
According to the United Nations World Tourism Organisation international tourist arrivals have risen from 25 million a year in 1950 to 1.4 billion a year now. An increase of over 50 times in under 70 years. This is just international arrivals too and does not take into account those tourists traveling short or long haul within the country itself.
Despite this dramatic increase in demand, little has been done to limit these numbers, as the benefits tourism brings to a country in terms of wealth are so attractive environmental impacts are often a secondary thought.
Activities tourists take part in have also changed in many areas of the world, moving from hiking and sightseeing to scuba diving, off-road vehicles and watersports.
As far back as 1988 J. Holder came up with the ‘self-destruct theory of tourism’. The theory was that any attractive destination in the world would first become a resort to up-market tourists wanting low-density exclusive luxury. However, after a while, new developers move in and due to the way the market works, when there is competition rates drop as all hotels try to fill their rooms. This continues until you have a mass tourist resort with high impacts. The rich who were there originally don’t like this and so move onto a new destination and the pattern repeats itself. (1)
So what are the main environmental impacts of tourism now that so many people around the world are seeking vacations.
1) Flights

Fast becoming the most talked about negative environmental impact of tourism is aviation. Not long ago flying abroad for a holiday was a luxury only enjoyed by a small number of people on the planet. But with a rising number of people now in the ‘middle-class’ bracket, coupled with lower flight prices and increased numbers of routes more people are taking to the skies than ever before.
All these airplanes fly by burning huge amounts of kerosene gas which emits carbon dioxide, water vapor, nitrous oxides, carbon monoxide and soot particles into the atmosphere. The Intergovernmental Panel on Climate Change (IPCC) estimates that the aviation industry alone is responsible for as much as 3.5% of climate change emissions, which could grow to 5% by 2050.
To show how much of a proportional impact on the environment this element of tourism has, one return flight to New York from London would generate more emissions that the average person in many people across the planet produces in an entire year.
The impact was recently realized to be even more significant as scientists found radiation caused by the contrails (trails left by planes in the sky) have an even bigger impact on climate than the CO2 emissions.
2) Use of natural resources

On a global scale the use of freshwater resources by tourism pales in significance to other uses such as agriculture. However, it becomes a concern because the resource is often exploited in areas where freshwater is scarce. In areas such as Cyprus, tourism accounts for up to 7.3% of national water consumption. (2)
Uses of water by tourists is often higher than by locals when you factor in increased laundry, air conditioning, watering of gardens and golf courses, preparation of food and swimming pools. In Spanish resorts tourists were found to use double the amount of water per day compared to local residents. (3)
Tourists also tend to eat more food whilst on holiday, on average 0.5kg per person per day more than at home. Food consumption from tourism is estimated to double by 2050.
3) Physical disturbance of wildlife

Disturbance from lighting, noise or approach can have negative impacts on wildlife in tourist destinations. Tourists are entering more remote locations with more frequency and often these are locations where animals have evolved with much lower levels of disturbance.
Turtle hatchlings naturally head towards the lightest part of the horizon when they hatch at night. In the past, this would have been over the sea, but now it could be a car headlamp or a streetlight. (4)
Noises from dolphin and whale watching boats have been shown to interfere with marine mammal acoustic communications. (5)
In Sri Lanka elephants were found to exhibit significantly higher levels of stress, fear and aggression in the presence of tourists which affected the amount of time they were able to feed. (6)
4) Habitat alteration

There are many examples of where increased infrastructure from tourism has lead to environmental impacts. One example is Cancun Island, where new quarries and causeways were constructed along the coastline, limiting the flow of freshwater into mangrove lagoons. Once the quarries were no longer producing the materials they were made for, they became rubbish dumps resulting in the pollution of groundwater. (7)
Coastal roads are often constructed purely with tourists in mind, connecting resorts and sights. In the Mediterranean, coastal development has had significant impacts on turtle species. Roads, car parks and landscaping have replaced natural nesting sites. And even where sand remains it is often too compacted to be suitable for nesting. This impact amongst others means green turtles now only breed in Cyprus whereas they once bred across most of the Mediterranean coast.
Beaches are often ‘cleaned’ to make them more aesthetically pleasing for tourists. Natural vegetation is cleared and strandlines are re-graded. Studies have shown that the removal of this vegetation decreases bird numbers which would feed on the invertebrates in the area. (8)
On ski resorts where forested areas are often cleared and habitats altered to make space for recreation, impacts on wildlife have been recorded. A study in the Western Italian Alps found a sharp reduction in the number of bird species around ski resorts, habitats where they would naturally be more abundant. (9)
5) Litter pollution

Tourists often bring with them a lot of litter, and often don’t dispose of it correctly or take it with them. One of the main places this litter is discarded is on beaches, where plastic litter has been attributed to tourists in as high as 96% of cases at Gopalpur beach in India. In the Mediterranean, beach litter increases three to seven times in the summer months when tourists are around, with the main litter culprits being plastics and cigarette butts.
Even the highest places in the world aren’t immune to the problem of litter from tourists. Tents, climbing equipment and gas canisters have been found on the route to the summit of Mount Everest as an increasing number of people try to ascend the worlds highest peak each year. Litter that had been dumped many years ago is slowly coming back to the surface too, as the snow melts from the effects of global warming.
6) Pollution from cruise ships

The discharge of pollutants from boats is common and has implications for oceanic ecosystems and wildlife. One of the main offenders are the gigantic cruise ships of which there are now 314 worldwide carrying over 500,000 passengers in total.
Pollutants come in various forms; sewage, hazardous waste, oil, ballast water and even solid waste. When these substances are not treated correctly they contain bacteria, nutrients and toxic substances that are harmful to marine life. The problem is exacerbated in certain areas because multiple ships will visit the same destinations which are set up to welcome these giant vessels.
The US Environmental Protection Agency estimates that a single 30,000 person cruise ship discharges the equivalent of 10 backyard swimming pools of sewage into the ocean each week. Cruise industry leaders say new sewerage treatment systems on boats are working to alleviate this issue, however, two fifths of the boats still use 35 year old treatment systems.
Then there are airborne pollutants, emitted by the burning of fuels required to move one of these floating cities through the water. A study showed that a single cruise ship has the equivalent emissions of 700 trucks and a million cars.
7) Physical degradation

Tourists can have a physical impact on ecosystems too.
In coral reefs for example, divers often break pieces of coral off either intentionally or accidentally by touching them. But a lack of consideration and care was found all too often with briefing from diving instructors having no effect on a diving tourist breaking a coral. (10)
Another study in the Red Sea revealed an average of 10 incidents per dive trip where a diver was making contact with corals either by raising sediments or by directly breaking them (11).
In Thailand 93% of divers were seen to make contact with corals with two-thirds of these resulting in damage or breaking of fragile corals (12)
With around one million new recreational divers being trained each year, even if damage is infrequent, with these numbers the cumulative impact will soon mount up.
Tourists walking over coastal areas has been found to cause damage to biodiversity. A study in New Zealand found just 10 tramples of an area reduced the abundance of algae and higher intensity reduced it by up to 90%. Thus resulting in impacts to the entire ecosystem in that area. (13)
Dune habitats that are trampled loose vegetation cover which would usually hold the sand in place. (14)
8) Air quality from transportation

Tourists have been found to have a noticeable effect on local air quality levels. A study in Mallorca, Spain showed a significant increase in particulate matter (PM10) pollution. This is tiny airborne solid particles from vehicle exhausts that can lead to human health problems. Large coaches with engines left running as tourists stop to see a sight are a large part of the problem. (15)
A study of national parks in the USA found that 85% of parks had air quality which was dangerous for humans, with the worst offending parks being Sequoia and Joshua Tree in California over the two months of the year when most tourists are present. Virtually all tourists enter these areas in vehicles and this causes spikes in levels of ozone which is dangerous to human health.
9) Naturalizing of animals

In many areas, large numbers of tourists have led to animals becoming used to their presence. Baboons at Cape Point in South Africa and vervet monkeys in Amboseli National Park, Kenya have both been documented as attacking and injuring tourists. This of course is not the fault of the animals and by entering their environment and natural habitat and presenting them with the opportunity of easy food, we are bringing about these moments of conflict that would not naturally have happened.
10) Introduction of invasive (non-native) species

Cruise ships and ferries which transport tourists have to take on ballast water to keep the ship stabilized. This water is taken on at the initial port and then discharged once the destination is reached. This has led to the accidental transportation of species from one region to another.
Yachts and other private vessels have been linked to the transportation of species such as he black-striped mussel which has been spread as far as Australia from it’s native central America as yachts move around. (16)
A large global assessment of data found that the abundance of non-native species increased in areas where tourist activities took place. (17)
Concluding remarks
Tourism has brought significant socio-economic benefits to many regions of the world which might have previously struggled. Many countries rely on tourism for the vast proportion of their economy. Caribbean countries for example are four times as dependent on tourism as the rest of the world.
But with many tourists traveling to these destinations to see unique wildlife or pristine scenery, the environmental impacts threaten to destroy the very those very things they go to see.
So how do we get past this worrying problem? With the global population set to rise above 9 billion in the coming decades and an increasing number of people entering the middle-class, it seems likely that these issues are set to get even worse.
Education is a part of it but another big step would to see an increased tax on aviation fuel, which currently is subject to no tax whatsoever. This currently allows airlines to sell tickets at eye-wateringly low prices, making the prospect of a long-haul trip to the other side of the world, seem like no big deal whatsoever.
Some sectors of the tourism industry are becoming more aware of these impacts, knowing that if they aren’t careful they will lose the things tourists want to visit. For example, a study into diving found that when experience increased and pre-dive training was provided, the incidents of damage to coral reefs was reduced. But how can we trust that all diving companies will enforce this level of care when there is money to be made?
If we don’t think about sustainability in tourism now, there will be no such thing as tourism in the future.
References
- Holder, J., 1988. Pattern and impact of tourism on the environment of the Caribbean. Tourism Management 9 (2), 119e127
- Gössling, S., Peeters, P., Hall, C.M., Dubois, G., Ceron, J.P., Lehmann, L., and Scott, D. (2012), Tourism and water use: supply, demand, and security. An international review, Tourism Management, 33(1), 1-15.
- Sunlu, Ugur. “Environmental impacts of tourism.” 2003 Conference on the Relationships between Global Trades and Local Resources in the Mediterranean Region.
- Tuxbury, S.M., Salmon, M., 2005. Competitive interactions between artificial lighting and natural cues during seafinding by hatchling marine turtles. Biological Conservation 121, 311e316.
- Van Parijs, S.M., Corkeron, P., 2001. Boat traffic affects the acoustic behaviour of Pacific humpback dolphins Sousa chinensis. Journal of the Marine Biological Association of the United Kingdom 81, 533e538.
- Ranaweerage, Eranga, Ashoka DG Ranjeewa, and Koun Sugimoto. “Tourism-induced disturbance of wildlife in protected areas: A case study of free ranging elephants in Sri Lanka.” Global Ecology and Conservation 4 (2015): 625-631.
- Davenport, J., & Davenport, J. L. (2006). The impact of tourism and personal leisure transport on coastal environments: A review. Estuarine, Coastal and Shelf Science, 67(1-2), 280–292.doi:10.1016/j.ecss.2005.11.026
- Llewellyn, P.J., Shackley, S.E., 1996. The effects of mechanical beachcleaning on invertebrate populations. British Wildlife 7, 147e155.
- Laiolo, Paola, and Antonio Rolando. “Forest bird diversity and ski-runs: a case of negative edge effect.” Animal Conservation forum. Vol. 8. No. 1. Cambridge University Press, 2005.
- Barker, Nola HL, and Callum M. Roberts. “Scuba diver behaviour and the management of diving impacts on coral reefs.” Biological conservation 120.4 (2004): 481-489
- Zakai, David, and Nanette E. Chadwick-Furman. “Impacts of intensive recreational diving on reef corals at Eilat, northern Red Sea.” Biological Conservation 105.2 (2002): 179-187.
- Worachananant, Suchai, et al. “Managing the impacts of SCUBA divers on Thailand’s coral reefs.” Journal of Sustainable Tourism 16.6 (2008): 645-663.
- Schiel, D.R., Taylor, D.I., 1999. Effects of trampling on a rocky intertidal assemblage in southern New Zealand. Journal of Experimental Marine Biology & Ecology 235, 213e235.
- Hylgaard, T., Liddle, M.J., 1981. The effect of human trampling on a sand dune ecosystem dominated by Empetrum nigrum. Journal of Applied Ecology 18, 559e569
- Saenz-de-Miera, Oscar, and Jaume Rossello. “Modeling tourism impacts on air pollution: The case study of PM10 in Mallorca.” Tourism Management 40 (2014): 273-281.
- Thresher, R.E., 1999. Diversity, impacts and options for managing invasive marine species in Australian waters. Journal of Environmental Management 6, 137e148
- Anderson, Lucy G., et al. “The role of tourism and recreation in the spread of non-native species: a systematic review and meta-analysis.” PLoS One 10.10 (2015): e0140833.