The Environmental Atlas has for more than 25 years gathered information and data on urban climatology (see SenStadtUm 1985). With the results of the application of the FITNAH Climate Model, comprehensive information about today’s climatic situation in the municipal area and the nearby surrounding areas is available (see Map 04.10 in Climate Model Berlin, Analysis Maps, 2009 edition, and Map 04.11 in Climate Model Berlin: Evaluation Maps, 2009 edition). Knowledge of the local urban climate, particularly the location and extent of urban heat islands and the climatic functional relationships between residential and green spaces, are important aspects of environmental precautionary policy and urban development.
For some years, the range of challenges has been increasing dramatically: the assessment of the effects of the changes to be expected from global climate change on thermal, hygric and air-purity conditions, particularly in metropolitan areas, requires additional answers to support the demands summarized under the concepts of “mitigation” and “adaptation”.
Climate protection has been an integral part of Berlin environmental policy for years (see Ziele und Grundlagen der Klimaschutzpolitik in Berlin (Goals and foundations of the climate protection policy in Berlin – German only)). The city has a long tradition of implementing numerous programmes on:
- increasing energy efficiency,
- using renewable energies,
- promoting energy savings.
Nonetheless, adaptation to climate change has been a topic of only marginal interest to date. However, the normal conduct of municipal administration is no longer conceivable without addressing the need to adapt to climate change. With the acceptance of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) of 2007, both the fact of climate change and the high probability that it is anthropogenically caused have been internationally recognized.
Observation data shows that the climate has been warming since the last century. The global mean near-surface air temperature rose by approx. 0.74°C during the period from 1906 to 2005. On average, mountain glaciers and snow cover have decreased worldwide. Such extreme events as heavy precipitation and heat waves – such as during the “summer of the century” in 2003 – have become more frequent, and since the 1970s, more intensive and longer lasting droughts have occurred in larger areas in the tropics and subtropics. The expected risks are increasing with rising temperatures (see Federal Environment Agency).
The global mean near-surface air temperature has been rising since the beginning of industrialization. The higher concentration of greenhouse gases caused by the anthropogenic burning of fossil fuels in the atmosphere has led to an overall warming of the lower layers of the atmosphere (see Fig. 1).