In a previous post, I outlined the effects that urbanization has on the environment, how cities are different from the areas that surround them, and trends in urbanization and population growth.
To recap, here are some facts about population growth in urban areas:
- Cities currently cover just 1 to 6% of the Earth’s surface but they are growing rapidly in all areas of the world. 1,2
- In 1900, only 9% of the world’s population lived in “urban environments”. By 2000, it was 50% and by 2025 it will be 66%.3
- In the past 30 years, the world’s population increased by 2.4 billion. Half of that growth took place in cities.4
- All the expected population growth from 2000 to 2030 (about 2 billion people) will be concentrated in urban areas of developing nations, largely due to urban migration and high birth rates.4
Given that developing countries will be playing such a large part in global climate change, population changes, and historical changes, it is important that we study them. But because any given change occurs in a unique spatial and temporal context, we need to be careful in studying underdeveloped and developing countries separately from developed countries. It is not enough to slap on a universal Bandaid to a seemingly identical problem.
Urbanization and industrialization set in motion processes that change societies’ political systems, cultures, and much more. Biotic effects are intimately linked to the social processes that occur in tandem with industrialization: new power structures, international relations, corruption, problems with accountability, public health crises, infrastructure failures, poverty, housing crises, runaway capitalism, and short-sightedness. These issues often stymie, and even reverse, efforts to maintain environmental health. Low-income cities operate in different socioeconomic patterns, revealing the need to introduce additional concepts that cover the issues of economic disparity (especially poverty and extreme non-uniformity of the distribution of wealth), political fragmentation (especially lack of resources and corruption), structural fragmentation of cities, and unequal access to basic infrastructure and services within urban ecological studies.5
The nature of environmental problems shifts in relation to the level of affluence.5As cities become more affluent, environmental problems shift in several ways6:
- type: from health threatening to ecosystem threatening
- temporal scale: from immediate to delayed impacts
- geographic scale: from local to global
These shifts are clearly reflected in new urban environmental agendas at different levels of government (from local governments to regional bodies, to international organizations).5
In the literature, these urban environmental agendas are divided into brown, gray, and green and are unified by a theory called urban environmental transition (UET).6 (Importantly, this theory is not a subsection of urban ecology, but a separate field.)
- Brown agenda issues are typically local in scale and impact homes and neighborhoods (e.g. lack of safe water, inadequate waste management and pollution control, occupation and degradation of sensitive lands).6-8
- Gray agenda issues refer to the negative aspects of industrial processes which have an impact at a regional and watersheds level, such as air and water pollution.6,8
- Green agenda issues deal with changes on continental or global levels, i.e., problems related to consumption, ecosystem health, ozone depletion, and greenhouse gas emission issues.6-8
The brown agenda is particularly relevant to poor urban dwellers while the green agenda is most relevant to future generations and natural systems.9 The gray agenda represents a transitional stage by focusing on both human health and ecosystem health, at a medium spatial and temporal range.5 Thus, increasing affluence typically reduces household and neighborhood environmental issues, while international and global environmental problems increase and then decline.7 For example, in low-income communities, local environmental hazards (e.g. lack of sanitation) are the principal source of poor health and low life expectancy.5 Middle-income cities experience improvements in local environmental conditions, but industrialization and increased use of cars and other fossil-fuel dependent machines lead to environmental problems on a city-wide or regional scale (such as local-regional air pollution).10 Affluent cities manage to reduce or transfer their most serious environmental threats, but their high consumption demands resources from distant areas and generates huge amounts of waste, all on the global scale.6 Such wealth-related differences observable not only between cities, but within cities.6
Because industrialization has already occurred in many regions of the world which have perfected mass production, capitalism in the marketplace, and other processes typical of the industrial revolution that are fundamental to how our world works, the process is currently occurring in underdeveloped and developing countries at much faster rates than it has in the past. Technologies and ideas are being imported and mass-replicated from former colonial powers to former colonies. Also contributing to this process is globalization, which has shortened the functional distances between many areas of the world via more efficient and widespread transportation and communication. A broad range of environmental challenges in developing cities are occurring sooner (at lower levels of income), rising faster (over time for similar ranges of income), and emerging more simultaneously (as a set of problems) than previously experienced by developed cities.53 In short, currently developing countries see a greater variety of environmental impacts concentrated at smaller scales than have been seen in their industrialized predecessors.11 Thus, the globalization that affects rapidly developing cities has created the conditions within which brown, gray, and green environmental issues increasingly overlap during development.12 This spatial and temporal increase in overlap means that cities currently facing industrialization and urbanization and their associated environmental problems cannot simply apply rules and solutions that have been developed by their industrialized predecessors. The only way to address these problems is to address them on their own terms.
While both urban ecology and urban environmental transition share the practical aim of achieving sustainable urban environments, they are not the same thing.5 While urban environmental transition more precisely defines the obstacles to achieving sustainable urban environments in developing cities, it lacks the framework to understand these challenges in a more comprehensive and systematic form—something that urban ecological theory provides.5
- Alberti, M., J.M. Marzluff, E. Shulenberger, G. Bradley, C. Ryan, C. Zumbrunnen. 2003. Integrating humans into ecology: Opportunities and challenges for studying urban ecosystems. BioScience. 53(12):1169-1179.
- Botkin, D.B. and C.E. Beveridge. 1997. Cities as environments. Urban Ecosystems. 1:3-19.
- McDonnell, M.J. & S.T.A. Pickett. 1990. Ecosystem structure and function along urban-rural gradients: An unexploited opportunity for ecology. Ecology. 71:1231-1237.
- UN. 2009. World Urbanization Prospects: The 2009 Revision. Department of Economic and Social Affairs. http://esa.un.org/unpd/wup/index.htm (accessed April 2013).
- Vega, A.Z. 2010. An urban ecology for the developing world. Submitted for Master’s Degree in Natural Resources, Virginia Polytechnic Institute and State University.
- McGranahan, G. and D. Satterthwhaite. 2002. The environmental dimensions of sustainable development for cities. Geography. 3:213-226.
- Marcotullio, P. 2003. Globalisation, Urban form, and environmental conditions in Asia-Pacific cities. Urban Studies. 40:219-247.
- Marcotullio, P.J., S. Rothenberg, M. Nakahara. 2003. Globalization and urban environmental transitions: Comparison of New York and Tokyo’s Experiences. The Annals of Regional Science. 37:369-390.
- McGranahan, G., P. Jacobi, J. Songsore, C. Surjadi, M. Kjellen. 2001. The Citizens at Risk: From Urban Sanitation to Sustainable Cities. London, UK: Earthscan.
- Satterthwaite, D. 2007. Scaling Urban Environmental Challenges. (Editors: Marcotullio, P. and G. McGranahan.) London, UK: Earthscan.
- Marcotullio, P.J. 2005. Time-Space Telescoping and Urban Environmental Transitions on the Asia Pacific. United Nations University Institute of Advanced Studies.
- Marcotullio, P.J. 2007