Urbanisation and demographic change

Across the globe, water security is being affected by a rising demand for water. Three trends are fundamental to this. Firstly, the rapid growth of our global population. Secondly, the associated increase in urban development across our planet. And thirdly, rising incomes around the world. In this part of the course, you will think about how increasing human pressure might affect water security in different parts of the world. The aim is to introduce the major pressures of increasing population, increasing incomes, and rising urbanisation. By the end of this part of the course, you should be able to critically consider the implications of these trends, and to consider how they might impact on water security.

The United Nations estimates that our global population will increase from 7.3 billion persons today to a population of around 10 billion by 2050, and to more than 11 billion people by the year 2100. If current patterns continue, then this means that our global water footprint will also increase from an estimated 4,600 cubic kilometres today to up to 6,000 cubic kilometres by 2050. Considering that the safe operating level for humanity– known as the planetary boundary– for freshwater consumption is estimated at around 4,000 cubic kilometres, the future challenges to water security are clearly visible. Of course, demographic change is not evenly distributed across the world, concentrating the water security challenge in key locations.

During the years 2015 to 2050, half of the world’s population growth is expected to be concentrated in nine countries. With the highest rate of population growth, Africa is expected to account for more than half of the world’s population growth between 2015 and 2050. Since the 1950s, the world’s urban population has more than quadrupled, and is projected to increase to around 7 billion people by 2050. In practise, this means that in the 100 years between 1950 and 2050, the balance between the proportion of the population living in urban and rural areas will have reversed.

The increase in the demand for water is not solely due to a rising population, but also to rising demand from associated industry and business, as well as the energy required to power our lifestyles. Whether our cities can cope with these rising demands is an important question, as many cities struggle to maintain and upgrade their ageing infrastructures, let alone invest in expanding capacity to meet rising demand. The world’s urban population has been growing most rapidly in middle income countries, particularly in Asia. This is putting significant pressure on water security in these countries, particularly those on lower and middle incomes.

This trend will continue in the future, with urban populations in Africa set to rise rapidly, presenting new challenges for water security in this region. Whilst it is a global challenge, water security is very much a local issue. It is not solely the rise in population or its concentration on our cities and towns that will impact on water security in the future. Equally important will be future consumption patterns as incomes rise. As we get wealthier, we also use more water. However, we also tend to become more environmentally conscious as we get wealthier. This suggests a rising debate is in store regarding how much water we can and should use, and how much we should protect our surrounding ecosystems.

With rising incomes, there are also opportunities to invest in technologies and solutions to promote stronger water security. Technological advances also bring costs down. Successful measures do not always require significant financial investments, better catchment management being just one example of this. Actions can be taken by public authorities and by firms and households themselves. However, individual responses to strengthen personal water security may act against water security for other societal groups and the wider ecosystem. This highlights the importance of good governance. If business as usual is not an option, then we should promote new approaches to strengthening water security for the future.

In their work on water-scarce cities, the World Bank advocates five sets of actions– demand management and infrastructure efficiency, innovative surface and groundwater management, nonconventional water resources, cooperation with other users, and adaptive water system designs and operations. To this list, we might also want to add strengthening behavioural changes to promote water conservancy and the role of water sensitive urban design and planning. What other actions would you suggest? Demographic change and urbanisation present growing challenges for global water security. If investment cannot keep pace with increasing population, then the risks of water shortages and of unsafe water may rise rather than fall, impacting on both ecosystems and on people.

Many of our fastest growing cities are located in areas prone to flooding and to drought, highlighting key water security considerations. What is clear is that we not only need to find better water management approaches, but also need to practise better water conservancy, which takes into account ecosystem impacts as well as human needs.