
• National – policies to increase use of renewable energy.
• Global – agreement between different coutries to reduce release of polluting gases.

Sustainability can include many different targets:

• Replant forests at the same rate at which they are cut down.
• Use fast growing trees.
• Replant hedgerows.
• Use organic fertilizers.
• Use less pesticides.
• Reduce the number of fish we catch.
• Recycle our waste.
• Reduce the amount of packaging we use.
• Use energy wisely:

• Insulate houses
• Use energy efficient light bulbs
• Switch things off!

• Use public transport.
• Walk and cycle more.
• Use non-polluting fuels.
• Generate electricity using renewable sources of energy.
• Create SSSIs – Sites of Special Scientific Interest – to preserve rare and fragile ecosystems.

Monitoring the success of sustainability

Living organisms can be used as indicators of pollution:

• Lichens can be used as air pollution indicators:

• They are very senitivie to pollution.
• Less lichens are found in polluted areas.

• Invertebrate animals can be used as water pollution indicators.

• Some invertebrate species tolerate different concentrations of pollution in water.