Editing IPCC:AR6/WGIII/Chapter-11 (section)

=== 11.3.1 Demand for Materials ===

<div id="h2-6-siblings" class="h2-siblings"></div>

Demand for materials is a key driver of energy consumption and CO 2 emissions in the industrial sector. Rapid growth in material demand over the last quarter century has seen demand for key energy-intensive materials increase 2.5- to 3.5-fold (Figure 11.6), with growth linked to, and often exceeding, population growth and economic development. The International Energy Agency (IEA) explains, ‘as economies develop, urbanise, consume more goods and build up their infrastructure, material demand per capita tends to increase considerably. Once industrialised, an economy’s material demand may level off and perhaps even begin to decline’ ( [[#IEA--2019b|IEA 2019b]] ).

<div id="_idContainer025" class="_idGenObjectStyleOverride-1"></div>

[[File:c4f683a0e2b8799cba0f35073f914ea7 IPCC_AR6_WGIII_Figure_11_6.png]]

'''Figure 11.6 | Growth in global demand for selected key materials and global population,''' '''1990–2019''' '''.''' Notes: based on global values, shown indexed to 1990 levels (=100). Steel refers to crude steel production. Aluminium refers to primary aluminium production. Plastic refers to the production of a subset of key thermoplastic resins. Cement and concrete follow similar demand patterns. Sources: 1990–2018: [[#IEA--2020b|IEA (2020b)]] . 2019–2020: [[#GCCA--2021a|GCCA (2021a)]] ; [[#International%20Aluminium%20Institute--2021a|International Aluminium Institute (2021a)]] ; [[#Statista--2021b|Statista (2021b)]] ; U.S. Geological Survey (2021); [[#World%20Bank--2021|World Bank (2021)]] ; [[#World%20Steel%20Association--2021|World Steel Association (2021)]] .

The Kaya-like identity presented earlier in the chapter (Equation 11.1) suggests that material demand can be decoupled from population and economic development by two means: (i) reducing the accumulated material stock ( ''MStock'' ) used to deliver material services; and (ii) reducing the material ( ''MPR'' + ''MSE'' ) required to maintain material stocks ( ''MStock'' ). Such material demand reduction strategies are linked upstream to material efficiency strategies (the delivery of goods and services with less material demand, and thus energy and emissions) and to demand reduction behaviours, through concepts such as sufficiency, sustainable consumption and social practice theory ( [[#Spangenberg--2019|Spangenberg and Lorek 2019]] ). Materials demand can also be influenced through urban planning, building codes and related socio-cultural norms that shape the overall demand for square metres per capita of floor space, mobility and transport infrastructures (Chapter 5).

Modelling suggests that per capita material stocks saturate (level off) in developed countries and decouple from GDP. [[#Pauliuk--2013b|Pauliuk et al. (2013b)]] demonstrated this saturation effect in an analysis of in-use steel stocks in 200 countries, showing that per capita steel in stocks in countries with a long industrial history (e.g., USA, UK, Germany) had saturation levels between 11 and 16 tonnes. More recently, [[#Bleischwitz--2018|Bleischwitz et al. (2018)]] confirmed the occurrence of a saturation effect for four materials (steel, cement, aluminium and copper) in four industrialised countries (Germany, Japan, UK and USA) together with China. These findings have led to the revision of some material demand forecasts, which previously had been based solely on population and economic trends.

The saturation effect for material stocks is critical for managing material demand in '''developed countries''' . Materials are required to meet demand for the creation of new stocks and the maintenance of existing stocks ( [[#Gutowski--2017|Gutowski et al. 2017]] ). Once saturation is attained the need for new stocks is minimised, and materials are only required for replacing old stocks and maintenance. Saturation allows material efficiency strategies (such as light-weight design, longer lifetimes, and more intense use) to reduce the required per capita level of material stocks, and material circularity strategies (closing material loops through remanufacture, reuse and recycling) to lessen the energy and carbon impacts required to maintain the material stock. However, it should be noted that some materials still show little evidence of saturation (i.e., plastics, see Box 11.2). Furthermore, meeting climate change targets in developed countries will require the construction of new low-carbon infrastructures (i.e., renewable energy generation, new energy distribution and storage systems, electric vehicles and building heating systems) which may increase demand for emissions intensive materials (i.e., steel, concrete and glass).

For '''developing countries''' , who are still far from saturation levels, strong growth for new products and the creation of new infrastructure capacity may still drive global material demand. However, there is an expectation that economic development can be achieved at lower per capita material stock levels, based on the careful deployment of material efficiency and circularity by design ( [[#Grubler--2018|Grubler et al. 2018]] ).

<div id="11.3.2" class="h2-container"></div>

<span id="material-efficiency"></span>