British lawmakers said on Thursday they would count the environmental cost of mass tourism amid warnings that leisure trips pose an ever greater threat to the planet.
Fast-growing tourism accounts for about 5% of greenhouse gas emissions worldwide while floods of visitors are damaging a host of hot spots, said the Environmental Audit Committee, which scrutinises the impact of government policy on the environment.
From queues up Everest to cruisers crowding Venice, 'must-see' landmarks are increasingly imperilled by their very popularity. And that's before the spew of emissions from planes, trains and automobiles is taken into account.
"Now that summer is here, families are looking forward to a well-earned holiday," committee chairwoman Mary Creaghin said in a statement. "But when we book a cruise, flights or visit a popular tourist destination, it's easy to forget about the environmental impact our holidays are having."
A study last year found that a global boom in tourism was complicating the drive to slow climate change, with flights the biggest single contributor to greenhouse gas emissions.
Some 1.4 billion people were international tourists in 2018, 6% up on the year before, as cheap flights and easy connections help fuel mass tourism, according to the World Tourism Organization, a United Nations agency.
Britain makes billions of pounds from overseas visitors - drawn by everything from royal intrigue to cutting-edge culture.
But the cost is also steep, with deep division over whether to expand London Heathrow, already Europe's busiest airport.
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Environmentally-sensitive tourism could boost economic growth and protect the environment, the lawmakers said, but in many cases "overtourism" had harmed people and their landmarks.
Thailand has said it will close access to Maya Bay, which featured in the hit film "The Beach" starring Leonardo DiCaprio, for four months a year after visitors damaged coral reefs.
Cities from Italy's Venice to Malaysia's George Town have also seen protests over the huge influxes of tourists, which can cause damage, boost rents and drive out local life.
The committee said it would consider whether the government should support sustainable tourism, if it should take more responsibility for the impact of British visitors' actions abroad, and how sustainable travel could help cut emissions.
Action is urgent to monitor the impact of tourism and protect treasured destinations, said Ben Lynam from the Travel Foundation, a charity that encourages sustainable tourism.
"No one benefits from getting to a point where things are so bad that you have to actually close attractions down," he told the Thomson Reuters Foundation.