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BACKGROUND: For decades, climate researchers have highlighted the unprecedented emissions reductions necessary if we are to meet global mitigation ambitions. To achieve these reductions, the climate change mitigation scenarios that dominate the literature assume large-scale deployment of negative-emissions technologies, but such technologies are unproven and present considerable trade-offs for biodiversity and food systems. In response, energy researchers have postulated low energy demand scenarios as alternatives and others have developed models for estimating the minimum energy requirements for the provision of decent material living standards considered essential for human wellbeing. However, a key question that our study aims to explore is how a climate-safe, low energy demand future, and universal decent living could be achieved simultaneously, given the magnitude of current global inequalities in energy consumption and technological access. METHODS: In this modelling study, we combined data that described current global and regional inequalities in energy consumption with scenarios for low energy demand in 2050, and compared the resulting distributions with estimates of decent living energy, drawing all of this data from published academic literature. Using a threshold analysis, we estimated how much of the 2050 global population would fall below the minimum energy required to support human wellbeing if a low energy demand pathway was followed but inequalities in energy consumption remained as wide as they currently are. We then estimated the reductions in energy inequality and increases in technological equity that were required to ensure that no one falls below decent living energy in a climate-safe future. Finally, we speculated about the implications for global income inequalities. FINDINGS: We found that unprecedented reductions in income and energy inequalities are likely to be necessary to simultaneously secure a climate-safe future and decent living standards for all. If global energy use is reduced enough to ensure climate safety, but the extent of energy inequality remains as it is today, more than 4 billion people will not have access to decent living energy. To avoid this occurrence, after remaining essentially flat for 150 years, the Gini coefficient for income inequality globally might have to fall by a factor of two (ie, to a lower extent than for some of the most egalitarian European countries) and at a rate of reduction more than double that observed in the so-called golden age of capitalism. In the Global South (South America, Central America, south Asia, southeast Asia, east Asia, the Middle East, and Africa) even greater reductions in inequality would be required, unless the average living standards in the Global North (North America, Europe, Australasia, central Asia, and Japan) and in the Global South fully converged, which would require even more substantial reductions in consumption in the Global North than low energy demand scenarios assume. INTERPRETATION: Resolving the contradiction between the current global economic system (with its inherent inequalities) and the need for planetary and human health necessitates transformational change. Reflecting on the limitations of our analysis, we discuss four ways that these global challenges could be met without the need for such drastic reductions in inequality. FUNDING: The Centre for Research into Energy Demand Solutions and the Leverhulme Trust.

Asunto(s)

Factores Socioeconómicos , Humanos , Europa (Continente) , Asia Sudoriental , Medio Oriente , Japón

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Ecological breakdown and economic inequality are among the largest contemporary global challenges, and the issues are thoroughly entangled - as they have been throughout the history of civilisations. Yet, the global economy continues toward ecological crises, and inequalities remain far higher than citizens believe to be fair. Here, we explore the role of inequality, alongside traditional drivers of ecological impacts, in determining global energy requirements for providing universal decent living. We consider scenarios from fair inequality - where inequalities mirror public ideals - through a fairly unequal world, to one with a super-rich global elite. The energy-costs of inequality appear far more significant than population: even fair levels increase the energy required to provide universal decent living by 40%, and a super-rich global 1% could consume as much energy as would providing decent living to 1.7 billion. We finish by arguing that total population remains important nonetheless, but for reasons beyond ecological impacts.

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Ambiente , Factores Socioeconómicos

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This paper presents an integrated modelling approach for value assessments, focusing on resource recovery from waste. The method tracks and forecasts a range of values across environmental, social, economic and technical domains by attaching these to material-flows, thus building upon and integrating unidimensional models such as material flow analysis (MFA) and lifecycle assessment (LCA). We argue that the usual classification of metrics into these separate domains is useful for interpreting the outputs of multidimensional assessments, but unnecessary for modelling. We thus suggest that multidimensional assessments can be better performed by integrating the calculation methods of unidimensional models rather than their outputs. To achieve this, we propose a new metric typology that forms the foundation of a multidimensional model. This enables dynamic simulations to be performed with material-flows (or values in any domain) driven by changes in value in other domains. We then apply the model in an illustrative case highlighting links between the UK coal-based electricity-production and concrete/cement industries, investigating potential impacts that may follow the increased use of low-carbon fuels (biomass and solid recovered fuels; SRF) in the former. We explore synergies and trade-offs in value across domains and regions, e.g. how changes in carbon emissions in one part of the system may affect mortality elsewhere. This highlights the advantages of recognising complex system dynamics and making high-level inferences of their effects, even when rigorous analysis is not possible. We also indicate how changes in social, environmental and economic 'values' can be understood as being driven by changes in the technical value of resources. Our work thus emphasises the advantages of building fully integrated models to inform conventional sustainability assessments, rather than applying hybrid approaches that integrate outputs from parallel models. The approach we present demonstrates that this is feasible and lays the foundations for such an integrated model.

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The rapid urbanisation of the twentieth century, along with the spread of high-consumption urban lifestyles, has led to cities becoming the dominant drivers of global anthropogenic greenhouse gas emissions. Reducing these impacts is crucial, but production-based frameworks of carbon measurement and mitigation-which encompass only a limited part of cities' carbon footprints-are much more developed and widely applied than consumption-based approaches that consider the embedded carbon effectively imported into a city. Frequently, therefore, cities are left blind to the importance of their wider consumption-related climate impacts, while at the same time left lacking effective tools to reduce them. To explore the relevance of these issues, we implement methodologies for assessing production- and consumption-based emissions at the city-level and estimate the associated emissions trajectories for Bristol, a major UK city, from 2000 to 2035. We develop mitigation scenarios targeted at reducing the former, considering potential energy, carbon and financial savings in each case. We then compare these mitigation potentials with local government ambitions and Bristol's consumption-based emissions trajectory. Our results suggest that the city's consumption-based emissions are three times the production-based emissions, largely due to the impacts of imported food and drink. We find that low-carbon investments of circa £3 billion could reduce production-based emissions by 25% in 2035. However, we also find that this represents <10% of Bristol's forecast consumption-based emissions for 2035 and is approximately equal to the mitigation achievable by eliminating the city's current levels of food waste. Such observations suggest that incorporating consumption-based emission statistics into cities' accounting and decision-making processes could uncover largely unrecognised opportunities for mitigation that are likely to be essential for achieving deep decarbonisation.