According to the most recent United Nations World Urbanization Prospects report, more than half of the world’s population now lives in cities compared to 30% 50 years ago and 10% 100 years ago.
In Africa where the combined urban population is expected to double from about 300 million in 2000 to 750 million in 2030, the next two decades will be immensely challenging. With rapid population growth and a history of low-density settlement, the rate of increase in urban land cover in Africa is predicted to be the highest in the world.
Urban growth in Kenya’s cities occurs organically, in an unplanned fashion through proliferation of slums in the inner city. Slums often develop in ecologically sensitive areas such as riparian buffers and wetlands. For example, 16 out 25 major slum settlements in Nairobi are located in very close proximity to rivers, dams and wetlands.
Kenya’s urban expansion has taken an unprecedented path, annexation of farmland and rangelands. In 2009, Thika Greens Limited purchased 1,706 acres from Othaya Farmers Cooperative Society to build an ultra modern golf city 40 km from Nairobi. Tatu City will soon rise upon an old coffee estate 15 km northeast of Nairobi. About 96 km south of Nairobi, concrete, glass and steel skyscrapers will transform pristine rangelands into Africa’s Silicon Savannah.
Kenya’s growing urban clusters are now transforming peri-urban regions, with significant impacts on biodiversity and the provision of vital services of nature such as water. Moreover, loss of agricultural land to urbanization, combined with weak food systems, is beginning to place severe constraints on future food security for Kenya’s rapidly growing urban population.
Worldwide cities are widely regarded as crucible or laboratory for experimentation, failure and success. One would expect our city planners to learn from this laboratory and formulate innovative models for 21st century urban design. In her seminal book, The Death and Life of Great American Cities, Jane Jacobs argues that there is nothing inevitable – socially or economically – about the decay of old cities or the fresh-minted decadence of new urbanization.
We will wind up this century as homo urbanus, wholly urban creatures. Such a demographic transition will see millions give up the vast airy purity of open rural spaces for a cloistered, stifling existence in the city – the concrete jungle of hard tarred roads, stone, glass, steel, parking lots, traffic gridlock and foul air. Global sustainability is now tightly linked with safe and healthy urban living.
The Cities and Biodiversity Outlook report, the first global assessment of the links between of urbanization and biodiversity ecosystem services was launched at the 11th Conference of Parties to the Convention on Biological Diversity held in Hyderabad, India last week. According the report, urban growth will have significant impacts on biodiversity, natural habitats and a range of vital ecosystem services that we depend upon.
The Cities and Biodiversity Outlook report argues that while urbanization is the cause of many socio-economic and environmental problems, it provides an unprecedented opportunity for finding novel solutions for sustainable urbanization. Sustainable urbanization presents a great opportunity for achieving water, food and energy efficiency while enhancing the maintenance of vital ecosystem services both within and outside the city boundaries.
The future growth and expansion of Kenyan cities must not be condemned to one of two paths: proliferation of slums or annexation of agricultural land or rangelands. The sustainable growth pathway must comprise re-designing existing cities with development aggregated around high-density residential areas, mixed-use development, public transit, pedestrianism, public recreational spaces (squares and parks) and urban gardens.
The global epidemic of non-communicable diseases such as heart disease, diabetes and chronic respiratory illnesses, are associated with urban. However, there is growing evidence that urban spaces that improve air quality and promote active living can enhance human health. We must therefore increase the quantity and quality of well-planned beautiful public spaces.
Through innovative building codes, Nairobi could mandate harvesting and storage of rainwater. Ecological engineering deploying constructed wetlands and wastewater aquaculture can effectively to treat and purify roof and urban storm runoff. Nairobi can achieve water sufficiency and end its wasteful appropriation of water from outlying agricultural areas.
The metastasizing of cars is an indictment of our incompetence at urban planning and design. A combination of incentives for transit-oriented, walkable and bicycle- friendly urban areas can promote healthy living and reduce greenhouse gas emissions.
A study published by Egerton University’s Tegemeo Institute in 2011 revealed that 30% of food insecure households live in urban and peri-urban areas. The study also showed that 44% of households in Nairobi are undernourished. Urban agriculture provides a complementary strategy to reduce urban poverty and food insecurity.
Smart urbanization must equitably allocate the costs and benefits of development, enhance natural and cultural resources and promote economic wellbeing and population health.