Anthropogenic Greenhouse Gas Research Articles

Anthropogenic aerosols mask increases in US rainfall by greenhouse gases

A comprehensive understanding of human-induced changes to rainfall is essential for water resource management and infrastructure design. However, at regional scales, existing detection and attribution studies are rarely able to conclusively identify human influence on precipitation. Here we show that anthropogenic aerosol and greenhouse gas (GHG) emissions are the primary drivers of precipitation change over the United States. GHG emissions increase mean and extreme precipitation from rain gauge measurements across all seasons, while the decadal-scale effect of global aerosol emissions decreases precipitation. Local aerosol emissions further offset GHG increases in the winter and spring but enhance rainfall during the summer and fall. Our results show that the conflicting literature on historical precipitation trends can be explained by offsetting aerosol and greenhouse gas signals. At the scale of the United States, individual climate models reproduce observed changes but cannot confidently determine whether a given anthropogenic agent has increased or decreased rainfall.

Energy policy pathways to inform climate policy in Saudi Arabia

In 2022, Saudi Arabia's anthropogenic greenhouse gas emissions amounted to 810 million tons of CO2e. The country has pledged to cut its emissions by 278 million tons of CO2e per year by 2030. This paper contributes a modeling view on the climate-related effects of various energy policies on the Saudi energy system. We use an energy system model designed to represent seven sectors in the Saudi economy. In addition to a baseline, which entails the continuation of current domestic policies, we look at a scenario that incorporates some of the plans announced by the Saudi government. We also examine the baseline scenario with a cap on total CO2 emissions equal to those exhibited with the announced plans. The model then makes the necessary decisions to abate CO2. We find that the energy system contributes 130 million tons of CO2e to the nationally determined contribution amount in 2030. Also, a non-prescriptive scenario that caps energy-system CO2 emissions produces the same emissions reductions as the announced plans while lowering the present cost by 2030 by $70 billion. The corresponding implicit marginal abatement cost of CO2 approaches 35 $/tonCO2 by 2045. This cost would displace around half of crude and fuel oil use in the Saudi energy system.

A method for estimating localized CO2 emissions from co-located satellite XCO2 and NO2 images

Abstract. Carbon dioxide (CO2) is the most important anthropogenic greenhouse gas. Its atmospheric concentration has increased by almost 50 % since the beginning of the industrial era, causing climate change. Fossil fuel combustion is responsible for most of the atmospheric CO2 increase, which originates to a large extent from localized sources such as power stations. Independent estimates of the emissions from these sources are key to tracking the effectiveness of implemented climate policies to mitigate climate change. We developed an automatic procedure to quantify CO2 emissions from localized sources based on a cross-sectional mass-balance approach and applied it to infer CO2 emissions from the Bełchatów Power Station (Poland) using atmospheric observations from the Orbiting Carbon Observatory 3 (OCO-3) in its snapshot area map (SAM) mode. As a result of the challenge of identifying CO2 emission plumes from satellite data with adequate accuracy, we located and constrained the shape of emission plumes using TROPOspheric Monitoring Instrument (TROPOMI) NO2 column densities. We automatically analysed all available OCO-3 overpasses over the Bełchatów Power Station from July 2019 to November 2022 and found a total of nine that were suitable for the estimation of CO2 emissions using our method. The mean uncertainty in the obtained estimates was 5.8 Mt CO2 yr−1 (22.0 %), mainly driven by the dispersion of the cross-sectional fluxes downwind of the source, e.g. due to turbulence. This dispersion uncertainty was characterized using a semivariogram, made possible by the OCO-3 imaging capability over a target region in SAM mode, which provides observations containing plume information up to several tens of kilometres downwind of the source. A bottom-up emission estimate was computed based on the hourly power-plant-generated power and emission factors to validate the satellite-based estimates. We found that the two independent estimates agree within their 1σ uncertainty in eight out of nine analysed overpasses and have a high Pearson's correlation coefficient of 0.92. Our results confirm the potential to monitor large localized CO2 emission sources from space-based observations and the usefulness of NO2 estimates for plume detection. They also illustrate the potential to improve CO2 monitoring capabilities with the planned Copernicus Anthropogenic CO2 Monitoring (CO2M) satellite constellation, which will provide simultaneously retrieved XCO2 and NO2 maps.

Contribution of Anthropogenic Activities to the Intensification of Heat Index‐Based Spatiotemporally Contiguous Heatwave Events in China

AbstractIn this study, we identified heat index‐based spatiotemporally contiguous heatwaves (HI‐STHWs) in China based on meteorological observations and Coupled Model Intercomparison Project Phase 6 global climate model simulations. We analyzed the spatiotemporal patterns of changes in HI‐STHWs in the past and future and quantitatively attributed these changes to anthropogenic activities. The results show that the duration, severity, average, maximum, and total impacted area of the annual strongest HI‐STHWs during the present period of 1991–2014 are 1.77, 2.0, 1.05, 1.14, and 1.89 times the historical period of 1961–1990, respectively. In the fingerprint results, the anthropogenic greenhouse gases (GHG) signal is significantly detected, while the aerosol (AER) and natural (NAT) signals are not. GHG is the primary factor driving the intensification of HI‐STHWs, which alone explains about 130%, 122%, 112%, 111%, and 114% of the above changes. The reason for GHG contribution exceeding 100% is that AER might have a negative contribution although nonsignificant. In the future warming climate, anthropogenic activities are projected to lead to more unprecedented HI‐STHWs. Under the high emissions scenario of SSP585, by 2100, the annual strongest HI‐STHW in China is projected to last almost the whole year and influence 96% regions of China in the most serious day. Meanwhile, its duration and total impacted area are 24.5 [17.2, 31.6] (90% confidence interval) and 107.2 [70, 129.9] times the preindustrial period. However, if the warming level could be limited to 2/1.5°C, those values would be 3.4/5.4 and 8.2/16.2 times smaller than that under the SSP585 scenario by 2100.

A pathway to 25% reduction in greenhouse gas emission by 2030 using GIS-Based multi-criteria decision making for renewables, date palm (phoenix dactylifera), and carbon credits: a case for Qatar

Qatar is making concerted efforts at the national level to decrease anthropogenic greenhouse gas emissions. The country has set its National Determined Contribution (NDC) in line with the Paris Agreement to reduce its overall emissions by 25% by the year 2030. This study identifies several pathways, which Qatar can explore to achieve its set goals. It explores Qatar’s potential for renewable energy generation (solar and wind), carbon offset through planting trees, and the purchase of carbon offset credits. The study starts by investigating the available wind and solar energy potential in the country, by considering physical and legal restrictions, which limit the available land to be utilized for RE generation. Multi-criteria Decision is carried out utilizing the Analytic Hierarchy Process (AHP) for variable percentage estimation in ArcMap Geographic Information Systems software. Next, a review based on Qatar’s climate is performed to identify suitable tree species that would promote atmospheric CO2 sequestration in the country. Finally, the cost implication of offsetting emissions using verified carbon credits is considered and compared with other options. Results indicated that while a considerable area is available for both wind (37%) and solar (53%) energy generation, only 6.2% and 13.8% of Qatar are highly suitable for wind and solar energy installations, respectively. Also, while Qatar has the potential to meet 20% of its energy demand by 2030 from renewable sources by using solar PV and wind, this will only account for a 14.28% reduction in overall emissions. Additionally, planting date palm trees (Phoenix dactylifera) would significantly benefit the nation in the area of carbon sequestration and revenue generation as compared to purchasing carbon offset credits.

Reactivity of Monoethanolamine at the Air-Water Interface and Implications for CO2 Capture.

The development of CO2-capture technologies is key to mitigating climate change due to anthropogenic greenhouse gas emissions. These cover a number of technologies designed to reduce the level of CO2 emitted into the atmosphere or to eliminate CO2 from ambient air. In this context, amine-based sorbents in aqueous solutions are broadly used in most advanced separation techniques currently implemented in industrial applications. It has been reported that the gas/liquid interface plays an important role in the early stages of the capture process, but how the interface influences the chemistry is still a matter of debate. With the help of first-principles molecular dynamics simulations, we show that monoethanolamine (MEA), a prototypical sorbent molecule, has a weak affinity for the air-water interface, where in addition it exhibits a lower nucleophilicity compared to bulk solution. The change in reactivity is due to the combination of structural and electronic factors, namely, the shift of the conformational equilibrium and the stabilization of the N-atom lone pair. Based on these results, strategies for improving the efficiency of alkanolamine sorbents are proposed.

Aircraft-based mass balance estimate of methane emissions from offshore gas facilities in the southern North Sea

Abstract. Atmospheric methane (CH4) concentrations have more than doubled since the beginning of the industrial age, making CH4 the second most important anthropogenic greenhouse gas after carbon dioxide (CO2). The oil and gas sector represents one of the major anthropogenic CH4 emitters as it is estimated to account for 22 % of global anthropogenic CH4 emissions. An airborne field campaign was conducted in April–May 2019 to study CH4 emissions from offshore gas facilities in the southern North Sea with the aim of deriving emission estimates using a top-down (measurement-led) approach. We present CH4 fluxes for six UK and five Dutch offshore platforms or platform complexes using the well-established mass balance flux method. We identify specific gas production emissions and emission processes (venting and fugitive or flaring and combustion) using observations of co-emitted ethane (C2H6) and CO2. We compare our top-down estimated fluxes with a ship-based top-down study in the Dutch sector and with bottom-up estimates from a globally gridded annual inventory, UK national annual point-source inventories, and operator-based reporting for individual Dutch facilities. In this study, we find that all the inventories, except for the operator-based facility-level reporting, underestimate measured emissions, with the largest discrepancy observed with the globally gridded inventory. Individual facility reporting, as available for Dutch sites for the specific survey date, shows better agreement with our measurement-based estimates. For all the sampled Dutch installations together, we find that our estimated flux of (122.9 ± 36.8) kg h−1 deviates by a factor of 0.64 (0.33–12) from reported values (192.8 kg h−1). Comparisons with aircraft observations in two other offshore regions (the Norwegian Sea and the Gulf of Mexico) show that measured, absolute facility-level emission rates agree with the general distribution found in other offshore basins despite different production types (oil, gas) and gas production rates, which vary by 2 orders of magnitude. Therefore, mitigation is warranted equally across geographies.

Using olive and apple pomaces for fattening pig diets: Environmental impacts under an attributional and consequential perspective

The livestock sector plays an essential role in anthropogenic greenhouse gas emissions, where fodder crop production has been largely identified as the main contributor to their environmental impact. This research evaluates the attributional environmental impacts of introducing food industry subproducts such as apple and olive pomaces to reduce the proportion of maize grain in the formulation of diets for fattening pigs, according to four alternatives, including the current diet with 69% maize. For this, the life cycle assessment (LCA) methodology has been used to determine the hotspots associated to these changes, considering a cradle-to-gate approach and two functional units: 1 kg of feed diet (FU1) and 1 kg of weight gain (FU2). Furthermore, the potential environmental consequences of using these subproducts for pig diet have also been considered with a consequential LCA methodology. The results show that the best diet was the one containing about 33% maize and 43% subproducts for all categories analysed. In addition, the allocation method used to assign subproduct loads, including mass, economic, and zero-burdens allocation, is crucial to validate the assumptions and recommendations for this strategy. The consequential LCA results suggest that this strategy could involve both positive and negative impacts (considered as environmental credits), depending on the substitutes for the avoided maize stover and the potential displaced bioproducts that could be obtained from these subproducts, mainly for bioenergy production.

Distinct anthropogenic greenhouse gas and aerosol induced marine heatwaves

In the era of escalating climate change, understanding human impacts on marine heatwaves (MHWs) becomes essential. This study harnesses climate model historical and single forcing simulations to delve into the individual roles of anthropogenic greenhouse gases (GHGs) and aerosols in shaping the characteristics of global MHWs over the past several decades. The results suggest that GHG variations lead to longer-lasting, more frequent, and intense MHWs. In contrast, anthropogenic aerosols markedly curb the intensity and growth of MHWs. Further analysis of the sea surface temperature (SST) probability distribution reveals that anthropogenic GHGs and aerosols have opposing effects on the tails of the SST probability distribution, causing the tails to expand and contract, respectively. Climate extremes such as MHWs are accordingly promoted and reduced. Our study underscores the significant impacts of anthropogenic GHGs and aerosols on MHWs, which go far beyond the customary concept that these anthropogenic forcings modulate climate extremes by shifting global SST probabilities via modifying the mean-state SST.

Oceanic Influence and Lapse Rate Changes Dominate the Recent Amplified Saharan Warming

AbstractThe surface air temperature (SAT) over the Sahara Desert has increased at a much faster rate than average tropical land in recent decades. This study examines the relative roles of anthropogenic greenhouse gas (GHG) forcing and sea surface temperature (SST) change in the observed Saharan temperature increase during boreal warm season from 1979 to 2020 using atmospheric general circulation model simulations. It is found that the SST forcing dominates the observed Saharan warming. Further analysis shows that the warming ocean forces the Saharan SAT increase by moving more energy to the Sahara Desert, while the water vapor feedback plays a secondary role. The reason for the stronger Saharan warming than the average tropical land given the same SST forcing is also explored. We found that the largest contributor to the warming contrast is the lapse‐rate feedback, which is attributable to the difference in the vertical warming profile.

Geothermal Solutions for Urban Energy Challenges: A Focus on CO2 Plume Geothermal Systems

The utilization of geological formations, distinguished by natural porosity and permeability and protected by low-permeability caprock, has emerged as an effective strategy for carbon dioxide (CO2) storage. This method significantly contributes to mitigating anthropogenic greenhouse gas emissions and addressing the challenges of climate change. Recent research has unveiled the potential of CO2 to enhance geothermal heat energy extraction in geothermal reservoirs by acting as a subsurface heat exchange fluid. This review paper explores the viability of CO2 in augmenting geothermal heat energy extraction, comparing it to conventional water-based geothermal systems. Special emphasis is placed on CO2 plume geothermal (CPG) systems, characterized by rapid deployment and long-term utilization of geothermal energy resources. With the overarching objective of establishing net-zero energy communities, the analysis of such systems offers a comprehensive understanding of their features, providing a fresh perspective on extracted energy within the context of energy supply in integrated, sustainable energy in built systems. Notably, these systems demonstrate efficacy in meeting the power requirements of an energy community, spanning both distinct heating and electricity needs. However, the key challenge lies in selecting suitable locations. This scientific review aims to comprehend the characteristics of CPG under specific temperature and pressure conditions while optimizing subsurface permeability. This insight is pivotal for identifying future locations for CPG operations with the intent of powering small energy communities.

Comparison of the effects of alfalfa meal and sorghum distillery residue supplementation on the methane emissions in black-feathered Taiwan native chicken.

The issue of global warming, primarily fueled by anthropogenic greenhouse gas emissions, necessitates effective strategies to address methane (CH4) emissions from both ruminants and nonruminants. Drawing inspiration from successful approaches employed in ruminants, this study evaluates the impact of supplementing the diets of Taiwan's native black-feathered chickens with alfalfa meal and sorghum distillery residues (SDRs) on CH4 emissions. Using a respiration chamber the results reveal a significant reduction in CH4 emissions when incorporating either 30% alfalfa meal or 30% SDRs into the chicken diet, demonstrating a 59% and 49% decrease, respectively, compared to the control group (P < 0.05). Considering that alfalfa meal contains saponins and SDRs contain tannins, the study delves into the mechanism through which these components mitigate CH4 production in chickens. Incorporating saponins or tannins shows that groups supplemented with these components exhibit significantly lower CH4 emissions compared to the control group (P < 0.05), with a consistent linear decrease as the concentration of the feed additive increases. Further in vitro analysis of chicken cecal contents indicates a proportional reduction in CH4 production with increasing levels of added saponins or tannins (P < 0.05). These findings suggest that the CH4-reducing effects of alfalfa meal and SDRs can be attributed to their saponins and tannin content. However, caution is warranted as excessive alfalfa meal supplementation may adversely impact poultry growth. Consequently, sorghum distillery residue emerges as a more suitable feed ingredient for mitigating CH4 emissions in Taiwan's native black-feathered chickens compared to alfalfa. Additionally, substituting SDRs for conventional commercial chicken feed not only reduces CH4 emissions but also enhances the utilization of byproducts.

Stronger increases but greater variability in global mangrove productivity compared to that of adjacent terrestrial forests.

Mangrove forests are a highly productive ecosystem with important potential to offset anthropogenic greenhouse gas emissions. Mangroves are expected to respond differently to climate change compared to terrestrial forests owing to their location in the tidal environment and unique ecophysiological characteristics, but the magnitude of difference remains uncertain at the global scale. Here we use satellite observations to examine mean trends and interannual variability in the productivity of global mangrove forests and nearby terrestrial evergreen broadleaf forests from 2001 to 2020. Although both types of ecosystem experienced significant recent increases in productivity, mangroves exhibited a stronger increasing trend and greater interannual variability in productivity than evergreen broadleaf forests on three-quarters of their co-occurring coasts. The difference in productivity trends is attributed to the stronger CO2 fertilization effect on mangrove photosynthesis, while the discrepancy in interannual variability is attributed to the higher sensitivities to variations in precipitation and sea level. Our results indicate that mangroves will have a faster increase in productivity than terrestrial forests in a CO2-rich future but may suffer more from deficits in water availability, highlighting a key difference between terrestrial and tidal ecosystems in their responses to climate change.

ИЗМЕНЕНИЕ КОНЦЕНТРАЦИИ ГАЗОВ В ТЕХНОЛОГИЧЕСКОМ МОДУЛЕ В ПРОЦЕССЕ ВЫРАЩИВАНИЯ БРОЙЛЕРОВ

There is no information on poultry emissions in national reports on anthropogenic gas release and greenhouse gas uptake. Gaseous pollutants are formed as a result of poultry enteric fermentation and fecal decomposition; their concentration depends on the ventilation efficiency and speed, as well as on density of poultry planting. Determination of greenhouse gas emissions amount from industrial poultry farming is an urgent task. The relative greenhouse gases emissions produced by poultry at the poultry house is approximately 0,045 kg in CO2 equivalent. At the same time, there is no information on the greenhouse gases’ concentration quantitative changing at poultry growing process. The aim of the study is greenhouse gases concentration change determining throughout the broiler chickens growing entire process. Studies of gases concentration in developed experimental technological module for broilers’ growing on each level of a two level battery have been carried out. Broiler chickens of the ROSS-308 cross for 6 weeks were raised. Greenhouse gas concentrations at the end of each week were measured. Due to the fact that the necessary temperature and humidity in the module were automatically maintained, only the natural ventilation system worked until the third week of cultivation, as a result the gas concentration inside the module increased, but did not reach the maximum of permissible concentration’s values. With the forced ventilation system’s automatic activation, the gases concentration at this technological module to minimum values was decreased. The gases’ concentration inside the module within the following limits varying: carbon dioxide - from 1029,9 to 4826,5 mg/m3, ammonia - from 2,05 to 23,11 mg/m3, hydrogen sulfide - from 0,12 to 0,96 mg/m3, methane - from 64,6 to 246,1 mg/m3. The gases’ concentration outside the technological module varies within the limits: carbon dioxide - from 366,4 to 1461,6 mg/m3, ammonia - from 0 to 3,42 mg/m3, hydrogen sulfide - from 0 to 0,35 mg/m3, methane - from 65,2 to 263,1 mg/m3.

Energy Conversion Technology of Fuel Cells on Ships to Mitigate Greenhouse Gas Emissions

Greenhouse gas emissions are something that contribute to climate change, which is getting hotter and causing concern for the condition of the earth. The shipping sector is a major cause of greenhouse gas emissions, accounting for 2.89% of anthropogenic greenhouse gas emissions and 919 million tonnes of CO2 emissions. This research aims to present different types of fuel cells that can be applied to different vessels. System Literature Review (SLR) is the method in this study to review the data sources obtained with a range of publications in 2019-2024. The result of this review is the acquisition of 2 types of fuel cells that can be used in 8 ships. The types of fuel cells are SOFC and PEMFC. Each fuel cell produces a high percentage of eficiency. Both fuel cells can be integrated into other technologies such as GT, ORC, SRC, and ICE. The companies that support the development of this fuel cell are KC, WHB, MCFC, PAFC, DEC, and LT. Therefore, fuel cells have high potential to mitigate greenhouse gas emissions due to marine transport.

Spatio-temporal dynamics of methane concentration and its association to climatic and vegetation parameters: a case study of the Northern Cape Province, South Africa

Methane (CH4) is the second most abundant anthropogenic greenhouse gas after carbon dioxide (CO2), accounting for about 20% of global emissions. CH4 anthropogenic emission sources include landfills, oil and natural gas systems, agricultural activities, coal mining, stationary and mobile combustion, wastewater treatment and certain industrial processes. In this work, we examine the spatio-temporal dynamics of CH4 and its relationship to climatic and vegetation parameters in the Northern Cape province in South Africa. Various datasets from the TROPOspheric Monitoring Instrument, Moderate Resolution Imaging Spectroradiometer, Atmospheric Infrared Sounder and the Global Precipitation Climatology Project were used. The results show an increasing trend of CH4 concentration throughout the entire province. The greatest increase in CH4 concentration is observed in the western parts of the province during June–July–August (JJA) season. CH4 concentration shows negligible correlation with most climatic parameters, i.e. Temperature (Temp), Precipitation (Precip) and NDVI for both seasons. The Temp–NDVI relationship shows high correlation values of r = –0.71 and r = 0.82 for the DJF and JJA seasons, respectively. Seasonality plays a critical role in the relationships of the CH4 to climatic and vegetation parameters. This study shows that we are in a crisis, and robust mitigation strategies are needed to combat this.

Environmental and Economic Assessment of Batteries for Marine Applications: Case Study of All-Electric Fishing Vessels

The increasing global warming problem has pushed the community to implement emission reduction measures in almost every segment of human life. Since the major source of anthropogenic Greenhouse Gases (GHGs) is fossil fuel combustion, in the shipping sector, these measures are oriented toward a reduction in tailpipe emissions, where the replacement of traditional internal combustion marine engines with zero-carbon technologies offers the ultimate emission reduction results. According to the International Maritime Organization (IMO) GHG strategy, vessels involved in international shipping must achieve a minimum 50% reduction in their GHG emissions by 2050. However, this requirement does not extend to fishing vessels, which are significant consumers of fossil fuels. This paper deals with the full electrification of two types of fishing vessels (purse seiners and trawlers), wherein different Lithium-ion Batteries (LiBs) are considered. To investigate their environmental footprint and profitability, Life-Cycle Assessments (LCAs) and Life-Cycle Cost Assessments (LCCAs) are performed. The comparison of all-electric fishing vessels with existing diesel-powered ships highlighted the Lithium Iron Phosphate (LFP) battery as the most suitable alternative powering option regarding environmental and economic criteria.

Carbon Sequestration Through Forestry: A Differential Equation Approach

Carbon sequestration through forestry represents a promising approach to partially counteract anthropogenic greenhouse gas emissions driving climate change. Tree growth naturally removes carbon dioxide from the atmosphere, storing it as biomass. Sustainably managed forests can effectively function as carbon sinks. However, determining optimal forestry policies involves balancing complex ecological dynamics with economic constraints. This study develops differential equation models quantitatively capturing forest growth, timber harvesting, and carbon sequestration dynamics. Logistic models are first adapted to simulate biomass accumulation of representative tree species. Lifecycle growth patterns spanning juvenile to mature phases are incorporated, along with climate effects. Biomass levels are proportionally related to carbon dioxide removal rates from the atmosphere. Deforestation impacts are analyzed by incorporating harvesting-induced biomass reductions. Sustainability constraints are implemented to ensure minimum viable tree densities across harvest rotations. Optimization techniques then identify management guidelines maximizing economic returns given ecological stability considerations. The goal is providing quantitative insights into rotation lengths, planting densities, and allowable cuts upholding both climate change mitigation and commercial demands. Findings can inform science-based forestry policies to leverage forests as sustainable natural carbon sinks.

Waste to Wealth: The power of food-waste anaerobic digestion integrated with lactic acid fermentation

Food waste (FW) costs the global economy $1 trillion annually and is associated with 8% of anthropogenic greenhouse gas emissions. Anaerobic digestion (AD) is an effective technology for recycling organic waste, including FW, for energy and nutrient recovery. Current major revenue streams for AD include the sale of biogas/power, gate fees, and digestate (fertiliser). However, subsidies provided by governments are a major profit driver for commercial facilities and are generally required for profitability, limiting its widespread adoption. Lactic acid (LA) is a high value intermediate of the AD process and literature evidence has indicated the recovery of LA can significantly boost the revenue generated from FW-AD. Moreover, FW fermentation naturally tends towards LA accumulation, promotion of LA producing bacteria, and inhibition of alternate competing microbes, making LA attractive for commercial production from FW. The integration of LA production and recovery into FW-AD could improve its economic performance and reduce the need for subsidy support, providing a platform for global adoption of the AD technology. However, challenges, such as 1) the low LA yield on FW, 2) seasonality of the FW composition, 3) unknown influence of LA recovery on downstream AD, and 4) impact of standard operational procedures for AD on upstream LA production, still exist making this focus area for future research. Even so, literature has shown the benefits of the LA-AD biorefinery, detailing improved process economics, increased FW utilisation, and elimination of subsidy support. Therefore, this review focuses on exploring the integrating LA production into AD by examining the current status of AD, LA integration strategies, challenges associated with LA production from FW, and identifies key challenges and considerations associated with downstream AD of fermented waste.

Redox potential is a robust indicator for decomposition processes in drained agricultural peat soils: A valuable tool in monitoring peatland wetting efforts

Peat decomposition driven by soil metabolic processes is responsible for approximately 2 % of global annual anthropogenic greenhouse gas emissions. A peat soil's redox potential (Eh) and pH reflect its biogeochemical state and are therefore linked to the rate of peat decomposition and greenhouse gas production. In this study, we aim to establish if continuous Eh measurements are an effective tool to monitor metabolic peat decomposition processes and thus to quantify the effects of peat wetting efforts. We applied continuous in-situ Eh measurements (>150 sensors 2020–2022) as a proxy for metabolic peat decomposition processes, which we validated under field conditions with extensive sampling of porewater chemistry (pH, NO3–, SO42−, Mn(II), Fe(II), S2− and CH4, >2000 samples) for five agricultural, drained, minerotrophic peatland sites in the Netherlands. These 5 sites consisted of plots with and without subsoil irrigation (SSI), where SSI aims to raise groundwater levels and thus wet the peat soil. We found that in-situ continuous Eh measurements closely reflected spatial and temporal heterogeneity in pore water chemistry. Therefore, we concluded that Eh is a robust proxy for peat decomposition processes. Building on this result, we used continuous Eh measurements to study the prevalence of specific metabolic processes from site-to-site in relation with groundwater level changes. We found that, while groundwater levels are an important driver for (an)aerobic conditions, groundwater levels do not explain the full dynamics and extent of (an)aerobic conditions. O2 intrusion was mostly limited to approximately 0.5 m depth at deep (>0.8 m) groundwater levels, likely due to air diffusion limitation. Higher and more constant groundwater levels year-round at SSI plots decreased oxygen intrusion and tended to deplete porewater Fe(II) and SO42−, which led to more reducing Eh and higher porewater CH4 concentrations. The depletion of electron acceptors and occurrence of methanogenesis differed from site to site. In summary, high-frequent Eh monitoring is found to be an effective tool to monitor metabolic peat decomposition processes and quantify the effects of peatlands wetting efforts. Therefore, this methodology is suitable to evaluate and further optimize peatland monitoring and preservation.