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Growing concern on climate change has supported technologies that reduce carbon dioxide emissions. The emission factor of the Brazilian grid electricity is low due to hydropower dominance. However, new hydropower plants have migrated to the Amazon region, with likely social and environmental consequences and rainfall shortage has demanded costly fossil fueled power plants. The grid's emission factor is increasing and new renewable energy alternatives such photovoltaic (PV) are one option to diversify the electricity mix. However, PV systems' efficiency in Brazil varies depending on the climatic region of its installation. This work evaluated the variance in CO 2 emissions reduction of grid connected PV systems for low-income housing in different Brazilian climatic regions. The analysis was based on the PV system, installed in low-income housing projects. Electricity generation was determined through RETScreen and CO 2 emission reductions were determined considering the emission factor of the national grid electricity. Variation of CO 2 emission reductions among bioclimatic regions reached up to 12%. Therefore, PV systems should be adopted in all low-income housing projects in Brazil, regardless of their region, to reduce household's expenditures, CO 2 emissions, and democratize the technology. • PV systems' efficiency varies depending on the climatic region of its installation. • Variance in CO 2 emissions reduction of grid connected PV systems is evaluated. • CO 2 emission reductions vary by up to 11.5% according to the bioclimatic region. • PV systems should be adopted in all low-income housing projects in Brazil. [ABSTRACT FROM AUTHOR]

Biotechnology, the fifth technological wave preceding the sixth wave of Sustainability, is crucial for achieving the 2023 Agenda's Sustainable Development Goals (SDGs), especially in biodiverse Brazil. This review uses composite indicators to compare Brazil with the USA across static and temporal evolutions. Technology Readiness Levels (TRL) 4 and 5 were assessed using patents from 2000 to 2019. Patents from 2000 to 2019 reveal a TRL gap at 4–5 in Brazil, skewed towards academic articles (TRL3), indicating lag behind the USA at TRL5. Brazil's patent growth rate surpasses the USA's by eightfold. Specialization between Brazilian academia and the nation converges. The revealed technological advantage and the distance between academies and between countries are nearing unification. Brazil focuses on SDG3 (Good Health and Well-Being) and SDG7 (Affordable and Clean Energy) but must intensify efforts on SDG2 (Zero Hunger), SDG6 (Clean Water and Sanitation), SDG13 (Climate Action), SDG14 (Life below Water), and SDG15 (Life on Land). The USA concentrates its technologies in SDG3 (Good Health and Well-Being). USA's modern biotech navigates the fifth wave, while Brazil's traditional biotech must modernize, focusing on SDG9 (Industry, Innovation, and Infrastructure) and SDG17 (Global Partnerships for Sustainable Development), requiring government policies for mid-range TRLs. [ABSTRACT FROM AUTHOR]

Sugarcane straw is identified as a potential energy feedstock to increase bioenergy production, but advances are required in understanding the straw removal impacts on soil organic carbon (SOC) stability and storage. The main objective of this study was to evaluate the quantity, quality and physical protection of SOC under areas with different straw removal rates over a six-year period. A field experiment was conducted in randomized blocks with four replications, including the following straw removal treatments: total removal (TR), high removal (HR), low removal (LR), and no removal (NR), corresponding to the quantities of 0, 5, 10 and 15 Mg ha−1 of dry straw maintained on soil surface, respectively. Effects of straw removal on SOC stocks and its temporal dynamics, as well as the rates of carbon (C) incorporated into the soil were evaluated to a 0.3-m depth. The effects on particulate organic matter (POM) and mineral-associated organic matter (MAOM) fractions were evaluated through physical fractionation of SOM. Finally, it was evaluated the distribution of aggregates, the C content of aggregates and the C preservation capacity (CPC) in fractions of aggregates. Our findings revealed that TR and HR decreased SOC stocks at 0.0–0.1 m and 0.0–0.3 m depths. The data indicated that about 24% of the C added via straw were retained in soil, and NR showed a SOC accumulation rate of 1.42 Mg ha-¹ year-¹ relative to baseline. Low straw removal increased POM (46.2%) and MAOM (12.4%) in surface layer as compared to TR. The straw maintenance in the field increased the proportion of soil macroaggregates, resulting in higher amounts of C preserved in this fraction. Our findings suggest that maintaining 10 Mg ha-¹ of straw was enough to favor physical protection and sustain storage of SOC over time. Therefore, the surplus of straw could be removed to produce bioenergy, although this management may hinder soil C sequestration and its benefits for sugarcane production and climate change mitigation. • High and total removal rates of sugarcane straw reduced soil carbon stocks. • Low straw removal increased POM (46.2%) and MAOM (12.6%) compared to total removal. • Straw retention increased soil aggregation and preserved C in macroaggregates. • Low removal rate was enough to sustain physical protection and storage of soil C. [ABSTRACT FROM AUTHOR]

Plastics account for 4.5% of global greenhouse gas (GHG) emissions, which are hard-to-abate due to the use of fossil fuels as feedstock. Our study develops a cradle-to-gate life cycle assessment of bioethylene production, exploring 33 pathways across Brazil, the EU, and the US. It aims to understand whether substituting fossil-based ethylene with bioethylene contributes to lowering carbon emissions, and in which of the relevant bioenergy-producing regions/countries the valorisation of biofuels as feedstocks would provide a less carbon-intensive bioethylene production. Results indicate that bioethylene production through catalytic dehydration of sugarcane bioethanol in Brazil presents lowest GHG emission. This pathway could deliver up to −2.1 kg CO 2 e/kg ethylene when accounting for biogenic carbon storage in long-lived applications such as infrastructure. In contrast, beef tallow performs the poorest as a raw material, regardless of whether land-use change (LUC) emissions are considered. When biogenic carbon storage is factored out, none of the pathways outperforms conventional fossil-based steam cracking; however, some are within the fossil-based range indicating potential indirect benefits through reduced refinery utilisation. Our study underscores that biomaterials production as a climate mitigation strategy must be on par with circular economy measures and the conservation of native forestry ecosystems. These results are particularly relevant to policymakers and industries seeking to align polymer manufacturing with sustainability objectives. • Bio-ethylene cradle-to-gate GHG emissions were assessed for 33 pathways. • Sugary, starch, lignocellulosic and oily crops are raw materials for bio-ethylene. • Local specificities such as biogenic carbon storage and land-use are critical to LCA GHG emissions. • Sugarcane bioethanol dehydration route yielded 2.1 kgCO 2 e captured per of kg ethylene. • Climate mitigation and circular economy policies must be designed coherently. [ABSTRACT FROM AUTHOR]

Deep decarbonization scenarios indicate a decline in fossil oil usage in the coming decades, meaning that oil refineries must adapt. This work evaluates the refining sector in deep decarbonization pathways using Brazil as a case study. BLUES – a national integrated assessment model – is employed to investigate the evolution of the sector in mitigation scenarios until 2050. The production of feedstocks for the petrochemical industry, of fuels for the aviation and maritime sectors, and biomass co-processing are analyzed. These strategies may bring resilience to the sector. The potential for avoiding emissions in refineries' operations is also explored. Findings show that the refining sector operates at 70% and 74% of its nameplate capacity in decarbonization scenarios. These results are used as the starting point for a detailed analysis of Brazilian refineries. Results show that the employment of refineries' assets for purposes aligned with decarbonization targets, along with emissions mitigation in the sector, reduces risks of carbon lock-in and of asset stranding. To our knowledge, this is the first study that evaluates emissions mitigation in the refining sector and also uses an integrated assessment model to investigate oil refining repurposing and co-processing options in the context of decarbonization. • The refining sector is evaluated using an integrated assessment model for Brazil. • A comparison is made between business- as -usual and decarbonization scenarios. • Opportunities for refineries' assets and mitigation measures are explored. • Opportunities for refineries depend on their location and type of processing units. • Risks of carbon lock-in and asset stranding can be reduced. [ABSTRACT FROM AUTHOR]

Future projections indicate an expansion for both food and energy demands, which can increase pressure on land use, while there is an urgent global need for climate change mitigation. Bioenergy is foreseen as key option to meet future energy demands and reduce greenhouse gas (GHG) emissions, however its sustainability depends on locations and regional characteristics. Simultaneously, agricultural production models that co-produce food, feed, and energy offer sustainability synergies and co-benefits, but site-specific sustainability assessments of their large-scale implementation are missing. This study presents a bottom-up approach to assess spatially explicit sustainability aspects of bioenergy-livestock integrated systems (BLI) in Brazil and shed light on their contribution to future energy demands, to climate change mitigation targets, and their impacts on selected ecosystem services, including bioenergy production, climate change mitigation, reduction of food competition, biodiversity conservation, and avoided deforestation. The proposed integration considers livestock intensification and use of biofuels by-products as animal feed supplement, taking advantage of synergies between these two value chains. The expansion of the BLI system in the Center-South region of Brazil produce up to 89 billion liters of ethanol, enough to meet future domestic ethanol demands from multiple shared socioeconomic pathways and generating surpluses for export. This production takes place on 16 million hectares of pastureland within the Sugarcane Agroecological Zoning, excluding the Amazon and Pantanal biomes, and biodiversity hotspots. BLI expansion mitigate up to 250 million tonnes of CO 2 eq and generate 15 billion dollars of profits. The best locations to maximize the selected ecosystem services are west of São Paulo, east of Mato Grosso do Sul, and the south-central region of the states of Goiás. This study may encourage the formulation of enhanced public policies for the integration of bioenergy and livestock value chains and guide a sustainable large-scale deployment of BLI systems. • Bioenergy and livestock integration (BLI): co-production of food, feed and energy. • BLI systems: 89 billion liters of ethanol and 250 million tonnes of CO 2 eq mitigated. • Enough ethanol to meet future Brazilian demands and surplus to be exported. • Biomass expansion only on pastureland inside Sugarcane Agroecological Zoning. • Without land displacement and deforestation of native vegetation. [ABSTRACT FROM AUTHOR]

The energy sector has a vital role in climate change mitigation. In Brazil, the electricity generation sector is strongly dependent on hydropower generation, but thermoelectricity contribution has increased leading to a more carbon-intensive electricity mix. This trend will be aggravated with the expected significant increase in the electricity demand until 2050 and with the potential limitation of hydropower generation expansion due to environmental constraints. The extent of the role of solar power to overcome these challenges in the future has been hidden by energy modelling assumptions. A review on how solar energy has been considered in different models, was performed. The research further assessed the relevance of assumptions by developing an optimization model to explore the cost-effectiveness of solar electricity large-scale deployment up to 2050. The work found that most published solar energy assessments based on long-term energy modelling for Brazil currently are not updated regarding several assumptions, leading to models results where solar appears with a marginal role. The energy modeling exercise shows solar PV is cost-effective for Brazil, providing more than 36% of total electricity in 2050. This is a different conclusion from the energy and power modeling exercises conducted until now, where solar deployment has been underestimated. • The work assesses how energy model inputs have affected solar cost-effectiveness for Brazil. • Assumptions on hydropower expansion and technology costs critically affect solar cost-effectiveness. • Energy model exercises have underestimated the potential of solar energy in Brazil. • Solar energy may have an important role in the future Brazilian power sector. [ABSTRACT FROM AUTHOR]

To foster the energy transition towards a low carbon economy, countries must set and report climate policy instruments. Since the Paris Agreement, nations have been strongly encouraged to increase ambitions and reduce carbon emissions in the coming decades. However, a wave of emerging parties has gained momentum around the world, advocating a hostile stance on climate change mitigation policies. Brazil, one of the traditional leaders of the climate agenda, has experienced an uptake in its greenhouse gas emissions, with no expectation of reversing this trend. The government has signaled that only economically attractive mitigation options will be considered. For this reason, it is crucial to develop scenarios that consider this upward trend. The model estimates carbon emissions at the highest level of detail available, providing abatement cost over time. The results indicate that Brazil has potential to meet its transport related NDC commitments, with 13% cuts by 2030 (26MtCO 2 e) achieved with an intensive use of biofuels. However, the cost-benefit of this strategy would not correspond to the mitigation potential, with financial losses above 1US$/tCO 2 e. The most suitable alternatives would be investments in electromobility and infrastructure, with gains exceeding 200US$/tCO 2 e. These outcomes may aware decision-makers about the cost-effectiveness of certain policies. • We conduct an in-depth assessment of transport-related energy transition paths for 2030. • Three scenarios were developed based on different political commitment. • Brazil has potential to meet its transport related NDC commitments. • The most suitable alternatives would be investments in electromobility and infrastructure. • The outcomes may aware decision-makers about the cost-effectiveness of certain policies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon sequestration potential of the clay fraction. • Determination of the carbon saturation deficit of each mineral of the clay fraction. • Identification of the equation for the prediction of carbon sequestration potential. • Identification of land uses with the greatest carbon sequestration potential. The capacity of soil to sequester carbon (C) is a key process that promotes the reduction of CO 2 in the atmosphere. Soils can absorb as much as 20% of anthropogenic carbon emissions, which can contribute to mitigate climate change. This capacity relies on the organo-mineral association, which includes different minerals, Fe and Al oxides, which have a critical soil organic carbon (SOC) sorption surface. Based on an equation of the potential C saturation deficit of fine soil particles (<20 μm/silt and clay fractions) for tropical regions, this study investigated the SOC sequestration potential of the clay fraction for soils in Piracicaba region, São Paulo State, Brazil as influenced by the clay minerals. This potential was fitted to a spatial regression model for soil depths 0–20 cm and 80 to 100 cm. In the surface layer, the sequestration potential was mostly explained by the relative abundance of soil minerals (Kaolinite, Hematite, Goethite and Gibbsite) determined using vis-NIR-SWIR spectroscopy. A direct relationship was observed with Goethite and Gibbsite, indicating that low concentrations would reduce the sequestration potential. At 80 to 100 cm depth, Kaolinite and Hematite explained most variation in SOC sequestration potential. Additionally, the C associated with the mineral fraction and the C saturation potential as a function of minerals were modeled and a strong importance of hematite in the C sequestration and stabilization cycle was identified at both depths. The individual mineral contribution to SOC sequestration potential was also mapped, which identified high contributions of goethite and gibbsite for deep soil layers. The influence of land use on the carbon sequestration potential of minerals was observed, with the greatest potential being found in areas with pasture and cropping mosaics and grassland and forest mosaics, with a high presence of kaolinite and hematite. These minerals have a greater potential for carbon sequestration at greater depths and, therefore, could be critical in climate change mitigation strategies. [ABSTRACT FROM AUTHOR]

Abstract Integrated assessment models are extensively used in the analysis of climate change mitigation and are informing national decision makers as well as contribute to international scientific assessments. This paper conducts a comprehensive review of techno-economic assumptions in the electricity sector among fifteen different global and national integrated assessment models. Particular focus is given to six major economies in the world: Brazil, China, the EU, India, Japan and the US. The comparison reveals that techno-economic characteristics are quite different across integrated assessment models, both for the base year and future years. It is, however, important to recognize that techno-economic assessments from the literature exhibit an equally large range of parameters as the integrated assessment models reviewed. Beyond numerical differences, the representation of technologies also differs among models, which needs to be taken into account when comparing numerical parameters. While desirable, it seems difficult to fully harmonize techno-economic parameters across a broader range of models due to structural differences in the representation of technology. Therefore, making techno-economic parameters available in the future, together with of the technology representation as well as the exact definitions of the parameters should become the standard approach as it allows an open discussion of appropriate assumptions. Highlights • Comparison of technology representation and techno-economic parameters of 15 IAMs. • Structural differences in representing technology in IAMs are identified. • Methods of projecting techno-economic parameters differ across IAMs. • Strict harmonization of techno-economic parameters across models is difficult. • Recommendation to publish techno-economic parameters and technology representation. [ABSTRACT FROM AUTHOR]

This work evaluates implications of incorporating LCA-GHG (life cycle assessment of GHG emissions) into the optimisation of the power generation mix of Brazil through 2050, under baseline and low-carbon scenarios. Furthermore, this work assesses the impacts of enacting a tax on LCA-GHG emissions as a strategy to mitigate climate change. To this end, a model that integrates regional life cycle data with optimised energy scenarios was developed using the MESSAGE-Brazil integrated model. Following a baseline trend, the power sector in Brazil would increasingly rely on conventional coal technologies. GHG emissions from the power sector in 2050 are expected to increase 15-fold. When enacting a tax on direct-carbon emissions, advanced coal and onshore wind technologies become competitive. GHG emissions peak at 2025 and decrease afterwards, reaching an emission level 40% lower in 2050 than that of 2010. However, if impacts were evaluated through the entire life cycle of power supply systems, LCA-GHG emissions would be 50% higher in 2050 than in 2010. This is due to loads associated with the construction of plant infrastructures and extraction and processing of fossil fuel resources. Thus, taxes might not be as effective in tackling GHG emissions as shown by past studies, if they are only applied to direct emissions. [ABSTRACT FROM AUTHOR]

Bioenergy production from sugarcane can be one of the sustainable means of mitigating climate change. This was the central idea of the Conference, "Carbon Balance in the Sugar-Energy Sector," held in Brazil on September 14, 2021. The various panels showed that sugarcane stakeholders, including scientists, farmers, industrialists, and investors, are committed to making large-scale sugarcane production a key ingredient in the mitigation of climate change. Their strategies include sustainable land use and management practices to increase soil carbon sequestration; the large-scale production of biofuel, bioelectricity and bioproducts; negative emission industrial technologies; industrial waste recycling; and sector-specific policies rewarding farmers with carbon credits for avoided greenhouse gas emissions. Therefore, the sugarcane sector is not only key to promoting the social-economic development of Brazil, but also to promoting energy transition, curbing greenhouse gas emissions and consequently, reducing global warming and climate change. • Conference Report: 2021 Carbon balance in the sugar-energy sector. • Carbon Balance in the Sugar-Energy Sector 2021 Conference held by Luiz de Queiroz College of Agriculture (Esalq), University of São Paulo (USP), Piracicaba-SP, Brazil on September 14, 2021. • Sugarcane-derived bioenergy is a key ingredient in fighting climate change while simultaneously maintaining a balanced ecosystem (including enhanced soil health and increased capacity to sequester carbon) and promoting socio-economic development [ABSTRACT FROM AUTHOR]

This study aims to quantify the environmentally sustainable and economically feasible potentials of agricultural and agro-industrial residues to generate electricity via direct combustion in centralised power plants in Brazil. Further, the energy savings and greenhouse gas (GHG) reduction potential of replacing natural gas-based electricity by bioenergy have been assessed. To this end, a methodology has been developed based on an integrated evaluation, incorporating statistical and geographical information system (GIS)-based analysis, and a life-cycle-assessment approach. Results reveal that the environmentally sustainable generation potential is nearly 141 TWh/year, mainly concentrated in the South, Southeast, and Midwest regions of the country. Sugarcane, soybean and maize crop residues are the major feedstocks for available bioenergy. On the other hand, the economic potential is far lower, accounting to 39 TWh/year. The total GHG mitigation is nearly 18 million tonne CO 2 e and could reach 64 million tonne CO 2 e yearly, if the technical potential is considered. The gap between technical and economic potentials implies that constraints to bioenergy are not related to a lack of resources, but rather associated to economic, logistical, regulatory and political barriers. [ABSTRACT FROM AUTHOR]

• Bioenergy-livestock integrated systems can alleviate pressure on land resources. • BLI has potential to meet global future biofuel demands and climate mitigation targets. • Production of feed using bioenergy by-products is techno-economically feasible. • Biofuels from integrated systems can reduce GHG emissions compared to fossil fuels. • There is still room to further explore the integration of bioenergy-livestock value chains. Bioenergy is seen as a key option to meet future energy demands and mitigate climate impacts. However, large-scale deployment of bioenergy can cause an additional pressure over land resources and correspondent sustainability impacts. Enhanced land management practices are fundamental to intensify land-based outputs under different climate mitigation scenarios. Bioenergy-livestock integration (BLI) is a win-win strategy to climate mitigation while ensuring food and fibers demands from the society by using bioenergy by-products as animal feed to release land to additional industrial crops production. This study comparatively assesses BLI opportunities in Brazil to better understand the sustainability issues of the alternatives for integration of these value chains, highlighting the key techno-economic and environmental aspects. When compared to conventional systems, the BLI systems present positive techno-economic impacts and lower greenhouse gas emissions, reaching mitigations up to 32 % and 22 % for meat and ethanol production, respectively. The expansion of BLI systems in Brazil could meet projected biofuels future demands, using less than 20 % of the expected area for this expansion. Potential expansion areas are concentrated in Center-South region of Brazil. BLI systems can be further advanced by including other synergies, such as codigestion of sugarcane vinasse and cattle manure, integration of flex ethanol plants with biodiesel plants, maximization of biofuels by-products as animal feed, and inclusion of novel promising alternative industrial crops such as macauba, sweet sorghum, energy cane and short rotation eucalyptus coppice. However, we identify many potential barriers including the operational complexity, specific know-how, and necessity of economic incentives. This study may provide important insights for strategic and integrated polices for both agricultural and livestock sections as the proper sustainability assessment of an early stage of the deployment of enhanced BLI systems may help to meet global future demands of energy while also contributing to climate change targets. [ABSTRACT FROM AUTHOR]

Abstract: For climate mitigation it is important to identify and protect landscape units that have disproportionally large carbon storage (CS). Here we report on CS of the upper 30 and 60cm of soil in transects of vegetation types in stream valleys in the Brazilian Cerrado savanna, including Pasture, nearly native Cerrado vegetation, Vereda wetlands, and Gallery Forests. We chose three areas with varying types of human impacts in each of which three degraded and reference transects were compared. For the 60cm CS in undisturbed sites, maximum and average values per area were highest for Gallery Forest (360.0 and 206.5MgCha−1) and Vereda wetland (201.9 and 142.4MgCha−1), while those of Cerrado (57.7 and 52.7) and Pasture (62.3 and 52.7MgCha−1) were considerably lower. Variation between the three areas was high. In an area degraded by cattle trampling, losses in the upper 60cm compared to reference sites were highest in the carbon-rich vegetation types Vereda (72%) and Gallery Forest (71%) and lower in the carbon-poorer Pasture (33%) and Cerrado (7%). In areas degraded by fire or by erosion, results were less conclusive. Our data appeal to an improved conservation of riparian ecosystems of the Cerrado biome. [Copyright &y& Elsevier]

Through its NDC, Brazil pledged to reduce its GHG emissions by 43% below 2005 levels in 2030, respectively. Carbon pricing could play a key role in meeting this objective. However, a range of issues can emerge when introducing it. Among these issues, the distributional impact has been frequently highlighted as an obstacle to the public acceptance of such a mitigation policy. This paper examines the short-run welfare and emission effects of an economy-wide carbon tax on Brazilian households. The distributional impact is examined by estimating the tax burden relative to annual expenditures and changes in total GHG emissions across income levels, using tax rates consistent with the Paris Agreement and considering a lump-sum rebate that keeps the government revenue neutral. For this, we calculate energy-related GHG emissions coefficients from fossil fuel burning for the whole household consumption basket, and price and expenditure elasticities which account for the zero-expenditure and underdeclaration problems. Our results indicate that the incidence of the carbon tax is effective in reducing emissions in the short run, but imposes welfare losses, especially on the poor. The consideration of compensation mechanisms is critical when designing this type of environmental tax, specially in the context of a highly complex tax-system. [ABSTRACT FROM AUTHOR]

Biofuels are predicted to constitute a large proportion of fuel consumption in the global transport sector under stringent climate mitigation polices in future. In Brazil, sugarcane ethanol has been widely deployed at large scale and an oriented expansion of sugarcane is considered to be a key measure to ensure the expected positive outcomes from biofuels. In this study, more recent and accurate georeferenced information were combined with an enhanced land use classification system to update the original Sugarcane Agroecological Zoning (SAEZ). We also excluded environmentally relevant areas (ERA) in our updated SAEZ to create a new set of reference maps for supporting future prioritization of areas for sugarcane ethanol expansion. We mapped 41.7 Mha as suitable land for sugarcane expansion in center-south region of Brazil, differently from the 50 Mha indicated in the original SAEZ. After excluding the ERA, 33.7 Mha was found to be suitable for sugarcane expansion, of which 20 Mha is currently occupied with pasture lands. About half of these areas were located in Mato Grosso do Sul and Minas Gerais states and an exploratory assessment of two microregions from these states demonstrated the importance of conducting regional assessments to prioritize the areas for a more sustainable sugarcane expansion to meet future bioenergy demands. • Our analysis identified an area 17% smaller than original agro-ecological zoning suitable for sugarcane expansion. • By excluding environmentally relevant areas, the total suitable area for sugarcane expansion is reduced to 33.7 Mha. • About two thirds of that area is currently occupied with pasture lands. • About half of suitable areas occupied with pasture lands are in two Brazilian states. • Local conditions are fundamental for oriented expansion of bioenergy production. [ABSTRACT FROM AUTHOR]

Enhanced weathering is a simple and scalable negative emissions technology with an estimated carbon dioxide removal potential of multiple gigatons per year. To date, the only life-cycle assessment of enhanced weathering was published by Lefebvre et al. (2019) in this journal. They estimated the carbon dioxide removal potential in Sao Paolo State in Brazil to be 1.3–2.4 Mt/y, examined the penalty from transportation greenhouse gas emissions, and pointed out that using life-cycle assessment can give more reliable estimates of climate change mitigation potential of enhanced weathering systems. In this letter, we discuss the limitations of life-cycle assessment of enhanced weathering, and then propose a more comprehensive life-cycle optimization approach, where the system configuration can be automatically synthesized to maximize environmental performance. This concept can be extended further to life-cycle sustainability optimization by including economic and social dimensions. • The first life cycle assessment of enhanced weathering was reported in 2019. • Life cycle optimization and life cycle sustainability assessment are also needed. • A combined life cycle sustainability optimization framework should be developed. • Hybrid models can be used to address future issues in enhanced weathering. [ABSTRACT FROM AUTHOR]

This study aims to provide an Integrated Assessment Model (IAM) perspective of the production and distribution of alternative marine fuels in Brazilian ports, considering the International Maritime Organization (IMO) emission reduction target for 2050 (IMO2050). Although other mitigation measures are available, it is likely that alternative fuels will be required, implying additional costs and entailing relevant impacts on other energy chains and land use. Hence, the national IAM BLUES model is adapted to represent the relevant part of the international shipping sector. A set of scenarios is developed considering different fuel alternatives, demand assumptions and national mitigation targets. Findings show that taking into account emissions of CO 2 only or of all greenhouse gases (GHGs) within the IMO strategy significantly impacts the optimal technological portfolio. Furthermore, achieving the IMO2050 goal without considering a national decarbonization strategy may result in potential spillovers. The intense use of the energy sector could partially compromise the gains obtained by maritime decarbonization or even surpass it. Therefore, only an integrated mitigation strategy would lead to more effective decarbonization of the entire marine supply. • There is no single optimal portfolio of alternative fuels for shipping. • Brazil can fulfil any low-carbon marine fuel strategy. • Marine fuels should be part of all national decarbonization strategies. • The decarbonization of shipping should be part of Brazil's deep mitigation pathways. [ABSTRACT FROM AUTHOR]

• A dynamic climate change impact evaluation framework is proposed. • Bamboo bio-concrete is a good climate change mitigation and adaptation alternative. • Bamboo bio-concrete presents a reliable carbon-thermal energy solution. • Bamboo bio-concrete provides a promising alternative for developing countries. This study aims to present a framework to quantify the climate change impact during the buildings' life cycle. The proposed framework is tested on a bamboo bio-concrete (BBC) building and compared with conventional constructive systems, in a Brazilian housing project considering six cities using Dynamic Life Cycle Assessment (DLCA) and thermal energy simulation. The increase of BBC in the building envelope, from 10 cm to 20 cm, leads to the improvement of carbon stock and reduces operational carbon. The BBC can be considered a potential alternative for climate change mitigation and adaptation and developed where bamboo is an available source. [ABSTRACT FROM AUTHOR]

Agriculture provides an array of ecosystem services including the sequestration and storage of carbon in the biomass of plants. Research has focused on commercial crops, especially tree crops, for their potential to mitigate the impacts of climate change. In Brazil interest is growing in the commercial cultivation of macauba (Acrocomia aculeata), a palm native to the tropical regions of the American continents with fruit that can be used as the primary ingredient in the production of oils and bioenergy. However, we did not find any prior studies that had assessed macauba's carbon sequestration potential nor any exploration in the literature of the income generation potential for commercial macauba producers to sell carbon credits. In order to understand opportunities to commercialize carbon credits from macauba, research was needed on the palm's long-term carbon sequestration and stock capacity. In this study we measured the accumulation of carbon in commercially cultivated macauba's biomass both below and above-ground using a selection of plants of different ages. An assessment was also made of the crop's potential to generate carbon credits. Macauba plants were sampled in a nursery with seedlings aged 3 and 8 months, and with more mature plants cultivated in fields aged 1.6, 4.8, and 9 years. The samples were fully harvested by complete removal (including roots and above ground structures), followed by separation, quantification and carbon analysis of the different plant biomass components. The data obtained allowed for estimating the production of carbon credits and the resulting annual income. Findings indicated a differential distribution of both biomass and carbon below and above-ground in field-cultivated macauba palms. The stock of carbon in the plants aged 9 years reached 61.6 t C ha−1 with a corresponding sequestration of 226.17 t CO 2 eq ha−1. The expected generation of carbon credits of palms from 1.6 to 9 years was 28.73 t CO 2 eq. ha− 1 per year, which could result in an annual gross income of € 761.06 per hectare. Significant amounts of stored carbon were found in both the above and below-ground biomass, suggesting that the macauba has significant potential to generate carbon credits and contribute to the mitigation of the effects of climate change. [ABSTRACT FROM AUTHOR]

Brazil is one of the world's major food-exporting countries that could be negatively impacted by climate change, and is also a leading greenhouse gas emitter through its agriculture. Crop diversification, as an agricultural practice, could lead to climate adaptation and mitigation. The aim of this study was to analyze the influence of climatic variability on categories of crop diversification so as to understand its role as an adaptive measure in response to climate change. An ordered probit model which allows for the separation of different categories of crop diversification was used for the 2006 period. The results showed that increases in temperature and precipitation did not affect each category in the same way. However, diversification intensity increases with climate variability: the greater the climate variability, the greater the likelihood of a municipality being in the very diversified category. Therefore, crop diversification appears as an adaptation strategy because it is influenced by climatic shocks. These results could be used to recommend Rural Extension programs to promote diversified systems as a resilient and cleaner type of agricultural production to improve climate risk management in Brazilian agriculture. [ABSTRACT FROM AUTHOR]

Decreasing upfront costs, governmental policies, and promises to reduce greenhouse gas emissions have provoked a sharp increase in the installed capacity of photovoltaic (PV) plants worldwide. In Brazil, PV plant installation has been growing since 2014, stimulated by the Ministry of Energy and Mines auctions dedicated to this technology. Net emissions vary depending on the emissions from the grid where PV plants are installed, and little is known about their actual payback times in tropical areas. This study calculates the carbon payback time of a 3.0 MWp PV power plant with a sensitivity analysis. We conclude that the PV plants installed in northeast Brazil are beneficial to climate change mitigation whether the PV module is mono-Si or poly-Si, manufactured abroad or not and, considering uncertainties about emissions from alternative technologies, especially hydropower. • Photovoltaic plant installed in northeast Brazil is beneficial to climate change mitigation. • Carbon payback time strongly depends on the energy matrix of the manufacturing country. • The hydropower emission uncertainty does not affect the benefits of the photovoltaic equipment. • The photovoltaic insertion is aligned with the country's national determined contribution. [ABSTRACT FROM AUTHOR]

• This sugarcane agro-system was a carbon sink. • The NEE of CO 2 fluxes (assimilation versus respiration) dominated the balances. • The N 2 O and CH 4 emitted totals were offset by the C gain. The sustainability of sugarcane farming for biofuel has recently become a subject of debate, because its expansion may contribute significantly to global climate change mitigation. Here we report greenhouse gases (GHG) fluxes, measured by the eddy covariance method, from a commercial scale rain-fed sugarcane plantation representative of the leading bioethanol production area in southeast Brazil. The measurements covered two harvests, during which the field received nitrogen fertilization and trash was not removed. The cumulative fluxes for nitrous oxide (N 2 O) (62.4 ± 1.3 and 52.3 ± 1.8 g N 2 O CO 2 eq. m−2 for the first and second years, respectively) and methane (CH 4) (12.1 ± 1.7 and 10.4 ± 2.3 g CH 4 CO 2 eq. m−2 for the first and second years, respectively) were minor sources to the atmosphere in comparison with the net ecosystem exchange (NEE) of carbon dioxide (CO 2), whose sink dominated the balances (−7643. ± 129. and -4615. ± 124. g CO 2 m−2 for the first and second years, respectively). Compared to the first year, the observed NEE in the second year decreased by 40%, as it covered the first re-growth from the stubble (ratoon) and exhibited a shorter growth cycle than the first year (304 versus 390 days). The second year also included the partial decomposition of the trash remaining on the soil after the first harvest (1581 ± 301 g CO 2 m−2). The net ecosystem carbon balances (NECB), obtained as the cumulative fluxes of GHGs and the stalk dry biomass removed in the harvests (4923 ± 459 and 3929 ± 352 g CO 2 m−2 for the first and second years, respectively) were -2646 ± 459 and -623 ± 352 g CO 2 m−2 for the first and second years, respectively. Although the yields in stalk fresh weight (SFW) were representative of the region (9.9 and 8.2 kg SFW m−2, in the first and second year respectively) other factors caused a decrease of 76% in NECB, stressing the importance of the CO 2 balance (assimilation versus respiration). Nevertheless, this sugarcane agro-system was an overall carbon sink with the N 2 O and CH 4 emitted totals being offset by the net carbon gain. Image, graphical abstract [ABSTRACT FROM AUTHOR]