Increased waste and pressure on wastewater infrastructure from tourism could spell "unavoidable consequences" in New Zealand, a report warns - an industry that it says began with Māori exploitation.
The Parliamentary Commissioner for the Environment, Simon Upton, warns that increasing numbers of tourists - both domestic and international - are putting New Zealand's environment under pressure.
The commissioner's new report highlights that, at the current level, environmental pressures are likely to grow in line with the size of the tourism industry - with international visitor numbers expected to rise to 10-13 million annually by 2050.
"The sheer numbers of people are eroding the sense of isolation, tranquillity and access to nature that many overseas tourists seek when visiting New Zealand. We need to ask: are we in danger of killing the goose that laid the golden egg?"
Upton warns that, despite progress being made for environmental issues such as the passing of the Zero Carbon Bill, total tourism-related emissions will only fall slightly by 2050 due to a growing share of emissions from international aviation.
In the year ending March 2019, 98 percent of international visitors arrived in New Zealand by plane.
Canterbury University Professor Michael Hall agrees that a "core issue for international tourism to New Zealand is going to be how to mitigate the emissions from tourists coming here".
New Zealand's history of tourism
Upton's report looks back on the history of how tourism has affected New Zealand, from as early as 1874, with the localised impact on Lake Rotomahana and the Pink and White Terraces, Ō-tū-kapua-rangi and Te Tarata.
The Pink and White Terraces was once a dominant feature on the shores of Lake Rotomahana, and considered to be the 8th Wonder of the World - but they were buried in the 1886 eruption of Mt Tarawera.
There were concerns at the time about the vandalism of geological features by European visitors, litter and user conflicts with locals.
"British royal visits in 1869 and 1870 aimed to show foreign audiences that New Zealand was a safe and attractive place to visit. A 50-mile road was constructed by 1500 Māori from Maketū to Tarawera to convey Prince Alfred to the terraces.
"There he signed his autograph on one of the silica terraces. This started a trend of visitors defacing the terraces, signing their names, taking away geological samples and leaving rubbish."
While the Pink and White Terraces' demise wasn't influenced by man, as Upton's report suggests, tourists were already starting to have a negative impact.
When the state took the lead in the development of tourism around 1880, Upton's report says Māori culture was exploited by being packaged and marketed as an exotic 'other'.
"In areas where tourism was growing, the traditional Māori way of living was breaking down."
As the Government further intervened in the tourism industry, tourism revenue previously going to Māori was diverted to the Crown, the report says.
An example of this was Māori-run accommodation and services at Ōhinemutu and Whakarewarewa, which were outcompeted by the Government's initiative to create the new township of Rotorua.
The Crown also obtained a purchasing monopoly under the Thermal-Springs Districts Act 1881. This meant that Māori could no longer charge for access to thermal areas.
Tourism growth was slow in New Zealand because of its distance from the rest of the world, the report says - but also due to globally significant events, such as World War I, the Great Depression and World War II.
Fast forward to the 1980s though, and the Government was no longer the principal manager of tourism in New Zealand - after conservation arms of government departments were separated.
The Department of Conservation (DoC) was established in 1987, and by that time, half a million international tourists were visiting New Zealand annually. Environmentalism had started to become a talking point.
It was in 1990 when a Parliamentary Inquiry was conducted on whether the growth was compatible with conservation and public access issues - but a committee determined there was nothing of major concern.
But by 1999, international visitor arrivals reached 1.6 million - driven by an expanding middle class in several Asian countries whose leisure trends were similar to those of British and American tourists.
That was the same year the '100% Pure New Zealand' global marketing campaign was launched by Tourism New Zealand, marketing New Zealand as clean and green - but Upton says it's often been taken with a grain of salt.
"Since its inception, there have been critiques of the 100% Pure New Zealand campaign as selling a fictitious version of the country's environment and culture, and of fostering expectations of a pristine environment."
Today, tourism is a billion-dollar industry in New Zealand, raking in $39.1 billion for the year ended March 2018 - the majority from domestic travellers: $23 billion.
Auckland, being the major international gateway to New Zealand, has about one-third of the market share of tourism spend.
Upton has decided not to make recommendations at this stage but is instead waiting got feedback on the issues raised in the report on how tourism is harming the environment.
"The overwhelming majority of New Zealanders would surely agree that the terms of our hospitality (manaakitanga) and responsibility for looking after our tourist destinations (kaitiakitanga) are ones the wider community, not just the industry, should determine."
The commissioner says tourist numbers are already straining popular tourist spots and this will get worse if we continue with a "business-as-usual approach".