The world today is experiencing unprecedented urban population growth. The trend is more dominant but not limited to developing and under-developed countries. It is estimated that by the year 2030, three-quarter of the world’s population will be living in urban areas, and developing countries like India and China will host the largest of these cities. According to North Carolina State University, the year 2007 proved to be a landmark year witnessing this transition. The world population turned more urban than rural on 23 May, 2007 – indicating that the pace of urbanisation is more rapid than expected. At the same time, urbanisation – which is indeed the most prolonged impact of the industrial revolution, has now become the driving force inviting even more intensive economic growth, exerting greater pressure on already overexploited natural resources. What makes matters worse is that every city depends on an area over two hundred times its size for its sustenance and growth.
Due to the availability of large number of amenities in an urban setting, the ecological footprint of individuals residing in developed megacities is usually more than those residing in developing and smaller towns and in rural areas. This fact is reflected in carbon footprints (CF) of individual cities. The CF of the city of London, for instance, is three times that of the city of Delhi. A high concentration of individuals and different lifestyles and aspirations of city dwellers is leading to an increase in the consumption pattern of global urban centres. The United Nations projections estimate that cities will house up to 9 billion individuals by until 2050 (World population prospects: The 2008 revision 2009, United Nations, New York). Rapid urban growth is thus threatening the sustainability of not just the urban centres but also the rural and natural hinterland that support them.
Urban growth and climate change: demographic impacts
The process of urbanisation has a two way cause-effect relationship with the global phenomenon of climate change. On the one hand, the increased resource consumption pattern of existing and emerging cities is leading to a greater extraction of natural resources; increased industrial emissions, and consequent and steady rise in carbon emissions from cities; all of which directly contribute to factors leading to climate change. On the other hand, the effects and impacts of climate change are resulting in worsening of the contemporary urban crisis in several ways. A key impact of climate change threatening urban sustainability is the large-scale influx of ‘environmental refugees’ into urban areas. The growth of urban population does not take place in a natural and isolated manner and ‘migration’ has always been an inherent component influencing it. For example, in the case of Delhi in the year 2007, natural growth of population comprised 52.58 per cent of the total percentage population growth while percentage growth of population due to migration in the same year was as high as 47.42 per cent (Economic Survey of Delhi 2008-09).
Since the industrial revolution the most dominant motivation behind migration to cities was better livelihood opportunities and a higher standard of living. In the last few decades, however, a significant group of migrants has emerged which includes persons who have been displaced from their homelands due to environmental factors of ‘unusual scope’. ‘Environmental refugees’, as they are being called, are people who are forced to leave or flee their long-established place of stay due to sudden or long-term changes to their local environment and/or weather patterns. These include changes such as increased droughts, unusual floods, desertification, sea level rise and disruption of seasonal weather patterns such as monsoons. Such changes compromise either the well being of individuals or their ability to secure livelihood or both forcing them to migrate to areas with better opportunities wherein cities become an obvious destination of choice. If the projection by the United Nations is to be believed, the number of global environmental refugees in the year 2005 may have been as high as 50 million. The figure, according to the same projection, could rise to as high as 150 million in the next four decades.
The most recent and apparent episode of ‘environmental refugees’ migrating to urban areas was witnessed earlier this year, in Maharashtra. A total of 15 districts in the State suffered from severe drought this year. As a result, the highways across the State witnessed open trailers packed with family and cattle moving to cities. Mumbai, Pune and Kohlapur were sought as destinations for truckloads of villagers from the rural hinterland. Migration by ‘environmental refugees’ also takes place across countries which further complicates the issue. In the case of Bangladesh, for instance, river erosion and sea-level rise is forcing the displacement of a large number of people. According to media reports, a good percentage of these ‘environmental refugees’ illegally cross the border into India leading to socio-political tensions between the two countries. It needs to be mentioned here that due to the uncertain nature of migration by ‘environmental refugees’, it is difficult to estimate the total number and pattern of migration. This calls for a greater focus and a policy strategy beyond the Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA) to address the root cause, evolve and implement nationwide mitigation and adaptation strategies towards climate change.
Urban growth and water availability
Water is an essential pre-requisite for supporting any population. Historians have noted that the words ‘aabadi’ (population) and ‘aabad’ (prosper) are both derived from the same Persian word ‘aab’ meaning ‘water’. Hydrologic changes due to climate change and nearly three billion additional urban dwellers in the near future will lead to large-scale water shortage in cities around the world. Megacities, Delhi, Mumbai, Chennai, etc., are already facing a water crisis in varying degrees in the wake of rapid urbanisation. Sustainable development of a city depends on three major performance indicators – economic, social and environmental. But water cuts across all indicators and threatens sustainability. Rainfall variabilities and disrupted weather patterns today and in the near future will make it difficult for scientists to model availability of water in rivers and in other water bodies. Since, the urban water scenario is governed by both natural and anthropogenic forces, increasing water demand by megacities could well threaten regional and global water resources leading to increased water conflicts.
Optimisation for a sustainable future
Rapid increase in size and number of urban centres will lead to the emergence of newer and more complex challenges in the near future. The alarm bells are already ringing. Cities are engines of economic growth, centres for the creative class and the topmost echelon of socio-political hierarchy. Large-spread megacities can become self sufficient and sustainable given the political will and necessary urban ecological inputs. The key is to introduce measures for optimising increasing ecological and carbon footprints of our cities. In the case of water resource, optimisation is even more important where governments and citizens alike buy their way out of a water crisis. In being able to do so, cities threaten not just their own sustainability but also that of the surrounding regions, towns and villages. Optimisation requires a detailed understanding of the resource demand as well as identification and adoption of most the efficient means for resource distribution. Optimisation will ensure urban sustainability and prove instrumental in ensuring effective urban growth amidst the constraints of a changing climate.