Strategies toward ambitious climate targets usually rely on the concept of 'decoupling'; that is, they aim at promoting economic growth while reducing the use of natural resources and GHG emissions. GDP growth coinciding with absolute reductions in emissions or resource use is denoted as 'absolute decoupling' , as opposed to 'relative decoupling' , where resource use or emissions increase less so than does GDP. Based on the bibliometric mapping in part I (Wiedenhofer et al, 2020 Environ. Res. Lett. 15 063002), we synthesize the evidence emerging from the selected 835 peer-reviewed articles. We evaluate empirical studies of decoupling related to final/useful energy, exergy, use of material resources, as well as CO 2 and total GHG emissions. We find that relative decoupling is frequent for material use as well as GHG and CO 2 emissions but not for useful exergy, a quality-based measure of energy use. Primary energy can be decoupled from GDP largely to the extent to which the conversion of primary energy to useful exergy is improved. Examples of absolute long-term decoupling are rare, but recently some industrialized countries have decoupled GDP from both production-and, weaklier, consumption-based CO 2 emissions. We analyze policies or strategies in the decoupling literature by classifying them into three groups:(1) Green growth, if sufficient reductions of resource use or emissions were deemed possible without altering the growth trajectory.(2) Degrowth, if reductions of resource use or emissions were given priority over GDP growth. (3) Others, e.g. if the role of energy for GDP growth was analyzed without reference to climate change mitigation. We conclude that large rapid absolute reductions of resource use and GHG emissions cannot be achieved through observed decoupling rates, hence decoupling needs to be complemented by sufficiency-oriented strategies and strict enforcement of absolute reduction targets. More research is needed on interdependencies between wellbeing, resources and emissions.

Summary The international industrial ecology (IE) research community and United Nations (UN) Environment have, for the first time, agreed on an authoritative and comprehensive data set for global material extraction and trade covering 40 years of global economic activity and natural resource use. This new data set is becoming the standard information source for decision making at the UN in the context of the post‐2015 development agenda, which acknowledges the strong links between sustainable natural resource management, economic prosperity, and human well‐being. Only if economic growth and human development can become substantially decoupled from accelerating material use, waste, and emissions can the tensions inherent in the Sustainable Development Goals be resolved and inclusive human development be achieved. In this paper, we summarize the key findings of the assessment study to make the IE research community aware of this new global research resource. The global results show a massive increase in materials extraction from 22 billion tonnes (Bt) in 1970 to 70 Bt in 2010, and an acceleration in material extraction since 2000. This acceleration has occurred at a time when global population growth has slowed and global economic growth has stalled. The global surge in material extraction has been driven by growing wealth and consumption and accelerating trade. A material footprint perspective shows that demand for materials has grown even in the wealthiest parts of the world. Low‐income countries have benefited least from growing global resource availability and have continued to deliver primary materials to high‐income countries while experiencing few improvements in their domestic material living standards. Material efficiency, the amount of primary materials required per unit of economic activity, has declined since around 2000 because of a shift of global production from very material‐efficient economies to less‐efficient ones. This global trend of recoupling economic activity with material use, driven by industrialization and urbanization in the global South, most notably Asia, has negative impacts on a suite of environmental and social issues, including natural resource depletion, climate change, loss of biodiversity, and uneven economic development. This research is a good example of the IE research community providing information for evidence‐based policy making on the global stage and testament to the growing importance of IE research in achieving global sustainable development.

HighlightsWe use a consistent inventory of methods and data to model global material flows.We cover material flows for 177 countries (by world region) from 1950 to 2010.We discuss patterns and trajectories of domestic extraction, imports, and exports.Our data cover a period of rapid industrialization and globalization.The shift from a biomass- to a minerals-based metabolism can be observed globally.

Ecologically unequal exchange theory posits asymmetric net flows of biophysical resources from poorer to richer countries. To date, empirical evidence to support this theoretical notion as a systemic aspect of the global economy is largely lacking. Through environmentally-extended multi-regional input-output modelling, we provide empirical evidence for ecologically unequal exchange as a persistent feature of the global economy from 1990 to 2015. We identify the regions of origin and final consumption for four resource groups: materials, energy, land, and labor. By comparing the monetary exchange value of resources embodied in trade, we find significant international disparities in how resource provision is compensated. Value added per ton of raw material embodied in exports is 11 times higher in high-income countries than in those with the lowest income, and 28 times higher per unit of embodied labor. With the exception of embodied land for China and India, all other world regions serve as net exporters of all types of embodied resources to high-income countries across the 1990-2015 time period. On aggregate, ecologically unequal exchange allows high-income countries to simultaneously appropriate resources and to generate a monetary surplus through international trade. This has far-reaching implications for global sustainability and for the economic growth prospects of nations. High-income nations (the 'core' of the global economic system)