Global socioeconomic material stocks rise 23-fold over the 20th century and require half of annual resource use.
Human-made material stocks accumulating in buildings, infrastructure, and machinery play a crucial but underappreciated role in shaping the use of material and energy resources. Building, maintaining, and in particular operating in-use stocks of materials require raw materials and energy. Material stocks create long-term path-dependencies because of their longevity. Fostering a transition toward environmentally sustainable patterns of resource use requires a more complete understanding of stock-flow relations. Here we show that about half of all materials extracted globally by humans each year are used to build up or renew in-use stocks of materials. Based on a dynamic stock-flow model, we analyze stocks, inflows, and outflows of all materials and their relation to economic growth, energy use, and CO2emissions from 1900 to 2010. Over this period, global material stocks increased 23-fold, reaching 792 Pg (±5%) in 2010. Despite efforts to improve recycling rates, continuous stock growth precludes closing material loops; recycling still only contributes 12% of inflows to stocks. Stocks are likely to continue to grow, driven by large infrastructure and building requirements in emerging economies. A convergence of material stocks at the level of industrial countries would lead to a fourfold increase in global stocks, and CO2emissions exceeding climate change goals. Reducing expected future increases of material and energy demand and greenhouse gas emissions will require decoupling of services from the stocks and flows of materials through, for example, more intensive utilization of existing stocks, longer service lifetimes, and more efficient design.
Institute of Social Ecology Vienna, Alpen-Adria University, A-1070 Vienna, Austria; fridolin.krausmann@aau.at.
Fridolin
0000-0002-9995-2372
F
Krausmann
Institute of Social Ecology Vienna, Alpen-Adria University, A-1070 Vienna, Austria.
Dominik
D
Wiedenhofer
Institute of Social Ecology Vienna, Alpen-Adria University, A-1070 Vienna, Austria.
Christian
C
Lauk
Institute of Social Ecology Vienna, Alpen-Adria University, A-1070 Vienna, Austria.
Willi
W
Haas
Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan.
Hiroki
H
Tanikawa
Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan.|Center for Industrial Ecology, School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511.
Tomer
0000-0003-4405-2382
T
Fishman
Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan.
Alessio
A
Miatto
Commonwealth Scientific and Industrial Research Organization, Black Mountain Laboratories, Acton, 2601 ACT, Australia.
Heinz
0000-0001-6399-4231
H
Schandl
Institute of Social Ecology Vienna, Alpen-Adria University, A-1070 Vienna, Austria.
Helmut
H
Haberl
carbon emission intensity; circular economy; manufactured capital; material flow accounting; socioeconomic metabolism