"Urban growth is so immense that it must urgently be channelled in new directions," said WBGU Co-Chair Dirk Messner, Director of the German Development Institute. If more and more new settlements were to be built with cement and steel in the cities of the developing countries and emerging economies, the energy-intensive production of this building material alone could release such huge quantities of greenhouse gases by 2050 that the world's emissions budget of the 1.5°C target would already be virtually exhausted. Yet there are alternatives, e.g. building with wood or other natural materials. "Without decisive political action and international cooperation, humanity's natural life-support systems would be jeopardized by the demand for resources and the CO2 emissions of urban construction," said Messner.
Striving for sustainability in major cities and slums
The living conditions of city dwellers are also an issue here. There are already more than 850 million people today living in inadequate housing conditions. In sub-Saharan Africa, about two thirds of the urban population live in slums, in Asia around a third. Urbanization pressure is especially strong in Asia and Africa, where 90 percent of the global urban population growth is expected to take place. The current refugee movements show how difficult it is even for prosperous countries to cope with a rapid influx of people into their cities. By 2050, the number of people living in inadequate housing could increase by 1?to 2 billion. "This is why the living conditions of people living in extreme poverty in particular must take centre stage in urban development," said Messner. It is this fundamental change of perspective for the new urban agenda that the WBGU aims to initiate at the forthcoming Habitat III conference.
"A city like Hong Kong with its extreme densification is only viable because it sucks in oil, metals and food from the surrounding area and the whole world, digests it, and disposes of residues such as waste, effluent, exhaust gases into the surrounding countryside," explained Hans Joachim Schellnhuber, WBGU Co-Chair and Director of the Potsdam Institute for Climate Impact Research. "The distributed nature of renewable-energy generation, the circular economy and even the digital economy makes disaggregation possible – and to some extent even requires it. Polycentric integration in regions such as the German Ruhr area, which is currently re-inventing itself, or the San Francisco Bay Area can be models for the urbanity of the future."
Create the global conditions needed for sustainable urban societies
In contrast to the great importance of urbanization for the transformation towards sustainability, the corresponding international institutions are only weakly positioned.
In order to intensify the global debate on urbanization and transformation, the G20 should take up the subject on a permanent basis. Germany's federal government has a key role to play here, since it will be assuming the G20 Presidency in 2017. It should put the topic on the agenda.
The United Nations Human Settlements Programme (UN-Habitat) should be reformed and strengthened, so that its influence and efficacy are at least on a par with such programmes as UNEP.
Regular scientific progress reports would help promote an awareness of urbanization among the international community and clarify the actions that are needed for the transformation towards sustainability. There could be a committee similar to the Intergovernmental Panel on Climate Change (IPCC) that could conduct an integrated assessment of the scientific status quo on global urbanization dynamics.
Selected core recommendations for urban transformation fields
Climate and resources
- Replace all fossil sources of CO2 emissions in cities with alternatives by 2070 and reduce energy consumption, e.g. by using local solar power plants in informal settlements; in addition, fully decarbonize the transport systems, primarily by creating a city of short distances with a mix of living and working districts, as well as by a massive expansion of local public transport;
- Press ahead with adaptation to climate change; identify vulnerable zones in cities and avoid building there; redevelop informal settlements to make them climate resilient;
- Establish a circular economy in cities, not only for electronic waste, but also, for example, in building legislation, stipulating that buildings must be easy to dismantle or recycle.
- Reduce inequalities between the rich and the poor by re-orienting urban development towards the needs of the 30-40% of the population with the lowest incomes; at the same time, the increasing concentration of real estate and wealth must be counteracted, e.g. by tax regulations;
- Develop a cross-sectoral perspective on urban health, combining environmental protection and the fight against stressors with the preservation and development of healthy urban habitats;
- Tie urban land use to a test of compatibility with the common good; stem real-estate speculation.
Cities and international politics
- Globally recognize and strengthen urban societies as political players, e.g. giving them a right to speak at international negotiations;
- At the national level, strengthen the self-determination rights of cities and the participation of the population in local decision-making processes;
- Gear international development finance more towards cities and sustainability criteria.
- Strengthen national and international research on how to ensure that development is sustainable in the 'century of the cities';
- Set up a Max Planck Institute for Urban Transformation to further advance research on the issue; launch global urban real-world laboratories.