More green instead of grey: Priority for urban greening and sustainable surface sealing
Summer is over, the heat is subsiding, but the climate crisis has clearly shown one thing this year: many of our cities in Germany are too heavily sealed, offer too little cooling greenery and are not sufficiently prepared for long periods of heat in their current structure. The first heat check by Deutsche Umwelthilfe (DUH) shows the consequences of land sealing and how the effects of heatwaves are exacerbated, jeopardising not only the environment but also people's health.
Land sealing as a core problem in Germany
Of the 190 cities analysed, metropolises such as Ludwigshafen, Heilbronn and Regensburg scored particularly poorly in the heat check, i.e. they have a high level of land sealing and few green spaces, which leads to a greater rise in temperatures and severely limits the opportunities for cooling down. Detmold, Ratingen and Potsdam, on the other hand, show that things can be done differently: here there is a high proportion of unsealed surfaces and a lot of green space that cools the cities.
Surface sealing - i.e. building on and asphalting areas - is a central problem in many urban centres. Every newly sealed area means less space for green spaces, parks and trees that provide natural cooling. The daily consumption of land is particularly dramatic: in Germany, more than 50 hectares of land are currently being used every day for new housing developments and transport infrastructure - that is equivalent to the size of a city like Hanover every year. This ‘land consumption’ not only results in the loss of valuable green spaces, but also significantly worsens the urban microclimate.
Barbara Metz, Federal Managing Director of Deutsche Umwelthilfe, emphasises: ‘We urgently need a stop to land sealing by 2035 and clear guidelines for binding green areas in cities.’ (DUH press release, 2024) Green is not just green: only large, shady trees can effectively cool cities, while flat lawns have a much lower cooling effect.
Sustainable use of space through ShareYourSpace
While many cities are focussing on building new office and residential space, there are alternative approaches that both reduce land sealing and use existing space more efficiently. The digital marketplace ShareYourSpace offers the flexible renting and leasing of office space, workspaces and coworking spaces, so that no new space is built on, but existing spaces are used optimally.
By brokering and temporarily utilising unused office space, the need for new buildings is reduced, thereby lowering land consumption. In many cities, numerous office spaces are vacant or underutilised. ShareYourSpace helps to reintegrate these spaces into the cycle and thus avoid unnecessary expansion of sealed surfaces. This is an important step towards stopping land sealing and creating more space for green areas.
The approach of making better use of existing areas is a key element in making cities sustainable and climate-friendly. Every new building area avoided means less sealed ground, more space for trees and green spaces and ultimately a cooler, more liveable city.
Health and climate protection combined
Green spaces in cities play an important role that goes far beyond their cooling effect. They are not only of great importance for the urban climate, but also for the physical and mental well-being of residents. As Frank Winkler, deputy head of the vdek state representation for the GKV Alliance for Health in Baden-Württemberg, emphasised in the DUH press release in July 2024, people in cities need recreational spaces in their immediate surroundings in order to benefit from the fresh air and improved climate.
Deutsche Umwelthilfe is also campaigning for a close link between green spaces and urban planning in projects such as ‘Gesund unterwegs im Stadtquartier’. The focus here is primarily on schools and densely populated neighbourhoods, which are to be improved both climatically and in terms of health through additional greenery - for example by planting groups of trees or designing green schoolyards.
Conclusion: conversion instead of new construction
The DUH's first heat check has shown that there is an urgent need for action: Germany's cities must transform themselves from concrete deserts into green, liveable places. With ShareYourSpace and a sustainable approach to land sealing as well as a focus on optimising existing buildings and spaces, the movement ‘More green instead of grey’ is being consistently implemented.
In times of climate crisis, remodelling existing structures is far more sensible and necessary than building new ones. Tobias Wagner, CEO of ShareYourSpace, puts it in a nutshell: ‘The most sustainable building is the one that is not built.’ The aim is to make better use of existing spaces, create green volumes and minimise sealing - for liveable cities and a healthy future.