Climate change allies

The Big Read: Cities contain more than half of the world's population, use two-thirds of its energy and generate about 70% of its carbon emissions. Cities, therefore, will play a crucial role in cutting emissions of carbon dioxide and responding to the effects of climate change.

At a recent meeting in Sao Paulo, Brazil, of mayors of the largest cities in the world about how to tackle climate change, World Bank head Robert Zoellick, New York mayor Michael Bloomberg,and former US president Bill Clinton were the prominent voices.

But it is cities in developing countries that are at the forefront of the climate challenge.

Climate change will affect the urban poor across the globe more than anyone else - flooding low-lying informal settlements, affecting jobs in economies forced to cut carbon emissions and threatening food security as crops fail.

The cost to cities of adapting to climate change is estimated at $70-billion (R472-billion) to $100-billion a year, 80% of which will be borne by cities in developing countries.

South African cities have been at the forefront of developing practical examples and steps that can be taken to deal with the challenge.

Durban, which is hosting the next UN Framework Convention on Climate Change, in December , has pioneered open-space management, long-range climate planning and innovative emission-reduction projects, for example.

There is a large pool of viable emission-reduction projects that, though commercially viable (energy efficiency projects are prominent examples), cannot easily raise funding from hard-pressed municipal treasuries for which service delivery is a higher priority.

City planning is crucial to long-term climate resilience. Denser urban settlements have lower CO2 emissions per capita, partly because they are more efficient in transport, energy and infrastructure services. And it is easier to respond to natural disasters in more densely populated areas. The cities of the future will have to be more concentrated.

But city planners need a paradigm shift. Because climate change has caused climate variability and increased the incidence of extreme weather, the head of Durban's Environmental Planning Department, Deborah Roberts, points out that planners can no longer use the past to plan for the future. Instead, they have to plan for an uncertain future, which could include a variety of changes to weather, natural resources and economies.

Importantly, building climate-resilient cities is not about returning to some idealised pre-climate-change state: it is about taking bold leaps forward into a new low-carbon future, a transformative process described by Roberts as "bouncing forward".

The mistake of environmental planning to date has been to leave it to environmental departments, which wield much less power in municipalities than the big infrastructure services departments. Climate change cuts across all socio-economic issues affecting all municipal services, and responding to it demands leadership and political champions who can drive the agenda at top level.

Information is crucial to planning and managing change, and a lot of work has been put into developing global city indicators that measure different cities' performances in dealing with climate change. In the words of mayor Bloomberg at the Sao Paulo meeting: "If you can't measure it, you can't manage it", or, as Bill Clinton put it, "We've got to keep score".

Ultimately, change will come from households.

UN Framework Convention on Climate Change negotiations have shown that national governments are the most conservative when it comes to taking appropriate action. Cities and the people who live in them are more proactive in rising to the challenge and cutting emissions.

So, while the UN climate-change negotiations make glacial progress towards a weakly worded text, real partnerships between local government, NGOs and communities are being forged around a low-carbon future.

Dan Hoorweg, blogging from the Large Cities Summit, was struck by the power of cities.

Cities "are bigger and more energised than any individual or organisation. Cities push and cajole, and cities act. Cities are where it all comes together".

• Olver, a former director-general of the Department of Environmental Affairs (1999-2005), is an environmental activist and consultant. He co-ordinated South Africa's preparations for the World Summit on Sustainable Development, in 2002