Some time this year or next, humanity will officially cross the line from being a rural to an urban species. For the first time in history, more of us will live in cities and urban areas than in the countryside, and the social and environmental implications of this transition to a predominanatly urbanised world are enormous.
UN figures for urbanisation, published this week in the State of the World 2007 report, show that more than 60 million people - roughly the population of the UK - are added to the planet's cities and suburbs each year, mostly in low-income urban settlements in developing countries. Unplanned urbanisation is taking a huge toll on human health and the quality of the environment, contributing to social, ecological, and economic instability in many countries.
Yet few governments or aid organisations seem to have grasped that a large part of the world's poverty is now in urban areas. Most aid agencies have no urban programmes and although reducing greenhouse gases will need strong urban programmes, urban issues are hardly mentioned in most discussions on climate change.
Urbanisation and the growth of large cities is mostly linked to economic success. The world's largest cities are heavily concentrated in the world's largest economies, including China, Brazil and India, as well as Japan and the US. The growth of "mega-cities" with 10 million-plus inhabitants is often highlighted as a problem, but these have less than 5% of the world's population, and most mega-cities have more people moving out than in, as smaller cities attract new investment.
Two other milestones help explain the increasingly urbanised world. By around 1940, the economic value generated by industry and services had grown to exceed that generated by agriculture, forestry and fishing. In the early 80s, for the first time, more than half the world's workforce was employed in industry and services; today, around two-thirds are.
In general, the more urbanised a nation the higher the average life expectancy and the literacy rate and the stronger the democracy, especially at local level. And, of course, cities are centres of culture, of historic heritage, of social, cultural and political innovation, of fun.
Inequality
In stressing these positive aspects, however, there is a danger of underplaying the scale of global problems. The positive aspects of urbanisation should not hide the deprivation and environmental problems that urban areas concentrate. Cities may be centres of wealth and opportunity, but they are also centres of huge and often growing inequality.
Around a billion urban dwellers - a sixth of the planet's population - are homeless or live in crowded tenements, boarding houses or squatter settlements, often three or more to a room. Most have to live with inadequate provision for water, sanitation, healthcare and schooling. Many are denied the vote, even in democracies, because they lack the legal address required for voter registration. They are often exploited by landlords, politicians, police and criminals. The global extent of urban poverty is under-estimated because it is usually measured by poverty lines based on the cost of food, ignoring the high costs that most low-income urban dwellers have to pay for renting a room or bed and for water, healthcare and transport.
Meanwhile, on the environment front, urban centres concentrate much of the world's pollution and greenhouse gas emissions. But most of these problems are not inherent to urbanisation. In fact, concentrating people and industries in cities lowers the costs of good provision for water, sanitation and healthcare and implementing environmental regulations.
Most urban problems are best seen as failures by governments and international agencies to adjust to the economic changes that drive urbanisation. This is not to pretend that these problems are easily addressed. But at their core are powerful corporations, real estate interests and politicians that oppose most of the needed changes - for pollution control, adequate wages, better working conditions, land for housing that low-income groups can afford and realistic charges for water, sanitation and electricity.
Because aid agencies provide money, "solutions" for lower income nations are always discussed in terms of how much money is needed. Yet most urban problems have to be addressed by local political changes. Many of the best urban innovations of the past 20 years required no aid because they were developed by citizen groups, often working with local non-governmental organisations and local politicians.
In Latin America, much progress has been made since democratically elected mayors were introduced and city governments got more scope to plan, act and raise revenues. Porto Alegre, in Brazil, which pioneered participatory budgeting - giving each district's population more influence in prioritising municipal investments - has a life expectancy and quality of life that rivals cities in Europe and North America. In Asia and Africa, hundreds of thousands of the poorest urban dwellers have benefited from better housing and services through their own slum-dwellers' and shack-dwellers' federations.
Such federations are now active in 16 nations and, where city governments work in partnership with them, the scale of what can be achieved multiplies. Urban resource centres in cities in Pakistan have shown how citizen alliances that include grassroots organisations can successfully challenge anti-poor and anti-environment policies and present viable alternatives. Similar centres are developing in cities in many other nations.
External funding is still required, but it has to support these kinds of processes. Aid agencies and international development banks were set up to fund national governments, not local processes. They are expected to spend their budgets, or make loans, with the least possible staff. Most have withdrawn from funding local initiatives because they are too staff intensive, and most avoid funding anything for extended periods. Yet the best support for urban areas would be funding that could be drawn on by grassroots organisations, local NGOs and local governments as and when needed, over long periods, while drawing in local resources wherever possible. This would not directly address global issues but global environmental agendas require competent local governments.
Cities also provide many opportunities to address global issues, including breaking the link between higher living standards and increasing greenhouse gas emissions - for instance, through urban designs that encourage people to choose to walk, cycle or use public transport. Concentrating people and industries and their wastes is dangerous without good waste management, but it provides more possibilities for waste reduction or recycling.
(...)
· David Satterthwaite, a senior fellow at the International Institute for Environment and Development, contributed a chapter to State of World: Our Urban Future report. worldwatch.org/urban
· Any comments on this article? Write to society@guardian.co.uk
