Over-processed, over-preserved and over-packaged foods mean that consumers are buying foods of low nutritional value. Diet related diseases such as heart disease, diabetes and appendicitis increase as societies move towards the Western diet, low in fruit and vegetables, and high in refined starches, fats and sugars. Pesticide residues pose additional health risks, although it is the farmworkers who are most likely to suffer immediate health effects rather than the final consumers.
When consumers buy food from supermarkets, almost all the money is lost to the local economy. It may be lost to the national economy if the food is imported, or the product of food companies based abroad... >
Air pollutants and climate change gases are released as fossil fuels are used for production, transport and packaging of food and drink products. The CO2 emissions created by producing, processing, packaging and distributing the food consumed by a family of four come to about eight tonnes a year. Road freight alone is responsible for a high proportion of toxic emissions, such as nitrogen oxides and volatile organic compounds, which are implicated in a number of public health problems, such as asthma and other respiratory diseases. Meanwhile, industrial agriculture supplying international markets involves overuse of pesticides which leach into groundwater and threaten wildlife, land erosion, loss of wildlife sites and reduced biodiversity in wild and cultivated species.
Air freight of fresh foods has doubled in the past twenty years, a trend which is set to continue. Air transport is particularly damaging to the environment as it results in 37 times more carbon dioxide emissions than sea freight, and because pollutants are emitted at high altitudes where more damage is done in terms of ozone depletion and global warming.
Driven to shop
Shopper miles are also an issue as more people are driving to out – and edge-of-town supermarkets to do their food buying. One shopping trip by car can use more fuel than freight transport up to the point of sale, even if the produce is imported (athough not by plane).
The 3 ‘P’s: processing, packaging, pesticides
Food is perishable and needs to be preserved for long distance transport, to prevent spoilage and contamination... >
Consumers in rich industrialised countries are accustomed to being able to choose from the global breadbasket whenever they go to the local supermarket. A UK shopper can buy grapes from Chile, green beans from Kenya and bottled water from Canada. However these food choices do not come cheaply: there is a whole range of environmental, social and economic costs which result from the increasing long distance trade in foods.
The distance food travels, as well as being environmentally damaging directly through transport emissions, adversely affects the way food is grown and treated on its journey along the various links in the food chain... >
Urban agriculture is an important aspect of the wider issue of urban sustainability, both by being able to supply food from close-by and by offering livelihoods for city people. Another important issue, as already discussed, is the efficient use of nutrients from the urban metabolism that would otherwise end up as pollutants in rivers and coastal waters.
In many cities attempts are being made to use wastewater in urban food production. This applies particularly to cities in hot and dry places. For instance, in Adelaide, Australia, tens of thousands of hectares of land on the edge of the city are cultivated using wastewater from the city for irrigation, growing vegetables as well as grapes and fruit... >
But, anybody who thinks that urban farming is only a phenomenon primarily of poorer countries, should have a look around parts of New York City. In the Bronx, for instance, an astonishing range of vegetable gardens sprang up in the 1980s, primarily in areas where drug-related gang warfare resulted in houses being burned down and gardens left abandoned. With the help of people from the New York Botanical Gardens, local people turned dozens of vacant lots into thriving vegetable gardens. Many also grew crops for the sake of their children who they wanted to teach about growing vegetables and keeping chicken and rabbits.
In California, too, urban farming is widely practised... >
Urbanisation, and the shift from rural to urban living by billions of people, has not only resulted in major environmental problems, but also in urban poverty, food insecurity, and malnutrition, particularly in developing countries. But, almost unnoticed, it has resulted in the growth of a remarkable phenomenon: urban agriculture. According to UNDP, in 1996 some 800 million people were engaged in urban agriculture worldwide, with the majority in and around Asian cities. Of these, 200 million were thought to be market producers, with 150 million people employed full-time. Urban agriculture now occupies large minorities in many cities around the world. Cities such as Havana, Accra, Dar-es-Salaam and Shanghai have been studied extensively... >
The site of Heathrow airport used to be London’s market garden. Its sandy soil is very suitable for vegetable growing. Today, even though it is largely concreted over, Heathrow is still London’s major food supplier, but in a rather different way: food is flown in from across the globe. Such a global harvest offers us great culinary variety, but it requires the availability of vast quantities of fossil fuels. By the time food that has been air freighted for thousands of miles reaches a London dining room table, it will have used hundreds of times as much energy as the calories it actually contains. But it is not only air freighted food that is tremendously energy intensive... >
At the start of the new millennium we live in a world of unprecedented human numbers. There are currently about 6.3 billion people, and this figure is expected to increase to some nine billion by 2050. About half of the world’s population live in cities, a figure which is likely to grow to two thirds by 2030. Most cities are being built on farmland, a factor that will certainly reduce the world’s food production capacity unless city people produce significant proportions of their own food. So some important questions need to be answered: can the global environment cope with this ‘age of the city’? Will there be any untouched natural systems left? How can the world’s growing numbers of city people be fed?
A very useful methodology in this context is to measur... >
There is no particular reason why fresh, local, seasonal food could not be promoted as powerfully as the limited number of international foods which are available throughout the year. It is understood that urban agriculture will not supply all food needs and that a degree of imported staple and ‘special’ food will always top up basic food or enliven the pleasure of eating. However, with a well-established local food market, these imports could be kept to a reasonable minimum.
One of the arguments raised against this principle is that developing countries rely on food exports for foreign currency. But as made clear earlier, the prevailing models of trade are not the only options available... >