Welcome to the cities and urbanization pages of PIKCities are the habitat of humans. Globally, more and more people live and work in urban areas. At the same time, the high concentration of people, assets, and infrastructure makes cities particularly vulnerable. Therefore, a better understanding of cities and the climate impacts on them is essential when improving quality of life and adapting to unavoidable climate change.
The research is focusing on the spatial and dynamical aspects of urban space, to identify possible synergies and trade-offs among processes playing key roles in enhancing GHG mitigation, adaptation, and sustainability of urban populations. Urbanization is a major facet of the current rapid development. Cities exhibit common features so that generalized reductionist descriptions of city systems could be achieved. Consequently, it is a debatable question, whether it is necessary to know cities in full detail, or if some first principles can be identified.
The purpose of this web-site is to make publically available the insights from the research of city and climate change (impacts, adaptation, and mitigation). This includes complementary information to the scientific literature as well as data and programming code. The provided material is intended to foster new research on cities and climate change.
City size, growth, and structure.Cities or urban areas in general represent highly complex systems. Before cities can be studied in the context of climate and climate change, a deeper understanding of cities themselves is necessary. An ongoing question is, what determines the size of a city and how does it relate to it's performance? Are small or large cities more efficient. Furthermore, if the climate of the future is to be studied, it is also necessary to investigate the cities of the future, e.g. characterize and project their growth.
Last but not least, an understanding of structural features helps to assess impacts and adaptation. Hereby, the newly proposed physical definition of cities as maximally connected urban clusters (based on the City Clustering Algorithm, Rozenfeld et al. 2008) is of great help for various problems.
Cities and climate change.Cities exhibit many peculiarities. On the one hand, the above mentioned high density and the rapid urban development in many regions of the world require special approaches when climate change impacts are being studied. On the other hand, they generate an own climate, the city climate. Understanding both aspects is the precondition for the development of effective adaptation decisions. The former is addressed by modelling the impact of projected climate change stimuli on future occurrences of relevant urban functions. This is the first interface between structural urban development rules and impact assessments. The second interface is the assessment of the applicability of adaptation measures regarding their compliance with the fabric of urban functions.
In order to assess the latter, i.e. the city climate, two approaches are followed to elude the relation between urban characteristics and the urban heat island effect. Firstly, an empirical approach systematically exploring remote sensing data in combination with city clustering and secondly, the simulation of the city climate employing dynamical numerical models.
Results can be browsed in the cities module of ci:grasp.