Developing sustainable urban infrastructure benefits not just the environment, but can also boost economic growth and social stability, according to a United Nations report released today, which stresses the need to transition to resource-efficient technologies in cities, given scarce natural resources.
"To date, the trend towards urbanization has been accompanied by increased pressure on the environment and growing numbers of urban poor," said the UN Environment Programme (UNEP) Executive Director, Achim Steiner, at the launch of the report in Nairobi, Kenya.
"But unique opportunities exist for cities to lead the greening of the global economy by increasing resource productivity and innovation, while achieving major financial savings and addressing environmental challenges," Mr. Steiner said.
The report, 'City-Level Decoupling: Urban Resource Flows and the Governance of Infrastructure Transitions,' argues that sustainable city infrastructures can sustain economic growth while using fewer resources.
Around three-quarters of the world's natural resources are already consumed in cities, and the proportion of the global population living in urban areas is set to rise to 70 per cent by 2050.
The study says much greater effort is needed to support new and improved infrastructure for water, energy, transport, waste and other sectors - generally located in and around cities - to wean the world off unsustainable consumption patterns, and avoid serious economic and environmental implications for future generations.
The report, which was produced by the UNEP-hosted International Resource Panel (IRP), features 30 case studies around the world that show how sustainable infrastructures have created scores of green jobs and reduced environmental degradation.
Fore example, in Melbourne, Australia, carbon emissions dropped by 40 per cent after the introduction of energy efficiency measures in public buildings, while in Cape Town, South Africa, a re-fit of low income housing with solar water heaters and efficient lighting has saved over 6,500 tonnes of carbon per year, cut respiratory illnesses by 75 per cent, and reduced the cost of hot water for poor households.
Other efforts involve reducing oil consumption by moving more people and goods onto public transport powered by electricity, or re-establishing urban farms to supply locally grown food.
The cost of meeting the urban infrastructure requirements of the world's cities between 2000 and 2030 is estimated at $40 trillion - both through the building of new infrastructure or retrofitting existing facilities, the report states.
"Older cities may have to retrofit and replace inefficient infrastructure into which they have been locked for decades to achieve decoupling, but newer and expanding cities have the advantage of flexibility. They can 'get it right' the first time," said the Executive Director of UN-HABITAT, Joan Clos.
"In an era of rising energy prices, an early transition to systems that consume increasingly cheaper renewable energy sources will pay off quickly," Mr. Clos said.
The report also provides recommendations for city planners to minimize environmental damage and maximize the potential for using resources more sustainably.