DAILY SCIENCE

Using less steel, cement, and copper in homes and cars could take a huge bite out of emissions

Material efficiency in home construction could save up to 50 billion metric tons of carbon emissions by 2050; for cars, the savings is up to 26 billion metric tons
July 5, 2022

Reducing the amount of cement, steel, and other industrial products needed to build cars and homes could cut greenhouse gas emissions from these parts of the economy by up to two-thirds, according to a new analysis.

Production of materials used to build other things accounts for one-quarter of greenhouse gas emissions. This industry is hard to decarbonize, requiring the development of new technologies and big investments in factories and other infrastructure.

Climate advocates have suggested that using materials more efficiently and recycling them more diligently could help save carbon emissions associated with production of industrial materials. But until now, there’s been little comprehensive analysis of the potential of this approach.

Researchers conducted a life-cycle analysis of residential buildings and vehicles (two of the largest consumers of industrial products), modeling their production, use, and disposal worldwide until 2050. They repeated the analysis for several different scenarios using different assumptions about future population size, climate policy, and socioeconomic trends.

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The researchers considered ten different strategies to reduce materials and emissions in the production of cars and homes, ranging from better collection and reuse of scrap materials to longer use of products to car sharing. They calculated how these material efficiency strategies would affect use of aluminum, cement, copper, plastics, steel, and wood over the coming decades.

If all ten of the strategies were implemented by 2040, then annual emissions related to homes and cars could be cut by one-third to two-thirds, depending on the scenario, the researchers report in Nature Communications.

Reducing the amount of material used in home construction could save the equivalent of 20-50 billion metric tons of carbon dioxide emissions by 2050, and reducing the amount of material used to manufacture cars could save the equivalent of 13-26 billion metric tons.

Three strategies provide the largest benefit for vehicles: ride sharing or carpooling (which reduces the number of cars needed and also distances traveled), car sharing (which also reduces the number of cars on the road), and smaller (and therefore lighter) cars.

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For homes, the most impactful strategies are downsizing homes (specifically, the researchers calculated the impact of shrinking floor space per person by 20%) and substituting timber for masonry and concrete in construction (a strategy that not only saves emissions but sequesters carbon to boot).

When it comes to cutting emissions, reducing demand for new products and materials is at least as important as increasing recycling, the researchers found.

Together, the ten strategies combined would reduce demand for newly-produced steel by five-sixths, cement by three-quarters, and copper by half. Primary materials would be replaced by recycled materials. “Reduced primary production will also lower industrial use of mineral resources, land, and water, thus yielding multiple co-benefits,” the researchers write.

What’s more, material efficiency can link climate action in wealthy countries to a climate-friendly rise in living standards in developing countries. “Excess steel scrap from demolished buildings and de-registered vehicles is recycled for use in the Global South, where it bolsters growth of in-use stocks and helps raise living standards and urbanization,” they write.

Strategies to reduce the use of materials could largely be implemented now, without need for any new technology – in contrast to the strategy of removing carbon dioxide from the atmosphere, the researchers note. Just like reducing the use of energy, reducing the use of materials can help meet climate targets without the need for carbon dioxide removal, the researchers argue.

Source: Pauliuk S. et al. “Global scenarios of resource and emission savings from material efficiency in residential buildings and cars.” Nature Communications 2021.

Image: Proggie via Flickr.

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