Nature-Based Climate Resilience

As climate change intensifies, cities face compounding stress from heatwaves, air pollution, flooding, and biodiversity loss. Addressing these challenges requires shifting from traditional, resource-intensive systems toward nature-based solutions (NBS) that harness ecological processes for urban resilience. 

At the 2025 CIBSE Technical Symposium, researchers presented innovative studies exploring how green walls and hydroponic facades can reduce cooling loads, improve air quality, and buffer cities against climate extremes. These technologies not only support passive cooling but also contribute to carbon reductions and bioremediation —key for sustainable development. 

Green Walls in Hot Arid Climates: Performance Insights from Dubai 

Authors: Dr Mohamed Elnabawi & Prof Neveen Hamza
Paper: “Integrating Green Walls for Energy Efficiency and Thermal Comfort in Hot Arid Climates”

In Dubai’s searing urban environment, cooling loads represent up to 70% of annual electricity demand. Elnabawi and Hamza conducted a simulation-based study of a seven-storey office building using two green wall systems: pre-planted modular panels and a double skin green façade, comparing them to a conventional building envelope.

Using DesignBuilder and ENVI-met, the research quantified reductions in energy use, indoor air temperature, and outdoor mean radiant temperature (MRT). 

Double-skin facades outperformed all alternatives, offering 4–17% annual energy savings, peaking in winter and summer due to better insulation and solar shading. Green walls also improved outdoor comfort, lowering MRT by up to 4°C at pedestrian level — critical for walkability in dense cities. However, simulations revealed indoor overheating in highly insulated facades without active ventilation, highlighting the need for integrated HVAC and facade design.

Key Takeaways 
  • Double-skin green façades provide superior insulation and energy savings (up to 17% annually). 
  • Modular panels are simpler but less thermally effective (3–6% savings). 
  • MRT reductions of >4°C can enhance pedestrian-level thermal comfort. 
  • Passive green systems need mechanical ventilation to prevent internal heat retention. 
  • Outdoor temperature reductions were modest (0.5–1°C), but meaningful in aggregate.

Hydroponic Phytoremediation Façades: Greener, Smarter, Deeper 

Author: Dr Dominic Clyde-Smith (UCL)
Paper: “From Grey to Green: Integrating Hydroponic Phytoremediation Facades for Carbon Abatement and Climate-Resilient Urban Infrastructure”

Traditional green walls offer proven thermal and aesthetic benefits, but hydroponic systems extend these further — combining carbon sequestration, air/water filtration, and bioenergy generation in a single vertical system.

Clyde-Smith’s study advocates for hydroponic phytoremediation façades using media like biochar and microbial electrochemical technologies (METs). These systems filter air pollutants (VOCs, NO₂, PM), extract nutrients from greywater, and sequester carbon more stably than soil-based walls. Hydroponic systems outperform soil in oxygen, nutrient, and fluid access, optimising plant health and microbial interaction. Biochar increases microbial activity and stabilises soil organic carbon (SOC) — key for long-term climate mitigation. METs generate energy from rhizosphere interactions while breaking down persistent pollutants (e.g. microplastics). Hydroponic façades also enhance ESG performance — aligning with biodiversity net gain, water quality targets, and urban wastewater directives.

Key Takeaways 
  • Hydroponic green walls filter both air and water pollutants via plant-microbe-media interaction. 
  • Biochar improves water retention and microbial function for deeper carbon storage. 
  • METs allow energy generation and pollutant breakdown directly at the façade level. 
  • Hydroponics overcome soil-based limits on root oxygenation and nutrient flow. 
  • Policy support (e.g. carbon credits, urban water regulation) is key to scalability.

From Performance to Policy: Scaling Nature-Based Urban Infrastructure 

 

Across both studies, the message is clear: nature-based solutions offer measurable energy, comfort, and sustainability benefits — but only when designed as part of integrated systems. In regions like the UAE or southern Europe, green walls reduce energy loads, enhance microclimates, and add resilience against extreme heat. 

However, these systems do not stand alone. The success of vertical greenery, particularly in hydroponic formats, hinges on: 

  • Mechanical coordination with HVAC systems (to avoid heat trapping). 
  • Monitoring and feedback loops, particularly where passive systems are expected to perform at scale. 
  • Maintenance and operational sustainability, especially regarding irrigation and nutrient delivery. 
  • Policy incentives, such as inclusion in ESG frameworks, water regulations, and climate adaptation planning. 

For MEP engineers and built environment professionals, these findings suggest that passive and active systems must work together – not compete. 

Let’s Make Urban Resilience Real 

Nature-based solutions can’t solve climate resilience alone. But combined with smart building management and side stream filtration, they unlock new levels of performance and sustainability. 

Ready to integrate green infrastructure with high-efficiency HVAC systems? 

Green call-to-action button with bold white text reading 'BOOK A DEMO' and two stylized green arrows pointing to the right, indicating navigation or scheduling options.
Green call-to-action button with bold white text reading 'GET IN TOUCH' and two stylized green arrows pointing to the right, indicating navigation or contact options.

References: 

  • Elnabawi, M. & Hamza, N. (2025) Integrating Green Walls for Energy Efficiency and Thermal Comfort in Hot Arid Climates.  
  • Clyde-Smith, D. (2025) From Grey to Green: Hydroponic Phytoremediation Façades for Carbon Abatement.  

To access and download all the papers from the 2025 CIBSE IBPSA-England Technical Symposium head over to: https://www.cibse.org/knowledge-research/knowledge-resources/technical-symposium-papers/2025-technical-symposium-papers/ 

more blog posts

Scroll to Top