By 2050, around 70% of the world's population of 9,2 billion people is expected to live in an urban environment. Especially in developing countries this increasing population and expanding cities pose great challenges with respect to access to clean drinking water, sanitation, waste water treatment and protection against floods.
On request of UN Habitat, PBL Netherlands Environmental Assessment Agency has published today ‘Towards a world of cities in 2050 - an outlook on water-related challenges’. In this study the PBL Netherlands Environmental Assessment Agency, together with Arcadis, UNESCO-IHE and VU Amsterdam University, explores, future trends and challenges on these topics as input for the upcoming UN Habitat Global Report.
The world’s population is expected to grow by more than 2 billion people to 9.2 billion by 2050. Most of this growth will take place in developing countries and, more specifically, in the developing cities. At this moment, around 50% of the world’s population lives in an urban environment, and this percentage is expected to increase to 70% over the coming decades. The PBL-study shows that, therefor, major challenges lie ahead regarding access to clean drinking water, proper sanitation an protection against floods. However, the study also shows that knowledge and technologies are available that may strongly reduce the water-related stresses and risks for the human population.
Access to water expected to improve; sanitation to lag behind.
In the coming years, substantial progress may be expected in the access to safe drinking water and improved sanitation. The Millennium Development Goals that target water supply have already been attained, globally, and further progress is projected. However, sanitation is expected to lag behind, particularly in cities developing in sub-Saharan Africa. Whe cost-benefit ratio of iAiming for universal coverage by 2050, an annual 70,000 deaths could be avoided in sub-Saharan Africa alone.
Quality of surface water expected to deteriorate
A century ago, the dominant pathway for nutrients was their reuse in agriculture; today, the dominant pathway is for them to end up in surface water. This results in eutrophication and pollution of rivers, lakes and coastal waters. Continued investments in waste-water treatment in developed countries are expected to stabilise and restore surface water quality. The quality of surface water in other countries, however, is expected to deteriorate between 2010 and 2050. To prevent this, sanitation needs to be improved and combined with adequate waste-water treatment. For cities large-scale developments in sanitation, sewage and waste-water treatment systems are required. For rural areas, on-site sanitation and better management of faecal sludge may be promising options.
By 2050, 15% of global population lives in flood-prone areas
Leaving aside the effects of climate change, the number of people living in flood-prone areas is estimated to be 1.3 billion by 2050, or around 15% of the global population. As urban areas expand, hundreds of trillions of dollars in infrastructure, industrial and office buildings and homes will be increasingly at risk from river and coastal flooding – particularly in Asia. The PBL-study shows that a wide range of flood risk strategies can strongly reduce the flood risks, both with respect to loss of lives and economical losses. The costs of adequate flood protection measures may not necessarily be high, and high concentrations of assets and people in cities may provide an opportunity for highly cost-effective flood protection strategies.
‘Smart water’ - integration of water challenges in urban development required
Each chapter in the PBL-report identifies potentially successful policy options that would result in an improvement regarding the issues at hand. However, there are also important interconnections between the various water issues. This calls for an integrated approach in urban development, in which these aspects are considered in combination. An interesting concept that allows for such an integrated approach is that of ‘smart cities’ or, in this case, ‘smart water’. Smart water encompasses both technical as well spatial development approaches and acknowledges social equality. The various developing city networks may provide important platforms to exchange knowledge, understand the common challenges and share best practices and innovations that can support cities in their economic, spatial and social development strategies.