Tourism carrying capacity is a now antiquated approach to managing visitors in protected areas and national parks which evolved out of the fields of range, habitat and wildlife management. In these fields, managers attempted to determine the largest population of a particular species that could be supported by a habitat over a long period of time. Many authors, such as Buckley, Wagar, Washburne, McCool, and Stankey have critiqued the concept as being fatally flawed in both the conceptual assumptions made and its limited practical application. For example, the notion of a carrying capacity assumes the world, such as the social-ecological systems in which protected areas and tourism destinations are situated, are stable. But we know they are dynamically complex and impossible to predict. We know that to implement a carrying capacity on a practical level, assumes a level of control of entries into a destination or protected area not usually found in the real world. We know that a carrying capacity, if one could be determined, requires considerable financial and technical resources to administer; and we know that when demand exceeds a limit, the ways in which scarce opportunities are allocated are contentious.

"Tourism Carrying Capacity" is defined by the World Tourism Organisation as “The maximum number of people that may visit a tourist destination at the same time, without causing destruction of the physical, economic, socio-cultural environment and an unacceptable decrease in the quality of visitors' satisfaction”. Where as Middleton and Hawkins Chamberlain (1997) define it as “the level of human activity an area can accommodate without the area deteriorating, the resident community being adversely affected or the quality of visitors experience declining” what both these definitions pick up on is carrying capacity is the point at which a destination or attraction starts experiencing adverse as a result of the number of visitors.

Unfortunately, there are no studies which support this notion of visitor management. For example, in areas which have an objective of maintaining pristine conditions, any level of visitor use creates adverse or negative impacts, suggesting that the carrying capacity is zero. Fundamentally, acceptable conditions are a matter of human judgment, not an inherent quality of a particular site. Understanding these acceptable conditions is the focus of the limits of acceptable change planning process referred to later in this article.

There are number of different forms of carrying capacity referred to in tourism, however this article will focus on the four most commonly used. However, these conceptions are useful only to the extent they focus discussion and discourse, not practical application.

Physical carrying capacity

This is the max number that area is actually able to support. In the case of an individual tourist attraction it is the maximum number that can fit on the site at any given time and still allow people to be able to move. This is normally assumed to be around 1m per person.
“PCC per a day = area (in metres squared) x visitors per metre x daily duration" (Mowforth and Munt)
This is a formula which has been used to calculate the physical carrying capacity.

Economic carrying capacity

This relates to a level of unacceptable change within the local economy of a tourist destination, it is the extent to which a tourist destination is able to accommodate tourist functions without the loss of local activates, take for example a souvenir store taking the place of a shop selling essential items to the local community. Economic carrying capacity can also be used to describe the point at which the increased revenue brought by tourism development is overtaken by the inflation caused by tourism.

Social carrying capacity

This relates to the negative socio-cultural related to tourism development. The indicators of when the social carrying capacity has been exceeded are a reduced local tolerance for tourism as described by Doxey’s Index of irritation. Reduced visitor enjoyment and increased crime are also indicators of when the social carrying capacity has been exceeded.

Biophysical carrying capacity

This deals with the extent to which the natural environment is able to tolerate interference from tourists. This is made more complicated by the fact that because it deals with ecology which is able to regenerate to some extent so in this case the carrying capacity is when the damage exceeds the habitat's ability to regenerate.

Environmental carrying capacity is also used with reference to ecological and physical parameters, capacity of resources, ecosystems and infrastructure.

Weaknesses of carrying capacity

The main criticism of carrying capacity is that is fundamentally flawed conceptually and practically. Conceptually, the notion of an inherent carrying capacity assumes a stable and predictable world, a "J-shaped" curve in the relationship between use level and impact, and techno-scientific view of what are essential value judgments. On the practical level, it is difficult to calculate a maximum number of visitors because this is also dependent on other factors like the way in which the tourists behave ‘a large group of bird Watchers moving through a landscape will have a different impact compared to a similar sized group of school children.’ In the case of natural heritage like national parks, visitor impacts change with seasons. What is important is the acceptability or appropriateness of these impacts, an issue that is largely dependent on social and cultural value systems with science having an input.

UNESCO (the organization responsible for administrating the World Heritage list) has expressed a concern that the use of Carrying capacity can give the impression that a site is better protected than it actually is, it points out that although the whole site may be below carrying capacity part of the site may still be crowded.

Limits of Acceptable Change

Limits of acceptable change was the first of the post carrying capacity visitor management frameworks developed to respond to the practical and conceptual failures of carrying capacity. The framework was developed by The U.S. forest service in the 1980s. It is based on the idea that rather than there being a threshold of visitor numbers, in fact any tourist activity is having an impact and therefore management should be based on constant monitoring of the site as well as the objectives established for it. It is possible that with in the Limit of acceptable change framework a visitor limit can be establishe but such limits are only one tool available. The framework is frequently summarised in to a nine step process.

1. Identify area concerns and issues.
2. Define and describe opportunity classes (based on the concept of ROS).
3. Select indicators of resource and social conditions.
4. Inventory existing resource and social conditions.
5. Specify standards for resource and social indicators for each opportunity class.
6. Identify alternative opportunity class allocations.
7. Identify management actions for each alternative.
8. Evaluate and select preferred alternatives.
9. Implement actions and monitor conditions.

The reader should note however, that there is a difference of LAC as a concept and LAC as a planning framework.

Visitor Experience and Resource Protection

This framework is based on the idea that not enough attention has been given to the experience of tourists and their views on environmental quality. This framework is similar in origin to LAC, but was originally designed to meet the legislative, policy and administrative needs of the US National Park Service.

Descriptive and evaluative

The process of estimating Tourism Carrying Capacity (TCC) has been described as having a descriptive and evaluative part. It follows (in principle) the conceptual framework for TCC as described by Shelby and Heberlein (1986), and these parts are described as follows:

Descriptive part (A): Describes how the system (tourist destination) under study works, including physical, ecological, social, political and economic aspects of tourist development. Within this context of particular importance is the identification of:

• Constraints: limiting factors that cannot be easily managed. They are inflexible, in the sense that the application of organisational, planning, and management approaches, or the development of appropriate infrastructure does not alter the thresholds associated with such constraints.
• Bottleneck
  Bottleneck
  A bottleneck is a phenomenon where the performance or capacity of an entire system is limited by a single or limited number of components or resources. The term bottleneck is taken from the 'assets are water' metaphor. As water is poured out of a bottle, the rate of outflow is limited by the width...
  
  s: limiting factors of the system which managers can manipulate (number of visitors at a particular place).
• Impacts: elements of the system affected by the intensity and type of use. The type of impact determines the type of capacity (ecological-physical, social, etc.). Emphasis should be placed on significant impacts.

Evaluative part (B): Describes how an area should be managed and the level of acceptable environmental impacts. This part of the process starts with the identification (if it does not already exist) of the desirable condition or preferable type of development. Within this context, goals and management objectives need to be defined, alternative fields of actions evaluated and a strategy for tourist development formulated. On the basis of this, Tourism Carrying Capacity can be defined. Within this context, of particular importance is the identification of:

• Goals and/or objectives: (i.e. to define the type of experience or other outcomes which a recreational setting should provide).

Differing definitions

First of all, the carrying capacity can be the motivation to attract tourists visit the destination. The tourism industry, especially in national parks and protected areas, is subject to the concept of carrying capacity so as to determine the scale of tourist activities which can be sustained at specific times in different places. Various scholar over the years have developed several arguments developed about the definition of carrying capacity. Middleton and Hawkins defined carrying capacity as a measure of the tolerance of a site or building which is open to tourist activities, and the limit beyond which an area may suffer from the adverse impacts of tourism (Middleton & Hawkins, 1998). Chamberlain defined it as the level of human activity which an area can accommodate without either it deteriorating, the resident community being adversely affected or the quality of visitors' experience declining (Chamberlain, 1997). Clark defined carrying capacity as a certain threshold (level) of tourism activity, beyond which there will be damage to the environment and its natural inhabitants (Clark, 1997).

The World Tourism Organisation argues that carrying capacity is the maximum number of people who may visit a tourist destination at the same time, without causing destruction of the physical, economic and socio-cultural environment and/or an unacceptable decrease in the quality of visitors' satisfaction (http://ec.europa.eu/environment/iczm/pdf/tcca_material.pdf. Date assessed 08/03/07). In the publication, ‘Agenda 21 for the Travel and Tourism Venture: towards environmentally sustainable development’, the Secretary-General of the World Tourism Organization.

As part of a planning system

The definitions of carrying capacity need to be considered as processes within a planning process for tourism development which involves:

• Setting capacity limits for sustaining tourism activities in an area. This involves a vision about local development & decisions about managing tourism.
• Overall measuring of tourism carrying capacity does not have to lead to a single number, like the number of visitors (http://ec.europa.eu/environment/iczm/pdf/tcca_material.pdf. Date assessed 08/03/07).
• In addition, carrying capacity may contain various limits in respect to the three components (physical-ecological, socio-demographic and political–economic).

“Carrying capacity is not just a scientific concept or formula of obtaining a number beyond which development should cease, but a process where the eventual limits must be considered as guidance. They should be carefully assessed and monitored, complemented with other standards, etc. Carrying capacity is not fixed. It develops with time and the growth of tourism and can be affected by management techniques and controls” (Saveriades, 2000).

The reason for considering carrying capacity as a process, rather than a means of protection of various areas is in spite of the fact that carrying capacity was once a guiding concept in recreation and tourism management literature. Because of its conceptual elusiveness, lack of management utility and inconsistent effectiveness in minimising visitors' impacts, carrying capacity has been largely re-conceptualized into management by objectives approaches, namely: the limits of acceptable change (LAC), and the visitor experience and resource protection (VERP) as the two planning and management decision-making processes based on the new understanding of carrying capacity (Lindberg and McCool, 1998). These two have been deemed more appropriate in the tourism planning processes of protected areas, especially in the United States, and have over the years been adapted and modified for use in sustainable tourism

Sustainable tourism

Sustainable tourism is tourism attempting to make a low impact on the environment and local culture, while helping to generate future employment for local people. The aim of sustainable tourism is to ensure that development brings a positive experience for local people, tourism companies and the...

and ecotourism contexts (Wallace, 1993; McCool, 1994; Harroun and Boo, 1995).