There are many different definitions of sustainable tourism that have been developed over the last decade. Most tend to assume that all tourists are responsible for respecting and conserving a location's economic, environmental, and socio-cultural balances.

Global economists forecast continuing international tourism growth, ranging between three and six percent annually, depending on the location. As one of the world's largest and fastest growing industries, this continuous growth will place great stress on remaining biodiverse habitats, often used to support mass tourism. Sustainable tourists are aware of these dangers and seek to protect their favorite destinations, and to protect tourism as an industry. Responsible sustainable tourists face many responsibilities to reduce tourisms impact on communities, including:

• informing themselves of the culture, politics, and economy of the communities being visited.
• anticipating and respecting local culture's expectations and assumptions.
• contributing to intercultural understanding and tolerance.
• supporting the integrity of the local culture by favoring businesses which conserve cultural heritage
• supporting local economy by purchasing local goods and participating with small, local businesses.
• conserving resources by seeking out businesses that are environmentally conscious, and by using the lowest possible amount of non-renewable resources.

Ecotourism is a subset of sustainable tourism, differing by its focus on ecology. Ecotourism is sustainable tourism that: "contributes actively to the conservation of natural and cultural heritage; includes local and indigenous communities in its planning, development and operation, contributing to their well-being; interprets the natural and cultural heritage of the destination to visitor; and lends itself better to independent travellers, as well as to organized tours for small size groups." ^[1]

Travel over long distances generally requires a large amount of either time or energy. Generally we do this by burning fossil fuels, a largely unsustainable practice and one that contributes to Climate Change, via CO₂ emissions.

Air Travel is perhaps the worst offender in this regard, contributing to between 2 and 3% of global carbon emissions ^[2]. Given a Business As Usual approach, this could be expected to rise to 5% by 2015 and 10% by 2050. Car (and other personal transport) travel, is the next worst offender.

Mass transport is the most climate friendly method of travel, and generally the rule is "the bigger the better" - compared to cars, buses are relatively more sustainable, and trains and ships are even more so. Human energy and renewable energy is the most efficient, and hence, sustainable. Travel by bicycle, solar powered car, or sailing boats produces no carbon emissions (although the embedded energy in these vehicles generally comes at the expense of carbon emission).

• The Global Development Reasearch Center
• United Nations Environment Programme
• UN Department of Economic and Social Affairs, Division for Sustainable Development

• Village Homestays
• International Ecotourism Club