PICCADILLY Circus used to be a byword for crowds, but these days it has rivals. As the summer season gets into gear, Edinburgh’s Royal Mile fills to overflowing, like a bath whose taps have jammed. The seething mass occupying every centimetre between Edinburgh Castle and the Canongate is enough to make a claustrophobe’s knees wobble. And this is by no means the worst example. The tide of incomers in the old walled city of Dubrovnik in Croatia, for example, has become so overwhelming, the numbers entering its streets are now restricted. There have been accounts of tourists in Venice unable to cross the romantic Rialto Bridge because of the crush, and of fights breaking out in Rome beside scenic attractions as people jostle to take selfies. Photos of the Great Wall of China show a surging wave of sightseers, greatly outnumbering the army of warriors who once patrolled it. If the Great Wall can be seen from the moon, then the visitors crawling all over it must surely be visible from Mars.

Stories and images like this come from all across the globe, from Machu Picchu to Everest and Bali. Planet Earth, it’s clear, is in over-drive, teetering perilously on the brink of overpopulation. Bluntly put, in some places there are just too many of us. We are not yet at the stage the gloomy Reverend Thomas Malthus predicted back in 1798, where population disaster and plague and starvation are imminent, but there is inarguably a feeling of squeeze. Malthus’s doom-laden vision was overtaken by the industrial revolution, which he had not anticipated. Today’s increasing demand for food is being met inventively, to an extent, with genetically modified crops and exceptionally intense farming, though at considerable cost to the environment.

Bad enough the pressure on land and resources in countries where there is not enough to go around. But for affluent and poor nations alike, the consequences of better health care and increased longevity when combined with climate change will have a significant social and political impact within our lifetime. We’re already catching a glimpse of that as we join the queue for a hospital appointment, or grind to a halt in six-lane traffic.

For the moment, though, a pressing issue for many of us is not simply reducing our carbon footprint but where we choose to set foot. When the well-off take to the skies and descend, like a plague of locusts, on the most appetising, celebrated spots, we become part of the problem. It’s not pleasant thinking of yourself as an ill-omened pest, but it’s not entirely hyperbolic. When countries like Italy or Greece suffer serious water shortages, and at times barely have enough for themselves let alone the influx of heedless holidayers; when the centre of prime destinations like Barcelona or Florence – or Edinburgh – are turning into tacky day-tripper ghettoes, where locals are unable to afford accommodation, it becomes evident that the travel industry as a whole, and tourists as individuals, have lost control. So far, Edinburgh is not in the dire state of Venice, but a recent survey showed that one in10 properties in the city centre is now an Airbnb rental. A friend who lived near Edinburgh Castle sold up last year when he became “the last man standing” on a tenement stair where every flat was a holiday let, and buskers screeched like car-alarms beneath his window. By comparison, despite its world-class attractions, Glasgow feels inexplicably neglected.

The explosion of tourism has been scarily swift, as has the saturation of the supposedly most alluring locations. Other than those who go to resorts specifically catering for high numbers, very few of us are blameless. Yet our part in ruining popular hot spots is often unintentional. Those of a certain vintage, like me, will have fond memories of their favourite getaways before the advent of budget airlines and bucket lists. Not so long ago, by which I mean only 15 or 20 years, the Cinque Terre region of north-west Italy was quaint, quiet, and attractively rough at the edges. In autumn you could walk its coastal paths, swim in the sea and sip espressos without catching sight of another tourist, let alone be jabbed in the ribs by an aggressive elbow. It was easy to delude yourself into thinking you were a discerning traveller, when in fact you were only in the vanguard of an incoming tide. We might as well have been sending up flares to direct the hordes towards us, because today this picturesque area is flooded by cruise ships. They disgorge passengers onto the harbour side in numbers that defy common sense, making intolerable demands on the available facilities before setting sail once more, a few hours later, laden with selfies and souvenirs.

It would be nice to suggest we all stay home and potter around our own neighbourhood, but that’s neither likely nor practicable. Everyone needs to stretch their legs occasionally, and with tourism a vital source of income for many countries, as it is for us, to destroy it would be devastating. The sensible answer, instead, is to cut down on the frequency of airline trips and take more trains. When we do leave the country, we should travel less like sheep and more like lone wolves. Rather than following the herd, we need to find a mind of our own, avoiding the most heavily-beaten paths and seeking out places where there is enough space to enjoy the sights. Would it really matter if you never set eyes on Leonardo’s Last Supper or get close to a Pan Handle alligator, or place a stack of chips in a Macau casino? Aren’t there countless atmospheric medieval towns beyond San Gimignano, Seville and Salzburg?

In the end, it probably won’t be a conscious ethical decision that changes the way we spend vacations, but one miserable experience too many. As fewer and fewer post messages reading, “wish you were here”, and as we discover enough bodies between us and the Mona Lisa or a Bali beach to fill a football stadium, we will quickly begin to disperse. The world’s population might be growing larger with every passing day, but if you metaphorically search out the dirt tracks rather than the autobahns, there is still room to roam.

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