One key method to combat climate change is to capture and store carbon dioxide. The U.S. Department of Energy is attempting to develop artificial methods to store carbon dioxide. These carbon sinks are already found in nature – in the oceans, soils, and forests.
Can the construction industry lower their carbon emissions by focusing on materials that act as a carbon sink? Researchers think the answer is “yes!”
What is A Carbon Sink?
A carbon sink absorbs and holds on to more carbon than it releases. A carbon source does the opposite – it releases more carbon than it absorbs.
Some of the biggest examples of a carbon sink in nature are the ocean, plants, and the soil.
The frozen tundra is a great example of the soil acting as a carbon sink. As the tundra melts and releases carbon dioxide it is turning into a carbon source.
Plants use and store carbon dioxide for photosynthesis. Oceans are also able to soak up and store carbon dioxide. The process in the ocean is somewhat like what happens when carbon dioxide is added to drinking water to make carbonated water, but at smaller concentrations.
Deforestation and changes to the ocean are threatening those carbon sinks. This could cause the carbon dioxide released into the atmosphere to increase exponentially. Researchers are looking for new ways to store carbon dioxide, like injecting liquid carbon dioxide underground.
Construction Materials Are a Critical Route
Currently the construction industry is one of the biggest contributors to carbon emissions. This is thanks to the high consumption of resources, the high amount of energy required for material production and emissions from the chemical reaction of some materials.
Researchers at the University of California, Davis hope that can be changed. Miller et al. think that storage of carbon dioxide within construction materials will be a “critical route for meeting net-zero emissions goal”.
Construction materials are ideal as a carbon sink because they have such long service lives. You want a material that is going to stand inert for many years – like a bridge or a building.
The researchers looked at wood, cement and concrete, bioplastics, and natural fiber composites. After assessing the opportunity and challenges of all of these potential carbon sinks, the researchers found that no one material is a magic bullet for turning the tide on carbon emissions.
All four of those materials have promise, however more research needs to be done to develop optimal versions.
Some materials, like wood, need to be taken from responsible sources, otherwise they will contribute to carbon dioxide levels. The forest itself is a huge carbon sink.
Alternative plant fibers like bamboo are a great option of carbon sink building materials. For a product like wood or bamboo, treatment or lamination to decrease the potential for damage from termites or moisture is essential.
Other materials, like cement and concrete, have a carbon emission heavy process for production. Conventional Portland cement contributes over 70% of the greenhouse gases produced from concrete production.
In order for cement and concrete to be a viable carbon sink, they will need to find alternatives to Portland cement.
Minimizing waste during production and construction is also essential. Any amount of waste, especially for aesthetics, minimizes the potential for a carbon sink.
One of the biggest advantages of using building material as a carbon sink is the financial aspect is less of an issue. The structure still has to be built. True carbon-sink materials are typically a local source and/or recycled – making them lower in cost.