Cities of the future — how will European cities adapt to new climate conditions?

In 2008, Barcelona ordered huge quantities of water delivered by tanker to serve its population and tourists. In 2003, the summer heat wave killed 14 800 people in France, 18 000 in Italy, and altogether around 52 000 across Europe. In 2002, photos of Dresden and other German cities under water showed the effects of extreme flooding along the River Elbe.

With a changing climate, extreme events like these are predicted to occur more frequently. Two lines of action are needed globally to keep the future impacts of climate change within manageable boundaries. First, large cuts in greenhouse gas emissions must be made to stabilise temperature rise at below 2 °C above pre-industrial levels. Above this threshold, there is a risk that the impacts will be extremely difficult for contemporary societies to cope with. However, even if the 2 °C target is achieved, there will still be residual impacts throughout this century. The second line of action therefore involves putting in place adaptive measures.

Cities have an important role to play in both areas. They are already making substantial efforts to cut emissions, improve their energy efficiency and step up the use of renewable energy (see Urban frontrunners — cities and the fight against global warming). But in adaptation, we have seen much less progress to date.

Cities and upcoming changes

With their high population density and physical structure, cities and towns are extremely vulnerable to the impacts of climate change. The threats vary across Europe:

• Many coastal cities face a serious risk of flooding as sea levels are predicted to rise by 18–59 cm by 2100 (see IPCC's 2007 report). At the recent climate change research conference in Copenhagen, scientists presented even more dismal projections, with a 1–1.5 m increase in sea level by 2100.
• Droughts and heat waves are mostly projected for the southern parts of Europe. However, the threat also exists elsewhere in Europe, as shown by the Paris heat waves in recent years.

It is not only a matter of location, however. The physical characteristics and design of a city can also lessen or worsen the impact. Think for instance of the 'urban heat island' effect, which is caused by differences in urban density and vegetation cover. Another example is the degree of soil sealing, which determines the potential for water infiltration after heavy rainfall.

Unless action is taken now, some cities will suffer considerably, both in terms of population and environment, with significant economic implications. In some cases, this may also aggravate social inequalities, as the poor might live in climatically less-favourable areas and not have the resources to adapt their housing. Climate change will also exacerbate other existing urban problems such as low air quality and poor water supply.

Investing now in mitigation and adaptation will help to avoid huge costs later. Some cities already see this as a wider opportunity for creating a better future.  Better urban planning will improve quality of life across the board and create new employment opportunities by enhancing the market for new technologies and green architecture.

How can cities adapt?

To cope with the climate conditions of the future, cities will have to find innovative solutions. The key question is how they will reduce health risks and secure the essential infrastructure for provision of energy, transport, electricity and heating, waste and water management.

Clearly, engineering approaches — such as flood barriers — are only a part of the solution. Adaptation also calls for a fundamental rethinking of urban design and management, and it should be "mainstreamed" in all related policies, including land use, housing, water management, transport, energy, social equity and health. Several solutions are already at hand:

• Planning new urban developments outside coastal and river flood plains — and if this is not possible, using adaptive designs such as floating houses.
• Using passive or highly efficient ventilation and cooling systems in public spaces and buildings — such as external solar shading.
• Putting water management schemes in place to keep water use within sustainable limits.
• Greening cities with parks, green walls and roofs — designed to provide cooling and ventilation as well as water storage and infiltration.

Initiatives at the city level also have to link in with action at the regional, national and European level. For instance, cities vulnerable to drought or excessive rainfall need to act in tandem with their surrounding regions to increase water storage capacity.

Exchanging knowledge and good practices

Those cities initiating measures early on are bound to see the best returns on their adaptation investments. Yet to date, only a few European cities have developed strategies enabling adaptation to the "new" climate change conditions — and actual implementation of measures is, as yet, mostly limited to small scale projects.

The plans proposed by London and Copenhagen offer some inspiring approaches:

• London's draft Climate Change Adaptation Strategy proposes action for increasing the city's green spaces to keep the city cool in summer; managing flood risk coming from tributaries to the Thames and heavy rainfall; encouraging Londoners to use less water and raising public awareness. The existing Thames Barrier and tidal defences will protect London for decades to come — it is unlikely that a new barrier would be required before the end of the century.
• Copenhagen's proposed Climate Plan announces an adaptation plan that "must also create synergy between all environmental initiatives and continue to improve the city's recreational opportunities." The city opts strongly for the creation of pocket parks, i.e. small green spaces which help cool the city on hot days and absorb rain on wet days.

Some countries, like the Netherlands, can draw on extensive experience of protecting their coastlines and cities. The Dutch Delta Committee Recommendations include a comprehensive action programme (up to 2050) to secure a "climate proof" Netherlands – safeguarding coasts, urban areas and the hinterland.

However, cities in other countries may not be so fortunate in terms of knowledge and resources and will require ongoing support and guidance. At this stage, improvement in the exchange of experience and best practices among cities would be most valuable.

The European Union is already working on an online knowledge management tool (EU Clearing House Mechanism) to share and manage information on climate change impact, vulnerability and best practices on adaptation (see the White Paper on adapting to climate change). This will be an important knowledge source for cities to tap into. Some countries have developed national adaptation plans — or are on course to do so. These will also provide valuable guidance for cities.

In June 2009, the Local Government Climate Change Leadership Summit issued a strong message: municipalities and regions want to be included and have their role in the implementation of national climate strategies and plans recognised. They also wish to obtain access to funds, e.g. for adaptation, to be agreed at the United Nations Climate Change Conference in Copenhagen this December. In the run-up to this, all eyes are on the upcoming Copenhagen Climate Summit for Mayors and the recommendations the mayors of the world will give to the heads of state.