IELTS Academic Reading Practice Test 19

Before mechanical refrigeration, ice was a luxury enjoyed mainly by the wealthy. In ancient times, rulers in China, Persia and the Roman world had snow and ice brought from the mountains and stored in pits, but such supplies were small and costly. In cold climates, landowners cut blocks from frozen ponds in winter and stored them in insulated ice houses, often built partly underground, for use during the summer. The idea that ice could be harvested on an industrial scale and shipped thousands of kilometres to tropical ports would have struck most people as absurd. Yet for much of the nineteenth century, frozen water from the lakes of New England was one of the more remarkable exports of the United States, reaching customers as far away as the Caribbean, South America and India.

The trade was largely the creation of Frederic Tudor, the son of a wealthy Boston family, who was only in his early twenties when he began. In 1806 he sent a ship called the Favorite to the Caribbean island of Martinique, loaded with ice cut from ponds near Boston. The ice survived the voyage reasonably well, but the venture was a commercial failure.

The island had nowhere suitable to store ice, and local people, having never used it, saw little reason to buy it. Over the following years Tudor lost a great deal of money, and at one point he was jailed for debt. He persisted nevertheless, building insulated storehouses in Caribbean ports and persuading bar owners to serve chilled drinks, on the reasoning that customers who had grown used to them would not want to give them up.

The industry was transformed in the 1820s by innovations in harvesting. Ice was cut only once it had grown thick enough to bear the weight of men and horses, and the work had previously been done slowly with saws and axes. Nathaniel Wyeth, who managed ice cutting for Tudor at Fresh Pond near Cambridge, Massachusetts, developed a horse-drawn cutter that scored the surface of the ice in a grid of parallel grooves.

Workers could then split the ice into blocks of identical size, which were quicker to handle and could be packed tightly together, leaving less of their surface exposed to warm air. According to one estimate, such improvements lowered the cost of harvesting from about thirty cents a ton to ten. Wyeth also experimented with better designs for ice houses, and the proportion of each harvest lost to melting fell dramatically.

Keeping ice frozen on long voyages required effective insulation. Early shipments were packed in hay, but the trade came to rely on sawdust, a waste product that the sawmills of Maine and other parts of New England produced in vast quantities and were glad to sell cheaply. Ice also had an advantage that made it attractive to shipowners. Vessels that brought sugar, cotton and other goods into Boston often had little to carry on the outward journey and needed heavy ballast to keep them stable at sea. Ice could serve as a paying form of ballast, so captains were willing to transport it at low rates.

The most ambitious voyage took place in 1833, when the Tuscany carried around 180 tons of ice from Boston to Calcutta, a journey of about four months that took the ship across the equator twice. More than half of the cargo survived, and the ice was received with great enthusiasm by the British community in the city, which had previously depended on small quantities of ice produced in shallow pits during cold nights. Ice houses were soon built in Calcutta, Bombay and Madras, and the trade with India continued for several decades. Writing about Walden Pond in the 1850s, Henry David Thoreau reflected that the water of his Massachusetts pond was now being drunk in India.

Most ice, however, was consumed in the United States itself. As American cities grew, ice became an everyday necessity rather than a luxury. Households kept food cool in wooden iceboxes lined with metal, supplied by delivery men who called several times a week. Ice made it possible to transport meat and fish over long distances in refrigerated railway wagons, and it allowed brewers to produce lager, which must be kept cool while it ferments, throughout the year. Harvesting spread from New England to the Hudson River and the lakes of the Midwest. In Europe, Norway became a major exporter, sending lake ice to Britain, where the Swiss-Italian businessman Carlo Gatti stored imported ice in deep wells beneath London.

The natural ice trade eventually fell victim to its own success and to new technology. As cities expanded, many of the lakes and rivers from which ice was cut became polluted by sewage and industrial waste, raising concerns about the health risks of natural ice. Mild winters periodically produced poor harvests and sudden shortages, which encouraged the construction of plants that made ice mechanically. By the early twentieth century, manufactured ice was replacing the natural product, and from the 1930s electric refrigerators began to remove the need for delivered ice altogether. Little physical evidence of the industry survives, but the demand for cold that it created helped to prepare the way for the refrigerated world we now take for granted.

Few animals are as easily overlooked as the earthworm, yet few have such a profound influence on the land. In fertile grassland, a single hectare may contain more than a million of them. Earthworms belong to a group of segmented animals known as annelids, and several thousand species have been described, ranging from a few centimetres in length to giants such as the Gippsland earthworm of south-eastern Australia, which can grow to more than a metre. Earthworms have no eyes or lungs; they absorb oxygen through their moist skin and detect light with sensitive cells near the front of the body. Each worm is a hermaphrodite, with both male and female reproductive organs, although two individuals must still mate in order to exchange sperm.

The first scientist to study earthworms seriously was Charles Darwin, whose final book, published in 1881, was devoted entirely to them. Darwin spent decades observing worms in his garden and in fields near his home in Kent. He noticed that stones and other objects lying on the surface of a field gradually sank, not because they were pushed down but because worms deposited their casts – the soil they had swallowed and excreted – on top of them. He estimated that in some parts of England worms brought up more than ten tons of earth per acre every year. He also tested their senses, finding that worms took no notice of loud notes travelling through the air but retreated rapidly into their burrows when a pot containing them was placed on a piano and a key was struck. The book proved remarkably popular, initially selling more copies than On the Origin of Species.

Modern ecologists divide earthworms into three broad groups according to where they live and what they eat. Surface-dwelling species live in leaf litter and decaying matter and seldom burrow; they include the red worms widely used in compost bins. A second group lives within the upper layers of the soil, digging horizontal tunnels and feeding on soil enriched with organic matter. The third group, which includes the common European earthworm Lumbricus terrestris, digs permanent vertical burrows that can extend more than a metre below the surface. These worms emerge at night to drag fallen leaves down into their burrows, mixing fresh organic material deep into the ground.

The tunnels created by worms allow air to penetrate the soil and enable rainwater to drain into it, rather than running off the surface and carrying topsoil away. As worms digest plant material and soil, they break organic matter into smaller fragments and leave casts that are richer in available nutrients, particularly nitrogen, than the surrounding earth. A meta-analysis published in 2014 by Jan Willem van Groenigen and colleagues, which combined data from 58 studies, found that the presence of earthworms increased crop yields by an average of 25 per cent. Interestingly, the effect disappeared where nitrogen was already plentiful, for instance where fertiliser had been applied generously, suggesting that worms help plants largely by releasing nitrogen locked up in dead plant material.

Earthworms are sensitive to the way land is managed. Repeated ploughing destroys their burrows, exposes them to predatory birds and buries the surface residues on which many species feed, so populations are generally larger where farmers disturb the soil less. Some pesticides are also toxic to worms, and populations decline where soil is compacted by heavy machinery or becomes very dry or acidic. In Britain and Ireland, a further threat appeared in the second half of the twentieth century in the form of the New Zealand flatworm, an accidentally introduced predator that feeds on earthworms and has reduced their numbers in some fields, particularly in Northern Ireland and Scotland.

For a long time, scientists assumed that earthworm diversity, like that of most groups of animals, would be greatest in the tropics. A global study published in 2019, led by Helen Phillips and drawing on records from thousands of sites, found otherwise. The number of species at a given site, and the abundance of worms, tended to be higher in temperate regions such as Europe and north-eastern North America than in the tropics. The researchers also found that climate, particularly rainfall and temperature, was more important than the properties of the soil in explaining where worms were found, raising concern that climate change could alter earthworm communities and the services they provide. Records were scarce for large parts of Africa, Asia and South America, however, so some of these patterns may change as more data are collected.

Earthworms are not welcome everywhere. Much of northern North America was covered by ice sheets during the last glacial period, which eliminated any native earthworms, and the forests that developed afterwards evolved without them. European species, introduced with soil and plants brought by settlers and later spread by anglers discarding bait, have since invaded many of these forests. There they consume the thick layer of fallen leaves on the forest floor, exposing the soil and depriving native wildflowers, tree seedlings and some ground-nesting birds of the conditions they depend on. More recently, Asian 'jumping worms', which thrash violently when handled, have spread across parts of the United States, turning rich forest soil into a loose, granular material. The same animal that Darwin admired as a builder of soil can, in the wrong place, become a destroyer of ecosystems.

In the summer of 2024, residents of Barcelona made international headlines by spraying tourists with water pistols during a march against mass tourism. Similar demonstrations took place in Mallorca, the Canary Islands and elsewhere in southern Europe. The word 'overtourism', which came into widespread use only in the second half of the 2010s, has become shorthand for complaints that are now heard in destinations from Amsterdam to Kyoto: overcrowded streets, rising rents, the disappearance of ordinary shops and the sense that a place is being turned into a stage set for visitors. These complaints are genuine, but the debate surrounding them is often confused, and some of the most popular remedies are unlikely to work.

It is tempting to see the problem simply as one of numbers. According to UN Tourism, the United Nations agency responsible for the sector, international tourist arrivals reached about 1.4 billion in 2024, almost back to the level of 2019 after the collapse caused by the pandemic. Yet total numbers explain surprisingly little. France receives more international visitors than any other country, but most of its towns and countryside experience no crowding at all. The real difficulty lies in concentration: visitors cluster in a small number of famous places, at the same times of year and often at the same times of day. A historic centre that is pleasant to stroll through in February may be almost impassable on an August afternoon, when the arrival of several cruise ships coincides with the peak of the holiday season.

Venice illustrates the consequences most starkly. In 2022 the population of its historic centre fell below 50,000, less than a third of what it had been in the early 1950s, while the city continues to receive millions of visitors every year. As apartments are converted into holiday lets and shops selling everyday goods give way to souvenir stalls, the remaining residents find it harder to live there, and further departures follow. In 2024 the city began charging day visitors a fee of five euros on busy days, and in 2025 the charge rose to ten euros for those who booked late. The scheme has raised money and produced useful data on visitor flows, but there is little reason to think that a fee of this size discourages many people from a trip that already costs far more.

Some destinations have used price more aggressively. Bhutan has long pursued a policy it describes as 'high value, low volume', and in 2022 it raised its daily sustainable development fee for most international visitors to 200 US dollars, before halving it the following year in an effort to revive arrivals. The government has said that the fee helps to pay for free health care and education, as well as for the protection of the country's forests and culture. Its experience shows the dilemma of using price as a means of control. A charge high enough to reduce numbers substantially is likely to turn travel into a privilege of the wealthy, while a modest one does little except raise revenue. Moreover, a country with a single international airport and a small number of land crossings can control access in a way that an open city cannot.

A more promising approach targets the specific mechanisms through which tourism harms residents, and the most important of these is housing. Short-term rental platforms have made it more profitable for owners to let apartments to visitors than to local tenants, reducing the supply of homes in popular neighbourhoods. In 2024 Barcelona announced that it would not renew the licences of more than 10,000 tourist apartments when they expire in 2028, and other cities, including Amsterdam and New York, have imposed strict limits on short-term letting. Critics argue that such restrictions may simply push rentals into an illegal market, and their effect on rents has yet to be measured. But they at least address a cause of local discontent directly, rather than attempting to manage tourism as a whole.

Natural sites present a somewhat different case, because there the damage is ecological as well as social. Maya Bay in Thailand, made famous by the film The Beach, was receiving thousands of visitors a day before the authorities closed it in 2018. When it reopened in 2022, boats were no longer permitted to enter the bay itself, swimming was banned and visitor numbers were limited, and blacktip reef sharks, which had largely disappeared, had returned in large numbers. The bay is now also closed for two months each year during the monsoon season to allow further recovery. Closure is an extreme measure, and it is rarely available to cities whose residents and businesses depend on access. It does demonstrate, however, that the harm caused by overcrowding is not always permanent if the pressure is removed in time.

The underlying lesson is that overtourism is less a matter of too many visitors than of poor management. Cities that attract tourists cannot simply wish them away, and many residents depend on the income they bring. What such cities can do is spread visitors more evenly across seasons and districts, require advance booking for the most fragile sites, regulate the conversion of homes into holiday accommodation and ensure that the revenue tourism generates benefits the people who bear its costs. None of these measures is as dramatic as a ban or as eye-catching as an entry fee. But a place that remains worth visiting is, in the end, one where people still want to live.