Big cities are commonly thought to be the place where can provide families with better living standard including better environment and better health care or employees with more potential working opportunities. According to the United Nations (2014), there will be 2.5 billion inhabitants added to the urban areas by 2050, with the concentration of 90% increasing in Asia and Africa. As a result, the population living in these cities has increasing significantly which also negatively contributes to environmental problems. The term “urbanization” can be defined as an increase in number of inhabitants who move to live and work temporarily or permanently in urban areas. This essay will argue that increasing urbanization does occur at the cost of environment by considering the number of disadvantages: overpopulation, industrialization impacts on landscape and energy overuse.
Firstly, increasing urbanization does occur at the cost of environment because population attracted by urban areas may be rising, which leads to serious environmental degradation such as air quality clean, water scarcity and traffic congestion. According to Organization for Economic Cooperation and Development (2013), the amount of nitrous oxide which is emitted rose 3 million tonnes from 2007 to 2010. The ubiquity of vehicles directly emitting a great amount of toxic gases into the public areas can be considered as a main culprit of air pollution and global warming. US Environmental Protection Agency (2016) stated that 26 percent of U.S greenhouse gas emissions came from transportation activities by burning fossil fuel which generates carbon dioxide and nitrous oxide. Moreover, the quality of water in these crowded areas may be affected seriously by human activities, typically household wastes dumping into the rivers. This can be supported by Kendy et al. (2007) report which showed that due to rapid urbanization, wastewater from domestic consumption increased remarkably faster than that from industrial process annually, leading to serious mismatch between supply and demand for water in urban areas. The most recent water quality survey in China has shown that nearly 88% of water coming from lakes or groundwater wells cannot meet the quality of drinking water sources (Hu & Cheng, 2013) . While it can be said that green technology as such environmentally-friendly equipment, vehicles or machines will be innovated and invested by creative suppliers if there has the large number of buyers who are willing to purchase to get high standard living in busy cities (Wan, 2012), there may not many urban inhabitants who can afford to buy them.
Secondly, urbanization has a negative impact on environment due to the increase in the number of industries. The investment in industry or factory construction increases in order to create more jobs and supply more outputs to meet the demand of crowded population which directly influences environmental conditions. Li, Guo, and Zhou (2011) stated that in agricultural industries, 70% of pesticides is herbicide absorbing directly into the soil and groundwater which is considered as a hazardous material. According to the report conducted by Sunny, Karimanzira, and Huang (2012), the workers in industrial zone in Bangladesh attending this survey claimed that dirty water, unpleasant smells and dust problems rise from these factories are serious problems in the long-term period. They also illustrated that leather companies released polluted water and solid items from producing process such as skins, hides or fats directly into the banks of rivers near residential areas. Untreated wastes not only contaminated water but they also lead to the extinct of many fish species which is a threat to ecosystem. McDonald et al. (2011) found that the survival of more than 293 fish species is in jeopardy in the Western Ghats of India where 81 million inhabitants have no access to clean water by 2050. It can be said that the increase in the amount of waste water from urban areas can imperil aquatic species which destroys the natural biodiversity. Furthermore, air pollution is caused by coal combustion when more than 10 million tons of coal soot and 15 million tons of sulfur dioxide coming from factories to the atmosphere in China (Healy, 2015). While Kendy et al. (2007) believed that urbanization can solve this problem by reusing and treating wasted water in agricultural industries through artificial recharge or by encouraging factories to use water-saving technologies, firms target to produce outputs at the lowest price and they may not spend extra expenses on this process which has no profit returned.
Thirdly, environmental problems and climate change are resulted from energy and resources overconsumption by residents living in big cities such as toxic gas emission or electricity overuse. Both ecological disruption and pollution are caused by processing energy to satisfy living activities (Mudakkar, Zaman, Khan, & Ahmad, 2013). Zhao, Niu, and Zhang (2012) pointed out that rapid urbanization in China leads to an unavoidable trend of increasing energy consumption when this country becomes the largest carbon dioxide emission country in the world. According to World Energy Outlook (2012) , energy generation such as coal or nuclear is becoming scarce in the face of growing water constraints which means that the world may face to both the water scarcity and energy shortage. Increasing population causes the requirement for infrastructure while buildings dominated 40% of the total world annual energy consumption such lighting, heating or air conditioning which raised the amount of carbon dioxide and nitrous dioxide (Omer, 2009). Sadorsky (2013) noted that urbanization is related to the economic activities in urban areas which requires more energy intensive manufacturing using fuel than agricultural energy. This can result in misallocation of resources needed for production process when there is a shortage in supply industrial fuel and a surplus in supply for agricultural fuel. While the result from investigation by Al-mulali, Sab, and Fereidouni (2012) concluded that 84% of the developing countries in the world have a positive long-run relationship between urbanization and energy consumption, a large amount of toxic gases has already been releasing into the atmosphere gradually changing the climate and environment.
In conclusion, this essay has argued that environment pollution is caused by the increasing population in urban areas. The reasons for this are overpopulation in these big cites results in environmental consequences including air and water pollution; industrial untreated waste or toxic gas comes of producing process comes from the number of factories released directly to environment which threatens aquatic species, contributes to global warming and climate change; daily energy used by overcrowded population is one of the major factors leading to excessive carbon dioxide emission, misallocating resources of fuel energy.