1. Introduction
Big cities have always been faced with different kinds of environmental problems, so it is no longer a new issue to the world at large. Many scientists have done a lot of research as to the causes and also adequate solutions to solving the problems. These problems have affected the growth of many big cities in terms of their economy and population growth. The environment around is constantly deteriorating. This fact cannot be denied. Therefore, as our environment changes, it becomes important to be aware of the increasing problems that surround it. In this urban transformation of the globe, one of the most dramatic and momentous developments has been the emergence of giant cities, often referred to as “megacities”.
Around half of the world’s population is now living in urban areas due to the fact that the opportunity for a better quality of life is readily available in urban areas (WHO 2010). Due this reason many of these urban centres are expanding rapidly leading to the growth of megacities, which are defined as metropolitan areas with populations exceeding 10 million inhabitants. These concentrations of people and activity are expending inflating stress on the natural environment (at urban, regional and global levels).
This essay will outline the major driving forces of environmental deterioration in a megacity and possible solutions to solving these problems.
Additionally Shanghai, China is a mega city being used as a case study in other to have a focus area of concentration and understanding of the essay.
2. Definition of “Megacity”
The term “megacity” can be defined as an urban agglomeration (accumulation) with more than 10 million inhabitants (UNICEF 2012). 60 years ago in 1950, there were only two megacities which were New York and Tokyo. In 1995, 14 megacities existed. Today, there are 22, mostly in the developing countries of Asia, Africa and Latin America. By 2025, there will probably be 30 or more (Neal Lineback et al. 2014). It is projected that the world urban population will have increased by 72% by 2050, from 3.6 billion in 2011 to 6.3 billion in 2050 of which the majority of the population will be concentrated in the urban areas of the less developed region (UN 2012). Megacities are more than just large cities; they are where much of the worldwide process of urbanization is taking place.
Figure 1: Map of Megacities in the World (http://www.seos-project.eu/modules/landuse/images/MegacitiesPGMS8-1_960.jpg)
3. Major Forces of Environmental Deterioration in Megacities (Shanghai China as a Case Study)
Shanghai is located in the centre of China's coastline from north to south. Shanghai lies on the edge of the broad flat alluvial plain of the Yangtze River Delta with a few mountains in the southwest, and Shanghai is linked to the Jiangsu and Zhejiang Provinces in the west, the East China Sea in the east, and the Hangzhou Bay in the south. Shanghai has an area of 6,340 km2 covering 18 districts and one county. Shanghai is strong in export processing and finance as well as heavy industries with major companies such as the Baoshan Iron and Steel Group Corporation and the Shanghai Petrochemical Complex. (Shanghai Statistical Yearbook 1997–2005, 1998–2006).
With a total population of over 23 million as of 2010, Shanghai is a global city, with influence in commerce, culture, finance, media, fashion, technology, and transport. Shanghai is a major financial centre, and the busiest container port in the world. Shanghai is a popular tourist destination renowned for its historical landmarks such as The Bund, City God Temple and YuYuan Garden as well as the extensive and growing Pudong skyline. Shanghai grew in importance in the 19th century due to its favourable port location and was one of the first cities in China opened to foreign trade. Shanghai is located at the centre of an arc of large and prosperous Asian cities. (World atlas 2015)
There are series of environmental problems being encountered in Shanghai, but the major occurring problems are;
3.1 Air Pollution
Air pollution is the contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the environment which has harmful or poisonous effects to human health (WHO 2014). The main causes, characteristics, and future trends of air pollution in China are related to the energy sector (Larssen, T.; et al 2006) as well as to industrial development, traffic, urbanization, and dust from construction sites, coal and straw burning. An estimated 70% of total smoke (aerosols), 90% of SO2, and 67% ofNO2 are released by burning coal (Zhang, Z. X. 2007).The ozone layer has recently aroused much attention because of its harmful impacts on agricultural production and human health. Air pollution problems in megacities and their immediate vicinities will continue to be one of the top environmental concerns in the next decade in China.( Chan, Chak K.; et la 2008) A study in Shanghai revealed that ozone levels are associated significantly with total and cardiovascular mortality, especially during cold seasons (Zhang, Y. H.; et al. 2006). Current understanding of air pollution in Shanghai is very limited and not sufficient for proactive pollution control.
3.2 Solid Waste Management:
Shanghai produces a huge amount of solid waste daily, it produces about 20,000 tons of solid waste per day, wastes has been an issue of public concern ever since humans started to live in towns, like all mega cities (Gilbert. V 2012). The many sources of waste include wastes produced by households, economic activities (shops, restaurants and schools), wastes generated by industrial activities, wastes from construction and demolition sector, waste generated by agricultural sector and hazardous wastes (Nasrin, S.T., 2014). Waste can simply be put as any material, which is no longer user to the owner, hence it can be reused or recycled. Due to the high population of inhabitants in megacities production of excessive amount of waste or garbage is inevitable. The over consumption of resources and creation of plastics are creating a major crisis of waste disposal. Lack of proper treatment of waste disposal is harmful to human health and they tend to litter the city. Shanghai’s waste disposal practices have lagged far behind its economic development (Pugh, C., 2013).
3.3 Water Quality
Only a little percent of Shanghai’s river and lake water is clean enough for household use. Water pollution, regional droughts, water wastage and global warming are leading to scarcity of water. Water pollution is any chemical, physical or biological change in the quality of water that has a harmful effect on any living. Water is our most precious resources. Water pollution is probably the worst aspect of environmental deterioration because of its impact on daily life, agriculture, and industry. Low water qualities are caused by industries waste water, oil wells, agriculture, human activities, sewage treatment plants and pollutants that enter the water through. About 80% of the water in Shanghai is from the Huangpu River. The remaining 20% comes from the Yangtze River (GU. J. S 2009). Unfortunately, both are among the most polluted rivers in the world.
"The total volume of sewage discharged into the Yangtze river reached nearly 30 billion tons, including at least 9 billion tons of domestic sewage in 2005, according to an annual report by the Yangtze River Water Resources Commission." (china daily 2010)
The most common pollutants in Shanghai drinking water are high levels of chlorine, bacteria, and lead and toxic heavy metals. Shanghai’s water authorities have publicly acknowledged that tap water portability is compromised largely by secondary contamination from old piping. The heavy use of chlorine is necessary for disinfection, but is also unhealthy and can create carcinogenic by-products (Chen .G. 2010).
3.4 Transport
Traffic congestion and transit service are major problems in mega cities because of the vast number of population making use of the transport system. Not surprisingly, in an old, densely populated city like Shanghai with a very rapid rate of economic development, traffic is a major problem as a source of congestion, noise and accidents, as well as air pollution (Pugh, C., 2013). Shanghai has the worst rush hour traffic jams of any major city in china (shanghai daily 2014).