‘Almost half of the urban infrastructure needed globally by 2050 is still to be built”, says Maarten Hajer. ‘It's very important that we do this differently and make sure that the new infrastructure is sustainable, inclusive and pleasant. We must intervene now to avoid a complete disaster in the future.’
Hajer is a member of the International Resource Panel launched by UN Environment. This panel is due to present a report – entitled The Weight of Cities – at the Resilient Cities Forum in Bonn this week. Hajer is one of the two co-chairs of the working group and one of the lead authors of the document. ‘In the report, we calculate the resources necessary if we carry on as we have done in the past. This calculation has never been attempted before. The report also makes a number of recommendations about how to realise sustainable urban planning, making cities enjoyable and healthy places in which to live.’
The report uses the DMC (domestic material consumption) unit of measurement, which reveals the number of tons of resources (sand, gravel, steel, ore, coal and wood, for example) used per resident per year. Sustainable resource use lies between just 6 and 8 tons a year. However, if no changes are made, the authors estimate that resource use will be between 8 and 17 tons per person per year in 2050, which is too high.
The recommendations made on how to reduce resource use are diverse and ambitious. For example, a city must be designed for people, not cars. To achieve this, 30 percent of the developed area in a city must have a minimum street length of 18 kilometres per square kilometre, with between 80 and 100 crossroads per square kilometre. Hajer: ‘We seem to be forgetting what we already know about what makes cities attractive. We will need to plan much better in the future – both here in the Netherlands and elsewhere. For example, a metre of train tracks, motorway and cable could be saved for every metre that people live closer to the places where they work. It's a misconception to think that a more densely populated city is less liveable too. However, you do need to design a city cleverly, including amenities like parks and public gardens.’