GREEN WALL SUSTAINABILITY ANALYSIS

Horticulture in urban communities plays an important role in sustaining and improving our quality of life. Through my education, I was encouraged to think critically about sustainability challenges faced in both horticultural organisations and in private and public landscapes. As part of this I extensively researched the case study of the One Central Park development in Sydney, Australia, specifically focusing on claims made around the sustainability of the vertical garden system installed by Patrick Blanc. I was able to carry out high level independent research, synthesize my findings and present a compelling research narrative that questions the validity of the system installed at One Central Park. The paper and my findings follow below:

 

INTRODUCTION

Now, more than ever, we live in an age where understanding how sustainability relates to all facets of our lives is of the highest importance. Mass extinction, depletion of natural resources our society has become completely dependent on, and the rise of global warming have forced our society to re-evaluate the deep level our actions may now be changing the environment that we live in. We must now look at our actions, both personal and society, through not only the lens of their immediate impact but how sustainable they will be into the changing, uncertain future.

Compounding this is the increasing urbanisation of the human population. The World Health Organisation predicts that the balance globally between people living in rural areas and urban areas is set to shift from it’s current 50/50 split to 70% living in cities by 2050 (Heilig 2012). As part of this, the WHO predicts that urban populations (separate from overall population) will double by the 2050, forming 6.4 billion of the 9.4 billion total projection (Heilig 2012). The Chinese government has announced intentions to move 250 million people from rural communities into newly built cities over a decade (Johnson 2013).

To facilitate this population shift, it follows that living densities in these urban areas will increase from their current level.

However, as these urban areas increase in density and size, there is potential for their ecological footprint to grow, and their sustainability to decrease. A study found that as a city, London requires an area twice the size of the entire U.K to sustain it (Best Foot Forward Ltd 2002). Ween (2014, p. 74) notes that the comparative lack of open space in Los Angeles leads to “isolation and results in a sterile urban realm”. She also notes that compact cities can lead to crowding and lack of light and air for their inhabitants. Benfield (1999) describe how urbanization is a rapidly growing cause of many environmental problems. Bhatta (2010) evaluates the consequences of this urban growth as including energy inefficiency, wealth disparity, impacts on wildlife and ecosystems, poor air quality, impacts on water quality and quantity and an associated increase in temperature known as the urban heat island effect. Equations by Karl, Diaz and Kukla (1988) indicate that for the annual mean temperature, urbanization during the twentieth century accounts for a warm bias of about 0.06°C in the U.S. Historical Climatology Network (HCN). Then Prime Minister of Australia Kevin Rudd used an address to the U.N to describe the changing climate as the “defining challenge of our generation”, noting that our choices now “will impact all future generations” (The Australian 2007).
Urban development is a serious threat to biodiversity, producing some of the greatest local extinction rates and frequently eliminating the large numbers of native species (Vale

& Vale 1976; Luniak 1994; Marzluff 2001). Studies by McKinney (2002) show consistent changes in species richness and species composition under urbanisation, following a negative gradient. All of these findings present serious implications when examining the sustainability of urban spaces.
Against this perilous backdrop exists the rise of the “green wall” or “vertical gardens” in cities and urban spaces. Most simply, green walls can be defined as “living wall systems”, constructed from modular panels, each of which contains its own soil or other growing medium and are based on hydroponic culture and the use of irrigation of nutrient solutions to provide for the plants water and nutrient requirements (Dunnett & Kingsbury 2004). They can be mounted on the interior or exterior of previously built forms, most typically retrofitted to structural surfaces of residential buildings (Knight 2012). They differ from the common architectural practice of growing climbers on the exterior walls of buildings (Perini et al. 2001).

Green walls are credited with offering numerous ecological, environmental and societal benefits; a positive influence on the comfort and well being in and around the building, social and aesthetic value (Knight 2012), reduction of the heat island effect in urban areas (Takebayashi & Moriyama 2007), air quality improvement (Ottelé, Bohemen & Fraaij 2010) and energy savings (Perini et al. 2001).

Seemingly here lies the “magic” bullet for the challenges of urbanisation; the implication that the very surfaces of urban developments can mitigate the aforementioned consequences they are responsible for. The rise of the green wall presents a convenient solution to the crises we face, an appealing “have your cake and eat it too” scenario. Urban development can continue unabated, the concrete jungle is greened and in doing so, becomes a more sustainable and enjoyable environment for all concerned. Indeed, under this scenario, property development rocketing skyward is seen as opportunity for expanding green space and sustainability. This thinking seductively subverts the current doom-and-gloom implications of modern urban living, in a way that has obviously proven popular. Green walls have seen a recent surge in popularity. Of the 61 large-scale outdoor green walls listed in an online database provided by greenroof.com, 80% were constructed in or after 2009 and 93% dated from no earlier than 2007 (APPENDIX 1). There is no denying that green walls have captured the zeitgeist of horticultural enthusiasm. Analysis for Google search term and news indexing trends (APPENDIX 3 & 4) shows a crescendo of popularity since 2005. The media breathlessly relays tales of “transforming drab urban facades into vibrant jungles of color” (Knight 2012).

This paper will demonstrate that the alignment of green walls with ideas of sustainability is completely baseless and in practice harmful. Through the use of the case study of One Central Park in Sydney, this paper will critically evaluate both the claims and operating practices of green walls against the criteria of sustainability. In doing so, this paper will encourage critical thinking be applied to not only this example but all green wall systems. The relevance of using sustainability as a critical criteria is supported not only by the claims of the supporters of these systems, but by the wider context they exist in. As Henry Thoreau (1860, p. 110) so succinctly put it, “What is the use of a house if you haven’t got a tolerable planet to put it on?”. This is regardless of the type of wall the house was built from, green or otherwise. It serves as a timely clarion call to consider the context of anything presented to us as “sustainable”, as ultimately this context is the greatest and most important one of all; the very planet we live on.
In doing so, this paper will seek to illuminate the marketing spin described by Mander (1972, pp. 45-56) as “ecopornography”; a shrewd linguistic ploy (akin to a judo move) where practices that are patently environmentally unfriendly are portrayed as being positive and sustainable for the sake of marketing.

BACKGROUND

Central Park is a major mixed-use property development project in Sydney, in the suburb of Chippendale. The first stage of the redevelopment is an apartment tower called One Central Park, a 117-metre-tall building designed by Jean Nouvel featuring “vertical gardens” by Patrick Blanc and LED art installations (CTBUH 2015) .
Bertram Beissel, architect at Ateliers Jean Nouvel (responsible for the development) describes the project as “
A flower for each resident, and a bouquet to the city” (Frasers Property 2015c). Marketing for the development describes how the vertical gardens by “the inimitable artist and botanist Patrick Blanc wrap the east and north facades” resulting in an effect “of an astonishing tree house retreat – a hi-tech tower of epic proportions, yet startlingly organic” (Frasers Property 2015d).

The building has won international acclaim for this “green” aesthetic, earning a 5 Star Green Building Council of Australia award recognising ‘Australian Excellence’, Best Innovative Green Building at the 2015 MIPIM Awards in Cannes, France and Best Tall Building 2014 by the Council on Tall Buildings and Urban Habitat (Frasers Property 2015a)

In 2014 it was awarded 5th best sky-scraper in the world by International construction data company Emporis (Frasers Property 2015a).

Blanc is a botanist and a self described artist, whose work with vertical garden has won international acclaim (utsarchitecture.net 2014). When completed, the vertical gardens by Blanc became the tallest living wall in the world (dezeen.com 2013). The garden installation covers nearly 50% of the building. To break it down further, the vertical garden installation consists of 21 panels covering 1 120m2, using 383 species for a total of 35 200 individual plants (junglefy 2015). The effect is unmistakable. Surely here is the most appealing rendition of Le Corbusier’s “Cities in the Sky”, one draped in verdant greenery and natural life that the modern urban environment has up till now only sought to trample. As the marketing for the apartments puts it, “finally, nature’s serene pleasures combine with dynamic city living” (Frasers Property 2015d).

As part of this image, the vertical gardens are explicitly marketed for their sustainability by those directly involved in their creation and veneration. When asked if the environmental footprint of the work was “in keeping with the aims and intent of the artwork”, Blanc replied “Perfectly. The environmental footprint will be positive” (Curating Cities 2013).

Antony Wood from the Council on Tall Buildings and Urban Habitat, when awarding the building the Best Tall Building Worldwide award in 2014 described how the project was about “the visibility of sustainable design”, and how the building represents a “new aesthetic” for cities, one “entirely appropriate to the environmental challenges of our age” (Daily Mail Australia 2014).

Central Park’s Project Director Mick Caddey openly states that the vertical gardens are “one of the most visible expressions of Central Park’s commitment to sustainable urban living” (Sekisui House 2014). From this we can see the vertical gardens are considered “sustainable” by those responsible for their creation and ongoing existence.

At this stage it is worth setting a definition of what exactly constitutes sustainability. In doing so, we create a standard by which the claims of sustainability by One Central Park can be held to.
In the seminal 1987 “Our Common Future” report (
Brundtland, G, et al. 1987, p. 41), the United Nations World Commission on Environment and Development defined sustainability as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. Pullman (2012) expands this by noting that the focus is on reducing non-renewable inputs and resources, favouring renewable inputs and reducing outputs.

It can be difficult to grapple with the somewhat nebulous implications of these definitions. Using a case study can help come to grips with the applications of these concepts. This is the power of the local example By using these definitions as a standard, we can now seek to analyse the integrity and consistency of the claims of sustainability made about One Central Park

ANALYSIS

COOLING

One of the more prevalent claims about One Central Park, and indeed green infrastructure in general, is that the adherence of plants to surfaces helps to cool the buildings. The idea is the plants create a micro-climate on the surface, intercepting heat before it reaches the surface and cooling the immediate surroundings by means of evapotranspiration (Wong, N et al. 2010). In doing so, the urban heat island effect that is created by the retention of solar energy (heat) buildings and impervious surfaces (University of Melbourne & Inner Melbourne Action Plan 2013).

Speaking on One Central Park, Blanc states that “thanks to its thermic isolation effect, the Vertical Garden is very efficient and aids in lowering energy consumption both in winter, by protecting the building from the cold, and in summer, by providing a natural cooling system” (Curating Cities 2013).
These claims do have proven scientific basis. A study by Perini et al. (2001) found a difference in surface
temperature difference of 3.64 C (or 20%) when comparing a green wall treatment with a bare wall. Admittedly, when taken in observation, these results seem convincingly conclusive. However, the history of building and thermal engineering is one that has existed for a lot longer than the recent birth of green walls technology. Mehaffy and Salingaros (2013), when dissecting what constitutes “green” architecture, note that older buildings often took a “passive” approach out of necessity in era where energy and transport were expensive or non-existent. This route was taken over “exotic” solutions.
With this in mind we can look at the findings of a study by Scherba et al. (2011) on green roof treatments. Although green roof composition is markedly different to that of green walls, the impacts on heat mitigation are comparable. The study found that although green roofs did reduce heat conduction when compared with a bare roof, in some cases standard white reflective paint was more effective than the green rood. The authors conclude “the results of this study may indicate that a white roof can mitigate the summertime urban heat island more effectively than a green roof” (Scherba et al. 2011, p. 2550). Indeed, when referring to green roof treatments, the Growing Green Guide (a document intended to promote and document green roofs and walls) states plainly that “A green roof provides significant cooling benefits compared to an uninsulated bare roof, although the most effective cooling comes from inclusion of insulation under the roof” (University of Melbourne & Inner Melbourne Action Plan 2013, p. 15).

Taking this as motivation, it is then logical to examine existing, proven and comparable technologies that can work in the same way to mitigate heat retention by surfaces. In doing so, we can analyse the efficiency of using heat mitigation as a justification for green wall treatments.

One of Australia’s leading independent and non-profit environment groups, Environment Australia (2015) recommends using shade cloth to prevent heat from penetrating a building. A prominent producer of such a product is Gale Pacific, under their Coolaroo shade cloth brand. In a report by the CSIRO commissioned by the company, their product was found to reduce temperatures by up to 32% compared with direct sunlight (Coolaroo 2015). Additionally, the specifications for their “extra heavy shade cloth” product in the “Heritage Green” colour provide for a shade factor of more than 85%, allowing only 16.96% of light to pass through the fabric (APPENDIX 4). The result is “substantially reduced temperatures” on any surface underneath the fabric (APPENDIX 4).

From this we can see that while green wall treatments do have a proven basis for mitigating heat retention and the urban heat island effect, there are other solutions that are more efficient at performing this role. This undermines this justification for choosing a green wall treatment, when substitutes exist can fill this purpose not only adequately, but in a superior way.

LABOUR AND MAINTENANCE

The maintenance of this system should also be considered, as it too is an input. The company responsible for maintaining the vertical gardens say the green walls alone require 6 team members, working for 8 hours a day 4 days a week (junglefy 2015).

If we take $70p/h as a base rate of pay from the schedule of rates for horticulturists published by the Landscape Industries Association Victoria (2009) , we can begin to get an idea of the enormous scope and expenditure in maintenance this garden requires. The following is a theoretical breakdown of costs, based on these figures:

$70 p/h (Landscape Victoria)

x 8 hours=$560

$560x 4 days worked= $2240

$2240 per week x 52 weeks

=$116 480

X6 team members

=$698 880 per annum in maintenance expenditure

/1120m2 (total garden area)

= $624 per m2 per year

Comparatively, we can look at the maintenance of a showcase garden of 12 000 m2 that requires one person per week (Layt 2015). Using the same theoretical rates this equates to little over $4.10 per m2, per year.

Although these sums are approximate (and it may impossible to determine the true extent of maintenance required to keep One Central Park performing), they give us a clear indicator of the exceedingly high inputs needed for this green wall. In practice, the rate of pay for workers at One Central Park may even be higher; due to the nature of the site that would have to qualified to work at heights. We can safely assume close to $700,000 each year (f not more) is spent on maintaining the plants in these systems, an enormous amount by any account. This cost comes both in terms of labour and expenditure, but also the associated unmeasured costs, for example fuel for scissor lifts and power tools (Radio National 2014). Such a comparatively high level of input just for the sake of maintenance cannot be considered sustainable, as it is consuming resources like labour, money and fuel at a rate that is astoundingly high. Contrary to the prior defined standards of sustainability, this huge maintenance expenditure signifies an approach to maintenance that seems to maximise, rather than minimise inputs.

LONGEVITY

We have established that green walls are input intensive. It then follows that we should examine the longevity of these systems; how long they are likely to prevail in the event that the finite resources they rely so heavily upon are not completely available.
The Paradise Park Children’s Centre in Islington, North London is host to London’s first green wall. It cost £100,000 of taxpayers money, was completed in 2005 and boasted and array of 30 plant species including strawberries, thyme and flowering shrubs (Evening Standard 2009). Four years later the plants are completely dead and the building is now adorned with their desiccated corpses. A water pump had failed, killing the entire installation. Councillor Barry Edwards stated “….we’ve had problems. Now the wall seems pretty well dead. The fancy watering system has never quite worked. Either it overwatered or it underwatered the plants” (Evening Standard 2009). The council faced criticism for “frittering away public money on a ‘green extravagance’ using untested technology” (
Evening Standard 2009) and would eventually spend another £130,000 on installing a renewed green wall system to replace the failure (Blunden 2010).

In response, Fionn Stevenson, co-director of the Oxford Institute for Sustainable Development, stated “The incident in Islington proves how vulnerable living walls really are” (Fulcher 2009). She notes that a “so-called living wall relies on an artificial supply of water and fertiliser to survive, and the design… is over-optimised and therefore very vulnerable. Unlike a natural eco-system it has no redundancy, so if one thing goes wrong, it all goes wrong” (Fulcher 2009).

Clearly the Islington example is a stark warning for anyone considering the longevity of these designs. However, the applicability of this example to One Central Park can be questioned. This example happened on the other side of the world, using public not private money and in a system not designed by Patrick Blanc. Yet the relevance can be directly traced when we discover that early on in the establishment of the One Central Park gardens an irrigation pipe was mistakenly cut by a tradesperson, leading to the death of a large patch of plants (Radio National 2014). This underscores the extreme vulnerability, lack of resilience and complete reliance on inputs these systems all have as part of their make-up.
Matthew Dodds from PTW Architects, a local collaborator on the project, states “The plants will live as long as the residents want them to” as the maintenance is controlled by the body corporate (
Manincor 2015) . This remarkably flippant viewpoint belies a disposable attitude to the long-term performance of a landscape; if it ever become undesirable or broken (for whatever reason), simply get rid of it. This thinking cannot be considered sustainable, as it would serve only to waste considerable embodied energy (Fulcher 2009) that has gone into the plants and system itself. This comes at the expense of working to creating a landscape that is more likely to be sustained over the long-term.

MATERIALS

Mora (2007, p. 1330) notes that the life cycle of a building product is “closely related to environmental impact”. By looking at the inputs and outputs of any potential environmental impacts caused by the materials throughout its life cycle, it allows allows us to learn about the environmental effects of a construction product. The environmental impact derived from the construction of a given structure, including its life time, reuse and demolition “should all be taken into account” through this analysis (Mora 2007, p. 1330). Research shows that the embodied energy of residential buildings can contribute up to 40% of the life-cycle energy use in residential buildings (Cole & Wong 1996). For this reason we can critically examine the building materials that have gone into One Central Park to establish the environmental impact of the choices made that lead to the construction of this system.

The construction of the Blanc system is reliant on the use of PVC as a mounting material for the wall (Radio National 2014). PVC is a material comparatively quite high in embodied energy intensity, far higher than materials like glass, concrete, roofing tiles and timber (Chen, Burnett & Chau 2001).

PVC is a petrochemical product, produced from ethylene which is in turn a product of the oil and and gas industry (PVC Europe 2015). The creation of PVC therefore uses the valuable finite resource of fuel, and should be considered an input with considerable embodied energy.

There has also been concern about the health impacts of PVC on humans (Canwest News Service 2008).
The fabric growing medium used by Blanc in this installation is made from recycled polyamide (
Curating Cities 2013) and is thus non-biodegradable, potentially existing and persisting beyond the life expectancy of the green wall.

The growing medium was manufactured in France and shipped to Australia, via boat (Curating Cities 2013). This is a considerable distance for anything to travel, let alone growing media that could perceivably been manufactured locally. Although boat is an efficient form of transport (Siegle, L 2014) the mere fact that the growing media had to be transported from the other side of the planet suggests significant embodied energy is attached to its use.

The shipping industry is responsible for 3% of greenhouse gas emissions and has traditionally used cheap, polluting fuel (Scott 2014). Greenhouse gas emissions from shipping may rise by 250% by 2050 (Scott 2014). Just 15 ships emit the equivalent sulphur dioxide emissions of every car in the world (Scott 2014)

Sulfur dioxide is a major air pollutant and has significant impacts upon human health ( United States Environmental Protection Agency 2015). Additionally the concentration of sulfur dioxide in the atmosphere can negatively influence the metabolic processes of both animal and plant life (Agrawal & Madhoolika 1999)

More startlingly the One Central Sydney development was found to have used rainforest timber logged in Malaysia, putting its advertised “five green star” rating at risk (Cubby 2011). The timber mill in question has been associated with serious breaches of sustainable logging practices over the past two years (Cubby 2011). Investigations by Malaysia’s auditor-general and environment groups found that trees had been cut down in an area slated for a national park, protected species habitat had been logged, and other logging in banned areas had caused water pollution (Cubby 2011). This is an obvious exploitation of valuable, fragile natural resources beyond a level that could ever be possibly considered sustainable, or even legal.

Clearly the serious misuse of materials (wilful or ignorant) and their associated negative costs to the environment and embodied energy casts a long, dark shadow over any claims of sustainability made about the One Central Park development.

WATER USE

The basis of Patrick Blanc’s gardens is hydroponics (Knight 2012); soil-less growing environments that have moisture and nutrient solutions applied directly . Blanc’s website proudly proclaims that plants don’t need soil, and that “only water and the many minerals dissolved in it are essential to plants” (Patrick Blanc 2015).
This water needs to be collected, stored and pumped before the tap on the irrigation system can be turned on. Transport of water in Australia used 36 petajoules of energy in 2009-10 (Australian Bureau of Statistics 2012). We then know that 73% of electricity generated in Australia is from coal (Origin Energy 2015). The use of any water in Australia therefore represents substantial embodied energy and emissions (Union of Concerned Scientists 2015).
One Central uses recycled and captured water for 70% of irrigation, leaving 30% mains use (Frasers Property 2015b). While the use of recycled water is admirable, the 30% used is still mains water that is (importantly) drinkable. These hydroponic systems also use water at a far higher rate to keep plants alive, substituting water where growing media or soil would otherwise exist.

The question then has to be asked if a wall mounted hydroponic system, one that pumps water up to be completely exposed to the elements and evaporation a “smart” use of water in a continent prone to drought? Given that temperatures are expected to substantially rise and become drier over the next year (Sturmer & Gribbin 2015), the sustainability of a system completely reliant on hydroponic water use in an exposed environment is questionable.

The CSIRO anticipates national total water requirements will increase by 60% from 24 000 GL/year to around 40 000 GL/year in 2050 (Foran, Lenzen & Dey 2005, p. 15) . They further state “water quality linked to human health will become an increasingly important issue”, and suggest demand for domestic water use under a 25 million population scenario could be “met through a combination of demand-reducing price increases” (Foran, Lenzen & Dey 2005, p. 15). This clearly indicates water is a valued resource, and will become more-so into the future. The sustainability of the nature of water use at One Central Park, which can reasonably be characterised as wanton, may be threatened by increasing demand and pricing for this resource.
Green (2010), when writing about green walls in L.A, a region gripped by drought, describes how it is “hard to imagine a less savoury or more whimsically destructive for a region in a water crisis”. Given the substantial drought the country has only just emerged from, the relevance of the LA example is undeniable.

Environmental scientist and advocate Shiva Vandana (2002, p. 1) summarises by saying “although two-thirds of our plant is water, we face an acute water shortage. The water crisis is the most pervasive, most severe, and most invisible dimension of the ecological devastation of the earth”. This has clear implications for the sustainability of systems so reliant on profuse water use like the one installed at One Central Park.

FERTILISER INPUTS

As previously detailed the Patrick Blanc system is hydroponic, entirely reliant on synthetic fertiliser input for plant growth. Nitrogen and potassium are essential macro-nutrients for plant growth (Raven, Evert, & Eichhorn 2005) and so form inputs to the gardens installed at One Central Park..

Nitrogen fertiliser is created through the Haber–Bosch process, an energy intensive process that uses annually 3–5% of the world’s natural gas production is consumed in the Haber process (~1–2% of the world’s annual energy supply) (Vaclav, S 2004).

Potassium fertiliser is a mined resource, it is therefore non-renewable. Australia is not a producer of potassium (United States Geological Survey 2008and so therefore any potassium used as an input must be mined and transported. This represents a non-renewable input substantial in embodied energy (accrued by transportation) used by One Central Park. Similarly, the use of synthetic nitrogen fertiliser is contributing to the significant global energy cost used to create this input. This process when turn uses non-renewable resources and has significant impact on the environment. The energy intensive and non-renewable nature of these inputs therefore directly impacts any assertion of sustainability on behalf of the green walls installed at One Central Park.

CONCLUSION

For our society, the road ahead is uncertain. It is likely that we will face significant changes to our very way of life within coming decades. Conspicuous consumption of resources with unchecked waste output cannot continue at their current rate, and it will require a fundamental change our mindsets. As Rachel Carson put it in her seminal work “Silent Spring” (1962, p. 277), “The road we have long been travelling is deceptively easy, a smooth superhighway on which we progress with great speed, but at its end lies disaster. The other fork of the road — the one less travelled by — offers our last, our only chance to reach a destination that assures the preservation of the earth.”.
Sustainability offers a powerful tool for analysing all of our actions to meet these coming challenges and their impacts. Proponents of green walls seek to market the technology as being both sustainable and a “cure all” for the impacts of urbanisation. The logic is that these systems are not only sustainable, but provide so many benefits that their retrofitting to our existing, hugely problematic built environment will actively increase the sustainability of these spaces.
A critical analysis of the case study of the vertical gardens installed at One Central Park Sydney proves this to be clearly divorced from the truth. The system is hugely reliant on non-renewable inputs, is completely wasteful and any services it provides are either replaceable by substitute solutions or deeply flawed by their grounding in conspicuous consumption. They appear to be nothing more than an absurdist folly of the moneyed elites that treats finite resources as theirs to squander freely. These are the same resources whose depletion (water, power) will affect the most vulnerable. The egalitarian ideals of public open space are replaced with corporate marketing write-offs; window dressing to an almost literal “ivory tower”.
Vandana (2005, p. 116) stated that “Whenever we engage in consumption or production patterns which take more than we need, we are engaging in violence”. For this reason the marketing of green wall technology as sustainable is particularly diffusive, and almost offensive. The responsibility of society is to seek, evaluate and practice truly sustainable solutions for our shared future, rather than chase foolish mirages these “vertical gardens” represent.

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