How Berlin’s Redevelopments Undermine Its Sustainability Goals

This contradiction is especially stark in light of Berlin’s stated environmental goals. The city and federal governments have both articulated strong commitments to sustainable development, including reductions in Flächenverbrauch (land consumption) and Versiegelung (soil sealing). Yet the physical outcomes of these high-profile projects seem disconnected from these commitments. They present a vision of the city that is impressive in scale but ecologically regressive in substance.

The Problem of Soil Sealing

Soil sealing refers to the covering of natural or semi-natural ground with impermeable materials such as asphalt, concrete, or stone. Once sealed, soils lose virtually all ecological function: they no longer absorb rainwater, filter pollutants, host plant or microbial life, or regulate microclimates. In Berlin, the sealed surface area already accounts for approximately 35% of the total land area, while settlement and traffic surfaces make up about 70%. According to the Amt für Statistik Berlin-Brandenburg, this figure has been rising by about 78 hectares per year since 2005.

The effects of this are not merely environmental; they are systemic. Sealed surfaces contribute to:

• Increased stormwater runoff and urban flooding

• Reduced groundwater recharge

• Urban heat island effects

• Habitat fragmentation and loss of biodiversity

• Degradation of public space utility and human comfort
  
  

Urban green space, by contrast, mitigates each of these issues. Tree canopies lower surface and air temperatures. Vegetated soils absorb and slow rainwater. Green areas provide essential habitat for insects and birds. And for residents and visitors, parks and plazas with trees offer social value, mental health benefits, and opportunities for rest and interaction.

Inconsistencies Between Policy and Practice

The German federal government set a target to reduce national land consumption from 130 hectares per day in 2002 to 30 hectares per day by 2020. While this target was not met nationally, Berlin performed better, averaging a comparatively modest 120 hectares per year during the 2000–2010 period. The city's planning policies further emphasize Innenentwicklung – development within the existing urban fabric – along with the reuse of brownfield sites and infill development.

In theory, this should lead to more efficient land use and a reduced ecological footprint. In practice, however, the city's most prominent developments consistently fail to reflect the green space standards applied in smaller-scale or residential projects.

For example, the Biotopflächenfaktor (BFF) – a biotope area factor used in Berlin’s planning code – requires new developments to retain or create a minimum percentage of permeable or ecologically effective surface. However, BFF requirements are often not applied to landmark cultural or commercial projects, particularly when developed through public-private partnerships or special planning zones.

Case Studies in Over-Sealing

Each of the following projects exemplifies a form of “monofunctional monumentalism” – highly designed spaces that prioritize visual impact, circulation, and institutional function at the expense of ecological performance.

• Am Tacheles: A former cultural hub replaced by a high-end commercial and residential complex. The internal courtyard offers limited vegetation, and most surface area is paved. Despite its central location and mixed-use designation, it has yet to attract meaningful foot traffic or community use, possibly due to its sterile and impermeable design.
  
  

  

  
  

• Humboldt Forum: Situated on the Spreeinsel, this reconstructed palace sits atop one of the most prominent sites in the city. The adjacent plaza is expansive but unshaded and uninviting. Despite its potential as a riverfront park, the open space is characterized by stone slabs rather than trees or landscape features.

  
  

• James-Simon-Galerie: Serving as a gateway to Museum Island, the building’s forecourt and terraces are architecturally coherent but ecologically barren. Shade is minimal, and the runoff management relies on engineered drainage rather than natural infiltration.
  
  

  

  
  

  
  

• Kulturforum and Bebelplatz: Both areas represent mid- and late-20th century planning paradigms where “open space” was often confused with “empty space.” Their vast, sealed plazas lack both social and environmental function, offering neither comfort nor biodiversity.
  
  

  

  
  

  
  

• Gendarmenmarkt: Once a mixed-use civic plaza, the recent redesign prioritized aesthetic symmetry and durability over ecological integration. Reports from visitors describe the space as harsh, overly reflective, and uncomfortable during warm weather.
  
  

  

  
  
  

Systemic Causes

This recurring pattern is not purely the fault of architectural design or market pressure. Rather, it reflects systemic gaps in Berlin’s urban development process:

1. Cost Externalization: Green space adds recurring maintenance costs. Developers have little incentive to include vegetation when the responsibility for care falls to either themselves or underfunded municipal services.
   
   

2. Cultural Priorities: The prevailing architectural culture still places high value on minimalism, formal clarity, and durable hardscaping – traits that often conflict with organic, variable, and living materials like soil and plants.
   
   

3. Institutional Fragmentation: Environmental goals are set at one level of government but implemented (or not) at another. Coordination between environmental agencies and planning offices remains inconsistent, especially in complex public-private projects.
   
   

4. Delayed Ecological Accounting: While Berlin has tools for evaluating the ecological cost of development (e.g. the Leitfaden zur Bewertung von Eingriffen, 2020), they are often applied too late to significantly influence design outcomes.
   
   
   

Recommendations

To address this disconnect between environmental policy and urban form, Berlin should consider:

• Expanding the mandatory application of the BFF to all major public and commercial developments

• Establishing minimum tree-per-hectare requirements for large-scale redevelopment sites

• Requiring life-cycle ecological assessments as part of competitive architectural selection processes

• Funding a green maintenance endowment as part of every major project approval

• Prioritizing retroactive unsealing (“Entsiegelung”) in adjacent or surrounding areas to offset unavoidable impacts

Berlin is not lacking in vision or policy. It is lacking in alignment – between the city it claims to want and the city it continues to build. Until that alignment is achieved, Berlin’s most iconic public spaces will continue to exemplify a paradox: well-funded developments that meet every metric except the ones that matter to the environment – and the people who live in it.