Historically, cities have played an integral part in producing food for their residents but efforts to feed the cities of tomorrow will increase as the global population is expected to soar over 10 billions in the next 80 years.
For example, in 2100, the population of Asia is expected to reach 4.71 billion, up from 4.6 billion in 2019, also, Africa will increase its population from 1.3 billion in 2019 to 4.2 billions. (2)
Megacities are the ones that absorb this population increase world wide. These cities are growing fast, depopulating the countryside and agglomerating its residents in larger urban areas. For example, the population density of some cities such as Tokyo with 12,296 persons per square mile or Mumbai with 76,790 per square mile (3), show the difficulties to keep the food system and mitigate the effects of the global greenhouse gas emissions.
Population in urban agglomerations of more than 1 million in World was reported at 24.01% (% of a country's population) in 2018, according to the World Bank collection of development indicators, compiled from officially recognised sources. (1)
Food systems refer to processes starting with agricultural production and continuing with the manufacture, packaging and transport to the final customer. In the next years, the food systems will have to face, together with the urban environmental impact, challenges like the management of food waste, deforestation, expansion of agricultural land areas and loss of productivity (5), depletion of fishery resources or the increase of greenhouse gas emissions from agricultural productions for example.
Also, urban centres are becoming food hubs increasing availability of products and attracting thousand of costumers. A poor control on the food system may lead in a high risk of foodborne or zoonotic diseases transmitted to humans. The 2020 coronavirus outbreak is believed to be started in a wet market in the overpopulated Wuhan and it has so far killed at least 131 people and infected more than 4,600 (8) (update 29 Jan 2020). In China, a wet market is a place where vendors often slaughter animals in front of customers or process meats and live animals, including chickens, donkeys, sheep, pigs, foxes, badgers, bamboo rats, hedgehogs, and snakes. (6)
Wildlife Conservation Society recently said in a statement "Poorly regulated, live-animal markets mixed with illegal wildlife trade offer a unique opportunity for viruses to spillover from wildlife hosts into the human population".
... but all is not lost
One of the options to make more sustainable a Megacity is promoting an urban agro-alimentary system where bringing agricultural production closer to urban areas will reduce the carbon footprint and the dependence from fuel supplies. Also, changing diet to reduce meat consumption is another strategy to reduce water consume and greenhouse gases.
Current cities still need to develop an efficient agro-system, including production, distribution, consumption and waste management but certainly, more and more people is aware of the sustainability of the cities. For example, this awareness is reflected in govern regulations such as the ban on plastic straws, drinks stirrers, and plastic cotton buds in England from 2020 (Over 80% of people voted in support of a ban on the sale of plastic straws in a public consultation) (7). Also, the European Parliament announced this year that single-use plastics will be banned as from 2021.
Obviously, we cannot eliminate plastic from one day to the next and, in return, get unsafe and contaminated food. The transition should be progressive and the costumers shouldn't feel confused with the new materials. A lack of public understanding could result in the mismanagement of used packaging.
Actually, more and more companies are increasing resources in research and development that finally will remove plastics from our lives but nowadays, the technology is light years away from reaching the industrial production scales. In the other hand, it is very encouraging that the new compostable materials are reaching very similar mechanical properties to the common plastics.
Other options to make more sustainable Megacities are the use of hydroponic growth systems which reduce water consumption in urban agricultural production or more controversial options such as the use of genetically modified organisms that increase agricultural yields.
Finally, a new huge market of plant-based meat and cell-based food has been created in just a few years. If these products become mainstream, they could release the pressure of high demand of protein in our diets and help to control the greenhouse gases and water use.
Undoubtedly, new technologies will be the lifeboat for the sustainability of cities and will move the main locus of food production from the rural field or urban farming plot to the city laboratory. (4)
(5) Luciene Gomes (2019). Agricultural Expansion in the Brazilian Cerrado: Increased Soil and Nutrient Losses and Decreased Agricultural Productivity. Accessed 28 January 2020
(8) Steven Jiang. CNN (2020). Death toll in mainland China now stands at 131. Accessed 29 January 2020