With the arrival of summer and high temperatures are noticeable temperature difference between the city and the surrounding villages. This is a phenomenon in the field called urban heat islands or "Urban Heat Islands".
When this is not about some new phenomena, but the urban population due to global climate change consciously perceived.
Temperatures in the city are at the present time to six degrees higher than in the peripheral areas of the city.
Such climate changes are particularly strong in the big cities that are far from the coast and therefore in Vienna.
In order to influence climate change still more mitigate City of Vienna has developed a strategy that involves as many as 90 different ways of planning and construction of residential buildings with the help of which the temperature in the summer can be reduced by five to six degrees.
The conventional wisdom is that the heat in cities creates primarily due to the large number of inhabitants, or too dark concrete surface, which is partly true, but this effect is created due to the lack of green space that is. plants and trees.
The Vienna experts found that the greening of courtyards, roofs and facades most effective means against the heat in the city and this for two reasons, because a residential area in this mode are not exposed to direct sunlight and because the leaves of plants during photosynthesis evaporate water. Precisely the lack of evaporation is one of the main reasons for the emergence of urban heat island. The nature of the soil water reserves for a long time, and she gradually evaporates into the atmosphere by plants. The effect of cold evaporation missing in the city.
In Vienna, therefore, in recent years run many projects greening of existing buildings, and to construct new architects trying to incorporate more plant cover in their concepts of horticulture, but also on the facades and roofs of the buildings themselves.
One of the great examples of greening in Vienna and the facades only utility company for the disposal of waste which is from top to bottom covered with various herbs and flowers.