A new green deal for climate challenges and urban regeneration
Copyright (c) 2020 A. Claudi de St. Mihiel
This work is licensed under a Creative Commons Attribution 4.0 International License.
A zero-emission Europe by 2050, this is the objective declared by the President of the European Commission Ursula von der Leyen during the plenary of the EU Parliament last January. The European “green deal” is based on a thousand billion investment plan for the next ten years in which Europe will have to play a leading role in achieving zero climate impact by investing in technological and innovative solutions, involving citizens and harmonizing interventions in key sectors, such as industrial policy and scientific research.
In Italy, issues relating to climate change and the related environmental implications are today at the center of a public and media debate like never before. Tackling the climate crisis and relaunching the country’s sustainable development based on the green economy jointly appears to be the only unavoidable way forward.
The future of our metropolitan areas therefore depends on the ability to encourage adaptation to the major changes taking place through a general rethinking of the city theme, in which interest is concentrated on the value of public space and on the resilience of urban contexts that present conditions of natural or anthropogenic vulnerability. The urban public space project therefore appears to be a strategic area of intervention as a device to protect the city from environmental emergencies, an ecological resource for improving the quality of urban life and fighting pollution and – indirectly – for promoting social cohesion and collective identity actions.
The programmatic and planning responses that try to face this emergency situation must necessarily and consciously recognize the ecological and environmental value of open spaces. «An evolutionary step that brings to the center of future design reflections – which interpret the city as a complex organism – the decisive contributions of environmental and landscape culture, of environmental functioning in terms of usability, comfort, safety, use of resources, integrability, environmental protection and welfare» (Clemente, 2017).
In this direction “CLEVER Cities” (Project financed with Horizon 2020 funds and with an experiment on the city of Milan) with the motto “Regenerating cities with nature” focuses attention on the decisive role that nature can play in improving environmental quality, biodiversity and the welfare of citizens in a process of urban regeneration through Nature-Based Solutions1.
Downstream of these preliminary considerations, this issue of the Rubric has identified Bonifico Group Srl as a qualified interlocutor, a historical reality operating in the landscape development sector with settled botanical knowledge and agronomic practices that expresses a high rate of innovation in naturalistic engineering interventions, design and construction of roof gardens, irrigation systems and water management, maintenance of urban and infrastructure greenery.
In the following pages, through a dialogue with Dr. Eduardo Bonifico, General Manager of the Bonifico Group, some arguments are developed on very topical issues and related to the company’s know-how through some exemplary projects carried out.
1. Recent urban redevelopment projects and interventions, related to the public space project and the vegetation system, have radically changed the face of some European cities, creating real “new landscapes”; I think of the “Madrid + Natural” program, developed through a collaboration between the Municipality of Madrid and Studio Arup Associates, consisting of guidelines to tackle the global problem of climate change through multiple local solutions that include green projects for buildings, green infrastructures and open spaces in the city of Madrid What skills and innovations does the Bonifico Group use for urban redevelopment projects?
The Bonifico Group provides, among others, planning and construction services for green spaces in urban areas for both public and private clients. To deal with the growing complexity of the projects and the requisites required, the company uses an interdisciplinary approach that intertwines different skills; from the architectural, landscape and engineering ones of the project to those related to the evaluation of economic, financial and environmental sustainability. The experiments that we carry out and constantly develop are divided into two main categories: application, with the development of the most effective and efficient design solutions in the specific urban contexts where the Bonifico Group carries out the redevelopment of public open spaces; methodology, with the construction of a system of appropriate technologies in relation to the variation of the combined data of the environmental context and the biophysical and microclimatic characteristics.
Our expertise aims to increase the accessibility and environmental quality of urban public space, thanks also to the ecological and intelligent management of the water and to the green enhancement in bioclimatic terms.
I refer, for example, to Dominique Perrault’s project for Piazza Garibaldi in Naples in which the role of the Bonifico Group was to reconstruct spaces of “nature” in the anthropized context. Twenty thousand square meters of greenery, the first urban “urban forest”, with 130 trees of various essences, equipped with basketball courts, five-a-side football, skateboard track, playground for children and a cavea for open-air cinema and shows. The surface arrangement is configured as an Urban Green Infrastracture (UGI) to underline the scalar dimension of investigation referred to the urban context. The presence of widespread vegetation in the square offers another great advantage: the reduction of the heat island effect, a persistent problem in urban centres; green and soil permeability are one of the possible solutions, because the heat absorbed by solar radiation does not accumulate.
2. This century has opened under the banner of awareness that the Earth is fragile and must be defended. The energy crisis and the protection of the environment are global emergencies, and the challenge is to create architectures with zero consumption and zero emissions, gentle machines to explore the relationship between building and nature in which, paraphrasing Renzo Piano «the roofing of buildings is metaphorically a roof that breathes to the rhythm of nature, or rather a portion of park that flies». Over the years, the Bonifico Group has dealt with important projects relating to green roof; what were the benefits brought to the structures and the surrounding environment?
In an industrialized society subjected to the pressures of continuous economic development, the territory undergoes rapid and profound transformations. Our goal is to help manage these processes by interpreting the community’s environmental demands. For this reason, thanks to the long evolutionary path in terms of acquiring new skills, we have been engaged for years in the promotion of the most advanced technologies for environmental sustainability, for the reduction of pollution and for the exploitation of renewable energies. In this field, projects relating to roof gardens and the benefits that these structures bring with reference to the mitigation of the microclimate, energy saving, the reduction of atmospheric and sound pollution, the reduction of the flow rate of the water, the growth of the biodiversity and the best performance of the photovoltaic panels on the roof. The spread of green roofs has increased in relation to the growing interest in sustainable architecture and green building. Their classifications (intensive or extensive) depend on several factors: the amount of land, maintenance work, weight and accessibility.
For example, for the project of the “Vulcano Buono” shopping centre, a work carried out by Renzo Piano in the province of Naples, a green roof system2 of approximately 80.000 square meters (one of the largest in Europe) was designed and targeted for the Mediterranean climate, able to confer various benefits to the building including:
- an improvement of the thermal performance of the roof both in winter and in summer;
- an energy saving favoured by the insulating and draining culture layer;
- the reduction of noise pollution and its improvement in terms of insulation;
- greater surface absorption capacity in rainfall and relative regulation of water runoff;
- an ability to originate natural ventilation by promoting the reduction of surface humidity values;
- the ability of the vegetation on the roof to retain harmful substances suspended in the air, which are thus absorbed through the photosynthesis process;
- a faunistic improvement with an increase in biodiversity;
- an improvement of the aesthetic and environmental impact also through specific tree species of Mediterranean area.
I think all these performances go in the direction of “a roof that breathes to the rhythm of nature” mentioned by Piano.
3. As is known, green facades act on the microclimate and influence the physical and technical behavior of a building, contributing on a large scale to stem climate change and atmospheric pollution. The Citicape House, a building designed by the architectural firm Sheppard Robson, will see the largest green wall in Europe consisting of about 400.000 plants with an extension of about 4.000 square meters capable of absorbing over eight tons of carbon every year, producing six of oxygen and lowering the local temperature from three to five degrees Celsius within a few years. What are the experiences of the Bank Transfer Group in this sense?
There is no doubt that the design of a green facade introduces a series of aesthetic-formal and environmental advantages in the context in which it fits. In the first few days of 2020, we are in the process of formalizing some projects concerning the use of greenery for building envelopes.
From the data in our possession, through the use of greening systems with green walls, various benefits are obtained: a decrease in temperature of 4.5 degrees centigrade and energy savings for cooling by 43% and from 4 to 6.3% for heating.
Another benefit of the green wall concerns the lowering of the air temperature of the environment surrounding the building; some estimates calculate a reduction in air temperature between 0.5 and 4.1 degrees centigrade, measured at a distance of two meters from the wall.
More specifically, some studies have shown that broad-leaved species could provide better performance in capturing the fraction of fine particulate matter, PM1, which is particularly harmful to health, while those with leaves characterized by the presence of epicuticular wax and a particular surface morphology can trap all fractions of particulate matter.
In general, the positive effects of a Living wall on the PMx concentration depend on the specific characteristics of the plants: the shape of the epidermis, the roughness or the level of air pollution in the area.
Vegetation also affects its thermal regulation of the building system, with advantages in both winter and summer. During the cold season it helps to limit heat losses and increase the insulation of the building, also protecting the wall from the wind. Although it is almost impossible to calculate precisely the amount of energy savings guaranteed by a live system and therefore variable, it has been estimated that the layer of foliage is able to increase the thermal resistance of the wall by about 6%.
During the summer, the green layer through shading ensures the reduction of the surface temperature of the building wall. The solar load on the surface can be reduced by up to 30% and the surface temperature of the facade can also drop by 10°C.
Furthermore, in cases where the green wall is a few centimetres away from the building, an air gap is formed which offers the advantages of a ventilated wall, increasing the thermal resistance of the wall.
Finally, the performance also in terms of acoustic insulation is amplified since the layer of foliage reduces the transmission of noise inside the building, absorbing the sound waves coming from outside.
Certainly in the next few years’ part of the company’s business will be oriented towards the study of innovative solutions and products to achieve the European standards mentioned above.