Editing IPCC:AR6/SR15/Chapter-4 (section)

== 4.3.4.2 Substitution and circularity ==

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Recycling materials and developing a circular economy can be institutionally challenging, as it requires advanced capabilities (Henry et al., 2006) <sup>[[#fn:r428|428]]</sup> and organizational changes (Cooper-Searle et al., 2018) <sup>[[#fn:r429|429]]</sup> , but has advantages in terms of cost, health, governance and environment (Ali et al., 2017) <sup>[[#fn:r430|430]]</sup> . An assessment of the impacts on energy use and environmental issues is not available, but substitution could play a large role in reducing emissions (Åhman et al., 2016) <sup>[[#fn:r431|431]]</sup> although its potential depends on the demand for material and the turnover rate of, for example, buildings (Haas et al., 2015) <sup>[[#fn:r432|432]]</sup> . Material substitution and CO <sub>2</sub> storage options are under development, for example, the use of algae and renewable energy for carbon fibre production, which could become a net sink of CO <sub>2</sub> (Arnold et al., 2018) <sup>[[#fn:r433|433]]</sup> .

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