We live in a world of cities. Chances are that you’re reading this from a city – now one of many thousands dotting the surface of the Earth, in which over 50% of the world’s population spend their lives. By 2050, it is thought that roughly 70% of people will live in urban areas.[1]

urban-pop-graph

There is no denying the inevitability – and potential for success – that this massive urbanisation carries with it. Historically, cities are intertwined with societal development; they are hotbeds of business, politics and culture [2], and offer efficiencies in terms of resource-use and delivery of services per person that rural areas simply cannot match. The majority of urban growth is now focused in ‘developing’ countries, forming the engines of these ’emerging economies’, while the urban centres of ‘developed’ countries have long been the weighty, beating hearts of nation-states.

In this series of blog posts we’ll explore the impacts that this urbanisation trend (along with others) is having on food systems across the entire globe, from London to Lagos, between megacities and market towns – and how a new agricultural revolution could mitigate them.

A city stretches further than you think…

So what’s the problem, and what does this have to do with feeding people? You probably already have some idea about what the answer to that question might be. Take a moment to look at the picture at the start of this blog, which is one of the most extreme examples of urbanisation – apart from a couple of islands of green, this city is a dense mass of concrete and steel that supports hundreds of thousands, if not millions, of people.

This city obviously can’t supply everyone with the required resources using only the land of the city itself – it is dependant on other regions (inter)nationally to supply it with energy, resources, food and other ecosystem services [3] . This seems to be a logical product of societal specialisation and ‘efficiency’– it’s suggested by much mainstream urban planning policy that optimal land use is  through building intense, small surface area cities which leave room for expansive semi-natural hinterlands to support them [4] [5].

The diagram below offers a simplified argument for why one larger, denser city may have a smaller ecological footprint than several smaller, more sprawling towns. Due to the ‘economy of scale’ mechanism, it is supposed that urban living allows us to do more, with less!

urban-efficiency

However, when we take a real world example like London, we reality isn’t so simple, with startling results…

The Mayor of London’s Food Strategy for 2006-16 found that the ecological footprint of London (in global hectares) was roughly twice the size of the UK landmass. The ecological resources required for food production alone make up 40% of this [6]  – a gargantuan area for growing food!

london-ecological-footprint

In the graph below from footprintnetwork.org, it’s shown that the demand for ecosystem services across the entire UK vastly outstrips the biocapacity of our land to support us. So… where are we getting our food from?

UK footprint.jpg

The reality is that the UK is totally beholden to other countries for our survival – this year, it was found that we now import over 50% of our food. In a world where our government is battling for independance from European and international influence, this is an ironically large achilles heel. Not only does this have geopolitical consequences, but an array of significant environmental impacts too [7] [8].

This isn’t an exclusively UK problem however – we may be an unusual example of one aspect of food (in)security, but globally the ecological footprint, and food demand, of our cities significantly outstrips the planet’s capacity to support us. This, in combination with a number of biophysical changes across our planet, have come together to create:

food-crisis

So you might be getting slightly concerned now, and wondering what we can do to solve this multitude of issues around feeding ourselves and our fellow citizens. However, you may also be asking yourself why one of the solutions to this problem that pervades all regions, habitat types and demographics should be focused in urban areas? After all we’ve seen that there isn’t much room in cities, and our rural agricultural systems need more attention and care than ever.

To fully demonstrate this in the next chapter, we need to investigate one more aspect of contemporary urban development that is becoming a pivotal issue, and which can be addressed at least in part by urban agriculture.

Urban Metabolism: The Metropolitan Costs

While concentrating the energy and vitality of our societies in dense cities has profound and wide-reaching benefits, the physical processes that are instigated as a result have a number of damaging results which are becoming harder to mitigate.

These can be described under the umbrella term of ‘Urban Metabolism’, which concerns itself with the movement and recycling of energy in & out of cities – or in this case, a lack thereof.

It hinges upon the efficient

  • input of resources and energy such as food, raw materials, electricity – and their appropriate use
  • removal of waste products such as organic and inorganic waste, pollutants, and heat – and their effective recycling back into source/sink systems in order to perpetuate supply lines

Pervasive impacts of poor urban metabolism include:

heat-islandsource

‘The Urban Heat Island Effect’,  which is characterised by urban temperatures soaring above those in the surrounding country, due to the hyper-absoprtion of heat by surfaces such as asphalt, concrete and metal, and the emission of heat by cars, buildings and infrastructural systems [9]. This poses significant health risks to inhabitants, the integrity of structures and machinery, and urban biodiversity – as well as increasing greenhouse emissions.

air-pollutionsource

Air pollution is a serious risk to human health in urban cities around the globe. It has effects “ranging from eye irritation to death” [10] – the WHO claims that it causes around 7 million deaths a year (that’s 1 in 8 of all deaths worldwide). Particulate emissions from cars, stoves, factories etc. are to blame, all of which are found at higher concentrations in urban areas.

bird-over-citysource

Noise pollution can take many forms, whether it’s construction work, traffic, aircraft, high-frequency or sub-sonic noise from factories, power stations and more. It has been shown to have adverse health effects, severely alter the way urban bird populations function, as well as disrupting sleep & putting a strain on communities.

city-wastesource

Concentrated waste is difficult not only for municipal administrators to get safely out of the city, but exceedingly hard to effectively deliver back into the systems from which it came. This results in overstretched waste services, extensive landfill sites outside of city limits, and incredible amounts of waste  in areas such as food and rare technological components. Concerning examples of this include: drugs present in city waste water affecting ecosystems, significantly higher food waste from urbanites, city dwellers of same wealth produce twice as much solid waste as rural counterparts.

Where do we go from here?

So, there are a lot of things going wrong in our urban world – but, lots of things going right at the same time. Now that we’ve established the issues, we can begin to explore the potential applications of Urban Agriculture.

Coming up: Urban Agriculture Pt. 2 – Finding The Hand That Feeds You