Global greenhouse gas (GHG) emissions can be traced to five economic sectors: energy, industry, buildings, transport and AFOLU (agriculture, forestry and other land uses). In this topical review, we synthesise the literature to explain recent trends in global and regional emissions in each of these sectors. To contextualise our review, we present estimates of GHG emissions trends by sector from 1990 to 2018, describing the major sources of emissions growth, stability and decline across ten global regions. Overall, the literature and data emphasise that progress towards reducing GHG emissions has been limited. The prominent global pattern is a continuation of underlying drivers with few signs of emerging limits to demand, nor of a deep shift towards the delivery of low and zero carbon services across sectors. We observe a moderate decarbonisation of energy systems in Europe and North America, driven by fuel switching and the increasing penetration of renewables. By contrast, in rapidly industrialising regions, fossil-based energy systems have continuously expanded, only very recently slowing down in their growth. Strong demand for materials, floor area, energy services and travel have driven emissions growth in the industry, buildings and transport sectors, particularly in Eastern Asia, Southern Asia and South-East Asia. An expansion of agriculture into carbon-dense tropical forest areas has driven recent increases in AFOLU emissions in Latin America, South-East Asia and Africa. Identifying, understanding, and tackling the most persistent and climate-damaging trends across sectors is a fundamental concern for research and policy as humanity treads deeper into the Anthropocene.

Mitigation solutions are often evaluated in terms of costs and greenhouse gas reduction potentials, missing out on the consideration of direct effects on human well-being. Here, we systematically assess the mitigation potential of demand-side options categorized into avoid, shift and improve, and their human well-being links. We show that these options, bridging socio-behavioural, infrastructural and technological domains, can reduce counterfactual sectoral emissions by 40-80% in end-use sectors. Based on expert judgement and an extensive literature database, we evaluate 306 combinations of well-being outcomes and demand-side options, finding largely beneficial effects in improvement in well-being (79% positive, 18% neutral and 3% negative), even though we find low confidence on the social dimensions of well-being. Implementing such nuanced solutions is based axiomatically on an understanding of malleable rather than fixed preferences, and procedurally on changing infrastructures and choice architectures. Results demonstrate the high mitigation potential of demand-side mitigation options that are synergistic with well-being.

Climate mitigation solutions are often evaluated in terms of their costs and potentials. This accounting, however, shortcuts a comprehensive evaluation of how climate solutions affect human well-being, which, at best, may only be crudely related to cost considerations. Here, we systematically list key sectoral mitigation options on the demand side, and categorize them into avoid, shift and improve categories. We show that these options, bridging socio-behavioral, infrastructural and technological domains, can reduce counterfactual sectoral emissions by 50-80% in end use sectors. Based on expert judgement and literature survey, we then evaluate 324 combinations of wellbeing outcomes and demand side options. We find that these are largely beneficial in improving wellbeing across all measures combined (76% have positive, 22% neutral, and 2.4% have negative effects), even though confidence level is low in the social dimensions of wellbeing. Implementing demand-side solution requires i) an understanding of malleable not fixed preferences, ii) consistently measuring and evaluating constituents of wellbeing, and iii) addressing concerns of incumbents in supply-side industries. Our results shift the emphasis in the climate mitigation solution space from supply-side technologies to demand-side service provision.

China is now the world's largest producer and consumer of household appliances and commercial equipment. To address the growth of electricity use of the appliances, China has implemented a series of minimum energy performance standards (MEPS) for 30 appliances, and voluntary energy efficiency label for 40 products. Further, in 2005, China started a mandatory energy information label that covers 19 products to date. However, the impact of these standard and labeling programs and their savings potential has not been evaluated on a consistent basis.This research involved modeling to estimate the energy saving and CO2 emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, or under development and those proposed for development in 2010. Two scenarios that have been developed differ primarily in the pace and stringency of MEPS development. The -Continued Improvement Scenario‖ (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step considering the technical limitation of the technology. The -Best Practice Scenario‖ (BPS) examined the potential of an achievement of international best practice MEPS in 2014.This paper concludes that under the -CIS‖ of regularly scheduled MEPS revisions to 2030, cumulative electricity consumption could be reduced by 9503 TWh, and annual CO2 emissions would be 16% lower than in the frozen efficiency scenario. Under a -BPS‖ scenario for a subset of products, cumulative electricity savings would be 5450 TWh and annual CO2 emissions reduction would be 35% lower than in the frozen scenario.

Urban areas, which are expected to host more than two--thirds of the world's population by 2050, provide unique opportunities for the implementation of the radical policies needed to meet the Paris Climate objectives. Pioneer municipalities in Europe are leading the transformation needed to achieve zero energy and/or zero carbon communities by integrating policies across different sectors (buildings, transport, waste, water and energy supply). Critical factors identified through the analysis of existing initiatives include first, having clearly defined long--term targets, community boundaries and values, second, linking targets to community priorities such as economic development and urban renewal, and third, transposing long--term goals into milestones and short--term objectives to avoid discouraging the community. Challenges identified include first, capacity building, second, citizen participation and third, adequate project documentation as well as monitoring of the achievements. This paper focuses on the zero energy target at a com--munity level, but some of the projects analysed aim at zero carbon and not necessarily at zero energy. The discussion on the differences between the zero energy and the zero carbon concepts is out of the scope of this paper. However,