Keeping Rethymno’s public spaces fresh with bioclimatic design

As summers temperatures rise and extend over longer time periods, the Cretan coastal town of Rethymno is implementing solutions to keep outdoor spaces cooler for the enjoyment and comfort of its residents and large tourist communities. Effective extreme heat early warning systems are also being developed to ensure everyone is better prepared.  

How is the city coping with heatwaves? 

Two major types of interventions are being carried out by the municipality of Rethymno and its municipal authority to address heatwaves, namely: 

• The use of bioclimatic designs of public spaces and streets to promote the thermal, acoustic and visual comfort of users of these spaces both during the day and evening and throughout all seasons.
• Use of metereological stations, installed by the National Observatory of Athens and the municipality of Rethymno, for extreme weather monitoring and early warning.

^{Kolokotroni street}

Rethymno's actions

Rethymno’s first bioclimatic design pilot, constructed in 2016, was a 25,000m² space that included Iroon Politechniou Square and, guided by bioclimatic design principles, incorporated the use of compressed soils, cool pavers and photo-catalytic road paint.  

^{Bioclimatic design at Iroon Politechniou Square, Rethymno, Greece © Alison De Luise (2023)} 

After the successful implementation of this original project, city authorities have completed four additional projects using this same approach, with the ultimate goal of reducing the impacts of climate change.  

These interventions were implemented using innovative materials and increased greenery, aiming at reversing the thermal climate change in the urban environment of the city of Rethymno, improving the microclimate, reducing the energy consumption of the neighbouring buildings during the summer months, reducing the peak electrical load and improving the thermal comfort levels of the population. Design elements include: 

• Use of cool materials with high reflectivity that prevent the heat island effect in areas with sufficient surface area and increased sun exposure rate.
• Replacement of asphalt with natural stone which has better thermal properties, while cold concrete blocks were placed in the staging areas where thermal comfort is also most needed,
• Planting designs aimed at ensuring adequate shading and the greatest possible absorption of carbon dioxide emissions. 

Additionally, the redevelopment in Angelou Sikelianou Street & the Agios Georgios Square integrated the construction of a new children's playground, the construction of a parking area in the east of the square, the supply of a system of shared electric bicycles and the undergrounding of the PPC network. All of theses facilities are free of charge for the citizens. 

Simultaneously, the municipality of Rethymno, in collaboration with the METEO unit of the National Observatory of Athens, has also installed nine meteorological stations aimed at improving the techniques of monitoring and predicting severe weather events through early warning and forecasting. 2024 was the first year of full operation of the entire network of meteorological stations and the two hydrometric stations of the Early Warning System.  

What has Rethymno achieved so far?

The Cretan city has already seen tangible results from these projects, including:

• Iroon Politechniou Square – Reduction in the mean maximum air temperature of 1.69°C and a mean maximum surface temperature of 8.45°C. User thermal comfort was improved by about 46% and the energy needs of the surrounding buildings were also reduced (Tsitoura et al., 2016). The photo catalytic road surface also reduced air pollution levels.
• Angelos Sikelianos Road – Reduction of the maximum ambient temperature up to 2°C or 5.90%; Reduction of the maximum surface temperature up to 11.5°C or 25.83%; Energy savings from cooling loads and reduction of greenhouse gas emissions of around 1% on the first two floors of buildings.

• Melissinou and Salaminos Streets – Anticipated results are for a reduction of 3°C in ambient temperature along the entire length of the road and average ambient temperature values of 30-33°C.

^{Current temperatures}

^{Anticipated temperatures}  

^{Before - Melissinou & Salaminos streets}

^{After - Melissinou & Salaminos streets}

• For the meterological stations, all nine stations have proven extremely useful in providing timely information regarding severe weather phenomena (very high or very low temperatures, heavy rains, gusty winds) and the sending of relevant alerts. The stations collect very useful measurements for the mapping of the weather in the wider area of the municipality of Rethymno, measurements which over time will form the basis for the climate description of the municipality as a whole. From this, a very useful database will be created in the municipality for basic meteorological parameters relating to a wide range of activities (agricultural, tourism, etc.) but also to support the design of policies and interventions for water management. 

Stakeholders engagement

The Technical Service Department took charge of planning and implementing the projects, drawing on valuable expertise gained through the municipality’s participation in European Union–funded initiatives. This know-how was instrumental in ensuring the successful design and implementation of the measures.

The mayor and city council played a pivotal role in approving and supporting the initiatives. Public consultation was essential in addressing concerns from residents and local businesses. A key message emphasised that these projects represent a forward-looking investment, aimed at enhancing quality of life for all, especially future generations. 

Ongoing collaboration with the National Confederation of Disabled People (NCDP) proved vital in ensuring that the projects were accessible to everyone.

Main challenges in addressing heatwaves: 

• Finding experienced experts in bioclimatic urban design.
• Finding a reliable simulation model.
• Good knowledge of the bioclimatic materials market.
• Getting the required permits to implement from the authorisation authorities.
• Secure funding - applying for funding requires strong justification.
• Original budget may be exceeded due to the complexity of interventions.
• Long construction works may arise opposition from local businesses.
• Τhe new design leads to reduced parking spaces - proper information to residents about the need for the intervention is required to avoid bottlenecks during implementation. 

Lessons learnt and next steps  

• Consultation with stakeholders is essential.
• Systematic maintenance is required which has a slightly increased cost.
• Early warning for “high” temperatures enables the municipality to provide air-conditioned rooms for vulnerable groups of the population. 

Replicability

Following the successful implementation of the above interventions, the municipality decided that all future interventions in the urban fabric will follow the principles of bioclimatic design. Good practices of other cities will be evaluated and implemented as far as possible. 

Rethymno's Refresh

Solutions to address heatwaves:

• Nature
• Urban Design and Technology
• Governance
  • Four key interventions using bioclimatic designs have been undertaken in the city center and it neighbourhoods.
  • The city has also installed meteorological stations, improving the monitoring and predicting of severe weather events through early warning and forecasting.

Expected results with the solutions implemented:  

• Reduced ambient and surface temperatures in public spaces
• Improvement of thermal comfort index
• Energy savings from cooling loads and reduction of greenhouse gas emissions
• Improved early warning and forecasting of extreme heat events 

Covenant Figures 

Signatory to the Covenant of Mayors since: 2011

Emission reduction ambitions:  

• Overall CO2 emission reduction target: 95.500 tn CO²
• % GHG emissions reductions by 2030: 40%
• % GHG emissions reductions by 2050: Climate neutrality

City Awards

• 2022: “CIVITAS AWARDS” CIVITAS Transformation Award - Winners of the CIVITAS Transformation Award 2022 for its transformative actions in relation to sustainable urban mobility awarded by the European Commission
• 2022: “URBAN REGENERATION AWARD” DISTINCTION AWARD - Award for Urban Regeneration from the GREEK MINISTRY OF ENVIRONMENT & ENERGY
• 2019:  “EUROPEAN MOBILITY WEEK AWARD” as a finalist for the recognition of the outstanding achievements during the EMW 2019 awarded by the European Commission
• 2013:  “EUROPEAN ENERGY AWARD”  RECOGNITION AWARD - For the communal energy policies of sustainability performance in efficient energy use and the increasing use of renewable energy technologies awarded by Medeea (EU Med Project)  

In addition to the above, the municipality of Rethymno has received lot of national awards for its efforts on sustainable development.

Related links 

• Municipality webpage
• Weather Station