Klimatsäkrare städer : klimatförändringar, stadsplanering och översvämningar

Abstract: The numbers of natural disasters caused by extreme weather are increasing through out the world. A large majority of the research concerning the climate shows that this is a trend that can be expected to continue. At the same time the urbanisation is increasing more than ever and for the first time in history more than fifty percent of the population lives in a city. How we build these cities will have a crucial importance for our adaption to the new climate. In Sweden, our capacity for an adaption are high because of our economic situation as well as our rather well built society. Other parts of the world will be hit considerably harder and it is the poor countries that will be affected the most. Today floods are the most common natural disaster in Europe. As an effect of climate changes, the number of severe floods is calculated to increase markedly in northern Europe. We have already seen that the number of severe floods have become more common in recent years and it is important to start adapting our societies to these new risks today. Flooding must be addressed on various levels in urban planning. Mapping of risk areas and foreseeing planning most be combined with on site protection in high risk areas. In the general plan one have the opportunity to work on an overall level and put on long-term aims for how to address the problems of flooding. On a more detailed level there may be reasons for specific regulations. Examples off such regulations might be to decide a lowest point above sea level under which buildings may be not be built or not to allow cellars within the specific plan. In some sites it can be justified to construct protection of various kinds. Embankments, quay-edges and walls can state examples on such protection measures. At the same time as the urbanisation is increasing more and bigger areas in the cities are being paved and thus the water in the cities has nowhere to infiltrate or to be detained. Through various stormwater solutions one can both decrease and level out the flows to the watercourses. This may happen by different solutions for example through vegetated swales, infiltration planters or ecoroofs. By bringing more green spaces in to the cities one also offers other benefits to the climate. Such benefits include lowering the average temperature and offering shadows in the increasingly warmer cities. It is also important to remember that the water in our cities is not only a problem and to take advantage of the assets water can bring to a city. Climate change will in various ways increase different risks in our cities and this has to be taken seriously. It is of great importance that the municipalities study what these changes will mean for each given location and make up plans for how one will meet these risks. The planning must happen both in the short time and in the long time perspective. We still need a lot more research in the area of climate change but it is important that the municipalities take an active part of the research that is carried out and keep oneself updated with new research results. Often, conflicts of interests may occur concerning exploitation of areas close to water. It is thus important that the municipality has established clear frameworks and recommendations for these areas.