Architect seeks pro-climate construction transformation

Architect seeks pro-climate construction transformation

Architect seeks pro-climate construction transformation to be generalised throughout the Middle East and North African regions of heavy urbanisation.  

The above image is of Place Pasteur, Beirut

 


French-Lebanese architect seeks pro-climate construction transformation

AFP
Lina Ghotmeh has pegged her career on sustainable construction.

The French-Lebanese architect wants to see her industry transformed by drastically reducing the use of concrete — a major CO2 contributor — using more local materials and reusing existing buildings and materials.

“We need to change our value system,” the 42-year-old told AFP last month.

Architect seeks pro-climate construction transformation

Lina Ghotmeh wants to reduce the use of concrete in building / © AFP

The aim is to reduce the carbon footprint of the construction industry and create buildings that can better resist the impacts of climate change.

But it’s not an easy battle.

The industry accounts for almost 40 percent of global greenhouse gas emissions, according to the United Nations.

Ghotmeh, who designed the Estonian National Museum and taught at Yale University, doesn’t advocate for fewer buildings — she knows that’s an unrealistic goal in a world with a growing population.

“That would be like saying ‘stop eating,'” she said.

– ‘Don’t demolish’ –

Instead, we should “keep what already exists, don’t demolish,” but refurbish and retrofit old buildings in a sustainable way where possible.

Building a new detached house consumes 40 times more resources than renovating an existing property, and for a new apartment complex that rises to 80 times more, according to the French Agency for Ecological Transition (Ademe).

Architect seeks pro-climate construction transformation

RTL

Lina Ghotmeh’s ‘Stone Garden’ in Beirut uses traditional building techniques / © AFP/File

And where new constructions are needed, local materials and design should be used in a way that incorporates natural surroundings and saves energy.

Ghotmeh used more than 500,000 bricks made from local dirt for a new Hermes building in France, expected to open early next year.

The bricks also regulate the building’s temperature and reduce energy needs.

The building will produce as much energy as it consumes, by being made energy efficient and using geothermal power.

– ‘Circular thinking’ –

Architects must, early in the project process, “think in a circular way,” Ghotmeh said, choosing reusable organic or natural materials like wood, hemp, linen or stone.

This shouldn’t stymie the design process either, she insists.

“In Canada, we build wooden towers, in Japan too. It’s a material that is quite capable of being used for tall buildings,” added Ghotmeh, who will build a wooden tower in Paris in 2023.

Another key approach is to build lighter, using less material and fewer toxins.

Architect seeks pro-climate construction transformation

RTL

Transforming the concrete jungle / © AFP

And then there’s concrete, the main material in so many modern buildings and perhaps the most challenging to move away from.

“We must drastically reduce the use of concrete”, she said, insisting it should only be used for essential purposes, such as foundations and building in earthquake-prone areas.

Some 14 billion cubic metres of concrete are used every year, according to the Global Cement and Concrete Association.

It emits more CO2 than the aviation industry, largely because of the intense heat required to make it.

Alternatives to concrete already exist, such as stone, or making cement — a component of concrete — from calcium carbonate. There are also pushes for low-carbon cement made from iron and steel industry waste.

– Beirut inspiration –

Building more sustainably often comes with a higher price tag — it costs more to double or triple glaze windows and properly insulate a house — but the long-term payoff is lower energy costs.

For Ghotmeh, it’s an imperative investment in our future.

It was her birthplace of Beirut that inspired her to become an architect, spurring a desire to rebuild the so-called “collapsed city” ravaged by war.

Architect seeks pro-climate construction transformation

RTL

The wall of Ghotmeh’s ‘Stone Garden’ / © AFP/File

In 2020, she completed the “Stone Garden” apartment tower in the city, built with concrete covered with a combed coating, a technique often used by local craftsmen. She used concrete in the construction because of earthquake risks.

The building was strong enough to survive the port explosion in 2020 that destroyed a large part of the city.

And the city continues to inspire her today, even when it comes to climate sustainability.

“Since there is practically only an hour of electricity per day, all the buildings have solar panels now. There is a kind of energy independence which is beginning to take place, by force,” she said.

“Does it take a catastrophe like the one in Lebanon to make this transition?”

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Facing heaviest delays in construction and infrastructure

Facing heaviest delays in construction and infrastructure

The Middle East seems to be facing the heaviest delays in construction and infrastructure, or so it is held in Consultancy-me

There is still much construction left in the gleaming steel and glass building of Qatar’s Doha Corniche (Google Maps street view picture above), which has stood incomplete and abandoned since 2010.  The reasons should not be very different from those elaborated on below.

 


Middle East faces heaviest delays in construction and infrastructure

 23 November 2022

 

Major construction projects in the Middle East run the highest risk of overruns in costs and delivery, with claims on derailed projects now averaging $154 million per project.

Now in its fifth edition, HKA’s annual CRUX Insight Report sheds light into the state of disputes in the major capital project and infrastructure sector. For its analysis, the global consultancy analysed claims and disputes on 1,600 projects in 100 countries for the period up to July 2022.

The analysis paints a worrying picture for project owners, contractors and other stakeholders. Globally, the combined value of claims stood at $80 billion, while cumulative delays added up to a staggering 840 years.

Facing heaviest delays in construction and infrastructure

Crux map

On average, costs claimed in disputes amounted to $98.7 million per project and more than a third of their capital expenditure (35% of CAPEX). From a time perspective, losses faced are even heavier. Claimed time extensions averaged 16.5 months – equivalent to 69% of the original planned project duration.

“Based on first-hand investigations by our expert consultants around the world, the report puts a number on the huge toll of project overruns on the global economy, our industry and project stakeholders,” said Renny Borhan, CEO of HKA.

The Middle East

According to the report, the Middle East is the world’s most challenging region for realising construction projects, with delays averaging 22.5 months or 83% of schedule duration. The average sum in dispute ($154 million) was more than a third of project expenditure (36% of CAPEX).

In the region, HKA’s experts assessed 380 projects in 12 countries, with the majority of projects in three segments: commercial buildings, onshore oil and gas, and transportation infrastructure.

Facing heaviest delays in construction and infrastructure`

Headlines figures

The prime causes of claims and disputes in the Middle East have been relatively steady for years. Since the first edition of HKA’s CRUX Insight Report, change in scope has topped the list.

“This chief cause is one seen in all regions. Projects are tendered and launched when designs are still immature. Change is inevitable in major construction projects and unless managed, inexorably leads to a wave of claims mounting into disputes,” explained Toby Hunt, a partner at HKA.

Scope change is followed by design information that was either issued late or incomplete, contract interpretation issues, and failure in contract management and/or administration.

Hunt: “Many of the dominant causes of claims and disputes in the region are design-centric and stem from lower levels of maturity in the construction and engineering industry.”

“The high-risk, low-margin contracting model rules in most parts of the Middle East. Risk allocation is skewed by heavily amended standard forms of contract with onerous terms on payments and liability. Often poorly drafted, they tend to include additional bespoke clauses that may have been designed to address problems that arose on previous projects, but conflict with other provisions of the current contract. Claims and disputes over contract interpretation ensue.”

Top causes of claims and disputes

Issues more specific to the region include foreign contractors’ reliance on (poorly) translated versions of Arabic contracts, and a relatively high competition for prestige projects – which results in over-ambitious bids.

Meanwhile, the growing skills deficit (exacerbated by the Covid-19 pandemic) is putting pressure on delivery, with builders and contractors struggling to recruit skilled employees. However, across the board, deficient workmanship was a far more significant cause of contention in Europe and the Americas than in the Middle East and other regions.

With construction and capital infrastructure activity buoyant in the region as national economies drive their diversification and investment visions, Haroon Niazi, co-leader of HKA in the Middle East, said that lessons being learnt from overruns should be captured and shared among the construction and engineering community across the region.

“Understanding the multiple reasons for distress on capital projects can help project promoters and the construction and engineering industry better mitigate problems on projects, and ultimately help them achieve better project outcomes.”

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The state of construction projects in the MENA

The state of construction projects in the MENA

New figures from GlobalData shed light on the state of construction projects in the Middle East and North Africa and around the world. Here they are as per Investment Monitor.

The state of construction projects in the Middle East and North Africa

By Ben van der Merwe

New figures from GlobalData show that the construction sector in the Middle East and North Africa (MENA) region is healthier than in most other regions and is continuing to improve.

The MENA region has received an overall score of 0.87 in GlobalData’s January 2022 Construction Project Momentum Index, which provides an assessment of the health of the construction project pipeline at all stages of development from announcement through to completion.

Every construction project in GlobalData’s database is assigned a score of between 5 and -5 based on its current progress, a score that is continually updated over time. These are then weighted by the value of each project in order to arrive at overall scores for countries, regions and sectors.

That score puts the MENA region in third place out of 11 regions, and is an increase on its score from December 2021 (0.62) when it ranked in seventh place.

One reason for the region’s relatively good performance in the index is its energy and utilities sector, which scores 1.21, putting it in first place out of 11 regions worldwide.

The MENA region’s institutional sector, by contrast, has performed somewhat worse, with a score of 0.48 (putting it in ninth place globally).

Within the MENA region, construction projects are proceeding with fewest obstacles in Qatar, which scores 2.15 in the index. The situation in Oman, however, is somewhat less positive, with a score of -0.02.

The improving health of the construction pipeline in the MENA region is partly due to the resolution of issues in the region’s energy and utilities sector, which has seen its score in GlobalData’s Construction Project Momentum Index move from 0.51 in December 2021 to 1.21 in January 2022.

The construction sector is also seeing fewer and fewer problems in Qatar, which has seen its score on the index go from 1.07 in December 2021 to 2.15 in January 2022.

The Construction Project Momentum Index

GlobalData’s Construction Project Momentum Index is based on analysis of thousands of individual construction projects around the world.

Each project is continually monitored for updates, with updates indicating progress increasing the project’s score, while updates indicating delays or cancellations reduce the score. The score always sits between 5, the best possible score, and -5, the worst.

The scores for individual projects are then weighted based on their significance in order to create combined indices for each region or sector.

Events that can reduce a project’s score include the project being cancelled or put on hold, delays, the rejection of applications or tender bids, or the reduction of the project’s scope.

Events that can increase a project’s score in the index, by contrast, include the completion or commencement of construction, the awarding of major contracts, or the approval of applications.

Ben van der Merwe is a data journalist at GlobalData Media, specialising in FDI. He joined from the Reach Data Unit, where he was a fellow of the Google News Initiative. His investigative journalism has previously appeared in the Observer, VICE, Private Eye and New Statesman.

The top featured image is for illustration and is credit to InvestorMonitor

Skyscraper design can remove up to 1,000 TONNES of carbon

Skyscraper design can remove up to 1,000 TONNES of carbon

American architectural firm proposes to safeguard the Environment with a Skyscraper design that can remove up to 1,000 TONNES of carbon from the atmosphere

By todayuknews

Designs for a green skyscraper that could remove up to 1,000 tonnes of carbon from the atmosphere on an annual basis — the equivalent to growing 48,500 trees — was unveiled at the COP26 conference last week.

Named for the world’s tallest trees, the ‘Urban Sequoia’ design is the brainchild of the Chicago-based architectural firm Skidmore, Owings & Merrill and is based on technologies that are all available for use today.

Each high-rise would employ multiple approaches to sequester carbon, including construction with carbon-absorbing materials, growth of plants and algae (for fuel, energy and food), and direct air capture technology.

The latter would be aided by the tower design’s ‘stack effect’, which would help draw in air to the centre of the building for processing a carbon extraction — while contributing to the building’s net zero energy system.

In fact, the company has claimed, their Urban Sequoia tower design would be capable, assuming a lifespan of at least 60 years, to absorb up to 4 times the carbon released in the atmosphere as a result of its construction.

Captured carbon could be used to produce biomaterials for roads, pavement, pipes and other items for developing urban infrastructure.

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Designs for a green skyscraper that could remove up to 1,000 tonnes of carbon from the atmosphere on an annual basis — the equivalent to growing 48,500 trees — was unveiled at the COP26 conference last week Pictured: a city of Urban Sequoias

Skyscraper design can remove up to 1,000 T. of carbon from the atmosphere
Each high-rise would employ multiple approaches to sequester carbon , including construction with carbon-absorbing materials, growth of plants and algae (for fuel, energy and food), and direct air capture technology — as depicted

Each high-rise would employ multiple approaches to sequester carbon , including construction with carbon-absorbing materials, growth of plants and algae (for fuel, energy and food), and direct air capture technology — as depicted

Environment: Skyscraper design can remove up to 1,000 TONNES of carbon from the atmosphere
Environment: Skyscraper design can remove up to 1,000 TONNES of carbon from the atmosphere

‘We envision a future in which the first Urban Sequoia will inspire the architecture of an entire neighbourhood — feeding into the city ecosystem to capture and repurpose carbon to be used locally, with surplus distributed more widely,’ said Skidmore, Owings & Merrill’s senior associate principal Mina Hasman. She added: ‘If every city around the world built Urban Sequoias, the built environment could remove up to 1.6 billion tons of carbon from the atmosphere every year’ Pictured: modern-day Laos, left, with the firm’s vision of a greener city, right

CONSTRUCTION’S CARBON FOOTPRINT

According to Skidmore, Owings & Merrill, ‘the need to transform the built environment is clear.’

Construction presently accounts for nearly 40 per cent of all global carbon emissions — a figure that could easily rise in the future without alternative approaches.

In fact, experts have predicted that, come 2060, an extra 230 billion square meters of building stock will be required in the world’s urban centres.

This, the architecture firm, is where Urban Sequoia comes in — allowing the built environment to turn buildings in to solutions, rather than problems, in the growing climate crisis. 

‘This is a pathway to a more sustainable future that is accessible today. Imagine a world where a building helps to heal the planet,’ said Skidmore, Owings & Merrill partner, Kent Jackson.

‘We developed our idea so that it could be applied and adapted to meet the needs of any city in the world, with the potential for positive impact at any building scale.’

‘The power of this idea is how achievable it is,’ agreed Skidmore, Owings & Merrill principal Yasemin Kologlu.

‘Our proposal brings together new design ideas with nature-based solutions, emerging and current carbon absorption technologies and integrates them in ways not done before in the built environment.’

While Skidmore, Owings & Merrill’s prototype design is a skyscraper that can sequester up to 1,000 tons of carbon on an annual basis, the carbon capture approaches it uses might be applied to buildings of all types and sizes.

By constructing buildings from materials like bio-brick, biocrete, hempcrete and timber — all of which use less carbon than alternatives, and some of which continue to adsorb carbon over time — it is possible to reduce the carbon impact of construction by 50 per cent as compared to using concrete and steel.

‘A progressive approach could reduce construction emissions by 95 per cent,’ the firm added.

‘We are quickly evolving beyond the idea of being carbon neutral. The time has passed to talk about neutrality,’ elaborated Skidmore, Owings & Merrill partner Chris Cooper.

‘Our proposal for Urban Sequoia — and ultimately entire “forests” of Sequoias — makes buildings, and therefore our cities, part of the solution by designing them to sequester carbon, changing the course of climate change.’

According to the firm, up to 120 tons of carbon could be sequestered per square kilometre (46 tons per square mile) if urban hardscapes were converted into gardens, cities were re-built as intense carbon-absorbing landscapes and streets were retrofitted with additional carbon-capture technologies.

Furthermore, they suggested, this figure could be nearly tripled if these strategies were also applied in parks and other green spaces. 

Skyscraper design can remove up to 1,000 T. of carbon from the atmosphere
Named for the world's tallest trees, the 'Urban Sequoia' design is the brainchild of the Chicago-based architectural firm Skidmore, Owings & Merrill and is based on technologies that are all available for use today. Depicted: an illustration of how the tower's design would allow it to take it carbon dioxide for storage or usage, while also producing products like biofuel

Named for the world’s tallest trees, the ‘Urban Sequoia’ design is the brainchild of the Chicago-based architectural firm Skidmore, Owings & Merrill and is based on technologies that are all available for use today. Depicted: an illustration of how the tower’s design would allow it to take it carbon dioxide for storage or usage, while also producing products like biofuel

Skyscraper design can remove up to 1,000 T. of carbon from the atmosphere
The tower design's 'stack effect' would help draw in air to the centre of the building for processing a carbon extraction — while contributing to the building's net zero energy system. Pictured: an artist's impression of the 'Urban Sequoia'  concept

The tower design’s ‘stack effect’ would help draw in air to the centre of the building for processing a carbon extraction — while contributing to the building’s net zero energy system. Pictured: an artist’s impression of the ‘Urban Sequoia’  concept

Skyscraper design can remove up to 1,000 T. of carbon from the atmosphere'
We are quickly evolving beyond the idea of being carbon neutral. The time has passed to talk about neutrality,' said Skidmore, Owings & Merrill partner Chris Cooper. 'Our proposal for Urban Sequoia — and ultimately entire "forests" of Sequoias — makes buildings, and therefore our cities, part of the solution by designing them to sequester carbon'

‘We are quickly evolving beyond the idea of being carbon neutral. The time has passed to talk about neutrality,’ said Skidmore, Owings & Merrill partner Chris Cooper. ‘Our proposal for Urban Sequoia — and ultimately entire “forests” of Sequoias — makes buildings, and therefore our cities, part of the solution by designing them to sequester carbon’

‘If the Urban Sequoia became the baseline for new buildings, we could realign our industry to become the driving force in the fight against climate change,’ said Skidmore, Owings & Merrill’s senior associate principal Mina Hasman — a nod to how construction presently accounts for nearly 40 per cent of all global carbon emissions.

‘We envision a future in which the first Urban Sequoia will inspire the architecture of an entire neighbourhood — feeding into the city ecosystem to capture and repurpose carbon to be used locally, with surplus distributed more widely,’ Ms Hasman continued.

‘If every city around the world built Urban Sequoias, the built environment could remove up to 1.6 billion tons of carbon from the atmosphere every year.

With immediate focus and investment in SOM’s prototype, we can start this process now and build the first Urban Sequoia,’ she concluded. 

The Urban Sequoia concept was presented by Mr Jackson and Ms Hason in COP26’s Blue Zone on Thursday. 

Skyscraper design can remove up to 1,000 T. of carbon from the atmosphere
While Skidmore, Owings & Merrill's prototype design is a skyscraper that can sequester up to 1,000 tons of carbon on an annual basis, the carbon capture approaches it uses might be applied to buildings of all types and sizes. Pictured: two architectural cross-sections of the high-rise design, showing how each floor integrates air capture and algae systems

While Skidmore, Owings & Merrill’s prototype design is a skyscraper that can sequester up to 1,000 tons of carbon on an annual basis, the carbon capture approaches it uses might be applied to buildings of all types and sizes. Pictured: two architectural cross-sections of the high-rise design, showing how each floor integrates air capture and algae systems

Environment: Skyscraper design can remove up to 1,000 TONNES of carbon from the atmosphere
Skyscraper design can remove up to 1,000 T. of carbon from the atmosphere
By constructing the buildings from materials like bio-brick, biocrete, hempcrete and timber — all of which use less carbon that conventional alternatives, and some of which continue to adsorb carbon over time — it is possible to reduce the carbon impact of construction by 50 per cent as compared to the use of concrete and steel. Pictured: two architectural cross-sections of the high-rise design, showing how each floor integrates air capture and algae systems

By constructing the buildings from materials like bio-brick, biocrete, hempcrete and timber — all of which use less carbon that conventional alternatives, and some of which continue to adsorb carbon over time — it is possible to reduce the carbon impact of construction by 50 per cent as compared to the use of concrete and steel. Pictured: two architectural cross-sections of the high-rise design, showing how each floor integrates air capture and algae systems

RESEARCHERS USE ‘ARTIFICIAL’ TREES CLEAN THE AIR IN CITIES

By keeping mosses in a container, such as those built by CityTrees, the conditions can be carefully controlled to ensure the plant is always thriving and therefore performing at optimum air filtration

By keeping mosses in a container, such as those built by CityTrees, the conditions can be carefully controlled to ensure the plant is always thriving and therefore performing at optimum air filtration

CityTrees – also known as artificial trees – use living plants and different types of mosses to capture toxins and remove pollutants from the surrounding environment to produce clean air.

Mosses, despite being a more primitive lifeform than most trees and flowers, conduct photosynthesis. 

This allows them to soak up carbon dioxide – a greenhouse gas – from the atmosphere and produce oxygen.  

They can also harbour friendly bacteria which further helps trap pollutants. 

By keeping mosses in a container, such as those built by CityTrees, the conditions can be carefully controlled to ensure the plant is always thriving and therefore performing at optimum air filtration. 

Each self-sustaining CityTree contains a water tank, irrigation systems and sensors to monitor plant growth and ensure they are healthy. The technology is powered by a combination of on-board solar panels and internal batteries. 

Each CityTree which has the pollution-reduction benefits of 275 normal trees.

Similar structures have previously been employed in other cities — including Berlin and Hong Kong — along with temporary trials across London. 

Plants also help soak up air pollutants directly. Studies have found that the worst offending air pollution for human health is PM2.5 or airborne fine particulate matter. 

These particulates are dangerous because they can get deep into your lungs, or even pass into your bloodstream. 

Particulates are found in higher concentrations in urban areas, particularly along main roads. 

One study from researchers at Beijing Forestry University in 2017 found ‘foliage acts as a bio-filter of air pollution and improves air quality due to the leaves’ rough texture and large contact area’. 

But the issue with relying on regular trees and plants to filter the air and remove carbon dioxide and pollutants is that they themselves are highly dependent on the environment.

If they are not thriving due to disease, drought or vandalism, they will fail to clean the air effectively.   

Skyscraper design can remove up to 1,000 T. of carbon from the atmosphere
Mosses, despite being a more primitive lifeform than most trees and flowers, conduct photosynthesis. This allows them to soak up carbon dioxide - a greenhouse gas - from the atmosphere and produce oxygen. Plants also directly soak up pollutants

Mosses, despite being a more primitive lifeform than most trees and flowers, conduct photosynthesis. This allows them to soak up carbon dioxide – a greenhouse gas – from the atmosphere and produce oxygen. Plants also directly soak up pollutants

  

Why low-rise buildings are the future – not skyscrapers

Why low-rise buildings are the future – not skyscrapers

As far as Cities and climate change are concerned: why low-rise buildings are the future – not skyscrapers. Skyscrapers are tall and/or very tall buildings. with advantages and disadvantages. They were considered a forward step within the current civilisation, up until these latter days or years where we started to realise that these structures mean a certain impact on the built environment as described by Ruth Saint, Edinburgh Napier University and Francesco Pomponi, Edinburgh Napier University.

The above image is for illustration and is of Abu Dhabi2.

More than half of the world’s 7.8 billion people live in cities and urban areas. By 2050, an additional 2.5 billion will be living there. As that figure continues to climb and ever more people flock to metropolitan areas in the hope of a better life, the big question is: how do we fit everyone in?

It is the job of city developers and urban planners to figure out how to build or adapt urban environments to accommodate the living and working needs of this rapidly expanding population. There is a popular belief that taller, more densely packed skyscrapers are the way forward, because they optimise the use of space and house more people per square metre and limit urban sprawl.

Why low-rise buildings are the future – not skyscrapers
Paris is an example of a densely built low-rise city. DaLiu/Shutterestock

But given the global commitments to emissions-reduction targets and mitigating climate change, is this the most sustainable solution from a carbon-reduction perspective?

Our recent study, which examined whether building denser and taller is the right path to sustainability, busts this myth: we found that densely built, low-rise environments are more space and carbon efficient, while high-rise buildings have a drastically higher carbon impact.

Impact on the environment

We assessed the whole-life cycle of carbon emissions – meaning both operational and “embodied” carbon – of different buildings and urban environments. Operational carbon is generated while a building is in service. Embodied carbon is all the hidden, behind-the-scenes carbon produced during the extraction, production, transport and manufacture of raw materials used to construct a building, plus any produced during maintenance, refurbishment, demolition or replacement.

This aspect is often overlooked, especially in building design, where operational efficiency is always to the fore. The argument for cutting carbon at the design stage has been made by numerous researchers, and it is gaining traction with leading international organisations such as the World Green Building Council. But it’s still something that is largely disregarded, mainly because embodied impact assessment is voluntary, and there is no legislation concerning its inclusion. But it must be advocated for if we are to reach our 2050 emissions targets.

At a global scale, the construction sector is responsible for a significant impact on the environment, as is clear from the graph below. The largest contribution comes from its consumption of energy and resources, which boils down to the design stage – the part of the process that no one is looking at.

Why low-rise buildings are the future – not skyscrapers
Graph showing construction sector's contribution to environmental impacts.
Construction sector’s contribution to environmental impacts. Edinburgh Napier University

Now that new buildings have to be more energy efficient and the energy grid is being decarbonised, this hidden embodied energy varies from 11%-33% for projects such as Passive House designs (a building standard that uses non-mechanical heating and cooling design techniques to lower energy use) to 74%-100% for near-zero energy builds (high performance buildings where the low amount of energy required comes mostly from renewable sources).

Given the focus on driving down the energy impact of day-to-day operations, the proportional share of embodied energy consumption has been driven up. So as energy demand becomes lower when the building is in use, the materials and activities required to build it in first place produce proportionally more impacts across the building’s lifespan. For example, low and near-zero energy buildings are made by improving insulation and using more materials and additional technologies, which greatly increases the hidden energy impact and carbon cost.

Moving to a smaller scale, the embodied carbon share across construction materials shows that minerals have the largest proportion by far, at 45%. The graph below shows the breakdown of materials, where concrete dominates in terms of hidden carbon contribution. This is important because skyscrapers rely heavily on concrete as a structural material. So the type of materials we use, how much we use, and how we use them is crucial.

Why low-rise buildings are the future – not skyscrapers
Graph showing the carbon contribution of different minerals used in construction.
The carbon contribution of different minerals used in construction. Edinburgh Napier University, Author provided

How we can fix it

We developed four different urban scenarios shown in the graph below, based on data from real buildings: high-density, high-rise (HDHR) which are tall and close together; low-density, high-rise (LDHR) which are tall but more spread out; high-density, low-rise (HDLR) which are low and close together; and low-density, low-rise (LDLR) which are low level and more spaced out.

To do this, we split the building stock into five main categories: non-domestic low-rise (NDLR); non-domestic high-rise (NDHR); domestic low-rise (DLR); domestic high-rise (DHR); and terraced/house. We gathered numerous data, including height, number of storeys, building footprint (the land area the building physically occupies), facade material and neighbouring constraints. This includes the number and area of blocks and green spaces within one square kilometre, average street width and average distance between buildings.

A graphic showing four different urban environments contained in the research study.
Four urban scenarios analysed in the study. Edinburgh Napier University, Author provided

These parameters were all fed into a computer model to analyse the data looking at the following:

1. How whole life-cycle carbon changed based on the buildings and the number of people accommodated within an area of 1km².

2. How whole life-cycle carbon changed due to an increasing population based on four fixed population sizes – 20, 30, 40 and 50 thousand people – and the land use required to accommodate them under the four different urban scenarios.

Our findings show that high-density low-rise cities, such as Paris, are more environmentally friendly than high-density high-rise cities, such as New York. Looking at the fixed population scenarios, when moving from a high-density low-rise to a high-density high-rise urban environment, the average increase in whole life-cycle carbon emissions is 142%.

Why low-rise buildings are the future – not skyscrapers
A panorama of New York's iconic skyscrapers.
New York’s densely packed skyscrapers. Sean Pavone/Shutterstock

Equating this to the potential savings per person, based on the fixed population size, building high-density low-rise offers a saving of 365 tonnes of CO₂ equivalent per person compared with high-density high-rise.

It’s time for urban planners to start embedding this new understanding of the whole carbon life-cycle of a building, balancing the impact of urban density and height while accommodating expanding populations. To achieve urban sustainability the world will need more Parises and fewer Manhattans.

Ruth Saint, Postdoctoral research fellow, Edinburgh Napier University and Francesco Pomponi, Associate Professor of Sustainability Science, Edinburgh Napier University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The Conversation

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