| For many thousands of years, humans were a | | | | gas emissions, which support the greenhouse effect |
| component of natural ecological systems of the | | | | and produce smog. |
| earth. When humans began to live a sedentary life, | | | | Acid rain, which is one of the products of the |
| they developed through creation of cultural landscape | | | | automobile exhaust gases and of the coal burning, |
| new ecological systems of their own.. | | | | damages our forests and rivers. Forests are dying |
| When more than 500 000 years ago humans started | | | | out, a situation that has a far-reaching impact on |
| to use fire, wood was the most important source of | | | | plants, people, and animals The balanced state of the |
| energy. Approximately in the 18th century humans | | | | waters of the past is losing its equilibrium due to |
| began to use fossil fuels. At that time, first steam | | | | numerous foreign and toxic materials penetrating into |
| machines were developed, signalling the beginning of | | | | the water table. This decimates the fish population, |
| the technological development. Today, all around the | | | | and the situation is so serious, that some of the |
| world every existing type of energy is being | | | | kinds of commercial fish became extinct. |
| exploited, which requires large investments. This | | | | Humans have to take care in the near future and |
| causes heavy burden on the environment, and this | | | | seek new solutions that would enable us to continue |
| trend is constantly increasing. Toxic matters, | | | | living a quality life on this earth even in the future. By |
| originating in the industrial and agricultural wastes, | | | | means of regional and extra-regional programs, the |
| pollute underground waters, soil, and oceans. | | | | search for new ways, which would mitigate the |
| Industrial fuel-burning processes used in manufacture | | | | destruction of nature and preserve it as much as |
| of many natural and synthetic materials produce toxic | | | | possible, goes on. |