For thousands of years people lived in harmony with environment and it seemed to them that natural riches were unlimited. But with the development of civilization man`s interference in nature began to increase. And nowadays there are many ecological problems. They are very serious for humanity.
The Earth is a home to millions of different kinds of living things, which are linked in many ways. Together, they make up the complex world of nature. Some are rivals or enemies while others depend on each other for survival. Wild plants and animals live in a particular set of surroundings, called their habitat. Nowadays people are in a hurry to change habitats to suit their own needs - to create farmlands or build cities, for example. The way people live threatens the delicate balance between living things and their habitats. People create pollution, which travels through the air and water from one habitat to another. They also destroy wildlife habitats by digging the ground up for mining, or by building roads through them. So there are different types of pollution: water pollution, air pollution, ground pollution and nuclear pollution.
One of the most important kinds of pollution is air pollution. Dirty air can cause various diseases. Many plants and factories, power stations, gasoline, burnt inside car engines poison the air. Every year world industry pollutes the atmosphere with about 1000 million tons of dust and produce less poison. Many cities suffer from smog. Factories and plants may clean their smoke. And new cars work better produce less poison.
Air pollution can cause water pollution. Acid rains are very dangerous. Acid rains fall when poisonous gases from power stations and vehicle exhausts mix with oxygen and moisture in the air. These gases become part of the water cycle and may be carried a long way by the wind before they fall as acid rain, or snow. Acid rain poisons or kills wildlife in lakes, rivers, and forests, and damages the surrounding plant life. Fish can`t survive in such water, trees and other plants die. The problem could be controlled by reducing vehicle emissions and limiting the gases released from power stations. Moreover, plants and factories produce liquid wastes that run into rivers and lakes, seas and oceans. One of the examples may be Baikal. It contains one fifth of the world fresh water. To preserve this great lake modern filtering techniques must be used. Nowadays the situation lives much to be desired. Another ecological problem is the problem of ozone holes. Destruction of the ozone layer is the result of men`s careless interaction with nature.
There is a very important problem. Ancient trees are being cut down. This process influences the ozone layer. Chemicals, we use in our life, also are eating away the ozone layer, our shield against the sun. And it can cause global warming. As the planet warms up, the water in the oceans will take up more space and water locked up in glaciers and the polar ice caps will start to melt. This could cause sea levels to rise and many habitats will disappear under water.
So you see that ecological problems are very important nowadays. For a long time, people have used their Earth home without thinking of what was happening with it. Now we see that we must treat it better or we are going to be in danger.