Shifting Trade Patterns as a Means to Reduce Global CO2 Emissions: Implications for the Aluminium Industry

This paper investigates how changes in the international division of labor can contribute to reducing CO2 emissions. The mitigation potential and costs implied by this mechanism are analyzed. Implications for the aluminium sector are assessed, including changes in the price of aluminium when global carbon emissions are constrained and the constraints are progressively tightened. The analysis makes use of the World Trade Model with Bilateral Trade (WTMBT), a linear program based on comparative advantage with any number of goods, factors, and regional trade partners. Minimizing factor use, WTMBT determines regional production, bilateral trade patterns, and region-specific prices. The model is extended for this study through the application of multi-objective optimization techniques and is used to explore efficient trade-offs between reducing CO2 emissions and increasing global factor costs. This application demonstrates how the WTMBT, with its global scope and regional and sectoral production detail, can be used to build bridges between global objectives and concerns about a specific industry in specific regions. This capability can extend the reach of more traditional studies in industrial ecology.

Connecting global emissions to fundamental human needs and their satisfaction

While quality of life (QOL) is the result of satisfying human needs, our current provision strategies result in global environmental degradation. To ensure sustainable QOL, we need to understand the environmental impact of human needs satisfaction. In this paper we deconstruct QOL, and apply the fundamental human needs framework developed by Max-Neef et al to calculate the carbon and energy footprints of subsistence, protection, creation, freedom, leisure, identity, understanding and participation. We find that half of global carbon emissions are driven by subsistence and protection. A similar amount are due to freedom, identity, creation and leisure together, whereas understanding and participation jointly account for less than 4% of global emissions. We use 35 objective and subjective indicators to evaluate human needs satisfaction and their associated carbon footprints across nations. We find that the relationship between QOL and environmental impact is more complex than previously identified through aggregated or single indicators. Satisfying needs such as protection, identity and leisure is generally not correlated with their corresponding footprints. In contrast, the likelihood of satisfying needs for understanding, creation, participation and freedom, increases steeply when moving from low to moderate emissions, and then stagnates. Most objective indicators show a threshold trend with respect to footprints, but most subjective indicators show no relationship, except for freedom and creation. Our study signals the importance of considering both subjective and objective satisfaction to assess QOL-impact relationships at the needs level. In this way, resources could be strategically invested where they strongly relate to social outcomes, and spared where non-consumption satisfiers could be more effective. Through this approach, decoupling human needs satisfaction from environmental damage becomes more attainable

Tracing the Uncertain Chinese Mercury Footprint within the Global Supply Chain Using a Stochastic, Nested Input-Output Model

A detailed understanding of the mercury footprint at subnational entity levels can facilitate the implementation of the "Minamata Convention on Mercury", especially for China, the largest mercury emitter worldwide. Some provinces of China have more than 100 million people, with economic activities and energy consumption levels comparable to those of smaller G7 countries. We constructed a stochastic, nested multiregion input-output (MRIO) model, which regionalized the China block in the EXIOBASE global-scale MRIO table, to model the mercury footprint associated with global supply chains spanning China's regions and other countries. The results show that Tianjin, Shanghai, and Ningxia had the highest per capita mercury footprint in China, which was comparable to the footprint of Australia and Norway and exceeded the footprint of most other countries. Some developed regions in China (e.g., Guangdong, Jiangsu) had higher mercury final product-based inventories (FBI) and consumption-based inventories (CBI) than production-based inventories (PBI), emphasizing the role of these regions as centers of both consumption and economic control. Uncertainties of Chinese provincial mercury footprint varied from 8% to 34%. Our research also revealed that international and inter-regional final product and intermediate product trades reshape the mercury emissions of Chinese provinces and other countries to a certain extent

Rising carbon inequality and its driving factors from 2005 to 2015

Carbon inequality is the gap in carbon footprints between the rich and the poor, reflecting an uneven distribution of wealth and mitigation responsibility. Whilst much is known about the level of inequality surrounding responsibility for greenhouse gas (GHG) emissions, little is known about the evolution in carbon inequality and how the carbon footprints of socio-economic groups have developed over time. Inequality can be reduced either by improving the living standards of the poor or by reducing the overconsumption of the rich, but the choice has very different implications for climate change mitigation. Here, we investigate the carbon footprints of income quintile groups for major 43 economies from 2005 to 2015. We find that most developed economies had declining carbon footprints but expanding carbon inequality, whereas most developing economies had rising footprints but divergent trends in carbon inequality. The top income group in developing economies grew fastest, with its carbon footprint surpassing the top group in developed economies in 2014. Developments are driven by a reduction in GHG intensity in all regions, which is partly offset by income growth in developed countries but more than offset by the rapid growth in selected emerging economies. The top income group in developed economies has achieved the least progress in climate change mitigation, in terms of decline rate, showing resistance of the rich. It shows mitigation efforts could raise carbon inequality. We highlight the necessity of raising the living standard of the poor and consistent mitigation effort is the core of achieving two targets

Allokering av klimagassutslipp fra avfallsforbrenning med energigjenvinning i livsløpsanalyser

Avfall som ved endt livsløp brukes til å produsere energi til bruk i et nytt livsløp, skaper et allokeringsproblem i livsløpsanalyser (LCA) der miljøpåvirkninger enten må allokeres til avfalls-behandling, energiproduksjon eller en miks av de to. Valg av allokeringsmetode kan påvirke miljøvurderingen og hvilke insentiver en LCA vil kunne gi til en avfallsprodusent eller en utbygger under design av energisystemer. Det finnes ingen objektiv vitenskapelig sannhet i allokerings-spørsmålet, men problemet kan løses på en måte som tjener formålet til en LCA. Problematikken har blitt diskutert av fageksperter over lengre tid uten at noen entydig konsensus har blitt oppnådd, og det er fortsatt uklart hvordan klimagassutslipp bør allokeres i metodikk for nullutslippsområder (ZEN) og hvordan ulike allokeringsalternativ påvirker resultatene. Her går vi gjennom nåværende allokeringsmetodikk anvendt for nullutslippsområder spesifikt, og i vitenskapelig litteratur generelt. Vi bruker systemekspansjon med substitusjon for å evaluere alternative behandlingsmåter for avfall. Effektene av allokering analyseres gjennom regneeksempler sett både fra avfallsprodusent og ved design av energisystemer i bygg. Vi viser hvordan kombinasjonen av ulik allokering og valg av ulike scenarioer kan påvirke resultatene i et klimagassregnskap og insentiver gitt til avfallsbehandlingsmåter, valg av energisystem, og energieffektivisering i bygg. Identifiserte allokeringsmetoder for bruk i klimagassberegninger for nullutslippsområder blir vurdert mot ti generelle kriterier for hva som anses som gode allokeringsmetoder i LCA og fem rammeverkspesifikke kriteria som beskriver mål og bruksmuligheter. Litteraturgjennomgangen viser stor bredde i allokeringsmetoder brukt både på tvers av studier og relevante standarder. En foretrukket allokeringsmetode bør være enkel nok til at den kan tas i bruk. Det er viktig at en samproduksjon som gir miljøgevinster relativt til separat produksjon, ikke skal allokeres mer miljøpåvirkninger enn separat produksjon. Energigjenvinning bør ikke gis disinsentiver så lenge blandet avfall eller farlig avfall bør forbrennes fremfor å behandles med teknologier lavere i avfallshierarkiet. Vi anbefaler derfor at det settes en enkel allokeringsfaktor B som allokerer miljø-påvirkninger til livsløpet som bruker energi, og at denne holdes på B=0, dvs. at alle avfallsfor-brenningsutslipp allokeres til avfallssystemet. Full allokering av miljøpåvirkninger til avfallssystemet vil minimere risikoen for feil avfallsbehandling av rene avfallsfraksjoner, som for eksempel å sende fossilt polyetylen til forbrenning. Full allokering til avfallssystemet vil gi fjernvarme med lave utslipp, noe som kan svekke insentivene til energieffektivisering og føre til at desentraliserte varmepumper velges bort i bygg som tilknyttes et fjernvarmesystem. Ved bruk av B=0 er det derfor viktig at tilstrekkelige insentiver for energieffektivitet sikres gjennom å vektlegge supplerende bruk av andre indikatorer enn bare klimapåvirkning. Dette gjøres i ZEN-definisjonen som har et sett av nøkkelindikatorer som både omfatter klimagassutslipp og energibruk, forutsatt brukt parallelt. Dersom løsninger i et utbyggingsområde skal vurderes ved hjelp av et metodisk rammeverk annerledes enn ZEN-definisjonen, og som ikke har en egen KPI for energibruk, er vi åpne for at det kan velges en verdi for B som fraviker anbefalingen B=0. I så fall må valget begrunnes ut fra rammeverkets formål og dokumenteres grundig gjennom både kvantitative og kvalitative analyser. På sikt må klimagassutslipp fra avfallsforbrenning elimineres i overgangen mot et nullutslippssamfunn, trolig både gjennom økt sirkularitet og med karbonfangst og lagring. Det er viktig å vurdere miljøkonsekvenser av avfallsforbrenning med energigjenvinning fra ulike synsvinkler og på tvers av livsløp for å øke miljøytelse.Waste that at end-of-life is sent for waste incineration with energy recovery produces energy that can be utilized in a new life cycle, thereby creating an allocation problem in Life Cycle Assessment (LCA) where environmental impacts must be allocated either to waste treatment, to energy production, or a mix of the two. Choice of allocation method can affect the conclusions of an LCA, including incentives given to different waste treatment options or to the choice of energy system during the development of buildings and neighbourhoods. There are no objective truths as to how this kind of multifunctionality in LCA should be solved, but allocation methods can be chosen in a way that serves the goal of an LCA. For the Zero Emission Neighbourhoods (ZEN) framework, it is still unclear how greenhouse gas emissions from waste incineration with energy recovery should be allocated and how different methodological choices may affect results. In this report, we critically assess the current practice used in ZEN and review and evaluate other allocation methods found in scientific literature. The allocation problem is tackled both from a waste producer perspective aiming to ensure environmentally beneficial waste treatment and from an energy planner perspective aiming to design sustainable energy systems for buildings. We use system expansion with substitution to assess alternative waste treatment methods for mixed waste and fossil plastics. The effects of chosen allocation methods on greenhouse gas calculations are analyzed and discussed. We show how a combination of varying allocation methods and scenarios affect incentives given through LCA to different waste treatment options, energy systems, and energy efficiency measures in buildings. Identified allocation methods used in literature are qualitatively evaluated considering ten general criteria for good allocation methods in LCA and five ZEN-specific criteria considering ZEN goals and framework usability. The literature review shows that a variety of allocation methods are used across scientific studies and relevant standards. The preferred allocation method should be simple enough that LCA practicians are able to use it in a real planning context. A joint production process that is environmentally beneficial relative to separate production of the same products or services should be allocated less environmental impacts than separate production. Energy recovery should not be disincentivized if mixed waste, non-recyclable waste, or hazardous waste is incinerated instead of treated with other waste treatment options further down the waste hierarchy. We recommend that a simple allocation factor B is defined that allocates a share of greenhouse gas emissions from waste incineration to the life cycle that uses energy recovered from the incineration, and that this factor is set to B=0, thereby allocating all emissions from burning waste to the life cycle that produced the waste. The recommendation ensures the competitiveness of energy recovery as an environmentally beneficial joint production relative to separate production. Allocating all environmental impacts to the waste treatment will reduce the risk of a waste producer sending fossil plastics for incineration instead of recycling. B=0 will also lead to a low emission intensity in district heating grids that rely on waste incineration with energy recovery. However, this can also weaken the incentives for advanced energy efficiency investments in buildings. If B=0 is used, energy efficiency measures in buildings should be motivated through supplementary usage of other indicators. In the ZEN-framework, this is done through a set of key performance indicators that includes both greenhouse gases and energy use that should be used in parallel. If construction projects are evaluated through other LCA frameworks that lacks indicators for energy use, we acknowledge that other values for B can be chosen that differs from our B=0 recommendation. In such cases, the choice must be justified based on the goal of the LCA and be thoroughly evaluated through both quantitative and qualitative analysis. In the future, greenhouse gas emissions from waste incineration must be eliminated, likely both through increased circularity measures and carbon capture and storage deployment. It is vital to evaluate the environmental consequences of waste incineration with energy recovery from different viewpoints and across life cycles to enhance environmental performance.publishedVersio

Material efficiency strategies to reducing greenhouse gas emissions associated with buildings, vehicles, and electronics - A review

As one quarter of global energy use serves the production of materials, the more efficient use of these materials presents a significant opportunity for the mitigation of greenhouse gas (GHG) emissions. With the renewed interest of policy makers in the circular economy, material efficiency (ME) strategies such as light-weighting and downsizing of and lifetime extension for products, reuse and recycling of materials, and appropriate material choice are being promoted. Yet, the emissions savings from ME remain poorly understood, owing in part to the multitude of material uses and diversity of circumstances and in part to a lack of analytical effort. We have reviewed emissions reductions from ME strategies applied to buildings, cars, and electronics. We find that there can be a systematic trade-off between material use in the production of buildings, vehicles, and appliances and energy use in their operation, requiring a careful life cycle assessment of ME strategies. We find that the largest potential emission reductions quantified in the literature result from more intensive use of and lifetime extension for buildings and the light-weighting and reduced size of vehicles. Replacing metals and concrete with timber in construction can result in significant GHG benefits, but trade-offs and limitations to the potential supply of timber need to be recognized. Repair and remanufacturing of products can also result in emission reductions, which have been quantified only on a case-by-case basis and are difficult to generalize. The recovery of steel, aluminum, and copper from building demolition waste and the end-of-life vehicles and appliances already results in the recycling of base metals, which achieves significant emission reductions. Higher collection rates, sorting efficiencies, and the alloy-specific sorting of metals to preserve the function of alloying elements while avoiding the contamination of base metals are important steps to further reduce emissions

Environmental co-benefits and adverse side-effects of alternative power sector decarbonization strategies

A rapid and deep decarbonization of power supply worldwide is required to limit global warming to well below 2 °C. Beyond greenhouse gas emissions, the power sector is also responsible for numerous other environmental impacts. Here we combine scenarios from integrated assessment models with a forward-looking life-cycle assessment to explore how alternative technology choices in power sector decarbonization pathways compare in terms of non-climate environmental impacts at the system level. While all decarbonization pathways yield major environmental co-benefits, we find that the scale of co-benefits as well as profiles of adverse side-effects depend strongly on technology choice. Mitigation scenarios focusing on wind and solar power are more effective in reducing human health impacts compared to those with low renewable energy, while inducing a more pronounced shift away from fossil and toward mineral resource depletion. Conversely, non-climate ecosystem damages are highly uncertain but tend to increase, chiefly due to land requirements for bioenergy