Overpopulation and the environment.
Natural resources such as land, water, energy, and ecosystems take a direct hit when populations grow. Remember, the concept of overpopulation is not so much about the number of people but in relation to what the natural resource can support.
Large areas of land will be needed to meet the housing, agricultural and other infrastructural needs of the growing population. This means peripheral forests lands may be destroyed to make space for such needs, and also to supply wood for the people. Additionally, the land is degraded as a result of continuous construction and land pollution.
Water pollution, water-shortage and water stress is often a characteristic of overpopulated regions. This is usually caused by the combination of poor sanitation, waste disposal, excessive dependence on freshwater systems.
People need energy to fuel their cars, industries, warm and heat their homes and so on. This energy comes from many sources, fossil fuels, hydro-electricity, wood and many other forms. Overpopulation means more energy is needed and all these sources directly affect the environment negatively.
Ecosystem structure, function, integrity, and composition, supported by land and water resources directly take a hit when populations grow. Habitat and food chains are destroyed as humans encroach on the living spaces of biodiversity. Animals are forced away to find new habitats, many more die and some species have become extinct as a result.