IMPACTS of URBANIZATION on ENVIRONMENT

                Probably most of the major environmental problems of the next century will result from the continuation and sharpening of existing problems that currently do not receive enough political attention. The problems are not necessarily noticed in many countries or then nothing is done even the situation has been detected. The most emerging issues are climate changes, freshwater scarcity, deforestation, and fresh water pollution and population growth. These problems are very complex and their interactions are hard to define. It is very important to examine problems through the social-economic-cultural system. Even the interconnections between environmental problems are now better known, we still lack exact information on how the issues are  linked, on what degree they interact and what are the most effective measures.

[A] IMPACTS ON THE ATMOSPHERE AND CLIMATE

1. The creation of heat island

                  Materials like concrete, asphalt, bricks etc absorb and reflect energy differently than vegetation and soil. Cities remain warm in the night when the countryside has already cooled.

2. Changes in Air Quality

                  Human activities release a wide range of emissions into the environment including carbon dioxide, carbon monoxide, ozone, sulfur oxides, nitrogen oxides, lead, and many other pollutants. Cities often receive more rain than the surrounding countryside since dust can provoke the condensation of water vapor into rain droplets.

[B] IMPACTS ON THE LITHOSPHERE AND LAND RESOURCES

1. Erosion and other changes in land quality

                  Rapid development can result in very high levels of erosion and sedimentation in river channels.    

 

2. Pollution

                   Pollutants are often dispersed across cities or concentrated in industrial areas or waste sites. Lead- based paint used on roads and highways and on buildings is one such example of a widely dispersed pollutant that found its way into soil. Burying tremendous amounts of waste in the ground at municipal and industrial dumps.

[C] IMPACTS ON THE HYDROSPHERE AND WATER RESOURCES

1. Flow of Water into Streams

                    Natural vegetation and undisturbed soil are replaced with concrete, asphalt, brick, and other impermeable surfaces. This means that, when it rains, water is less likely to be absorbed into the ground and, instead, flows directly into river channels. 

2. Flow of Water through Streams

                      Higher, faster peak flows change streams channels that have evolved over centuries under natural conditions. Flooding can be a major problem as cities grow and stream channels attempt to keep up with these changes. 

3. Degraded Water Quality

                        The water quality has degraded with time due to urbanization that ultimately leads to increased sedimentation there by also increasing the pollutant in run-off.

 [D] IMPACTS ON THE BIOSPHERE

1. Modification of Habitats

                     The fertilizers that spread across lawns finds its way into water channels where it promotes the growth of plants at the expense of fish. The waste dumped into streams lowers oxygen levels during its decay and cause the die-off of plants and animals.

2. Destruction of Habitats

                     There is also complete eradication of habitats as an outcome of urbanization and native species are pushed out of cities.

3. Creation of New Habitats

                      New habitats are also created for some native and non-native species. Cities also create habitats for some species considered pests, such as pigeons, sparrows, rats, mice, flies and mosquitoes. Urbanization has, for example, eliminated many bat colonies in caves, but has provided sites such as bridges for these species to nest.