Air, water, food and natural resources
- What are the planetary boundaries and the constraints of natural resources that we live within?
- What are the challenges facing cities in this context of limited resources, and how can cities use them better for inter-generational equity?
In October 2015, one of the biggest cities of the Western Hemisphere, Sao Paulo in Brazil faced its worst drought in 80 years. Climate Change was only part of the problem. Other factors included the damage caused by pollution to the existing reservoirs and changing rainfall patterns due to the deforestation of the Amazon forests. Cities shape and in turn are shaped by their natural environment.
They are systems of systems that are located within wider ecological systems within the biosphere. They are dense networks of interwoven social, spatial processes that are simultaneously local and global, human and physical, cultural and organic. The close relationship between urban settlements and Nature or natural resources is as old as settlements themselves. Early cities were located close to rivers and lakes as well as cultivated lands to ensure a regular supply of food and water.
Not only do we continue to depend and draw on natural resources for our sustenance but urban economies and cultures are also inherently tied to the natural environment. As our cities and economies have grown more complex there’s been an increasing tendency to externalise nature and diminish the value and status of indigenous populations that have learned over many generations to read, understand and live within the limits of local and regional ecosystems.
This lecture will focus on the relationship between natural resources and cities; looking specifically at air, water and biodiversity. It will raise questions about the sustainability of what our urban regions need and consume, the challenges that this creates and how to begin tackling them. Cities need nature, indeed depend on it, for their survival and are now facing the dual challenge of balancing rapid urbanisation with the over use of natural resources, environmental degradation and Climate Change. Cities like all other human systems need to follow basic ecological principles in the medium to long-run to be sustainable, to give you some examples- to limit the rate of use of renewable resources like forest-based biomass or timber to below their rate of regeneration or assimilation, to limit the rate of use of non-renewable resources like fossil fuels to their rate of substitution by renewable sources like wind and solar energy. Cities occupy about 2% of the Earth’s surface but consume about 75% of the world’s natural resources, about three-fourths of the global energy supply and produce about 75% of the world’s carbon emissions. Although this raises serious questions about the future sustainability of cities, it also offers us a unique opportunity to enable urban regions to transition to sustainable development pathways.
Infrastructure choices that are made today ranging from building design, transportation and waste management to food, urban ecosystem management, energy and water system design have critical implications for the sustainability of urban regions. As metropolitan regions have grown, they’ve placed increasing demands on their rural hinterlands. The relationship between cities and the natural environment is a circular one.
Natural resources have shaped cities as much as cities have been impacted by the environment. Cities have created a conjoint; built and natural environment that has developed its own local microclimate in many locations that is different from the surrounding non-urban areas in terms of temperature, rain and even wind patterns. Ecosystem conservation within cities and urban regions is not only important for the natural environment, but also to protect critical ecosystem services that provide urban areas with clean air and water, help reduce the impact of urban heat island effects, drainage and flood control, provide rich and diverse sources of food and recreational locations like forest, lakes, rivers and beaches. A critical question within urban areas is the proportion of land and waterscapes that should be conserved for ecological uses, ‘How much of this should be wild or untouched?’ and to cater to the needs of other species and maintain ecosystem health and also deliver essential ecosystem services to urban areas.
Moreover as urban regions expand into their peripheries, they often encroach on and disrupt diverse ecosystems. Several cities around the world have incorporated a range of growth control measures to help curb this and restrict impact on surrounding areas, the example of the city of Portland in the United States and Vancouver are very interesting in this context. As the symbiotic relationship between biodiverse natural systems and human habitation is increasingly realised, cities across the world have started to pay serious attention not only to urban forests, wetlands and agriculture but to fauna and conservation areas. Some of the most liveable cities in the world including Vancouver, Sydney and London have carefully protected and managed their relationship with Nature.
There are also growing instances of human settlements coming into conflict with biodiverse natural systems both within and on the peripheries of urban regions. The wolves of Los Angeles and the leopards of Mumbai are a couple of interesting examples of this. City populations require food, water, fuel and raw materials for industry and other economic uses and must reach well-beyond their natural boundaries to fulfil these needs. These resource-sheds assume transcontinental proportions for large metropolitan regions.
Moreover, the rate at which these are being consumed is rapidly increasing as we are consuming resources faster than ecosystems are able to replenish them. Over-consumption impacts not only the sustainability of cities but also of the regions from where these resources are drawn. Water is perhaps the most critical of these natural resources. Early cities were located close to water sources or devised technology that would enable them to store or access reliable water supply throughout the year, whether this is the elaborate irrigation projects in the mines or the baolis or step-wells of Rajasthan, in India.
As the freshwater needs of urban regions grew and better technology became available, a growing amount of water was extracted through dams, wells and other waterworks. Water sources like rivers, lakes, tanks and even the seas also emerged as sinks for wastes from cities.
Effluents were dumped into rivers and pumped into groundwater. This sharply changed the dynamics of water systems, destroyed fish populations, polluted groundwater aquifers and deprived downstream users of adequate and unpolluted supplies. The process of regeneration and replenishing of water supply has been disrupted by urban development as an increasing amount of surface area in a city becomes impervious and generates run-off. These changes have meant changes in water supply and availability.
According to the World Resources Institute- WRI, more than 50% of India faces severe water-stress and this is only likely to increase as cities and populations grow. Air and land have also emerged as sinks for waste disposal in cities.
According to the World Health Organization WHO, over 80% of residents are exposed to unhealthy air quality that exceeds WHO limits. Air pollution seems to come from a range of sources: ranging from emissions from fossil fuels to large-scale construction activity and biomass burning. The critical thing about air pollution however is that its effects are not localised or limited within urban boundaries. Air pollution not only causes severe health conditions including respiratory diseases, but also affects crop patterns and rainfall.
According to the latest WHO ambient urban air-quality update, outdoor air pollution has grown in the amazing 8% in the last 5 years with fast growing cities in the Middle East, Southeast Asia and the Western Pacific among the most impacted. They show levels that are 5 to 10 times above WHO recommended levels. The top 5 polluted cities in Asia according to WHO estimates are Delhi, Beijing, Islamabad, Kathmandu and Dhaka. Outdoor air pollution causes more than 3 million deaths annually, more than Malaria and HIV/AIDS combined and is now the biggest single killer in the world.
These numbers are expected to double as urban populations increase and car numbers are supposed to approach 2 billion by the 2050s. The impact of this and other environmental issues is disproportionately borne by low-income and marginalised urban populations. During the 2008 Summer Olympics, China faced an air pollution emergency. Air pollution in and around Beijing was at least 2 to 3 times higher than levels deemed safe by the WHO. In response, the Chinese government introduced strict emergency pollution controls including suspending production at factories and coal-fired power plants, lowering the number of cars on the road and introducing other driving restrictions.
Although this provided temporary relief, there were no longer term measures that were successfully implemented. In January 2016 Beijing issued a pollution Red Alert closing schools, factories and construction sites and ordering half of all private vehicles off the road.
This also represents an opportunity for change. In 1992, Mexico City had one of the highest rates of air pollution in the world because of increasing population, industry and transport.
Recognising this the Mexican government implemented a series of programs that would help reduce air pollution in the city: these include encouraging the use of public transport, greeting the public transport feat by switching to electric buses, implementing a city bike scheme and encouraging the adoption of technology that would enable the reduction of emissions.
These measures were effective for some time but by 2016 pollution levels had slowly began to rise again indicating that continuous innovation is necessary to address the challenges of sustainable management of our cities.
On the other side of the globe, Delhi also went through a significant improvement in air quality in the 2000s after a fuel switch to gas for all public transport, but by 2015 it would become one of the most polluted cities in the world despite a massive investment of over 4 billion dollars in a 200 plus kilometre long Metro System.
The growth of personal vehicles in Delhi, almost 8 million vehicles for a population of about 19 million, driven by sprawl, poor public transport, population and income growth and an unsustainable urban trajectory had negated almost all the gains of a focused sectoral air pollution reduction strategy.
In short, we have to completely rethink the relationship between people, cities and the biosphere, to plan, develop and manage human settlements within local and global resource and ecological boundary. This implies putting ecosystem-health first and integrating cities, the urban metabolism and economies symbiotically into the interstitial spaces- an inversion of what people have done for over 5,000 years.
What have we learned in this chapter? Cities and natural resources have a circular relationship, urban regions shape and are shaped by the natural environment. Natural resources are critical to the survival of cities, they provide essential ecosystem services such as clean air and water, flood control, rich and diverse sources of food and recreational locations. As cities grow they are increasingly consuming greater proportions of global resources at faster rates.
This has implications for the future sustainability of cities as well as a relationship that cities have with their hinterlands. While urban regions have begun to think about ways in which to address these challenges, we need to completely rethink the relationship between people, cities and the natural environment.