Despite his and wife Meghan's occasional penchant for private jets, Prince Harry knows it's true: we need to change the way we travel. His newly announced Travalyst initiative, partnering with industry heavyweights including TripAdvisor and booking.com, is focused on finding ways to make travel more sustainable. He is not the only one to have noticed the problem; nor is he the only one working on a solution.
''Sustainable travel is very much in mindset, both of the public and of business,'' says James Thornton, chief executive of Intrepid Travel. ''For companies like Intrepid, it's in our DNA, but we need to see it become the default setting for all travel.''
We are more aware than ever of the downsides of travel. Fly somewhere long-haul and check into an air-conditioned hotel and you're helping speed up climate change, or head for a holiday in a popular city and you may find the locals are well and truly over tourists.
The good news is that making ethical choices is also easier than ever, with travel companies changing their practices to meet customer demand. ''People are excited about supporting [operators] who speak to their values,'' says Michael Londregan, managing director Asia-Pacific of travel advisor network, Virtuoso. ''They are as interested in the values as they are in the product.''
Getting travel right is especially important given the industry's economic impact. According to the World Travel and Tourism Council, the $US8.8 billion industry sustains 319 million jobs - that's 10 per cent of all the jobs in the world. With such a huge economic impact, we don't want travel to disappear, but we do want to do it better. Do your bit by making sure you are across these issues before you take your next trip.
WHAT THEY SAY Barcelona and Venice, Dubrovnik and Iceland: increasingly, destinations are declaring themselves fed up with floods of tourists crowding their streets.
WHAT WE SAY Overtourism is often about ''when'' rather than ''where''. Even Venice can be crowd-free if you visit in the cooler months.
WHAT YOU CAN DO Perhaps, counter-intuitively, spending longer in a destination helps reduce crowding, as long-stay visitors tend to move around the entire city rather than just hitting the must-see spots. And, of course, longer stays give you a more in-depth experience.
WHAT THEY SAY From dolphins bred in captivity to tourists posing for photos with lion cubs, awareness of animal exploitation is rising.
WHAT WE SAY According to World Animal Protection (WAP), more than 3000 captive elephants are used in tourism in Asia - that's 30 per cent more than five years ago. WAP found that 96 per cent of venues offering elephant rides keep their animals in unacceptable conditions.
WHAT YOU CAN DO This one is simple: avoid all activities which involve taming or training wild animals.
WHAT THEY SAY What could possibly be wrong with heading to a foreign country to make a difference, perhaps helping out in a school or hospital? Critics say that voluntourism is a short-term fix that ignores the systemic root of the problems.
WHAT WE SAY Studies have documented shocking cases of unqualified volunteers actively displacing health professionals and taking work opportunities from locals.
WHAT YOU CAN DO Pick your project carefully: look for a charitable organisation with transparent processes and outcomes that doesn't cut across existing aid initiatives. Citizen science projects run by environmental charity Earthwatch are a good choice.
WHAT THEY SAY Remember orphanage tourism? Travellers flocked to spend an afternoon playing with ''orphans'', until it became clear that not only were some of the children not actually orphans, but that exposing children to endless strangers isn't a great idea.
WHAT WE SAY Orphanage visits may be a thing of the past, but child exploitation is still way too common. Never buy from children or give them money - all you are doing is turning children who should be at school into income earners.
WHAT YOU CAN DO A simple rule: if you wouldn't want someone doing it to your child, don't do it to someone else's. (Yes, that includes handing out sweets). If you want to help, donate to a reputable charity or NGO.
WHAT THEY SAY Air travel generates around 5 per cent of the world's carbon emissions and passenger numbers are expected to double in the next two decades. The flight shaming movement urges travellers to choose alternatives such as train travel.
WHAT WE SAY Flight shaming has swept Europe, a continent with excellent rail and road links, but is less popular in the United States and Australia, where distances are much longer.
WHAT YOU CAN DO Apart from investing in carbon offsets, rethink your long-haul trips. Instead of hopscotching across Europe, for instance - flying from Paris to Berlin to Moscow - consider basing yourself in one spot and exploring the surrounding area in depth.
WHAT THEY SAY It's known as the Airbnb effect: landlords listing their properties on online rental platforms such as Airbnb, leaving locals struggling to find somewhere to live.
WHAT WE SAY It is ironic that a business selling the idea of ''living like a local'' has led to crippling rent increases. On the upside, however, online platforms now give exposure to traditional pensiones and guesthouses.
WHAT YOU CAN DO Renting an Airbnb room in a remote, rarely visited village is a very different thing to booking yourself into a centrally located apartment in Amsterdam, so use the technology wisely. And remember that locally owned hotels, hostels and guesthouses are a great alternative.
WHAT THEY SAY Zika. Ebola. Cholera, malaria, HIV, swine flu, bird flu - all dangerous diseases ready to strike down the unwary traveller. The rise of drug-resistant microbes just adds to the fear factor.
WHAT WE SAY News flash: travellers are not only victims of diseases, they are also carriers. And it's not just exotic diseases that are dangerous, as a number of measles outbreaks spread by travellers have recently shown.
WHAT YOU CAN DO Keep your immunisations up to date, including measles, mumps and rubella. If you are taking antibiotics, finish the entire course. And, of course, don't leave home without comprehensive travel insurance.
WHAT THEY SAY Some countries should be no-go zones. Rather than supporting a corrupt or authoritarian regime, travellers should spend their money elsewhere.
WHAT WE SAY You can find reasons to boycott just about any country if you try. Australia could be targeted for our track record on Indigenous health, treatment of refugees and even the state of the Great Barrier Reef. And who gets hurt most by boycotts? Not the government, but locals trying to eke out a living from tourism.
WHAT YOU CAN DO Wherever you choose to travel, do your research and travel with a company that supports local business and communities.
WHAT THEY SAY According to a UN report released in May, one million of the world's species are under threat from extinction. We are in the middle of the biggest spate of extinctions since the disappearance of the dinosaurs, and species from lions to polar bears are vulnerable. Some say that taking a safari to see these animals is akin to a death watch.
WHAT WE SAY Tourism is actually the best hope for many species. It is particularly in areas where animals are subject to poaching that wildlife tourism can give locals an alternative income stream.
WHAT YOU CAN DO Choose an operator with a commitment to conservation, such as African specialists Wilderness Safaris or andBeyond.
THE TROUBLE WITH TREKKING
WHAT THEY SAY High-altitude treks are often based on the exploitation of local porters, who work long hours, carrying huge weights, for very little money.
WHAT WE SAY A number of international companies and porters' organisations have banded together to support porters' rights and identify local issues. One Nepalese study found that porters suffer four times as many accidents and illnesses as trekkers.
WHAT YOU CAN DO International organisations follow set standards on minimum wages, maximum loads and educational initiatives, but some smaller local companies don't. Opt for an organisation that advertises its commitment to porters' rights - and give your porter a generous tip.
WHAT THEY SAY The downsides of cruising: carbon emissions and dangerous particulates generated through heavy fuel oil, along with some cases of dumping rubbish, fuel and sewage into the ocean.
WHAT WE SAY Almost every choice a cruise company makes, from the fuel it uses to the shape of the ship's bow, to how it treats wastewater, has an impact on the environment, and standards vary across the industry.
WHAT YOU CAN DO Choose one of the cruise companies switching from heavy oil to liquefied natural gas, electric and battery power. If you are heading to a fragile environment such as Antarctica, look for a cruise company affiliated with the International Association of Antarctic Tour Operators, which imposes strict regulations.
WHAT THEY SAY To its supporters, slum tourism - visiting deprived neighbourhoods in cities such as Rio, Cape Town and Mumbai - replaces stereotypes with reality. To its detractors, it turns human beings into exhibits. As a former resident of Nairobi's Kibera slum wrote in The New York Times, ''They get great photos, we lose a piece of our dignity.''
WHAT WE SAY It all depends on which tour operator you choose. Some work closely with the communities and have strict guidelines. Some even ban the taking of photos.
WHAT YOU CAN DO Ask whether the company uses locals as guides, and what percentage of their profits goes to the community.
WHAT THEY SAY As cities grow ever larger, travellers are increasingly keen to experience true wilderness. Unfortunately, tourism can pose a threat to these destinations - and we're not just talking about Antarctica.
WHAT WE SAY An example close to home: during one of the recent floods of Australia's largest lake, Kati Thanda-Lake Eyre, experts warned visitors that by gathering firewood they were destroying the natural habitats of insects and small mammals.
WHAT YOU CAN DO Be aware of your destination's issues before you head off. Even something as simple as vibrations from jet skis have caused behavioural change among marine creatures in some destinations.
WHAT THEY SAY The plastic straw is public enemy No.1. Hotels, resorts and cruise lines around the world have all banned plastic straws in an effort to curb plastic pollution.
WHAT WE SAY Clearly it's not that simple. Just about any journey you take will involve endless excess plastic, from the mini shampoos in the hotel to that bottled water you just bought.
WHAT YOU CAN DO Hotel chains such as Intercontinental Hotel Group and Marriott are ditching mini toiletries and you can do your bit by thinking ahead. Pack a refillable drinking bottle (with water filters, if necessary), reusable cutlery and some reusable carry bags for any shopping you do.
WHAT THEY SAY When images of Norway's remote Trolltunga cliff went viral on Instagram, visitor numbers skyrocketed from 500 people to 40,000 annually. The result? Long queues of people waiting to get their shot, destroying the isolation that was once the attraction.
WHAT WE SAY Snap-happy crowds aren't the only downside of Instagram. Travellers in search of the perfect shot are also becoming reckless, with several selfie deaths around the world.
WHAT YOU CAN DO We all treasure a great holiday snap, but a trip should be about more than just photos. Tell the truth on social media: if you had to queue for hours to get a shot, say so.
REEFS AT RISK
WHAT THEY SAY With coral reefs in crisis, tourism can be a lifeline: the more money generated by tourism, the more likely governments are to try to help preserve them.
WHAT WE SAY Tourism can also have negative impacts, from careless visitors damaging coral to the recent discovery that even relatively low amounts of artificial light at night can disrupt the breeding cycle of clownfish, which has implications for overwater accommodation.
WHAT YOU CAN DO Travel with reputable operators who are committed to protecting the reef, and slap on a mineral sunscreen - chemical sunscreens are toxic to reefs.