Annual Global Greenhouse Gas Emissions Research Articles

Greenhouse gas emissions trends and drivers insights from the domestic aviation in Thailand

Domestic aviation is a swiftly expanding contributor to global greenhouse gas (GHG) emissions. Presently, economic volatility and the Coronavirus disease (COVID-19) crisis have resulted in the decline of domestic aviation, but domestic aviation is rapidly recovering in many countries. However, from a GHG emissions viewpoint, the domestic aviation sector is largely unenforced even though the International Civil Aviation Organization's (ICAO) Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) provision for international aviation is currently in place. Accordingly, the knowledge base on emissions and their drivers from domestic aviation is weak, especially in developing countries, thus hindering an evidence-based policy debate. In this context, we have estimated and analyzed the pre-COVID-19 GHG emissions and their trends from commercial domestic aviation in Thailand; and provided insights on the role of key drivers that influence GHG emissions that are expected to be useful not only for Thailand but also for other developing countries. Emissions are estimated following Intergovernmental Panel on Climate Change (IPCC) Tier-II. Specifically, activity-based landing/take-off (LTO) cycle and cruise. This is compared to the Tier-I method, and key drivers were analyzed using an index decomposition method. The total annual average GHG emissions for all LTO cycles and cruises of commercial domestic aviation for 2015–2020 was 2254 Th. tonnes of CO2-eq. During the LTO cycle of the aircraft, GHG emissions were at an average of 983 Th. tonnes of CO2-eq. Additionally, during the cruise stage, emissions averaged 1270 Th. tonnes of CO2-eq. The choice of accounting methods (i.e., IPCC Tier II vs. Tier I) seems to have had only nominal implications. Our analysis showed that, in the 2008–2020 period, the aviation activity effect and economic growth were the key decisive factors in this sector's GHG emissions growth. It was followed by the fuel energy intensity levels and the population effect in descending order of impact. These findings have significant ramifications for present and future policies aimed at decreasing GHG emissions, aiding Thailand in achieving its climate targets by 2050, and enhancing energy efficiency as the domestic aviation market adapts.

A Comparative Techno-Economic Assessment of Alternative Fuels in SOFC Systems for Cruise Ships

Maritime transportation accounts for about 2.9% of global greenhouse gas (GHG) emissions, according to the fourth International Maritime Organization (IMO) GHG study. In the period from 2012 to 2018, shipping emissions have increased by almost 10%. Facing growing political and societal pressure, the IMO has established GHG emissions reduction targets consistent with the Paris Agreement temperature goals, aiming to reduce the total annual GHG emissions by at least 50% by 2050 compared to 2008 levels. In this context, alternative fuels and innovative technologies are needed to allow the maritime industry to comply with forthcoming regulations, as well as to fulfil decarbonisation targets within the European and the global markets.The shipping industry has already started to transition from traditional marine fuels, such as heavy fuel oil and marine diesel oil, to Liquified Natural Gas (LNG) in Internal Combustion Engines (ICEs). However, this can only be regarded as a bridging solution. In recent years, three major research lines can be identified: First, battery-electric propulsion, exploring the potential benefits of shaving peak thruster power and improving the energy efficiency and range of ships. Second, Solid Oxide Fuel Cells (SOFCs), which have a marked advantage of fuel flexibility and offer higher electrical efficiencies than ICEs and other fuel cell technologies, as well as higher-grade waste heat. Third, alternative marine fuels, such as synthetic hydrocarbons, biofuels, ammonia and hydrogen, as a way to significantly reduce or even phase out GHG emissions and other air pollutants.The present study bridges the aforementioned research lines by proposing a novel integrated marine energy system composed of an SOFC-battery hybrid genset that consumes LNG. The objective is to perform a techno-economic assessment of the hybrid genset for LNG and four identified potential alternative fuels (i.e. methanol, diesel, ammonia, and hydrogen). The best solutions will be identified and analysed, and a decision-making framework will be proposed. The comparison will identify the critical conditions for the genset processes being competitive to the state-of-the-art engine-based energy system.The analysis is divided into two main parts. The first part is dedicated to the SOFC module, which is composed of the SOFC stack and the balance of plant equipment. The BOP includes fuel storage, reformer, combustor, heat recovery system, pumps, and blowers. Previous work by the authors has developed the thermodynamic analysis of the genset systems that provide the starting point for the present analysis. The flow-sheet software Cycle Tempo was used in those analyses. The SOFC module has a nominal power production of 100 kWe, which is achieved by combining several stacks of 10 kWe, and produces hot water at 90 °C and saturated steam at 180 °C from waste heat recovery.In the second part, the SOFC-battery hybrid genset is achieved by combining several 100 kWe SOFC modules into power blocks and hybridizing them with batteries. The systems are designed to cover all the electricity and heat demands of the vessel, including propulsion and hotel load. A representative electrical demand of a large cruise ship is selected in the range of 30-60 MWe, of which about 80% is required for propulsion while the remaining is needed for the hotel.Among the main criteria for comparing the hybrid genset running on different fuels are the total annual cost, composed of the annual investment cost and annual operation cost, and the Levelized Costs of Energy, Electricity and Exergy. The latter is especially important because of the joint production of electricity and heat (saturated steam at 180 °C and hot water at 90 °C) that takes place in the genset. The investment cost was estimated using data collected from the literature or provided by manufacturers. The necessary replacement of SOFC stacks is taken into account, given the stack lifetime. Weight and volume requirements associated with the use of different fuels are assessed. The annual operation cost consists of fuel consumption and maintenance costs, as well as the application of an environmental tax for CO2 emissions.Different scenarios are proposed to evaluate the impacts of improvements in key parameters on the overall feasibility of the systems. The robustness of the results is evaluated by sensitivity and uncertainty analyses of the key technical and economic parameters used in the model, including, among other parameters, the fuel purchase price, SOFC and battery investment costs, stack lifetime, and interest rate. This research provides a systematic comparison of the techno-economic feasibility of five alternative fuels for cruise ships. The results will aid decision-makers, including shipyards and policymakers, in designing new energy systems with low emissions for maritime applications.

Cradle-to-grave emissions from food loss and waste represent half of total greenhouse gas emissions from food systems.

Global greenhouse gas (GHG) emissions from food loss and waste (FLW) are not well characterized from cradle to grave. Here GHG emissions due to FLW in supply chain and waste management systems are quantified, followed by an assessment of the GHG emission reductions that could be achieved by policy and technological interventions. Global FLW emitted 9.3 Gt of CO2 equivalent from the supply chain and waste management systems in 2017, which accounted for about half of the global annual GHG emissions from the whole food system. The sources of FLW emissions are widely distributed across nine post-farming stages and vary according to country, region and food category. Income level, technology availability and prevailing dietary pattern also affect the country and regional FLW emissions. Halving FLW generation, halving meat consumption and enhancing FLW management technologies are the strategies we assess for FLW emission reductions. The region-specific and food-category-specific outcomes and the trade-off in emission reductions between supply chain and waste management are elucidated. These insights may help decision makers localize and optimize intervention strategies for sustainable FLW management.

District heating system as the infrastructure for competition among producers in the heat market

Heating and electricity account for one-quarter of annual global greenhouse gas emissions. Many countries still use natural gas and oil for central heating, but interest in district heating as a possible low-carbon alternative is growing. District heating is well-developed in some countries, such as Sweden, Denmark, Poland, and Lithuania. However, there are considerable differences in the organisation of district heating markets in different countries. As these differences may have apparent implications for district heat pricing, competitiveness against other heat supply options, and clean energy uptake, this research explores existing approaches toward competition in the district heating market. We describe the differences in the conceptual frameworks and quantitative outcomes of district heat markets in selected countries and discuss the consequences of the different approaches. This study also considers the possible impacts on consumer prices relative to market opening to competition among heat producers. An important conclusion is that introducing third-party access on the supply side and a one-sided auction may positively affect consumer price downhill development. Finally, we provide insights that could interest other countries and contribute to the future development of the district heating market.

Governing industry decarbonisation: Policy implications from a firm perspective

Industry is responsible for around 1/3 of annual global greenhouse gas emissions. To limit global warming, many nations, including Switzerland, have committed to a (near) net-zero emission industry target by 2050. While the policy relevance of an industry transition increases, specific knowledge on the key barriers and drivers towards industrial decarbonisation is still largely missing. With the objective to contribute to the decision basis for effective policy development and based on 17 semi-structured interviews with firms from the Swiss industry, we investigate the key factors that hinder or accelerate a timely adoption of decarbonisation technologies. We relate the identified barriers and drivers from our interviews to an adapted St. Gallen Management Model (SGMM), a well-known, system-oriented management framework. Our study shows that the SGMM categories technology & economy (e.g. high technology costs), state & policymakers (e.g. emission price) and finance & controlling (e.g. pay-back periods) are most frequently mentioned by the interviewees and that the firms’ decarbonisation decisions are influenced by both the firm itself as well as external stakeholders, such as the government, consultants, customers, NGOs or suppliers. Therefore, we conclude that the firm itself and each of these stakeholders must play a key part in fostering industry decarbonisation. We suggest future research to (1) quantitatively assess the importance of the identified barriers and drivers and (2) investigate how policy actions of the relevant stakeholders could be effectively orchestrated and incentivised.

Countries with sustained greenhouse gas emissions reductions: an analysis of trends and progress by sector

ABSTRACT While global greenhouse gas (GHG) emissions are still rising, a number of countries have emerged with a sustained record of emissions reductions. In this article, we identify these countries and examine their progress, exploring how fast, how deep, and in which sectors they have reduced emissions. We analyse changes in all major GHG emissions sources, with both production – and consumption-based accounting, but exclude very small countries with high volatility, along with land-use, land-use change and forestry CO2 emissions. We find that 24 countries have sustained reductions in annual CO2 and GHG emissions between 1970 and 2018, in total equalling 3.2 GtCO2eq since their respective emissions peaks. In all but three countries, overall GHG reductions are less than energy and industrial CO2 reductions alone. We group countries into three types of emissions pathway: six former Eastern Bloc countries, where emissions declined rapidly in the 1990s and have continued on a downward trajectory since; six Long-term decline countries, which have sustained reductions since the 1970s; and 12 Recent peak countries, whose emissions decline began in the 2000s. In all cases, emissions reductions were achieved primarily in the energy systems sector, specifically in electricity and heat generation, which still remains the largest source of emissions in most countries. By contrast, in the transport sector, emissions tend to be stable or increasing. Transport is the second largest source of current emissions in Recent peak and Long-term decline countries. While the total GHG reductions of these 24 countries are trivial compared to recent global emissions growth, some have achieved a decline of up to 50% in their annual emissions, showing what is possible even under very moderate climate action. Most countries achieved emissions reductions alongside sustained economic growth, and some approached the fast annual rates of change that will be needed across the world in the coming decades to limit warming to 2°C. This raises the hope that more substantive climate policy, as planned in a growing number of countries, may bring about deeper and more rapid emissions reductions than some may expect today. Key policy insights 24 countries have sustained CO2 and GHG emissions reductions between 1970 and 2018 The annual emissions reductions of some countries are within the range of those needed to limit global warming to 2°C, but not consistently, nor across all underlying sectors Most emissions reductions were achieved in the energy sector; transport emissions have remained stable or continue to grow

Conditions are ideal for a new climate club

Annual global greenhouse-gas emissions have been rising steadily for decades and show no sign of peaking. That is, humankind is not making enough progress to exclude a possibly catastrophic climate scenario. Protecting the climate is difficult because of free-riding: emissions abatement costs are largely national but the benefits from climate stability are global. Dealing with this problem needs to be at the core of a new climate strategy. This article argues that both technological and political conditions are now ideal to establish a new climate club, in which members commit to stronger domestic climate measures and agree on the coordinated introduction of carbon border adjustment measures. On the technology side, there have been stunning clean technology cost reductions. This will underpin the climate club: as abatement costs fall, club stability can be more easily achieved. On the political side, we now see the United States, European Union and China – representing half of global greenhouse gas emissions – sharing for the first time a common climate ambition while popular support in all economies is also high for substantial climate actions. These two changes make a climate club more likely stable as the benefits from deviating from the club have diminished. A relatively weak penalty, such as carbon border adjustment measure, may then suffice for club stability. This climate club would also create incentive for other countries to join the club, thus making it a catalyst for tougher climate action worldwide.

Spatiotemporal Assessment of GHG Emissions and Nutrient Sequestration Linked to Agronutrient Runoff in Global Wetlands

AbstractWetlands play a key role in regulating global greenhouse gas (GHG) emissions but anthropogenic impacts on nutrients may severely alter this balance. Recent assessments indicate that almost 22% of the global wetland area may be affected by agricultural runoff. In this work, we developed and applied a dynamic mechanistic reaction network model of soil organic matter linking the carbon (C), nitrogen (N), and sulfur (S) cycles at 0.5° × 0.5° spatial resolution across the globe. The model was used to estimate GHG emissions and nutrient sequestration rates in wetlands, driven by environmental stressors including N, P, and S fertilization. Wetland annual GHG emissions are estimated to be 136 ± 12.5 Tg C‐CH4, 589 ± 45.8 Tg C‐CO2, and 0.3 ± 0.04 Tg N‐N2O; in contrast, C, N, and S annual sequestration rates are estimated to be 576 ± 88.1 Tg C, 20 ± 4.4 Tg N, and 7.4 ± 0.8 Tg S, between 2000 and 2017. N fertilization inputs were responsible for 13% N2O emissions in wetlands in the Northern Hemisphere, while tropical wetlands were major reservoirs for C, N, and S. Temperature, net primary productivity, and methanogenic microorganisms exert the major control on GHG emissions. Wetland CH4 and CO2 emissions were found to have a hysteretic relationship with seasonal soil temperature, but not N2O. A global‐scale assessment is pivotal for best nutrient management practices, reducing nutrient losses, and controlling gas emissions.

Microbial Resources as a Tool for Enhancing Sustainability in Winemaking.

In agriculture, the wine sector is one of the industries most affected by the sustainability issue. It is responsible for about 0.3% of annual global greenhouse gas emissions from anthropogenic activities. Sustainability in vitiviniculture was firstly linked to vineyard management, where the use of fertilizers, pesticides and heavy metals is a major concern. More recently, the contribution of winemaking, from grape harvest to bottling, has also been considered. Several cellar processes could be improved for reducing the environmental impact of the whole chain, including microbe-driven transformations. This paper reviews the potential of microorganisms and interactions thereof as a natural, environmentally friendly tool to improve the sustainability aspects of winemaking, all along the production chain. The main phases identified as potentially interesting for exploiting microbial activities to lower inputs are: (i) pre-fermentative stages, (ii) alcoholic fermentation, (iii) stage between alcoholic and malolactic fermentation, (iv) malolactic fermentation, (v) stabilization and spoilage risk management, and (vi) by-products and wastewater treatment. The presence of proper yeast or bacterial strains, the management and timing of inoculation of starter cultures, and some appropriate technological modifications that favor selected microbial activities can lead to several positive effects, including (among other) energy savings, reduction of chemical additives such as sulfites, and reuse of certain residues.

Using CO2 as a feedstock could slash emissions

Using carbon dioxide as a chemical feedstock instead of oil would reduce annual global greenhouse gas emissions by about 3.5 billion metric tons (t) in 2030. This estimate, based on a new model of the chemical industry, is about an order of magnitude greater reduction than previous ones (Proc. Natl. Acad. Sci. U.S.A. 2019, DOI: 10.1073/pnas.1821029116). Without an in-depth life-cycle analysis of CO2 use by the chemical industry, scientists have previously estimated it would mitigate about 200 million t of CO2 per year. Sangwon Suh, an environmental scientist at the University of California, Santa Barbara, collaborated with Andre Bardow, an expert in chemical life-cycle analysis at RWTH Aachen University, to fill in the details. Their work is based on a quantitative data set that includes details about the processes involved in emerging technologies for using captured CO2 and renewable energy to make chemicals such as methane, olefins, and styrene. They

Temporal and spatial variation of greenhouse gas emissions from a limited-controlled landfill site

Landfilling biodegradable waste is an important source of global greenhouse gas (GHG) emissions. Among the several types of landfill, limited-controlled landfill is a common method used to dispose of domestic solid waste, especially in developing countries. However, information about GHG emissions from limited-controlled landfill sites has rarely been reported. In this study, the GHG emissions from a typical limited-controlled landfill site were investigated under a regular period for one year. The number and positions of static chambers were arranged according to the guidance on Monitoring Landfill Gas Surface Emissions by the UK Environment Agency to obtain representative data from the heterogeneous surface of the landfill. Inverse distance weighting (IDW) was applied to evaluate and visualise the GHG emissions from the whole landfill surface based on the measurements of distributed static chambers. As an important GHG source of the landfill site, the emissions from the landfill leachate treatment plant were also measured. The results revealed that CH4 and N2O emission fluxes from the landfill area were 1324.73 ± 2005.17 mg C m−2 d−1 and 2.16 ± 2.33 mg N m−2 d−1, respectively, and the fluxes from the leachate treatment plants were 23.92 ± 29.20 mg C m−2 d−1 and 16.40 ± 16.89 mg N m−2 d−1, respectively. CH4 and N2O releases preferred to present spatial heterogeneity, while temporal heterogeneity was expected to exist in CH4 and CO2 emissions. The annual GHG emissions from the limited-controlled landfill was calculated to be 1.078 Gg CO2-eq yr−1, which was the least among all types of landfill sites. In addition, the GHG emission factor was 0.042 t CO2-eq t−1 waste yr−1 which could not be ignored compared to the sanitary landfills. Therefore, it is advisable to give more attention and determine a potential solution for reducing GHG emissions from limited-controlled landfill sites.

Contributions of natural systems and human activity to greenhouse gas emissions

In this study, we conducted a literature review of relevant research and then statistically analyzed global greenhouse gas (GHG) emissions from natural systems, including forest fires, oceans, wetlands, permafrost, mud volcanoes, volcanoes, and earthquakes. Drawing on the Global Carbon Project (GCP) report, we also summarized the global anthropogenic GHG emissions. We then compared the global annual GHG emissions from natural systems with those generated by human activity. The results indicate that the global annual GHG emissions range approximately between 54.33 and 75.50 Gt CO2-eq, of which natural emissions account for 18.13–39.30 Gt CO2-eq, with the most likely value being approximately 29.07 Gt CO2-eq. According to the GCP report, the global anthropogenic emissions have increased from 22 Gt CO2-eq in 1990 to 36.2 Gt CO2-eq in 2016. The amounts of natural and anthropogenic GHGs emissions are roughly of the same order of magnitude. Anthropogenic emissions account for approximately 55.46% of the total global GHGs emissions (2016 value), i.e., the ratio of natural to anthropogenic emissions is approximately 0.8. In addition, the annual amount of GHGs absorbed by Earth systems (ocean and terrestrial ecosystems) ranges between approximately 14.4 Gt CO2-eq and 26.5 Gt CO2-eq, with natural system GHG emissions and sinks also having roughly the same order of magnitude. This finding indicates that the GHG emissions generated by human activity exert extra pressure on what is otherwise a self-balancing Earth system.

Energy Recovery Together with Amorphous Nanosilica Production from Rice Straw via Dry Anaerobic Digestion

Rice straw burning is the most widely used industrial process for silica production, resulting in the loss of carbohydrate energy and environmental pollution. In this study, dry anaerobic digestion was applied to convert an organic fraction of rice straw into biogas while generating a solid digestate rich in silica. The methane yield obtained from the dry digestion was 119 L per kg of volatile solids of the straw. The silica content in the ash of the digested straw was 20.7% higher than that of the ash from raw rice straw. The X-ray diffraction pattern revealed the existence of amorphous silica in the ash of the digested straw. The Fourier transform infrared analysis dispelled concerns about the addition of silica impurities by the anaerobic digestion process. The transmission electron microscopy results revealed the formation of nanosilica with particle sizes between 15 nm and 30 nm. It was concluded that high-quality nanosilica can be obtained from anaerobically digested rice straw. The application of this process can decrease the annual global greenhouse gas emissions by 10.5 million tons.

Methane matters: from blue-tinged moos, to boozy roos, and the health of humans too

• Methane emissions from ruminant livestock are proposed to contribute ~10 to 20% of annual global greenhouse gas emissions. • Recent efforts have shown that low methane emitting animals can be identified both within and across species, including nondomesticated herbivores. • Methanogens are also present within the human gut and some other body sites, and variations in their diversity and/or abundance has been linked to some functional gastrointestinal disorders and non-communicable chronic diseases. • Recent advances in -omics technologies have provided new insights of the roles that methanogens play in both feed digestion and host-microbe interactions. • Although much research and understanding has been derived from the study of the numerically dominant Methanobrevibacter genus, the recent studies outlined above have shown that other, heterotrophic methanogens warrant greater attention. • Here, we provide a brief overview of our recent research of the Methanosphaera genus and outline the possible consequences associated with its presence in the gut of livestock, native Australian herbivores, and humans.

Health Impact Assessments A Tool for Designing Climate Change Resilience Into Green Building and Planning Projects

Historical records have documented considerable changes to the global climate, with significant health, economic, and environmental consequences. Climate projections predict more intense hurricanes; increased sea level rise; and more frequent and more intense natural disasters such as heat waves, heavy rainfall, and drought in the future (1; 2). The coast along the Gulf of Mexico is particularly vulnerable to many of these environmental hazards and at particular risk when several strike simultaneously—such as a hurricane disrupting electricity transmission during a heat wave. Due to its significant contribution to global greenhouse gas (GHG) emissions, the building sector already plays an important role in climate change mitigation efforts (e.g., reducing emissions). For example, voluntary programs such as the LEED (Leadership in Energy and Environmental Design) Rating System (3), the Architecture 2030 Challenge (4), the American College and University Presidents' Climate Commitment (5), and the Clinton Climate Initiative (6) focus almost exclusively on reducing energy consumption and increasing renewable energy generation. Mandatory regulations such as the International Energy Conservation Code (7), the International Green Building Code (8), and CalGreen (9) also emphasize GHG emission reduction targets. This leadership role is necessary. After all, the United States EPA estimates that the building sector accounts for 62.7% of total annual GHG emissions in the U.S., when the construction sector, facility operations, and transportation are factored in. In fact, the construction sector alone is the third largest industrial emitter of GHGs after the oil and gas and chemical industries, contributing 1.7% of total annual emissions (10; 11). As significant as these contributions appear, the built environment's true contribution to climate change is much larger than the GHG emissions attributed to building construction and operations. It is also a major determinant of which populations are vulnerable to climate change-related hazards, such as heat waves and flooding (12; 13). Architecture and land use planning can therefore be used as tools for building community resilience to the climate-related environmental changes underway (13). Climate change regulations and voluntary programs have begun to incorporate requirements targeting the built environment's ability to work in tandem with the natural environment to both reduce greenhouse gas emissions and protect its occupants from the health consequences of a changing climate. For example, 11 states have incorporated climate change adaptation goals into their climate action plans (14). In 2010, the not-for-profit organization ICLEI: Local Governments for Sustainability launched a climate change adaptation program (15) to complement their existing mitigation program, which supports municipalities who have signed the U.S. Conference of Mayors' Climate Protection Agreement (16). New tools have been introduced to measure community vulnerability to the impacts of climate change. One of these tools, Health Impact Assessments (or HIAs), has emerged over the past decade as a powerful methodology to provide evidence-based recommendations to decision makers and community planning officials about the likely health co-benefits and co-harms associated with proposed policies and land use development proposals (17). While HIAs are becoming a more common feature of community planning efforts, this paper introduces them as an approach to designing climate change resilience into specific building projects. HIAs have been used in Europe and other parts of the world for decades to provide a science-based, balanced assessment of the risks and benefits to health associated with a proposed policy or program (18). In the U.S., they have been used over the past decade to evaluate transit-oriented developments, urban infill projects, and California's capand-trade legislation, among other topics (17; 19). To date, HIAs have been used mainly to inform large-scale community planning, land use, industrial, and policy decisions. However, the recommendations generated through the HIA process often bring to light previously unforeseen vulnerabilities, whether due to existing infrastructure, building technology, or socio-economic conditions. Designers can make use of the HIA process and its resulting recommendations to prioritize design/retrofit interventions that will result in the largest co-benefits to building owners, the surrounding community, and the environment. An HIA focused on the health impacts of climate change will likely generate recommendations that could enhance the longevity of a building project's useful life; protect its property value by contributing to the resilience of the surrounding community; and result in design decisions that prioritize strategies that maximize both short-term efficiencies and long-term environmental, economic, and social value.