Oil: for and against

The greenhouse effect

We contribute to the greenhouse effect in many ways. People burn fossil fuels, such as coal, gas and oil and wood. This produces huge amounts of carbon dioxide which traps heat, much like a blanket, in the upper atmosphere. Additionally, large increases in animal numbers in order to feed the world's population is producing excess methane gas which is also trapping heat. Cutting down tropical forests also adds to the problem. Trees absorb carbon dioxide which people and animals produce. Trees also 'breathe out' oxygen which all living things need. These processes are vital for a balanced existence. However, people are cutting down vast areas of tropical forests, and so upset this balance.

On top of all this, the increase in temperature of the Earth's atmosphere is causing the climate in some areas to change. This is especially true in areas which normally receive little but vital rainfall. When this rain does not fall, it causes drought, crop failure and famine. Another problem is the melting of the ice caps which creates a rise in sea levels. This rise may cause some island nations in the South Pacific Ocean to disappear. There is also increased rainfall and flooding in some areas, such as in Bangladesh and Mozambique, leading to destruction and death. One solution is to reduce the burning of fossil fuels and use other sources such as solar, wind and wave energy. Planting more trees would also help increase the oxygen supply.

Negative effects of acid rain

Acid fog can directly damage human health. In times of such fog, people may breathe in tiny droplets of nitric or sulphuric acid. Such acids are believed to result in illnesses such as asthma. Acid rain releases minerals that damage plant roots. These two processes reduce crop yields and farm incomes.

Acid rain results in heavy leaching, which deprives tree roots of the nutrients they need. The trees then become 'malnourished' and are more likely to be killed by diseases or parasites.

The acidification of groundwater in Sweden has been linked to foul-tasting water, children's diarrhea and even to people's hair turning green after washing.

Many angling lakes have been rendered lifeless by acid rain, which destroys the food chain that fish need to survive. Thousands of lakes in Norway and Sweden have been thus affected.

Minerals and nutrients are leached or washed out of the topsoil, reducing the soil's fertility.

Chemicals in acid rain also weaken the ability of trees to tolerate cold. This results in the death of many conifers in Northern Europe. It is estimated that more than half of Germany's evergreen trees have now been damaged by acid rain.

The surfaces of old buildings flake away as they undergo severe chemical weathering by acid rain. It is estimated that famous 'tourist trap' buildings such as the Coliseum in Rome have suffered more acid rain damage in the past BO years than they did in the previous 2,000.

Oil: for and against

Oil is the world's most popular source of energy and is the world's most important trading commodity. Petrol has many advantages as a fuel. There is a plentiful supply of oil with enough to last for another fifty to a hundred years. Having said that, oil is a finite source of energy. This means that there is only a certain amount of it in the ground to extract. Many people predict that, unless energy is conserved or much more oil is discovered, the present world's oil supply could be used up by the end of the 21^s' century. It is a relatively clean fuel to burn. It gives off few fumes or smoke and so to a certain extent may be considered environment-friendly.

There have, however, been numerous infamous occasions of catastrophic oil spills from damaged ships at sea which create great environmental pollution. As a result coastal wildlife, such as seagulls, are killed and beaches are damaged. It is an efficient fuel which gives off great heat when burnt. It is easy to handle and transport. Huge oil tankers can transport millions of litres at a time. It is easily stored in domestic tanks and is piped directly to domestic burners in people's homes. Numerous by-products such as synthetic fabrics, paint, dyes and other chemicals are manufactured from oil.

Population growth

In the past, the world's population fluctuated. War, famine, plagues like the Black Death, and lack of medicine prevented rapid population growth. It is estimated that the population of the world in 9000 ВС was about ten million. At this time people wandered from place to place in search of wild cereals. Then, people in Mesopotamia (present-day Iraq) discovered that by using seeds from wild cereals and scattering them in a fertile area they would grow, flourish and produce crops for food. This eliminated their need to wander and so they became the first farmers.

The discovery and spread of agriculture led to a speeding up of population growth. Initially population growth was slow. When Christ was born there were about 260 million people on Earth. Growth rates continued to fluctuate because of war, famine and other natural disasters. It took the next 1,700 years for the world's population to double to 520 million. However, from 1750 onwards the world's population grew faster than before. Around then, new farming methods in Europe such as the development of better breeds of animals and the use of new farm machines, led to a large increase in food production. The invention of the steam engine provided employment for thousands of workers in coalfield areas in Europe. At this time hygiene and medical knowledge also improved. Europeans were healthier, lived longer and had more children than before. They conquered new lands in the colonies, which increased land for agriculture. So the world's population grew faster than ever. Throughout the twentieth century the world's population grew so fast that it was called a population explosion.

Date: 2015-12-18; view: 866