1.  BACKGROUND

a.  Urbanization as a factor of global change

Urbanization has long been one of the major forces shaping the world, and it will continue to be so. Few protected areas will not be affected by urbanization in some way.

Urbanization refers to the process by which rural areas take on urban characteristics. It also refers to more concentration of people in human settlements.

Currently, most attention to urbanization is focused on a United Nations estimate that, in 2007, 50% of the world’s population will be living in cities, rising from about 30% in 1950. This figure is projected to reach 61% by 2030 (UN 2004).

Although these estimates are useful in drawing attention to the urbanization phenomenon, they are just that, estimates. They are based on national definitions of “urban” that use different criteria (UN 2005) and on numbers that sometimes derive from outdated or questionable census data.   

Also, these are global figures. When the data are disaggregated by world region, they show marked differences in the level and pace of urbanization. In the Americas, Europe, and Oceania, the proportion of people living in urban areas is already over 70%. Although the figures for Africa and Asia are currently much lower, 39% and 37%, respectively, many cities in those regions will double their populations in the next fifteen years (UN 2004).   

In addition, there are pronounced differences among countries within these world regions.  In Africa, for example, the degree of urbanization ranges from under 15% in Burundi and Malawi, to over 85% in Libya. In the Americas, it ranges from under 40% in Haiti and Guatemala, to over 85% in Argentina, Chile, Uruguay, and Venezuela.²     

In the first three decades of the 21st century, the world’s urban population is projected to increase from 2.9 billion to 5 billion. Almost all of this increase will be absorbed by urban areas of less developed regions. Based on current trends, most of these new urban dwellers will live in overcrowded slums, often situated on marginal and dangerous land, without sanitation or easily accessible access to clean water. According to the Cities Alliance, a World Bank-based partnership of official development agencies and global associations of local authorities, “ignoring this policy challenge risks condemning hundreds of millions of people to an urban future of misery, insecurity, and environmental degradation on a truly awesome scale” (CA 2004).

Contrary to a commonly held belief, “megacities” (urban agglomerations of 10 million inhabitants or more) account for less than 4% of the world’s population. Most urban dwellers live in settlements with fewer than half a million inhabitants. Some of the world’s fastest growing cities have between 1 and 5 million people or are much smaller (UN 2004). In this paper, the word “cities” includes smaller as well as larger human settlements.  Even villages can have significant impacts on ecologically sensitive protected areas. (See Note 3 for definitions of urban terms.)

Much has been written about why the world is urbanizing. The reasons are complex. Rural-to-urban migration and international migration account for most urbanization, but migration from cities to rural areas that then become urbanized also occurs. Wars can bring people into cities, but they can also have the opposite effect, depending on where people feel safer. Natural disasters can cause people to move out of cities, but those people may then contribute to urban growth elsewhere.

b.  Uncertain consequences of climate change

To these already significant trends must be added the consequences of climate change. Two of these deserve special mention: rising sea levels, and more frequent and more intense weather events.

Rising sea levels, combined with storm surges, will force migration to higher ground. Roughly a billion people live at sea level or just a few meters above it (Mastny 2006), and many of the world’s cities are situated in coastal lowlands. As conditions worsen, where will these people go? How will their resettlement, guided or unguided, affect protected areas?

Rising sea levels will also submerge low-lying coastal protected areas in and near cities, making nature less accessible to urban residents and resulting in increased use of inland protected areas.

The UN’s Intergovernmental Panel on Climate Change projects a rise in global sea level of up to 88 cm between 1990 and 2100 (IPCC 2001a), with regional variations. However, other scenarios are much less optimistic, such as the “abrupt climate change” scenarios set out by the U.S. National Research Council (2002). The cities most immediately vulnerable to sea-level rise are Asian megacities sitting on subsiding river delta land. However, many other coastal cities throughout the world are vulnerable to flooding from storm surges, and will become uninhabitable well before they disappear underwater because of waterlogging and saltwater intrusion (IPCC 2001b). More than words can tell, an online interactive map produced by the University of Arizona (2006) shows in graphic detail the inundations that would occur with one- to five-meter rises in global sea levels. 

Another consequence of climate change is more frequent and more intense weather events. Such events demonstrate the value of protected areas to cities. During a 24-hour period on 26-27 July 2005, an unprecedented monsoon rainstorm dumped almost a meter of rain on Mumbai, India, a city on the Indian Ocean that ranks sixth among the world’s urban agglomerations, with a population of 19.8 million. Severe flooding resulted, and over a thousand people lost their lives. But loss of life and property damage could have been much greater had it not been for 104-sq-km Sanjay Gandhi National Park, which lies entirely within the city limits. The heavily forested park absorbed much of the rainfall (Sahgal 2005). 

c.  What is “urban”?

A final general point about urbanization: The urban-rural distinction is becoming less meaningful. For centuries, city and countryside have been seen as opposites. Now, in much of the world, differences between urban and rural communities are becoming blurred as advanced technologies and the global economy penetrate areas formerly considered remote, and urban and rural areas become more linked and interdependent.  Steve Bass (2004) of the UK’s Department for International Development calls for “Ditching the Dichotomy” in terms of development strategies and points out that it has become hard to even define the terms “urban” and “rural.”   

d.  Cities and larger ecosystems: The context

The Task Force on Cities and Protected Areas of IUCN’s World Commission on Protected Areas has arrived at some general conclusions about connections and disconnections between cities and larger ecosystems (IUCN 2006b) that are useful context for this paper: 

·      Cities depend on a multitude of goods and services from their surrounding regions, and increasingly from ecosystems far removed from the cities themselves. These ecosystem services are cogently described in Ecosystems and Human Well-being: Synthesis (MA 2005), a report of the Millennium Ecosystem Assessment.

·      Cities can relieve pressure on rural and natural areas by concentrating human populations; achieving economies of scale in such areas as energy, housing, transportation, and solid waste reuse and recycling; and providing services such as health and secondary and higher education. On the other hand, cities are centers of consumption of resources and can cause harm to their surroundings through sprawl; depleting such resources as water and forests; and generating solid, liquid, and gaseous wastes. This consumption and pollution often also imposes burdens on distant ecosystems. These complex relationships are discussed in detail in the “Urban Systems” chapter of another volume of the Millennium Ecosystem Assessment (McGranahan, Marcotullio, et al. 2005).

·      Nature is essential to people’s well-being. Most importantly, children need direct experience of nature for healthy intellectual and emotional development. This has been well-documented (Kahn and Kellert 2002, Louv 2005). Natural areas in and near cities are anchors to the Earth; they provide opportunities for exercise, education, and renewal. Nature is important even for the poorest of the urban poor.

2.  HOW URBANIZATION AFFECTS PROTECTED AREAS

a.  Forms of urbanization

Urbanization that affects protected areas takes several forms that are not mutually exclusive: