The linear and wasteful ways in which humans partner with the materials that make up the economy result in significant greenhouse gas emissions throughout the life cycle of the products that meet our daily needs. A linear life cycle where material is extracted, processed, transported, manufactured, utilized, and discarded leaves a terrific atmospheric and financial footprint from the energy wasted, the embodied energy in the materials themselves, and the burden of handling the waste streams resultant from wanton consumption.
Project Drawdown has measured, mapped, and modeled a set of solutions that, collectively, show a pathway forward to a more circular economy where material already extracted, produced, and used is recovered and efficiently reprocessed into reincarnate forms or, in some cases, more thoughtfully disposed of or transformed so as not to release potent gases with significant global warming potential into the atmosphere. In some cases, simply more judicious use of materials results in significant energy savings, which mitigate emissions. In others, substituting energy-intensive feedstocks with biologic or recovered feedstocks mitigates greenhouse gas emissions.
With all Material Sector solutions, the concept of life cycle is critical to the Project Drawdown assessment; the models have discrete and specific boundaries drawn to be able to assess the relative impact of these solutions separate from Energy, Land Use, Food, or Transport solutions. Many of the solutions correspond to the energy-intensive consumption patterns of urban human settlement, and measuring the impact of the solutions requires first a modeling and mapping of the future of municipal solid waste and urban populations. A more circular economy will play a key role in achieving drawdown. Indeed, the single most significant mitigation solution published in Drawdown is found in this sector.
Included in the Project Drawdown list are 7 impactful solutions related to human use and treatment of materials which have a significant mitigation effect on carbon dioxide-equivalent emissions. These solutions are listed as follows:
Alternative cement – the use of an increased percentage of fly ash instead of Portland cement in concrete. Recovering and using fly ash has a smaller carbon emissions load than an equivalent amount of Portland cement.
Bioplastic – replacing petroleum-based plastics with biomass feedstock-based plastic materials. Petroleum-based plastics have a higher emissions load compared to biomass-based plastics.
Household recycling – the increased recovery of recyclable materials, not including paper and not including organic materials, from the residential sector of the economy. Recycling here refers to metals, glass, plastics, and other materials including e-waste and bulky items. The carbon mitigation impact results from comparing the emissions resulting from the manufacturing of materials from virgin feedstocks to those of manufacturing equivalent materials from recovered materials.
Industrial recycling – the increased recovery of recyclable materials, not including paper and not including organic materials, from the commercial and industrial sector of the economy. Recycling here refers to metals, glass, plastics, and other materials including e-waste and bulky items. The carbon mitigation impact results from comparing the emissions resulting from the manufacturing of materials from virgin feedstocks to those of manufacturing equivalent materials from recovered materials.
Recycled paper – the increased recovery and reprocessing of used paper into paper products that replace virgin paper feedstocks. The mitigation impacts measured result from the comparison of the transport and processing of recovered scrap paper to that of virgin feedstock (trees). The carbon biosequestration impact of trees not cut down is not measured in the results of this solution.
Refrigerant management – controlling leakages of refrigerants from existing appliances through better management practices and recovery, recycling, and destruction of refrigerants at the end of life. Refrigerant gases have significant global warming potential, and limiting emissions by control or destruction mitigates negative climate change impacts.
Water saving (home) – the use of low-flow fixtures and pressure regulators in the household. Saving water, in particular hot water, in the household reduces emissions related to heating water.
Additionally, Project Drawdown modeled other solutions which directly interact with other Materials solutions. They are listed here with their corresponding sector:
Each solution in the Materials Sector was modeled individually, and then integration was performed to ensure consistency across the sector and with the other sectors. Information gathered and data collected were used to develop solution-specific models that evaluate the potential financial and emission-reduction impacts of each solution when adopted globally from 2020-2050. Models compare a Reference Scenario that assumes current adoption remains at a constant percent of current electricity generation, with high adoption scenarios assuming a reasonably vigorous global adoption path. In doing so, the results reflect the full impact of the solution, i.e. the total 30-year impact of adoption when scaled beyond the solution’s current status.
The clusters and flow (left to right) shown in Figure 1 roughly indicate the connections of the solutions and form the basis for the approach to integration. Not all the solutions in the Materials Sector are subject to significant integration effects. The primary Materials solutions requiring an integration analysis are the solutions (and related solutions from other sectors) that effect municipal solid waste (MSW). The amount and composition of municipal solid waste sets the total addressable market, and/or functional unit adoption limits of a number of solutions.
Each Materials Sector model required customized total addressable market forecasts, and used the core Drawdown methodology of comparing a statistically assessed and calculated prognostication of solution adoption against a Reference Scenario that fixes adoption at its measured percentage of the market in 2014 and scales it according to the growth or decline of the overall total addressable market. The difference in adoption is then multiplied against statistically assessed variables to determine atmospheric emissions mitigation results and financial results.
Three scenarios were developed.
Many of the materials solutions interact with each other in determining the total addressable market. These interactions were handled through an integration process.
The approach to integrating the materials solutions starts with generating a composite assessment of municipal solid waste. Using data from the Intergovernmental Panel on Climate Change (IPCC); World Bank (What a Waste); Bahor, et al; Hoornweg (2014); and International Energy Agency (IEA) Annex I, we construct, using a best fit trend analysis and extrapolation, a composite measure of prognosticated MSW from 2015-2060 and label it the Pre-Integration MSW Scenario.
Additionally, based on the calculated markets for composting, household recycling, commercial recycling, and recycled paper, we create a Pre-Integration fractionation of MSW into three classifications that correlate with those solutions as follows:
The approach follows an order of operations, by using the results from solutions that are upstream from other solutions to impact the market or adoption of downstream solutions. The order of integration of solutions that impact MSW is as follows:
Reduced food waste
The first-order interaction is to reduce the total MSW by the total amount of food waste reduced in each year from 2014-2060, according to the results from the reduced food waste model. The amount of this annual reduction is also subtracted from the organic fraction of MSW.
The second order of integration is to assess how the increased adoption of bioplastics impacts MSW and waste fractionation. An assumption as to the percentage of bioplastic that is compostable is required. We start with very conservative percentage and scale to a significant one (ultimately 95 percent of bioplastic is compostable by 2060, up from 5 percent in 2015). This increased adoption of bioplastics both increases the organic fraction of MSW and decreases the recycleable fraction (recovered plastics decrease as bioplastics make up a greater portion of plastic demand over time) and impacts the remainder fraction of MSW (the portion of bioplastic that is adopted that is not factored as organic adds to the remainder fraction.)
After considering the reduction of organic MSW from reduced food waste (reduced food waste already incorporates considerations of plant-rich diet adoption) and the increase in organic fraction from the compostable percentage of the increased annual adoption of bioplastic sets a limit on the market for composting. Modeled compost adoption is compared to the new organic MSW market and adjusted as needed (i.e., when composting adoption exceeds all or a reasonable percentage of organic MSW).
Industrial and household recycling
After adjusting the recycleable fraction of MSW from the impact of increased adoption of bioplastic, the adoption of industrial and household recycling is compared to this new market and is adjusted as needed.
The adoption of recycled paper forecast in the recycled paper model is compared with the adjusted Remainder fraction of global MSW that contains recovered paper for recycled paper production, and is itself adjusted if needed based on the limits imposed by the integrated market.
After accounting for composting, industrial and household recycling, and recycled paper, a new comprehensive (post-integration) MSW amount and MSW fraction table was created. This table was used to determine the average low heat value of the waste mix that would be available to go to waste-to-energy facilities. The adoption of waste-to-energy is limited by the amount of remaining MSW not composted, recycled, or recycled as paper, and the energy value is also determined by the fraction mix.
After accounting for directing a portion of remaining waste to waste-to-energy, the remainder of MSW becomes the limiting factor for the adoption of landfill methane.
Together, Drawdown’s Materials Sector solutions are ranked fifth after Food, Energy, Land Use, and Women and Girls in the global impact of greenhouse gas emissions mitigation. They are responsible for 10.63 percent of the mitigation impact in the Plausible Scenario (i.e. 111.78 gigatons of carbon dioxide-equivalent greenhouse gases), 8.48 percent in the Drawdown Scenario (122.36 gigatons), and 7.69 percent in the Optimum Scenario (124.01 gigatons).
© 2017 Project Drawdown
Looking at individual solutions (Figure 4), refrigerant management accounts for 80.3 percent of total Materials Sector avoided greenhouse gas emissions from 2020-2050, followed by alternative cement (5.98 percent), water savings - household (4.13 percent), bioplastics (3.85 percent), household and industrial recycling (2.77 percent each), and recycled paper at 0.81 percent.
© 2017 Project Drawdown
|Total Atmospheric Greenhouse Gas Reduction (in Gigatons)|
|Plausible Scenario||Drawdown Scenario||Optimum Scenario|
|Water savings - home||4.61||5.64||6.33|
© 2017 Project Drawdown
Adopting the Materials solutions in the Plausible Scenario from 2020-2050 would, collectively, cost US$1,125 billion and result in a lifetime savings of US$1,040 billion. The net savings from this sector are largely attributed to one solution: water savings (home). Without that, the adoption of solutions in this sector would have been measured as a net cost, attributed to refrigerant management. Given the boundaries of life-cycle assessment, the recycling solutions show a modest savings from a larger upfront cost.
Net Implementation Costs (Billion US$)
Net Operational Savings (Billion US$)
|Water savings - home||72.44||1,800.12|
© 2017 Project Drawdown
 All monetary values are presented in US2014$.
For the Materials Sector, it is critical to consider identical life cycle assessment boundaries when comparing against benchmark values for emissions mitigations or costs. Some benchmark data in the literature discloses the boundaries and sources, and some do not. Here is a sampling of benchmarks for the entire sector and for individual solutions:
“Project Mainstream report estimates that the transition to a circular economy would provide $1tn in annual savings by 2025 and create 100,000 new jobs within five years.”
“Altogether, circular economy may lead to a reduction of approximately 550 Mt CO2 eq [Million metric tons carbon dioxide equivalent greenhouse gas emissions]” per year (includes food waste but likely not refrigerant management). (Deloitte Sustainability; Circular economy potential for climate change mitigation, November 2016)
“Circular economy could bring 70 percent cut in carbon emissions by 2030.” (The Circular Economy and Benefits for Society Jobs and Climate Clear Winners in an Economy Based on Renewable Energy and Resource Efficiency, Club of Rome, 2016) – (applies to Finland, France, the Netherlands, Spain, and Sweden)
“The material efficiency scenario is likely to cut carbon emissions in all the countries by between 3 and 10%” (The Circular Economy and Benefits for Society Jobs and Climate Clear Winners in an Economy Based on Renewable Energy and Resource Efficiency, Club of Rome, 2016) – (applies to Finland, France, the Netherlands, Spain, and Sweden)
Thoughtfully managing the inputs and processes of the material economy to be more efficient, more energy conserving, more biologically based and more circular will have a significant mitigation effect on greenhouse gas emissions. Innovation will be important to reduce the cost of implementation for most Materials solutions to make them more economically self-evident. When cascading benefits of climate beneficial material selection, recovery, and reprocessing are included (these were not explicitly modeled by Drawdown)—including health, jobs, and environmental impact—the economic business case for each of the Materials solutions appears more compelling.
There is significant variation in the literature on boundaries of study for life cycle assessment of materials. In many cases, assumptions needed to be made to compare variables from different studies in order to model the impact of Materials Sector solutions.
What is refrigerant management and why is it ranked so high as a solution?
Refrigerant management is the act of controlling leakages of refrigerants from existing appliances through better management practices and recovery, recycling, and destruction of refrigerants at the end of life. Refrigerant gases have significant global warming potential, and limiting emissions by control or destruction mitigates negative climate change impacts.
What is the alternative to cement that was modeled?
The model for cement assumes a high volume of fly ash is used to replace a certain percentage (up to 45 percent) of ordinary Portland cement in concrete production. This substitution lowers the processing energy and emissions resultant from creating ordinary Portland cement used in concrete. The amount of fly ash is, however, limited, and will decrease over time in all Drawdown scenarios as the amount of coal-fired electricity generation decreases. This limitation in included in all the modeling.
Why does saving water at home mitigate greenhouse gas emissions?
Saving water, in particular hot water, in the household reduces emissions related to heating water.
How does recycling reduce greenhouse gas emissions?
In most cases, extracting, processing, and manufacturing goods from virgin material sources requires more energy and generates more emissions than reprocessing and manufacturing goods from recovered materials after industrial or household consumption (even when including energy used in the recovery and transportation of recovered materials).
Does recycled paper include the impact of sustainable forestry?
The current carbon mitigation advantage of recycled paper rests on the reduced emissions from the lower energy footprint in processing recovered paper as compared to processing raw virgin timber/pulp. It takes more energy and results in more emissions to harvest timber (whether sustained yield forest or clear cut forest), debark it, chip it, and either chemically (kraft) or mechanically pulp it to prepare it for hydropulping than it takes to recover, transport, sort, and shred post-consumer paper as a feedstock to prepare it for hydropulping. The system boundaries for the Drawdown analysis start at energy used in harvesting timber and recovering paper through to finished paper product manufacturing. The emission impacts of landfilling virgin paper (possible methan emissions) and the biosequestration impacts of conserved forest not processed into paper are not included in the Drawdown analysis of recycled paper. Any carbon impact related to forest management practices would be captured in other Drawdown Land Use solutions (e.g., forest protection and afforestation).
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