Greenhouse Emissions

"As a key input into concrete, the most widely used construction material in the world, cement is a major contributor to climate change. The chemical and thermal combustion processes involved in the production of cement are a large source of carbon dioxide (CO2) emissions. Each year, more than 4 billion tonnes of cement are produced, accounting for around 8 per cent of global CO2 emissions." - Chatham House: Making Concrete Change: Innovation in Low-carbon Cement and Concrete 

Global Warming & Climate Change

Heat Island Effect

Mercury

"The raw materials such as lime, coal and oil that are used for cement production usually contain trace concentrations of mercury. In addition, solid residues from other sectors such as fly ash and gypsum often used as raw materials for cement production contain mercury as well. Also the waste that is sometimes used as fuel in cement manufacturing may significantly increase the total input of mercury to cement production.

Sometimes the use of materials with low concentrations of mercury could lead to significantly high releases of mercury into the atmosphere if the consumption of these materials is in very large quantities.

Emissions from cement production amount to 9.8% of the global mercury emissions to air." - Zero Mercury: Cement Production

Solutions

As usually we have tried to list solutions in this section from most impactful, to less impactful.

Reduce > Reuse > Recycle or Create Something Different!

"Moving towards net-zero emissions for all new construction will require a rapid scale-up in the deployment of novel cements. Some can achieve emissions reductions of more than 90 per cent. Others can sequester carbon, theoretically capturing more carbon than is emitted in their production, rendering them carbon-negative. So far, however, the majority of these products have failed to achieve commercial viability. Achieving breakthroughs in this area will require concerted investment in research and large-scale demonstration projects, as well as education and training of consumers to build the market for novel products."  - Chatham House: Making Concrete Change: Innovation in Low-carbon Cement and Concrete 

Use Alternatives Building Materials

"Most cement emissions scenarios depend on projections of consumption that deserve far greater scrutiny. Concrete demand can be reduced, sometimes by more than 50 per cent, by taking a new approach to design, using higher-quality concretes, substituting concrete for other materials, improving the efficiency with which it is used on construction sites, and increasing the share of concrete that is reused and recycled. Deploying an array of such demand-side approaches in key growth markets such as China, India and African countries will be essential if the sector is to reach net-zero emissions. Action on material efficiency will, however, depend on the cooperation and motivation of a host of actors beyond the cement sector."  - Chatham House: Making Concrete Change: Innovation in Low-carbon Cement and Concrete 

Cob

Hempcrete & Hemp Blocks

Plastic Bricks & Buildings

While not a perfect solution, recycling plastic into bricks or other building components can provide a light-weight, easy-to-produce solution in places where other materials may be hard to come by. Plastic can help provide durable homes, reduce local plastic pollution, provide economic stability for locals, and provide an alternative to deforestation.

Clinker to Cement Ratio Reduction

"Clinker substitution involves replacing a share of the clinker content in cement with other materials. This could play a greater role than currently anticipated. Achieving an average global clinker ratio of 0.60 by 2050, as set out by the 2018 Technology Roadmap, has the potential to mitigate almost 0.2 gigatonnes (GT) of CO2 in 2050.9 The share of clinker needed can be reduced even further in individual applications, with the potential to lower the CO2 emissions of those applications by as much as 70–90 per cent. At the very ambitious end of the scale, if 70 per cent replacement was achieved on a global scale, this could represent almost 1.5 GT of CO2 emissions saved in 2050.10 Clinker substitution is not only a very effective solution, but also one that can be deployed cheaply today, as it does not generally require investments in new equipment or changes in fuel sources. It is, therefore, especially important to scale up clinker substitution in the near term while more radical options, such as the introduction of novel and carbon-negative cements, are still under development. The greatest constraints are the uncertain availability of clinker substitute materials and the lack of customer demand for low-clinker cements."  - Chatham House: Making Concrete Change: Innovation in Low-carbon Cement and Concrete 

Clinker ingredients can be a source of mercury, so changing clinker content can help reduce the impacts of more than just CO2!