According to the latest United Nations World Tourism Organization’s (unwto) world tourism barometer, International tourist arrivals grew by 4

According to the latest United Nations World Tourism Organization’s (UNWTO) world tourism barometer, International tourist arrivals grew by 4.4 per cent in 2011 to a total 980 million, up from 939 million in 2010 and it is expected to cross 1 billion mark in 2012. The argument for the integration of tourism with conservation was first made widespread by Budowski (1976) in an article.
However, the term “Ecotourism” has become prevalent concept since the mid 1980s and it has experienced the fastest growth of all sub-sectors in the tourism industry. The popularity shows a proof of change in tourist perceptions, increased environmental awareness and a desire to explore natural environments.
The tourism activities stretch from conventional tourism to ecotourism and there has been a lot of contention to the limit at which biodiversity preservation, local social-economic benefits and environmental impact should be considered in ecotourism For this reason, environmentalists, special interest groups and governments define ecotourism differently.
Environmental organizations have generally insisted that ecotourism is nature-based, sustainably managed, conservation supporting and environmentally educated. The tourist industry and governments, however, focus more on the product aspect, treating ecotourism as equivalent to any sort of tourism based in nature. As a further complication, many terms are used under the rubric of ecotourism.
Nature tourism, nature travel, low impact tourism green tourism, soft tourism, bio-tourism, ecologically responsible tourism and others have been used in literature and marketing, although they are not necessary synonymous with ecotourism. Presently the Ecotourism as industry is one of the fastest growing economic sector in the globe.
The concept of ecotourism is probably equally due to the widespread and growing interest in the natural environment and a corresponding recognition of the importance of conserving natural environmental quality. The idea of visiting and experiencing high-quality natural environments and also protecting them from harmful impacts is now an acceptable and marketable one. Ecotourism involves nature conservation by tourists who visit several attraction sites. This is aimed at securing threatened species of plants and animals that depend of nature to survive. This is done mainly by tourists with an aim of sustaining the beauty and attraction of the sites. It is the exercise that is worthy investing in since the outcome benefits the generations to come and creates a sustainable source of government revenue. 
When the visiting tourists explore a certain site and encouraged to conserve the environment, it becomes a source of inspiration and fun to them. On the other hand, the tourists gain an experience of what makes the site attractive and they become eager to visit the same site in future in order to see the outcome of what their work. It is a partnership that enables all the parties to participate in sustaining the attractive sites. 
Ecotourism has numerous merits to the environment and nature in general. It has a long run benefits to the climate which in turn improves the favourable weather in the area. By adopting ecotourism as a sustainable model, the forest cover is increased, the canopy is created and in the long run, the climate improves. 
This reduces the effects of global warming and improves the water reservoir. It is a common knowledge that nature conservation is easier and cheaper compared to the painful outcome of the nature destruction. For this reason, the environment authorities across the world have adopted ecotourism as a sustainable model. Eco tourism is one of the fastest growing trends in the worldwide tourism industry. Environment has an intrinsic value which outweighs its value as a tourism asset.

It is also agreed upon by environmental experts that the three elements, viz., political acceptability, social responsibility and sound environment with a perfect balance between quality and quantity, in tourism development/ promotion, can ensure quality tourism.

Whilst there is a general support for a symbiotic relationship between the two, i.e., tourism and environment; the dilemma is that the residents lay greater stress on tourism development whereas the tourists focus on environmental protection.In this context, ‘eco tourism’ is being promoted as a means of ‘giving nature value’ and hence of achieving sustainable tourism. The term ‘eco tourism’ has been defined in many ways and is usually used to describe tourism activities which are conducted in harmony with nature.
It is a form of tourism which fosters environmental principles with an emphasis and visiting and observing natural areas; the emphasis on tourism as much as this can be separated from recreation is deliberate.
Eco tourism relates to the quality of the environment and to ensure that the impacts from the activity are controlled comprehensively. Eco tourism can be defined as “purposeful travel to natural areas to understand the cultural and natural history of the environment, taking care not to alter the integrity of the eco system, while producing economic opportunities that make the conservation of natural resources financially beneficial to local citizens”.Eco tourism is one of the most popular alternative tourism forms. Its advocates believe that it engenders a sense of need for environmental protection among local population once the latter realize conservation does not mean loss of economic opportunity.
Hopefully, eco tourism can provide the local community with jobs, enabling a shift away from unsustainable practices such as over grazing, mining or logging in environmentally sensitive eco systems.
However, the critics argue that with the establishment of bio-diversity protection-cum-tourism conservation projects, people living in the area tend to lose their shelter and means of livelihood.
On the contrary, some of the deleterious effects not withstanding, tourism has also contributed to the protection of natural environment and cultural heritage; in particular to the restoration of historical and archaeological buildings, works of art.Nature parks in many parts of the world have been established partly to boost tourism, thus, protecting natural environment (landscape, fauna and flora) from destruction by modern development.
Preservation and conservation of environmental qualities, recreation and education are, indeed, the core themes behind the development of national parks and reserves. As an ideal principle, tourism should be developed within the carrying capacity of the park and not at the cost of the park resources.
Despite all this, eco tourism’s attraction analysts urge against blindly embracing it as a benign alternative to mass tourism. Academics warn that like any other form of tourism, eco tourism attracts visitors to isolated and remote areas which often cannot sustain intensive human activities.
Although eco tourism supposedly increases local involvement in the industry, government policies typically counteract this object through exclusion of the poorest. Moreover, similar to mass tourism, many organizations controlling eco tourist flows are powerful transnational companies, allowing the destination only a minor part of income generated by it.
Nevertheless, eco tourism is regarded as a positive dimension of tourism involving minimum density, low impact activities taking place at natural sites of sufficient biological, cultural and geographical interest to tourists.
The major factors contributing to the boom are an international awareness of global ecological realities, the desire among a rapidly growing and relatively affluent segment of the industrialized world to have nature based experiences, and the developing world’s conviction that natural resources are finite and ought to be conserved for future generations.
The development of nature based tourism products by the tourism organizations is an acknowledgement of the perceived value shifts in modern society favouring environmental conservation and liable to be translated into greater active tourist participation, interest and concern for the environment.
An understanding of the notion of ‘Sustainable Development’ gaining currency over the last two decades or so, central to all public discourse and public policy agenda is imperative to have a thorough understanding of the implications of eco tourism. Eco tourism, indeed, has the phenomenal potential as a tool for sustainable development.