Policy case

Impact on the availability of resources as well as their effect on living organisms, ecosystems, and components of the environment.

Ecological Impact

Impacts on the social fabric of the community and well-being of the individuals and families.

Social Impact

Impacts on the financial condition of a company, as well as the the economicconditions of its stakeholders and on economic systems at local, national, andglobal levels.

Economic Impact

Impact on the quantity or quality of jobs, and shifts in the labour market

Jobs

Impact on the ease of innovation, and facilitating uptake of innovations

Innovation

Reduced green house gas emissions released into the biosphere

Reduce Emissions (SDG13)

Reduced use of virgin materials and/or an increase of the use of secondary and bio-based materials

Reduce Material Consumption (SDG12)

Minimise waste through diversion: Instead of sending waste to landfill, it is redirected into other industrial processes for handling, treatment, recycling, recovery, or reuse in various forms. 

Minimise waste through design: At the outset of a process of project, plan and design such that there is zero waste or minimal waste during production, use, and at end of life. 

Minimise Waste (SDG12)

Reduced use of fossil fuel energy sources and/or increased use of renewable energy

Reduce Energy Consumption

Producing building materials and providing services to create residential and non-residential infrastructure and real estate


Construction and Infrastructure

Producing building materials and finished and semi-finished building products for construction

Construction Materials and Products

Ensure renewable, reusable, non-toxic resources are utilised as materials and energy in an efficient way

Prioritise regenerative resources

Utilise bio-based, reusable, non-toxic and non-critical materials

Regenerative materials

Using bio-based materials such as bioplastics, mushroom-based materials, etc.

Alternative bio-based materials and inputs

'Inform' increases the overall levels of awareness and builds the necessary skills and knowledge around the circular economy to foster long-term change.

Inform

Encourage workplace training

Build countries consume 13% of the global material footprint, while they account for almost 50% of the population. 

Examples include countries in Sub-Saharan Africa and South Asia such as: 
- Bangladesh
- Ethiopia
- Nigeria
- Pakistan
- The Philippines
- Some small island states, ...

Minimal contribution to the overshoot of planetary boundaries: these countries contribute 20% of land use change, 30% of
freshwater use, 23% of phosphorus emissions to soil, and 11% of nitrogen emissions.

To find out what country profile your country belongs to, explore [this interactive story](https://circularity-gap.world) and search for your country on the final map.

Build

The need that represents the largest resource footprint, with 42.4 billion tonnes, is for construction and maintenance of houses, offices, roads and other infrastructure, especially in the developing world.

Housing

- Construction materials with recycled content
- Diversion of construction and demolition waste

Saving: 1.14 Gt emissions and 3.55 Gt material use 

🏠 Circular construction materials

Regenerate strategies phase out hazardous or toxic materials and processes and substitute them with regenerative biomass resources. A circular economy aims to mimic natural cycles—by shifting to more regenerative farming practices, for example—while also maximising the share of circular biomass that enters the economy. Regeneration can happen both at the systems level (by designing regenerative processes) as well as at the product level (by switching synthetic to organic fertilisers, for example).

Regenerate

Impacts

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Industries

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A framework of policy instruments that enabled and encourage the transition to the circular economy

Policies

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A framework of policy instruments that enable and stimulate the transition to the circular economy

The principles of a circular economy concern designing out waste, regenerating ecosystems and keeping items in use. Decoupling the economy from material flows—improving the rate of resource productivity faster than the economic growth rate—is also a consistent guide. By evolving with the growing number of applications of circular economy principles, and consolidating these strategies across thematic areas, Circle Economy’s Key Elements Framework (KE) renders the elements of the circular economy salient and serves as a basis to derive contextual strategies and interventions. 


The Framework consists of:
- Core Elements: Activities directly handling product or material flows; and uniquely,
- Enabling Elements: those that remove obstacles for core actors.


Key elements of the circular economy

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Circle Economy's framework of strategies and activities that define the circular economy

Whilst no two countries are the same, there are still obvious similarities between some of them, with discernible development patterns and parallels in evidence. Common problems and shared solutions help place unique country identities and individual issues in context.

Whilst this classification is far from clear-cut and exhibits some overlap, it does underline how the discourse on transitioning to a circular economy needs to account for both differences and commonalities, if we are to arrive at a more strategic and instructive analysis. It also allows to highlight a set of key themes that are likely to be central to the countries that fall under the respective profiles. 

Country profiles (Build, Grow, Shift)

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A framework to distinguish between different country profiles and their circular transition needs.

The framework consists of 21 complementary interventions, across six scenarios - one for each of the six societal needs we model. These interventions can mitigate climate impact by curbing GHG emissions

Note: interventions are currently focused on:
- 🏠 Housing 
- 🍎 Nutrition
- 🚗 Mobility
- 👚📺 Consumables
- 👩‍⚕️👨‍⚕️ Healthcare
-  🔊 Communication

These 21 interventions are spread across six societal needs and wants, with a set of solutions. Within these solutions are strategies on ’how to get there'.  

The framework moves beyond incremental action and provides solutions that will require behavioral change (dietary shifts towards less meat consumption, for example) and the adoption of state-of-the-art technologies in the industry to mitigate emissions in hard-to-abate sectors (such as steel manufacturing). It illustrates how continued globalisation can benefit from the uptake of digital solutions. The combined interventions showcase the mitigation potential that begins where the current country pledges end; illustrating the additional impact our interventions can bring to the NDCs. In short, the interventions provide input for a more profound fundamental transformation than the more current pathways that make up the vast majority of NDCs. 

Together, the combined interventions can almost double the current global Circularity Metric of 8.6%, bringing it to 17%. 

This results in:
• Shrinking global material use and extraction by 28%. 
• Cutting global GHG emissions by 39%—fully closing the Emissions Gap as defined in our report and taking into account the updated NDCs.
• Allowing the world to achieve the Paris Agreement’s goal of keeping at 1.5-degrees of warming by 2032.

*This framework was developed in the Circularity Gap Report 2021. Read more about it [here](https://www.circle-economy.com/resources/circularity-gap-report-2021)*






Global Circularity Gap Report

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An intervention-based framework for nations and stakeholders working towards circular countries

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Based on the work of [Bocken et al. (2016)](https://www.researchgate.net/publication/309699661_Product_design_and_business_model_strategies_for_a_circular_economy), the Four Flows Framework serves as a simple framework for managing resource flows in a circular economy by using less (Narrow), using for longer (Slow), using again (Cycle), and using clean, regenerative materials and energy (Regenerate).

These different principles of circular economy can be applied to our socioeconomic metabolism: we can design stocks like buildings, infrastructure, machinery, and vehicles to be rich resource mines for the future, and design manufactured goods and consumables to be cycled and made regenerative. Furthermore, the focus must also centre on getting more value out of fewer materials. Achieving the aims of a circular economy—minimising material use, regenerating the Earth, and preventing material losses—can be done through these four key strategies mentioned above.

Source: Circle Economy. (2023). *[The circularity gap report 2023](https://www.circularity-gap.world/2023)* (p.22). Amsterdam: Circle Economy. 

Four Flows Framework

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 This report is the result of a comprehensive analysis of resource flows and their impact on the quality of natural assets in The Gambia. This met analysis served as the basis for a stakeholder process to identify circular greenhouse gas (GHG) mitigation opportunities. It is the first of its kind outside of the OECD context. The report supports an update of The Gambia’s GHG mitigation commitments under the Paris Agreement and has been developed with generous support from the UNDP Climate Promise programme.
Although this report focusses on the Gambian context, it aims to inspire other countries to choose a circular low-carbon development pathway that values regenerative materials, human resources, creativity and knowledge. By stepping away from growth models based on monetizing finite resources and overexploiting the commons, a circular low-carbon development pathway seeks to preserve natural assets to serve current and future generations alike.
Aligning with environmental and socio-economic development priorities
The Gambia’s environmental priorities are to improve climate resilience in the agricultural sector, protect watersheds by increasing the forest area under community management, and preserve natural assets by reducing waste accumulation and the excessive extraction of primary resources. 
“Effective climate change mitigation is only possible when countries cooperate and take responsibility along value chains, even if these value chains extend far beyond national borders” An accelerated transition to a circular economy should also be aligned with socio-economic development priorities. For The Gambia, these priorities are to create jobs; increase the country’s self-reliance by reducing the monetary trade deficit; expand the tax base; develop the private sector; and, strengthen the country’s position as a regional trade hub.
The trajectories of all materials flowing though the Gambian economy. Systems analysis to connect climate action with key development priorities
Development is too often accompanied by a gradual decrease in the quality of ecosystems and the deterioration of natural resources such as soils, marine environments, fish stock and forest standing stock. The identification of circular economy opportunities for The Gambia combines an analysis of material use and flows with an analysis of trends in the quality and volume of natural assets. The analysis of stocks sheds light on whether the extraction and disposal of materials have a positive or negative effect on the ability of the country’s natural assets to regenerate and serve future generations. This report refers to that combined review of both flows and stocks as a metabolic analysis, while material flows are analysed both in material tonnes and in their embodied GHG footprint in tonnes of CO2 equivalents (tCO2e).
The objective is to identify GHG mitigation opportunities that extend beyond the climate mitigation commitments that The Gambia outlined in its first (NDC), or Paris Pledge. The circular economy strategies that determine that consumption in The Gambia is 45 percent circular.
Consumption in The Gambia is 45 percent circular
The circularity of The Gambia has been calculated by distinguishing 251 national material flows and assessing whether each is circular or linear. The consumption-based circularity gap for The Gambia specifies the share of domestic consumption from renewable or secondary resources, and for which materials are recovered at the end-of-life phase. Consumption in The Gambia is estimated to be 45 percent circular. This is attributed primarily to largely sustainable and, even, partly organic agricultural and forestry sectors, the use of largely renewable firewood, materials recycling, product reuse, and the use of regenerative construction materials.
On the other hand, production in The Gambia is considerably more circular – estimated at 74 percent – than consumption. When analysing the circularity of production, imports are excluded and only products from The Gambia are accounted for, including those that are exported.
Imported goods and materials account for 25 percent of the consumption-based GHG footprint
Analysing the carbon footprint of consumption in The Gambia helps to prioritize interventions that can reduce the GHG emissions, whether they occur in The Gambia or elsewhere. For 2020, national GHG emissions are estimated at approximately 4.9 million tCO2e. Upstream emissions generated during the production of imported goods and materials total an additional 1.2 million tCO2e.
Around 85 ktonnes CO2e of territorial emissions are related to the production of goods and materials that are exported to serve consumers in other countries; some of them are re-exports.
Territorial GHG emissions from The Gambia and GHG emissions embedded in imported and exported goods and materials.
Circular GHG mitigation brings a net zero GHG economy within reach
The circular economy offers an opportunity for The Gambia to combine economic development and job creation with reduced GHG emissions, improved climate resilience and reduced reliance on imports. The circular economy can help safeguard and restore the quality of the country’s natural assets, notably the soils, forest stock and fishing grounds on which large parts of The Gambia population rely for their subsistence needs. In a circular future, the country should continue to prioritize sourcing materials from regenerative, rather than depletive, sources and avoid waste.

“The Gambian waste management system is not designed to handle many types of imported goods and materials”
The measures proposed in the first Nationally Determined Contribution, complemented by nature-based solutions proposed by UNDP and additional circular mitigation opportunities, can reduce GHG emissions in The Gambia from a baseline level of 6.4 GtCO2e to around 1.64 GtCO2e by 2030. This estimate accounts for overlap, as the first NDC included circular mitigation potential of 0.22 GtCO2e for the period 2021 to 2025. Estimated GHG mitigation potential of the circular economy, compared with the first NDC, and nature-based solutions.
Twenty circular economy opportunities in The Gambia and their co-benefits
Twenty circular GHG mitigation opportunities are proposed within the sectors addressed. Taken together, they can reduce national GHG emissions by 36 percent, reduce The Gambia’s international carbon footprint by 38 percent and reduce national solid waste volumes by 37 percent. These percentages address only the sectors and GHG emissions within the scope of this analysis. The 20 opportunities would also lower government expenditures on fertilizer subsidies, shift the tax base away from labour to encourage job creation, and reduce the trade deficit by $116 million, or 7 percent of import volumes.
Combined with the measures already proposed in The Gambia’s NDC and nature-based solutions, such as peatland restoration and reforestation, total mitigation potential could reach 72 percent when disregarding overlap between the NDC and the circular greenhouse gas mitigation opportunities identified.
Six of the 20 circular GHG mitigation opportunities identified are in food value chains, representing 52 percent of domestic circular mitigation potential. In addition, 10 of the 20 opportunities have a high or very high job creation potential. The opportunities identified are structured by sector and then ranked based on their GHG mitigation potential within both The Gambia and international value chains. The co-benefits covered include the estimated potential impact on primary resource extraction, waste production, reduced reliance on imports and job creation.
The circular GHG opportunities and their impact on waste disposal,raw material extraction, GHG emissions, trade and jobs. Donors:








Client: UNDP
Partners: Katim Seringe Touray, EnviroSense, Circular Vision, Energy Changes, Climate Focus, Subbarao Consulting Services Ltd
Media coverage: All Africa, IIED,
2020-21 

 Construction materials have always been one of the most essential elements in architecture. Every construction material has its different qualities and so is the process of its application. During ancient times, people only used natural building materials such as stone, mud/earth, wood, etc. However, with the growing population and the need for better efficiency, we started using energy-intensive, eco friendly construction materials and techniques. These energy-intensive techniques have now brought us to a point where we need to reconsider our choices in building materials. Mud is one of the most commonly available materials which can bring about a lot of change if well start using it more intensely in construction. WHY MUD? Mud has been the most basic building material since the beginning of human existence. Moreover, is still being used by almost 1/3rd of our world’s population for housing purposes. Even after being used so extensively, mud is often regarded with detriment. Mud has numerous inherent properties that give the material its potential importance throughout the world. Image courtesy: Sai Goutham https://www.instagram.com/gomzi_17/ AVAILABILITY: Mud is found in abundance in almost every part of the world. This attribute makes it cheaper than any other conventional building material. There are certain circumstances when it is difficult to transport construction materials from one place to another. In such cases, mud, because of its easy availability could be used as an alternative eco friendly material for construction.ENERGY CONSUMPTION: An enormous amount of fossil energy is consumed in the manufacturing and transporting of modern construction materials. However, due to the abundance and easy availability and lesser use of energy-consuming construction equipment, mud directly reduces the consumption of energy.RECYCLING: Recycling of modern materials for building construction is expensive, and does even not apply for most of the materials. However, the recycling of soil does not even require the input of any external source. Therefore, saving a lot of time and money. Another important benefit of using earth is that the characteristics of recycled soil post-construction remain the same. Whereas, in the case of modern building materials, it acquires sub-standard characters after recycling. This characteristic makes mud a perfectly reusable resource for construction.INSULATION: It is extremely malleable and offers a way better insulation than steel and concrete structures. It decentralizes the construction process as it utilizes local materials and construction technology. Mud as an insulation material prevents external heat from entering inside the building while maintaining a cool environment inside. WHAT TYPE OF MUD SHOULD BE USED FOR CONSTRUCTION? Mud doesn’t have to be transported from far off places. It can be dug directly from the construction site itself for use. As soon as we start digging, we see different layers of soil coming out of the earth. All of these soil types cannot be used for construction. Some of these earth types, when combined with different material, can act as a better material for construction. But how do we know which layer is the most suitable for construction? Materials such as Gravel, sand, silt, clay and organic soils cannot be used separately. However, clay, when mixed with other binders and aggregates, acts as one of the main ingredients which are used throughout the building. The use of Binders, aggregates and stabilizers vary according to the technique that we are using. Soils like gravel, sand and silt are often mixed with stabilizers such as cement, slaked and un-slaked lime for stability purposes. MUD CONSTRUCTION PROCESS FOUNDATION Foundation is an integral part of any building. If the foundation is strong and can transfer load effectively then the building can stand still for even 1000’s of years. When considering Mud construction, the foundation has to be constructed out of some other stronger material rather than mud. There are various alternatives that can be used for the foundation in mud construction: Stone can be used in the foundation if locally available.In some cases, the topsoil might be loose and useless. However, the subsoil can be strong enough to carry the weight of a single-story house. In such a case, we can excavate the topsoil just like we would do for a stone or brick foundation. Then slightly dampen the excavated soil and put it back into the trench. Ram it to achieve the required proctor density. Repeat this until the trench is full.If bamboo is readily available, we can split it into halves for narrow rafts to be used in the foundation.A local alternative is, laying broken Matka (earthen pots) followed by ramming of the earth to achieve the required Proctor density. MUD WALL CONSTRUCTION TECHNIQUES: The type and process of mud construction differ from place to place. It varies as per the climate and the type of soil availability. As for every different type of mud we use a different construction method. Mud construction techniques can broadly be divided into 5 types: Wattle and DaubRammed earthAdobe constructionCob wall constructionEarthbag construction All of these techniques are still used throughout the world for pocket-friendly, sustainable and Eco friendly construction. 1. Cob wall construction: Cob is easy to learn and the most inexpensive mud construction technique. This vernacular technique has no contribution towards deforestation, pollution, and nor does it depend upon manufactured materials and power tools. Cob doesn’t require skilled laborers and is completely recyclable. Image courtesy: Sai Goutham https://www.instagram.com/gomzi_17/ The word cob means “a lump of the soil “in old English Latin origins. Cob is formed by mixing 25-30% clay along with 70-75% sand and straw. The properties of this material are very similar to lean concrete. As the water from cob dries out, it hardens and takes its shape just like concrete. All the cobs are simply piled one above the other layer by layer in the desired shape that we want. When creating window openings, regular operable windows or fixed glass windows can be placed at the preferred location and height while the layers are building up. 2. Adobe  Adobe or sun-dried bricks is one of the most popular mud construction techniques used throughout the world. Even today various workshops are being conducted to spread awareness and use of this particular technique. This natural building material is created using 25-30 % clay, 70-75 % sand, water, and other organic material like straw, manure, or sticks.The Masson mixes all of these ingredients and pours them into a wood-framed container to shape this mixture into bricks.The rectangular bricks are then kept under the sun for a few days.After drying for a few days, bricks are moved into a shaded area for air drying up to 4 weeks. During this process, the bricks are sprinkled with water to keep them from drying completely. Adobe bricks are more beneficial in hot climates due to their greater thermal mass. It provides insulation from external heat waves. Sun-dried bricks are most commonly used in West Asia, West Africa, Spain, Eastern Europe, and South America. 3. Rammed earth Another commonly used mud construction technique. Rammed earth walls are derived from the cob wall which had ununiformed widths. However, due to the framework used in this process, a standard width can be maintained throughout the building. Step 1- Buckets filled with mud mixSTEP 2- Two Wooden planks placed at the desired width.STEP 3- Rmming of earth filled in the cavity with the help of Ramrods layer by layerFinished Rammed earth wallImage courtesy: Sai Goutham https://www.instagram.com/gomzi_17/ The raw materials used in this technique are clay (minimum 15% and maximum up to 30%) and the rest is sand, chalk, lime, and gravel. The compressive strength of concrete of similar thickness is better than rammed earth. However, carefully built rammed earth houses and domestic buildings can survive for years. Two parallel planks are held at a fixed distance with the help of metal rods or small cross pieces of wood while creating a cavity in between.The material mix is then tossed into the cavity between the two planks. It is further rammed with the help of wooden or metal ramrod.When one section is completed and is hard enough to stand still, the two boards are moved along. This entire process gets repeated again.For the second course, the two planks are moved up and the entire process is repeated over the first course. These rammed earth walls, when constructed without reinforcements cannot withstand earthquakes. However, if we use reinforcement bars, wood, or bamboo reinforcement, it can prevent the failures caused by earthquakes and storms. 4. Wattle and Daub Image courtesy: Sai Goutham https://www.instagram.com/gomzi_17/ Wattle- a woven lattice of wooden strips, and Daub- mud mixed with other binders’, aggregates and reinforcements, is used. The daub is either mixed by hand or with the help of livestock. Binders are those substances that hold the soil together, these include Clay, lime, chalk dust, and limestone dust.  Aggregates provide the mix with its dimensional stability and strength. The materials include earth, sand, crushed stone, and crushed chalk. The size of these aggregates depends upon the wattle design that we are using.Reinforcements materials such as straw hair, hay, or some other fibrous materials hold the mud mix together. It preventing shrinkage and allows flexibility. This method is one of the most sustainable and eco friendly construction types due to its better stability and quick construction: First, a mesh of bamboo cane and straws is created and hung in between the gaps of the timber-framed structure.Mud mix is then plastered over this bamboo meshFurther, it is whitewashed to increase resistance to rain. 5. Earthbag construction Earthbag Construction This construction method was inspired by the bunkers built by the military. As the name suggests the process includes earth (mud) and gravel-filled bags as a construction material. The bags are either artificial or organic. The most used bag is made of woven propylene which is an artificial material. Other organic materials include hemp, gunny sacks, burlap or other natural fiber bags. Earthbag construction begins by first digging a trench.Multiple rows of these bags are filled with readily available inorganic material.Each layer above the foundation will have one or more strand of barbed wire on top.The heavyweight of these earth-filled bags pushes down on the barbed wire strands while locking the bag in place.This process is then repeated layer by layer in the desired shape and height of the structure. MUD MORTAR: Mortar is a material mixture used for filling in between the gaps for holding the bricks and blocks in place. The clay that we use for construction can also be used as mortar. There are few factors that we need to keep in mind before using clay as a mortar: The clay should be free from all the unnecessary elements such as gravel and pebbles. To avoid this, clay can be sieved when dry.To avoid cracks and shrinkage, too much clay should not be used.When constructing the walls, sometimes we prefer adding stabilizers such as lime or cement for better strength of the walls. In such cases, mortar should be stabilized at least 1.5 times more than the mud blocks. Ideal mortar mix= clay + 45-50% sand + 7.5 % cement/lime PLASTER The cob, rammed earth and adobe walls often have a rough finish so to smoothen it out, we need to apply a finishing layer of plaster on it. It is often recommended to leave the mortar between the mud blocks a little rough and not scrape the extra part out. This extra mortar would act as a key to hold the plaster. Plaster could be of just mud or mud with some other stabilizer such as cow dung, lime, or cement.  Image courtesy: Sai Goutham https://www.instagram.com/gomzi_17/ Building with earth is a sustainable, eco friendly as well as a cost-effective alternative. With proper stabilization and structural techniques, mud can surely prove to be a material of the future. Various environment friendly construction materials, including Compressed and stabilized earth blocks (CSEB) even have the power to be used for high rise structures. The researchers are still working upon bringing the best out of this eco friendly construction material. 

  The planetary boundaries signify the Earth’s capacity to tolerate change and set out the science-based limits that must not be surpassed if the Earth is to remain hospitable for future generations.

This timely report explores how we can design the built environment within the ‘safety rails’ established by the Stockholm Resilience Centre’s Planetary Boundary Framework. It sets out 20 regenerative actions to help us achieve sustainable development within these limits, whilst restoring natural systems.

   

  Building constructed from compressed earth bricks at Sandele resort. Photo: RFI/Daniel Finnan    A new construction technique is being rolled out in The Gambia in the hope it will help create more jobs. The method, which has been imported from India, fabricates blocks and bricks using soil from the local area. It aims to be more environmentally friendly through the sourcing of materials. The initiative is being funded by an EU project with the goal of creating opportunities for the youth.  “The blocks are made with natural add, which is abundantly available all over the world,” says Alpha Omar Jallow, the construction manager at Earthworks Construction. “In The Gambia we have the right material, the right soil, to do compressed stabilised add.” The “add” is the cement or lime used to stabilise the mix of soil.Earthworks Construction is an offshoot company of the Sandele Eco Retreat near Kartong, a village in the south west of the country. Many of its buildings were made from the Compressed Stabilised Earth Brick (CSEB). The resort is nestled in the forest by a beach and aims to offer visitors upmarket lodgings with minimal environmental impact.Sandele was originally developed in 2004 and the owners wanted to find the best sustainable design and techniques for construction. Jallow researched the CSEB technique and then visited India for a course. It gave him further instruction on producing  the blocks.  Report: Innovative compressed earth bricks boost Gambia's construction industry      “The key thing is the block itself - how it is manufactured,” says Jallow. “It needs to be made properly and then cured - this is key, this is the key essence.” The blocks are produced using a metal machine applying pressure - a huge lever compresses the mix and the blocks are left to cure under plastic tarps. They do not need firing in a kiln, so you remove the need to burn material to cure them.The construction manager says the big advantage is the sourcing of the materials. “It's abundantly available and its local, so it depends how you plan ahead.” He built a reception hall, dining area, several different types of lodges as well as staff quarters. The resort is extensive and blends into the trees lining the coastline.The buildings made from these blocks have a distinctive rusty, red colour from the local earth. The lodges also avoid corrugated iron roofs and ceilings are constructed in a domed or vaulted fashion.    

  Vaulted ceiling in one of Sandele's lodges. Photo: RFI/Daniel Finnan   “You can acquire all the materials - 90 per cent of materials - to build your structure within your locality,” says Jallow. “The maintenance of it is very minimal, it's not like with sand and cement.”Jallow says the bricks themselves have been tested for tensile strength and are just as strong as the typical bricks or blocks. They can also be manufactured in different sizes depending on the needs of the project.Putting out the word about compressed bricksThe Sandele eco resort is somewhat of an isolated example in the architecture of buildings across The Gambia. Most do not have the distinctive earthy colour and are constructed using blocks and materials that need to be transported to the development site.But through promoting and supporting the work of Jallow and Earthworks Construction, it is hoped compressed blocks could become a more permanent fixture in the construction industry.The Youth Empowerment Project (YEP) is partnering with Jallow to train young people to learn how to manufacture the bricks and build with them. YEP is funded by the EU’s Emergency Trust Fund for Africa and is a project implemented by the International Trade Centre.YEP hopes to create more employment and opportunities for young Gambians. And it sees the CSEB technique as being something it can help step up through support. Earthworks Construction has already built an entire resort in Sandele. It also has space for an area where the block-making machine is housed and bricks left to cure.    

  Bricks left to cure outside under a plastic tarp sheet. Photo: RFI/Daniel Finnan   Through this initiative, YEP sent 14 young people for a two week course in India - following in Jallow’s footsteps, learning about the compressed blocks. They learnt the basic techniques to manufacture the bricks. These new experts could then come back home and practice the method with Jallow at Sandele.“I think introducing this technology, once we get the idea and the ways of doing it, we are going to decentralise it,” says Sheikh Wadda, a 29-year-old building contractor and participant in the Indian course.Wadda hopes to convince clients to use this method instead of transporting bricks and iron for future construction projects. He also talks of YEP’s plan to buy five more compressed brick machines for similar facilities across the country.“There is one already in place for the Greater Banjul region,” says the young builder. “By next year we will have other machines in various regions, whereby we will go and train different regions.”Each block-making machine costs about 10,000 USD. The idea is that it helps minimise the use of environmental resources as well as create employment for people to make the blocks or bricks. The technique is very specialised, especially with the more advanced ceilings.Bakary Njie, a 27-year-old independent builder, sees the potential cost savings as a big advantage for home builders. It supposed to be cheaper per square metre than sand and cement.“Many of the Gambians are middle income earners or low income earners,” says Njie, who completed the same course as his fellow builder Wadda. “Using cement and sand to build its more expensive than using these compress-stabilised add blocks.”Both Njie and Wadda describe a mini-construction boom in The Gambia at the moment. More than a year since former strongman leader Yahya Jammeh gave way to the democratically elected government, many Gambians in the diaspora have returned home. Some of them want to build new homes in the country they left behind during Jammeh’s rule.The builders will be part of YEP’s plans to create a group of trainers who can go out and advocate for this method, eventually creating different blocking-making sites across The Gambia.“It's really changing our perspective of how we see designing and constructing in Gambia,” says Njie. He and Wadda will be attending another final advanced course in India where they will learn about the techniques required for creating the domed and vaulted ceilings.Once a certain scale is reached with the number of practitioners, YEP believes this construction technique could take off. The CSEB method for construction is already being used in other African countries such as Burkina Faso, Ghana and Nigeria.YEP is hoping that through support of this technique, taking the work of Jallow and Earthworks Construction to the next level, it can spark a construction revolution in The Gambia. At the very least it wants to help create more opportunities for young people through learning about the environmentally friendly compressed brick.Reporting assignment supported by the International Trade Centre 

   


 Sustainable BuildingsConstruction   Image credit: Unsplash / Ritchie Valens



 
Half of the world’s population is living in mud constructions. And we can understand why. Take a look at the following facts, primary building methods, and the main uses of earth in construction to find out how the very substance beneath our feet can be utilised in buildings and why it could be vital in finding sustainable solutions. While some of you might feel that mud is only used in far-flung nations with little option other than to construct using earth, we’re here to bust that myth and fling it like a mud pie. The truth is mud has been used for thousands of years in both rural and urban settings. And it’s not just suitable for housing: 15% of the architectural masterpieces on UNESCO’s World Heritage List were built using earth. However, don’t be fooled into thinking that this is an outdated option or one that won’t hold up against the elements. There are actually some buildings which are over 150 years old and still standing proud. Keep reading to find out more. Types of Mud Construction and Their Uses Remember, the following techniques can also be used in combination. There are lots of different types of earth even within a single country and region. First, investigate your construction site (i.e., where you will be building): dig a hole to look at the types, proportions, and depths of each earth sort. Just a note: if wet soil smells slightly musty, it could be a sign that it contains organic matter, which should be avoided. The supply chain will depend on what is available, what you need, and where you can get this from. There are numerous other earth construction techniques, but here’s a look at just six to let your mind start wandering: 1. Rammed Earth This technique uses earth, chalk, lime, and gravel. While it can be hard work to construct without using machinery (powered rammers), the method is generally simple. Rammed earth walls, also called pise, are made by ramming or compacting moistened subsoil in layers into position using temporary panels. The final step is the removal of the framework. The final build will meet sustainability goals (if materials such as cement are left out) and also be fire-resistant, strong, and durable. In fact, rammed earth constructions are so strong that parts of The Great Wall of China were built using this method. It is even loadbearing, allowing the construction of multiple floors.Rammed earth constructions can already be found all over the world in a wide variety of climates. You simply have to use local soil and be satisfied with the building design that best suits your region’s weather conditions. Be aware that not every type of soil is suitable for rammed earth structures. 

 2. Moulded and Compresed Earth Bricks and Blocks To create the standard mud bricks used in construction, earth is combined with water to form a mixture which is poured into moulds. These are then dried in the open air. It is also possible to add straw or other fibres which have a high tension in order to prevent the bricks from cracking. To build a structure, mud mortar is used to join the bricks.Mud brick constructions can be extremely simple. Therefore, even beginners and self-builders can use this technique.Mud bricks can be used to make walls, vaults, and domes. 3. Cob Building or Stacked Earth The term cob means ‘lump’ or ‘rounded mass’. This technique uses moist subsoil combined with sand and unchopped straw. The straw is employed to reinforce the binding element and to prevent cracking. A bit like bread, the mixture is kneaded and turned into loaf shapes. All of this is to be done by hand which has the added advantage of being able to shape and design the building however you want. The technique is super simple which is great for self-builders, however, it does take longer than other natural material building techniques. The walls are constructed in layers by stacking the mud loaves, allowing each layer to dry and harden before adding the next. These walls can either be left unfinished or covered with clay or lime plasters. Bear in mind that if using this technique in wet climates, an unfinished wall will need to be protected by eaves, overhang, or some kind of shelter. Cob building is perfect for creating organic shapes, such as curved walls, arches and niches. 

 4. Light Earth or Straw Clay As a combination of cob and rammed earth, this method means the final structure is lighter than cob and has a better insulation value, though it isn’t as strong. It must, therefore, be used as infill with a timber frame.Fibrous materials, such as loose straw, are covered in a clay slip which is rammed tightly in layers into the timber frame. Before plastering, walls must be left to dry. This technique can also be used as roof insulation between rafters or underneath earth floors. 5. Adobe Adobe is a sun-dried clay brick: one of the oldest building materials used by man. Due to the drying process, they require a period of warm, dry weather to ensure they are properly structured. This technique sees thick mud that is easily workable being mixed with straw. It can then either be shaped by hand or by using wooden moulds. The adobe mix can also be used to join the individual bricks together, meaning the wall structure is simple to assemble.The durability, high thermal mass of the structure, and the low investment in basic materials required are all advantages. Nevertheless, in the wrong location and without appropriate reinforcement, adobe constructions can be easily damaged by earthquakes. Additionally, the amount of usable interior space is lower than other techniques as adobe bricks take up a fair amount of room. 6. Wattle and Daub This is one of the most common techniques for wall infill. Timber is used to create a woven lattice which is then plastered with an earth mixture containing wet soil, clay, sand, animal dung, and straw. The name says it all here as it describes the two stages of construction: wattle is a woven structure of small plant elements (e.g., tree branches, bamboo, reeds) which all firmly hold together; daub refers to the mud mixture which is similar to the one used for mud bricks with dung as the organic binder. Covering the wattle with daub is done by hand. To finish, the wall can either be smeared in a final layer of daub or be whitewashed with lime. In comparison to other earth techniques, wattle and daub is actually very thin and flexible, though, as a result, its’ thermal mass properties are not as good. 

 Mud Around The World Yemen Towers, Yemen Interestingly, in Yemen, the height of the towers indicates the wealth and power of its owner: the higher the tower, the wealthier and more powerful they are.Construction begins by digging deep to find firm soil, where a layer of animal droppings is deposited, followed by salt. Timbers are positioned parallel to the walls with stones in the spaces. The walls are constructed in this way up to street level, after which mud bricks that have been dried in the sun are used to build up to six storeys. The walls therefore become thinner higher up the structure. New Gourna Village, Upper Egypt The design of earth buildings developed by the architect Hassan Fathy in 1946 showed how the traditional elements of Arab urban architecture could be combined with the use of mud bricks. His aim was to construct a sustainable and socially conscious village using locally sourced materials while respecting the ancient techniques.The entire village is an interconnected and incredibly strong structure. The houses in this village are all topped with a dome functioning as a heat regulator. This element along with traditional methods provide exceptional ventilation. The versatility of earth in design can also be witnessed: arches, domes, square and rectangular forms, all carved out of mud. Proof of the aesthetic appeal is how Fathy carved the windows in various shapes which create shadows on the ground that change throughout the day as the sun changes position. Rudrapur, Bangladesh A village school built in Bangladesh shows the capability of earth to be used in combination with bamboo to construct a stable, sustainable, non-residential building. Here, mud loadbearing walls with bamboo framing were the chosen method. Three layers of bamboo posts were bound together for the floor beams which are connected to the mud walls at both ends. Conventional engineering ideas and steel dowels were used to connect the layers of bamboo. Mud bricks formed the foundation and straw was additionally mixed into the clay and sand. The rammed earth of the walls was rendered in such a way that it exposes the straw reinforcement which also meant that no further rendering/finishing was required. The climate, availability of materials, and lack of electricity in the village encouraged the architects to insert apertures in the mud wall as well as slatted walls. The material and these design elements mean the school remains cool in the hot summers but also pleasant in the winter. Lyon, France But it’s not just in arid climates that mud construction methods flourish. France is one of the few places where there are examples of all four of the main earth building techniques: rammed earth, adobe, torchis cob and bauge cob. Earth construction isn’t shy of the urban world, as the structures in France are proving with a variety of bourgeois homes and large cities or districts being constructed using mud. To top it off, 15% of France’s architectural heritage is built from raw earth. Image credit: Unsplash / Christian V In the city of Lyon, you can find rammed earth structures predominantly on the border areas where rural meets urban. One such example is the district of Croix-Rousse. While rammed earth constructions are usually low-builds with no more than two or three storeys, in Croix-Rousse buildings can have up to seven storeys. Hollow terracotta tiles usually cover Lyon’s rammed earth buildings. The frame is made only of beams (horizontal, longitudinal, or vertical) as there are typically many shear walls (meaning they are built with the purpose of being able to withstand forces, such as wind and earthquakes). Walls are constructed by taking earth directly from the ground without requiring extra water. In Lyon, walls with a mixed composition – e.g., with rubble, brick, and pebbles – are not uncommon. Mortar connects all of the layers that form the walls. Usually, rammed earth constructions in urban settings are coated to protect them from moisture and improve the durability of the earth walls. Advantages Mud bricks may have the least significant environmental impact of all construction materials for multiple reasons:They should be made only with clays and sands, no living soil.Although they require a lot of water to produce, they need very little energy.Their embodied energy is probably the lowest in comparison to other materials. This would only rise if other ingredients, such as cement, are added, if it travels long distances, or if significant energy is generated in the mechanical processes associated with the construction.Construction using mud/earth can work on a large scale. i.e., not just for single storey houses, but also multiple storey high builds.Mud bricks, for example, can be used to construct loadbearing structures.Mud as a material has a high thermal mass meaning it can absorb, store and then release the heat again later on. This is due to its high density.As a result of this, you can save money on operating costs in summer as there is less need for air conditioning.The high density also means mud constructions have good acoustic insulation. Mud brick walls can have almost the same sound insulation quality as usual masonry structures.Moreover, construction costs when using earth as the primary material can be kept very low. In general, if local resources are used, mud can be a very cost-efficient option. It also depends on the amount of wall to build, the design and the height.Highly fire-resistant.Mud bricks (or small mud units) can offer a lot of flexibility in terms of design.This material can store volatile organic compounds which, if otherwise released, could be harmful to humans and the environment.Mud is a breathable material, offering a healthier indoor air quality. For instance, at 50% humidity (an easily attainable level when building with earth), it is more difficult for bacteria and mould to grow and the air is better, in particular for asthma and allergy sufferers.It can also be used decoratively, offering the choice of a flat or a very colourful and textured finish.It requires very little energy to manufacture. In fact, the only energy it needs is the sun.Using earth in construction also fits perfectly into circular building and the circular economy structure we should be advocating. The bricks can just be turned back into earth once the building reaches the end of its life. Disadvantages Mud and earth can be vulnerable to water damage and easily destroyed by wind, rain, and flooding if not protected and maintained well enough.Low moisture resistance can be a breeding ground for bacteria if not looked after. This also means that the material must be looked after and protected from the weather, in particular from driving rain. One way to do so is by having deep-set eaves.Rammed earth structures in particular can stain easily.Mud has a low tensile strength and can come apart easily, making mud walls susceptible to rodents and unwanted visitors.This also means mud roofs are difficult to construct and will usually need to be combined with another material in order to do this.Therefore, mud/earth buildings require regular maintenance.Some mud brick recipes contain bitumen, which may release hydrocarbons. Ideally, the earth should be used as close to its natural state as possible.While earth is ideal for keeping buildings cool in summer, this can prove problematic in winter. The low thermal resistance means a lot of heat is lost through the walls as air cannot be trapped in the structure.This technique requires quite a lot of work, in both construction and maintenance. Mud in a Nutshell Now you’ve witnessed how simple, sustainable, and accessible building with mud can be, it’s time to seriously stop and consider whether it could be employed for your next construction project. We all need to be playing our part in constructing urban environments in a healthier, renewable, and longer-lasting way and what could be better than using one of the many materials that mother nature provided us with? Happy digging! If you want to find out more about constructing with natural materials, take a look here or at some of the other natural building materials on offer:  

Mud buildings are remarkably good at keeping us cool in summer and warm in winter, and withstanding extreme weather. In the search for more sustainable buildings, architects are returning to this overlooked, age-old construction material.In Yemen's ancient walled city of Sana'a mud skyscrapers soar high into the sky. The towering structures are built entirely out of rammed earth and decorated with striking geometric patterns. The earthen buildings blend into the nearby ochre-coloured mountains.
Sana'a's mud architecture is so unique that the city has been recognised as a Unesco World Heritage site.
"As an outstanding example of a homogeneous architectural ensemble reflecting the spatial characteristics of the early years of Islam, the city in its landscape has an extraordinary artistic and pictorial quality," Unesco writes in its description of Sana'a. "The buildings demonstrate exceptional craftsmanship in the use of local materials and techniques."
Even though the buildings in Sana'a are thousands of years old, they remain "terribly contemporary", says Salma Samar Damluji, co-founder of the Daw'an Mud Brick Architecture Foundation in Yemen and author of The Architecture of Yemen and its Reconstruction. The ancient structures are still inhabited today and most remain private residences.
Damluji says it is easy to see why these mud buildings have not lost their appeal – they are well-insulated, sustainable and extremely adaptable for modern use. "It is the architecture of the future," says Damluji.
Architects around the world are reviving raw-earth construction as they seek to construct sustainable buildings that can withstand extreme weather events such as flash floods and intense heat. Could this ancient form of architecture influence the design of our future homes and cities? Could this back-to-basics technique provide an important solution to the climate crisis?
Construction's climate problem 
The construction industry accounts for 38% of global carbon dioxide emissions. The building sector has an important role to play if the world is to meet its goal of reaching net zero by 2050 and keep global temperature rise below the critical threshold of 1.5C. 
Swapping concrete for less polluting materials is critical to achieving our climate goals, scientists warn. Concrete, a staple of modern construction, has a huge carbon footprint. Building with concrete accounts for around 7% of global CO2 emissions – substantially more than the aviation industry which is responsible for 2.5% of emissions. Worldwide 4 billion tonnes of cement, the key component of concrete, is produced each year.
"We cannot live in these concrete jungles anymore," says Damluji. "We have to consider the environment and biodiversity. We cannot construct in isolation."
Mud could be the perfect sustainable alternative to concrete, according to Damluji. Constructing with mud has a very low impact on the environment and the material itself is fully recyclable, she says.Every year all the residents of Djenné, Mali, gather to repair and reclay the Great Mosque, the largest mud building in the world (Credit: Michele Cattani / Getty Images)Reviving an ancient tradition
The city of Djenné lies in the Niger delta region of central Mali. Founded in 800 AD, it became an important meeting place for traders travelling from the Sahara and Sudan. Djenné is known for its magnificent earthen architecture, especially its Great Mosque which is the largest mud building in the world, standing almost 20m (66ft) tall and built on a 91m-long (300ft) platform.
Every year the residents of Djenné gather together to repair and reclay the mosque, supervised by a guild of senior masons. These master builders are revered for their expertise and artistry in Malian society, says Trevor Marchand, emeritus professor of social anthropology at London's School of Oriental and African Studies and author of The Masons of Djenné.
"Master builders are recognised for their supernatural powers to bring protective elements to the buildings and people who live there," says Marchand.
The re-claying is an important symbol of social cohesion, says Marchand. "Everyone takes part. Boys and girls mix the mud, women bring the water and masons direct the activity. 
Djenné's mud architecture is constantly changing as residents re-clay, repair and rebuild their homes.
"There is a dynamism to it," says Marchand. "Mud is very malleable and it responds to the changing demographics of a home." If the family grows, buildings can easily be added to the home and if it shrinks, buildings are left to decompose and turn back into soil.
Sustainable construction
The ancient building practice is inspiring modern-day architects, such as Serbian Dragana Kojičić, who specialises in raw-earth construction.
"Our ancestors were really clever and really practical – they used what they had around them," says Kojičić. "The earth was everywhere and it could be used for everything: walls, floors, ceilings, stoves and even roofs."
Kojičić, who completed her training at the Centre for the Research and Application of Earth Architecture, restores and builds earthen houses across Serbia, reviving ancient building methods.
"Mud is contagious – it is love at first touch," she says. You don't need to wear any protective gear when handling the material, she adds. "With earth, you can just play."
You might also like:  Anna Heringer, an Austrian architect who creates buildings using natural materials such as mud and bamboo, agrees. "It is a wonderful feeling to touch the earth," she says. "You don't need any tools to build with it, you just use your hands."
Heringer has been working with mud for almost 20 years and has designed many notable earthen buildings, including the METI handmade school in Rudrapur, Bangladesh, for which she received the Aga Khan Award for architecture in 2007. "Mud is a very inclusive material; poor and rich can build with it," she says.
The METI handmade school was built entirely with local materials, such as mud, straw and bamboo, and constructed by a team of local builders, craftsmen and the students themselves.
"Earthbound materials such as loam and straw are combined with lighter elements like bamboo sticks and nylon lashing to shape a built form that addresses sustainability in construction in an exemplary manner," the Aga Khan jury said.The annual reclaying of the Great Mosque of Djenné in Mali is considered an important symbol of social cohesion (Credit: Michele Cattani / Getty Images)"Mud is the champion of future sustainable construction," says Heringer. "It is the only material we can recycle as often as we like, without using any energy," she says. "It actually gets better the more you use it." It's a bit like a dough, Heringer says – as you work with it, the material changes and responds.
But using mud for construction should be done in a sustainable way and should not reduce land availability for growing crops, says Marchand. "It can be a solution, but only on a certain scale," he says, noting that the global population is expected to reach 9.7 billion people by 2050, mounting pressure on land.  
Healthy, resilient buildings
One of the best qualities of mud buildings is that they are warm in the winter and cool in the summer, architects say. Mud walls have a high thermal mass which means they slowly absorb heat and store it, preventing the house from becoming too hot.
"Mud walls collect heat during the day from solar radiation and release it at night. The temperature never fluctuates – it's always at a comfortable level," says Pamela Jerome, a US architect and president of the Architectural Preservation Studio, which focuses on restoration projects around the world. 
This reduces the need for air conditioning units, which consume large amounts of electricity and contain refrigerants that are potent greenhouse gas emissions.The emissions from travel it took to report this story were 0kg CO2. The digital emissions from this story are an estimated 1.2g to 3.6g CO2 per page view. Find out more about how we calculated this figure here.In a 2021 report, the UK's Environmental Audit Committee recommended using "sustainable, bio-based and breathable" products, such as clay and lime-based plasters and natural fibres, to improve the insulation of existing homes.
"In comparison to buildings constructed of concrete or corrugated metal, mud brick buildings keep relatively stable interior temperatures across a 24-hour period and thus supply inhabitants with far superior thermal comfort," says Marchand. "An added bonus is that the thick mud-brick walls also reduce noise levels from outside or next door."The breathable nature of mud has other benefits too. Mud is porous and allows moisture into the house, improving the indoor air quality. "The earth has the ability to absorb excess moisture from the air, and to release it, if necessary, which is why we say that these houses 'breathe'," says Kojičić.
 "They are healthy buildings which breathe in the same way we breathe and have skins that adapt to hot and cold," says Damluji. "The way they are constructed is in reference, in proportion even, to the human body."Austrian architect Anna Heringer constructed the METI handmade school in Bangladesh entirely from local materials, such as mud, straw and bamboo (Credit:Benjamin Staehli)Mud structures are also incredibly sturdy and resilient to extreme weather, such as heatwaves, floods and droughts, which scientists say will become more frequent and intense as temperatures continue to rise. The UN's Intergovernmental Panel on Climate Change (IPCC) warned in a report this year that cities and settlements are largely unprepared to cope with extreme weather events. To avoid costly damages and protect people, they must invest in climate-resilient buildings and infrastructure, the IPCC said.
Earthen architecture can withstand extreme events such as earthquakes and heavy winds "because of the ability of its structure to distribute the load that it faces on its surface, unlike concrete or cement," says Damluji.
But mud building's resilience to earthquakes depends on the intensity of the seismic waves and the soil in which they are built, says Jerome.
Mud buildings are "also protected from seasonal rains and flash floods due to the damp-proof and protective external rendering used in several layers of refined mud, ash and lime coating and plaster", says Damluji.  
The impact of flooding on mud buildings varies, depending on whether they are built in a flood plain and have strong foundations, according to Jerome.
A severe flood in the Hadhramaut region in east-central Yemen in 2008 damaged 5,000 mud buildings, which had mostly been built on a flood plain, with few or no foundations, she says. The flood damage in Yemen's nearby desert valley Wadi Dawan was far less severe because the mud dwellings' foundations are more than 1.5m (4.9ft) deep and built of dry stone, which means water does not rise up through the soil, she adds. Paths in the valley are "designed as breakwaters that channel water into the irrigation channels of the date palm groves. Only about 25 buildings were impacted throughout Wadi Dawan".
People who wish to live in a modern, comfortable home should consider one made of mud, architects say.
"Mud buildings are extremely adaptable," says Damluji. "If you want to pull a wall down or change the design, you can recycle all the materials."
Overall, this makes for highly sophisticated as well as sustainable design, says Jerome. "Every mud house is comfortable, can be totally adapted and easily retrofitted with electricity and plumbing."
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      Cement manufacturing (such as that at this plant in Russia) accounts for 8% of the world’s carbon dioxide emissions.Credit: Getty  
Wet concrete has been poured into buildings, roads, bridges and more for centuries. Structures using concrete have survived wars and natural disasters, outlasting many of the civilizations that built them1. Alongside its strength and resilience, concrete is also a staple of building because it is relatively cheap and simple to make. Worldwide, 30 billion tonnes of concrete is used each year. On a per capita basis, that is 3 times as much as 40 years ago — and the demand for concrete is growing more steeply than that for steel or wood2.Versatile and long-lasting, concrete buildings and structures are in many ways ideal for climate-resilient construction. But concrete has a colossal carbon footprint — at least 8% of global emissions caused by humans come from the cement industry alone3. We must decarbonize its production.Concrete is made by adding sand and gravel to cement, whisking the mixture with water and pouring it into moulds before it dries. Making the cement is the most carbon-intensive part: it involves using fossil fuels to heat a mixture of limestone and clay to more than 1,400  °C in a kiln. Also, when limestone (calcium carbonate) is heated with clays, roughly 600 kilograms of carbon dioxide is released for every tonne of cement produced (see go.nature.com/3exhg82).  Lithium-ion batteries need to be greener and more ethical There are alternatives to cement, but they’re in the early stages of development, and cement itself remains highly profitable — two disincentives for companies to change.Alternatives include the leftover compounds from iron and steel production, known as slag, and heaps of unused fly ash, a residual material from coal plants. Researchers are also experimenting with reducing the temperatures needed in the cement-making process — thereby decreasing the energy used.In carbon-accounting terms, such replacements and procedural changes will reduce cement’s environmental impact, and that of concrete, too. But they still involve carbon emissions. Coal is being phased out, so fly ash isn’t a long-term solution. And alternatives have yet to be certified for use in building; for this to happen, long-term studies on their performance are needed.Cement will be around for the foreseeable future, so cement production itself needs to be decarbonized, which could happen in a number of ways. For example, low-carbon fuels — such as hydrogen or biomass — could be substituted for fossil fuels in heating the limestone and clay. And scientists are examining whether electricity — instead of combustion — could be used for the heating.Carbon capture could be part of the cement industry’s transition process4. In Sweden, for example, a company announced in July that it wants to capture 1.8 million tonnes of CO2 from a cement plant and bury it in the North Sea. Another possibility is to pump the captured CO2 into concrete itself, locking it up forever — which might also improve the properties of the resulting material. The injected CO2 reacts with calcium ions in the cement, producing more calcium carbonate, and potentially making the concrete able to withstand larger loads.Concrete optionsTechnological changes can be accelerated through regulation and legislation. A huge proportion of concrete is used in public building projects. In North America alone, public agencies buy as much as one-third of concrete manufactured annually. That means they have leverage in the low-carbon transition: they could work with researchers and manufacturers to reshape the concrete industry.In New York and New Jersey, a bill is making its way through state legislatures that, if passed, will mandate that state agencies and departments prioritize cement that has a lower carbon footprint.  An ancient battle between environment and concrete Other states are introducing legislation that requires construction proposals to declare the environmental impact of cement mixes. Some regions, such as Honolulu, Hawaii, have added a requirement that city construction projects must consider using concrete that stores CO2.In Europe, the European Union’s Waste Framework Directive requires 70% of construction waste to be reused. Another idea, known as materials passports, could also help. When buildings are demolished, the waste concrete is smashed up and discarded, or sold for low-grade use such as backfilling in road construction. But a passport would ensure that concrete is recorded ‘at birth’ and then tracked throughout its life cycle — making it accessible for more kinds of reuse.Finally, the cement industry needs to publish better emissions data so that progress can be tracked. In a study published last month, researchers from Columbia University in New York City report that some of China’s cement-making companies have an ambition for emissions to peak in 2023 (see go.nature.com/39z1sdd). But only one of the ten companies surveyed is reporting emissions data. China is the world’s largest cement producer (55% of global capacity), and cement accounts for 15% of the country’s carbon emissions. Without data, it will be impossible to know whether national targets are being met.Next month, a cement-industry campaign called Concrete Action for Climate will announce its road map for carbon neutrality by 2050. This is overdue, but the road map must also explain interim steps, how companies intend to achieve neutrality and how progress will be measured.Parts of the ancient world were made with concrete, and the material was used to build much of the modern world, too. Researchers and governments must work with the cement industry to slash its carbon footprint, driving the climate-resilient construction the world now sorely needs. Nature 597, 593-594 (2021)doi: https://doi.org/10.1038/d41586-021-02612-5 Jackson, M. D. et al. Proc. Natl Acad. Sci. USA 111, 18484–18489 (2014).Article  PubMed   Google Scholar  Monteiro, P., Miller, S. & Horvath, A. Nature Mater. 16, 698–699 (2017).Article  PubMed   Google Scholar  Ellis, L. D., Badel, A. F., Chiang, M. L., Park, R. J.-Y. & Chiang, Y.-M. Proc. Natl Acad. Sci. USA 117, 12584–12591 (2020).Article  PubMed   Google Scholar  Fennell, P. S., Davis, S. J. & Mohammed, A. Joule 5, 1305–1311 (2021).Article   Google Scholar  Download references 

Senegal

Gambia

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Arup is an independent firm of designers, planners, engineers, architects, consultants and technical specialists, working across every aspect of today’s built environment.

ARUP

UNDP

Understanding the circular economy opportunities in a jurisdiction or company, requires merging a top-town system’s approach with bottom-up anecdotal evidence. Shifting Paradigms relies on a metabolic analysis to map out the systems flows, conversions and stocks of materials and energy. Rather than looking at the individual elements of a linear “take-make-waste” supply chain and aiming for incremental improvements, we focus on the systemic opportunities which can drive change.

The systems’ analysis is combined with information on the socio-economic, cultural and spatial context, with anecdotal evidence on existing circular economy initiatives and with regional development ambitions. By preference, Shifting Paradigms collaborates with in-country experts, supporting them with trainings on the circular economy, systems' analysis data collection and visualisation, circular design, business models, finance and policy.

Shifting Paradigms

Elementerre

Earthworks Construction

Worofila

<p>West African design collectives and construction companies are using traditional building materials and techniques to create more sustainable and carbon neutral structures. </p>