National Inventory Research Articles

Nitrous Oxide Emissions during Cultivation and Fallow Periods from Rice Paddy Soil under Urea Fertilization

Rice cultivation serves as a significant anthropogenic source of methane (CH4) and nitrous oxide (N2O). Although N2O emissions remain relatively small compared to CH4 emissions, they are remarkably affected by nitrogen-fertilized soil conditions during rice cultivation. While numerous studies have investigated nitrous oxide emissions in response to nitrogen fertilization, existing research assessing nitrous oxide emissions based on nitrogen fertilizer levels has often been limited to cultivation periods. Therefore, there is a need for comprehensive analyses covering the entire year, including the dry periods, to address nitrous oxide emissions as an important source throughout the entire agricultural cycle. In this case study, we investigated the characteristics of N2O emissions in a central region of South Korea, where a single rice-cropping cycle occurs annually over a span of three whole years, from May 2020 to May 2023. We investigated the impact of variations in temperature and soil moisture on N2O emissions during rice cultivation and fallow periods. In this context, we attempted to discover the complex dynamics of N2O emissions by comparing longer fallow periods with the rice cultivation periods and extended non-dry periods with irrigated periods. We discovered that the greater contribution of cumulative N2O emissions during the fallow period made a much greater contribution (up to approximately 90%) to the whole-year N2O emissions than those during the rice cultivation period. During the fallow period from rice harvest to rice planting in the following year, variations in N2O emissions were associated with high-flux events after rainy periods on dry soils. This highlights the considerable influence of soil moisture content and weather conditions on N2O emissions during the fallow period. This affects high emission events, which in turn significantly impact the cumulative emissions over the entire period. We underscore that assessing N2O emissions solely based on the rice cultivation period would underestimate annual emissions. To prevent underestimation of N2O emissions, periodic gas collection throughout a year covering both rice cultivation and fallow phases is required in alignment with the monitoring of different temperature and soil moisture conditions. We captured statistical differences in cumulative N2O emissions due to nitrogen fertilization treatments across the three years. However, no significant difference was observed in the three-year average emissions among the different (one, one-and-a-half, and double) nitrogen fertilization treatments, with the exception of the control treatment (no fertilization). Based on the findings, we recommend at least three whole-year evaluations to ensure the estimation accuracy of N2O emissions under different nitrogen fertilization conditions. The findings from this study could help prepare the further revision or refinement of N2O emission factors from rice cultivation in the national greenhouse gas inventories defined by the inter-governmental panel on climate change (IPCC).

Chemical Space Covered by Applicability Domains of Quantitative Structure-Property Relationships and Semiempirical Relationships in Chemical Assessments.

A significant number of chemicals registered in national and regional chemical inventories require assessments of their potential "hazard" concerns posed to humans and ecological receptors. This warrants knowledge of their partitioning and reactivity properties, which are often predicted by quantitative structure-property relationships (QSPRs) and other semiempirical relationships. It is imperative to evaluate the applicability domain (AD) of these tools to ensure their suitability for assessment purpose. Here, we investigate the extent to which the ADs of commonly used QSPRs and semiempirical relationships cover seven partitioning and reactivity properties of a chemical "space" comprising 81,000+ organic chemicals registered in regulatory and academic chemical inventories. Our findings show that around or more than half of the chemicals studied are covered by at least one of the commonly used QSPRs. The investigated QSPRs demonstrate adequate AD coverage for organochlorides and organobromines but limited AD coverage for chemicals containing fluorine and phosphorus. These QSPRs exhibit limited AD coverage for atmospheric reactivity, biodegradation, and octanol-air partitioning, particularly for ionizable organic chemicals compared to nonionizable ones, challenging assessments of environmental persistence, bioaccumulation capability, and long-range transport potential. We also find that a predictive tool's AD coverage of chemicals depends on how the AD is defined, for example, by the distance of a predicted chemical from the centroid of the training chemicals or by the presence or absence of structural features.

Greenhouse gas emissions and their trends over the last 3 decades across Africa

Abstract. A key goal of the Paris Agreement (PA) is to reach net-zero greenhouse gas (GHG) emissions by 2050 globally, which requires mitigation efforts from all countries. Africa's rapidly growing population and gross domestic product (GDP) make this continent important for GHG emission trends. In this paper, we study the emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) in Africa over 3 decades (1990–2018). We compare bottom-up (BU) approaches, including United Nations Convention Framework on Climate Change (UNFCCC) national inventories, FAO, PRIMAP-hist, process-based ecosystem models for CO2 fluxes in the land use, land use change and forestry (LULUCF) sector and global atmospheric inversions. For inversions, we applied different methods to separate anthropogenic CH4 emissions. The BU inventories show that, over the decade 2010–2018, fewer than 10 countries represented more than 75 % of African fossil CO2 emissions. With a mean of 1373 Mt CO2 yr−1, total African fossil CO2 emissions over 2010–2018 represent only 4 % of global fossil emissions. However, these emissions grew by +34 % from 1990–1999 to 2000–2009 and by +31 % from 2000–2009 to 2010–2018, which represents more than a doubling in 30 years. This growth rate is more than 2 times faster than the global growth rate of fossil CO2 emissions. The anthropogenic emissions of CH4 grew by 5 % from 1990–1999 to 2000–2009 and by 14.8 % from 2000–2009 to 2010–2018. The N2O emissions grew by 19.5 % from 1990–1999 to 2000–2009 and by 20.8 % from 2000–2009 to 2010–2018. When using the mean of the estimates from UNFCCC reports (including the land use sector) with corrections from outliers, Africa was a mean source of greenhouse gases of 262221863239 Mt CO2 eq. yr−1 from all BU estimates (the subscript and superscript indicate min–max range uncertainties) and of +263717615873 Mt CO2 eq. yr−1 from top-down (TD) methods during their overlap period from 2001 to 2017. Although the mean values are consistent, the range of TD estimates is larger than the one of the BU estimates, indicating that sparse atmospheric observations and transport model errors do not allow us to use inversions to reduce the uncertainty in BU estimates. The main source of uncertainty comes from CO2 fluxes in the LULUCF sector, for which the spread across inversions is larger than 50 %, especially in central Africa. Moreover, estimates from national UNFCCC communications differ widely depending on whether the large sinks in a few countries are corrected to more plausible values using more recent national sources following the methodology of Grassi et al. (2022). The medians of CH4 emissions from inversions based on satellite retrievals and surface station networks are consistent with each other within 2 % at the continental scale. The inversion ensemble also provides consistent estimates of anthropogenic CH4 emissions with BU inventories such as PRIMAP-hist. For N2O, inversions systematically show higher emissions than inventories, on average about 4.5 times more than PRIMAP-hist, either because natural N2O sources cannot be separated accurately from anthropogenic ones in inversions or because BU estimates ignore indirect emissions and underestimate emission factors. Future improvements can be expected thanks to a denser network of monitoring atmospheric concentrations. This study helps to introduce methods to enhance the scope of use of various published datasets and allows us to compute budgets thanks to recombinations of those data products. Our results allow us to understand uncertainty and trends in emissions and removals in a region of the world where few observations exist and where most inventories are based on default IPCC guideline values. The results can therefore serve as a support tool for the Global Stocktake (GST) of the Paris Agreement. The referenced datasets related to the figures are available at https://doi.org/10.5281/zenodo.7347077 (Mostefaoui et al., 2022).

Blue carbon accounting to monitor coastal blue carbon ecosystems

In the global context, countries must reduce carbon dioxide emissions to "net zero" by 2050 to limit global warming to 1.5 °C above pre-industrial levels. China's Nationally Determined Contributions (NDCs) are to peak carbon dioxide emissions by 2030 and achieve the carbon neutrality target by 2060. To monitor the achievements of the NDCs, establishing an annual-based accounting mechanism is necessary to record the carbon stocks in China, especially for Blue Carbon. The paper aims to present China's first national-scale systematic Blue Carbon accounting for mangroves, salt marshes, and seagrasses, covering the accounting subjects of physical and monetary assets, as well as relevant indicators for investors. It focuses on the design of the accounting method and system, the selection of data categories applied to this system, and the application of China's Blue Carbon accounting based on this accounting system. Taking Blue Carbon accounting as a starting point, this paper analyses the restoration prospects of these ecosystems and their application potential for NDCs in China compared with the terrestrial ecosystems. The results indicate that mangroves are the most cost-effective type of ecosystem, even compared to terrestrial forests. Thus, the paper provides policymakers with a new perspective on the decision-making of carbon sequestration relevant decisions, aiming to promote the monitoring, restoration, and expansion of China's coastal blue carbon ecosystem through the establishment of a sound Blue Carbon accounting system, and to help achieve the carbon neutrality goal in China's NDCs through regular and systematic monitoring of its national Blue Carbon inventories.

First national inventory of high-elevation mass movements in the Italian Alps

Climate change in the European Alps, in particular in the high-elevation environments, is causing an increase in mass movements and hazards. To learn more about relationships between mass movements and climate drivers, the location of the starting zone and date of the instability events need to be known. Nevertheless, not all existing inventories of mass movements are suitable for the purpose. For these reasons, we have implemented a specific inventory of mass movements which occurred in the Italian sector of the Alps at an elevation >1500 m.Currently, the inventory contains information relating to 772 mass movements. The most frequent types of processes documented are rockfall and debris/mud flows, with 279 and 191 cases respectively. The highest number of events occurred in 2022 (71 events), and an evident trend towards an increase over the years and during summer was found.This inventory is an excellent support tool for many activities that take place in and for the mountains, its consultation, both online and offline, makes the inventory suitable for use with different types of devices and can be used not only as a consultation tool on mass movements occurred in the past, but also to insert new events. This use can be particularly suitable for monitoring activities, managed by civil protection structures, municipalities, natural parks, environmental agencies, researchers, freelancers and so on.

High emissions or carbon neutral? Inclusion of “anthropogenic” forest sinks leads to underreporting of forestry emissions

Recent research has shown forest-related emissions reported in national greenhouse gas inventories are much lower than global estimates from models summarized in Intergovernmental Panel on Climate Change reports. A substantial part of this discrepancy could be explained by conceptual differences in what is counted as part of the anthropogenic forest carbon sink and the way countries report on their forest harvesting sectors. With Canada as a case study, we used published National Inventory Report and Common Reporting Format tables to isolate emissions and removals directly associated with forestry from those associated with forests more broadly. Forestry-related factors that affect CO2 emissions and removals include tree harvesting, post-harvest forest regeneration and growth, and carbon storage in long-lived harvested wood products. We found that between 2005 and 2021, forestry in Canada represented a net source of carbon (annual mean = 90.8 Mt. CO2e), and that total area logged was a significant predictor of net forestry emissions. In contrast, Canada’s NIR reported a small net carbon sink during the same time period (annual mean = −4.7 Mt. CO2e). We show this discrepancy can be explained by Canada’s GHG reporting approach that claims GHG emissions from wildfires are natural, but GHG removals from forests at the age of commercial maturity, despite being primarily natural disturbance origin, are anthropogenic. This reporting approach may lead to climate mitigation policies that are ineffectual or detrimental to reducing net carbon in the global atmosphere.

Soil organic carbon stocks in native forest of Argentina: a useful surrogate for mitigation and conservation planning under climate variability

BackgroundThe nationally determined contribution (NDC) presented by Argentina within the framework of the Paris Agreement is aligned with the decisions made in the context of the United Nations Framework Convention on Climate Change (UNFCCC) on the reduction of emissions derived from deforestation and forest degradation, as well as forest carbon conservation (REDD+). In addition, climate change constitutes one of the greatest threats to forest biodiversity and ecosystem services. However, the soil organic carbon (SOC) stocks of native forests have not been incorporated into the Forest Reference Emission Levels calculations and for conservation planning under climate variability due to a lack of information. The objectives of this study were: (i) to model SOC stocks to 30 cm of native forests at a national scale using climatic, topographic and vegetation as predictor variables, and (ii) to relate SOC stocks with spatial–temporal remotely sensed indices to determine biodiversity conservation concerns due to threats from high inter-annual climate variability.MethodsWe used 1040 forest soil samples (0–30 cm) to generate spatially explicit estimates of SOC native forests in Argentina at a spatial resolution of approximately 200 m. We selected 52 potential predictive environmental covariates, which represent key factors for the spatial distribution of SOC. All covariate maps were uploaded to the Google Earth Engine cloud-based computing platform for subsequent modelling. To determine the biodiversity threats from high inter-annual climate variability, we employed the spatial–temporal satellite-derived indices based on Enhanced Vegetation Index (EVI) and land surface temperature (LST) images from Landsat imagery.ResultsSOC model (0–30 cm depth) prediction accounted for 69% of the variation of this soil property across the whole native forest coverage in Argentina. Total mean SOC stock reached 2.81 Pg C (2.71–2.84 Pg C with a probability of 90%) for a total area of 460,790 km2, where Chaco forests represented 58.4% of total SOC stored, followed by Andean Patagonian forests (16.7%) and Espinal forests (10.0%). SOC stock model was fitted as a function of regional climate, which greatly influenced forest ecosystems, including precipitation (annual mean precipitation and precipitation of warmest quarter) and temperature (day land surface temperature, seasonality, maximum temperature of warmest month, month of maximum temperature, night land surface temperature, and monthly minimum temperature). Biodiversity was influenced by the SOC levels and the forest regions.ConclusionsIn the framework of the Kyoto Protocol and REDD+, information derived in the present work from the estimate of SOC in native forests can be incorporated into the annual National Inventory Report of Argentina to assist forest management proposals. It also gives insight into how native forests can be more resilient to reduce the impact of biodiversity loss.

A comparison of Tier 1, 2, and 3 methods for quantifying nitrous oxide emissions from soils amended with biosolids

Municipal biosolids are a nitrogen (N)-rich agricultural fertilizer which may emit nitrous oxide (N2O) after rainfall events. Due to sparse empirical data, there is a lack of biosolids-specific N2O emission factors to determine how land-applied biosolids contribute to the national greenhouse gas inventory. This study estimated N2O emissions from biosolids-amended land in Canada using Tier 1, Tier 2 (Canadian), and Tier 3 (Denitrification and Decomposition model [DNDC]) methodologies recommended by the Intergovernmental Panel on Climate Change (IPCC). Field data was from replicated plots at 8 site-years between 2017 and 2019 in the provinces of Quebec, Nova Scotia and Alberta, Canada, representing three distinct ecozones. Municipal biosolids were the major N source for the crop, applied as mesophilic anaerobically digested biosolids, composted biosolids, or alkaline-stabilized biosolids alone or combined with an equal amount of urea-N fertilizer to meet the crop N requirements. Fluxes of N2O were measured during the growing season with manual chambers and compared to N2O emissions estimated using the IPCC methods. In all site-years, the mean emission of N2O in the growing season was greater with digested biosolids than other biosolids sources or urea fertilizer alone. The emissions of N2O in the growing season were similar with composted or alkaline-stabilized biosolids, and no greater than the unfertilized control. The best estimates of N2O emissions, relative to measured values, were with the Tier 3 > adapted Tier 2 with biosolids-specific correction factors > standard Tier 2 = Tier 1 methods of the IPCC, according to the root mean square error statistic. The Tier 3 IPCC method was the best estimator of N2O emissions in the Canadian ecozones evaluated in this study. These results will be used to improve methods for estimating N2O emissions from agricultural soils amended with biosolids and to generate more accurate GHG inventories.

Methane output across life stages in sheep, how it differs from lambs to adult ewes using portable accumulation chambers.

Methane (CH4) produced from enteric fermentation is a potent greenhouse gas produced by ruminant animals. Multiple measurements are required across life stages to develop an understanding of how CH4 output changes throughout the animal's lifetime. The objectives of the current study were to estimate CH4 output across life stages in sheep and to investigate the relationship between CH4 output and dry matter (DM) intake (DMI). Data were generated on a total of 266 female Suffolk and Texel animals. Methane and carbon dioxide (CO2) output, estimated using portable accumulation chambers, and DMI, estimated using the n-alkane technique outdoors and using individual penning indoors, were quantified across the animal's life stage; as lambs (<12 mo), nulliparous hoggets (12 to 24 mo) and ewes (primiparous or greater; > 24 mo). Ewes were further classified as pregnant, lactating, and dry (non-pregnant and non-lactating). Multiple measurements were taken within and across the life stages of the same animals. A linear mixed model was used to determine if CH4 and CO2 output differed across life stages and using a separate linear mixed model the factors associated with CH4 output within each life stage were also investigated. Methane, CO2 output, and DMI differed by life stage (P < 0.05), with lactating ewes producing the greatest amount of CH4 (25.99 g CH4/d) and CO2 (1711.6 g CO2/d), while also having the highest DMI (2.18 kg DM/d). Methane output differed by live-weight of the animals across all life stages (P < 0.001). As ewe body condition score increased CH4 output declined (P < 0.05). Correlations between CH4 output measured across life stages ranged from 0.26 (SE 0.08; lambs and lactating ewes) to 0.59 (SE 0.06; hoggets and pregnant ewes), while correlations between CO2 output measured across life stages ranged from 0.12 (SE 0.06; lambs and hoggets) to 0.65 (SE 0.06; hoggets and lactating ewes). DMI was moderately correlated with CH4 (0.44; SE 0.04) and CO2 output (0.59; SE 0.03). Results from this study provide estimates of CH4 output across life stages in a pasture-based sheep production system and offer valuable information for the national inventory and the marginal abatement cost curve on the optimum time to target mitigation strategies.

Effect of animal and diet parameters on methane emissions for pasture-fed cattle

Context Estimates of enteric methane emissions for agricultural emissions trading schemes or national inventories can be a simple single emission factor, but the accuracy of the predictions may be affected by other diet- and animal-related parameters. Aims Determine the animal and dietary factors that affect methane yield (methane per unit of dry-matter intake) in pasture-fed cattle. Methods Methane emissions and dry-matter intake (DMI) of cattle of various ages and in different physiological stages that were fed different-quality fresh-cut pastures were quantified in respiration chambers. The animals used in the various trials were post-weaned calves, heifers and steers of various ages and some older lactating dairy cows. Diet quality of the pastures offered was determined using near-infrared spectroscopy. Mixed linear modelling was used to assess the impacts of animal and diet parameters on methane emissions. Key results Our results indicated that diet quality does not have a major effect on methane production. For individual composition parameters, the correlation (Pearson’s r) with methane production was less than 0.25. Only estimates of metabolisable energy (ME) content showed a higher correlation (r = 0.43). However, despite this correlation, ME, like the other diet composition variables, was not a useful parameter to predict daily methane production, as indicated by the Akaike’s information criterion (AICc). Including data on concentrate supplementation at a level of 30% of the DMI did not improve the prediction of methane production. The resulting model indicated that besides DMI, bodyweight, physiological state and sex significantly affected methane production. Methane production was mostly explained by DMI. This was illustrated by the observation that when methane production is expressed per kilogram DMI (methane yield, g kg−1 DMI) none of the diet or animal related characteristics showed a significant correlation with methane yield. The model performed well, but needs to be validated with an independent dataset. Conclusions For ryegrass-based pasture dry-matter intake is the single most important factor that affects methane yield, while pasture composition has no effect and animal-related factors such as physiological stage and age only appear to modulate methane emissions. Implications Our findings have implications for methane accounting and national inventories in pastoral agricultural systems, which account for the majority of ruminant production systems.

ІНВЕНТАРИЗАЦІЯ ЛІСІВ: ОБЛІКОВО-ПРАКТИЧНИЙ АСПЕКТ

The article examines the process of forest inventory in Ukraine as a key element to ensure effective management of forest resources. The inventory is a system of regular sample surveys that allows you to obtain statistically based information on quantitative and qualitative indicators of the state and dynamics of forests, their resource potential, as well as for the needs of state management, strategic planning, environmental monitoring and international reporting. In Ukraine, experimental production work on the preparation and implementation of the national forest inventory began in 2006. The National Forest Inventory Center of the "Ukrderzhlisproekt" VO was identified as the responsible organization, and state budget funding was provided for the national forest inventory, which was to be implemented over a 5-year cycle and to develop technical documentation regulating the technological aspects of the national forest inventory work. It was established that the inventory procedures involve a reconnaissance survey of crops, an assessment of their condition, the transfer of forest crops to forested land and the preparation of primary documents. The technical documentation compiled by forestry enterprises and their subordinate forestry companies mainly contains natural and qualitative indicators. An important component is data quality control, which includes three stages: data entry control, data collection control, and reliability control. The results of the inventory are used to evaluate the effectiveness of forest protection and regeneration measures, as well as to monitor negative impacts. The importance of integrating the components of the national inventory and forest monitoring, improving the inventory methodology to optimize the use of forest territories and the development of protective afforestation is determined. The conclusions of the article confirm that the forest inventory is the basis for the development of effective plans for forest use, protection and restoration of forests, providing accurate information for sound management of forest resources.

A Greenhouse Gas Budget for Mexico During 2000–2019

AbstractApplication of the best available science to improve quantification of greenhouse gas (GHG) emissions at regional and national scales is key to climate action. Here, we present a two‐decade (2000–2019) GHG (CO2, CH4, and N2O) budget for Mexico derived from multiple products. Data from the National GHG Inventory, global observations, and the scientific literature were compared to identify knowledge gaps on GHG flux dynamics and discrepancies among estimates. Total mean annual GHG emissions were estimated at 695–910 TgCO2‐eq year−1 over these two decades, with 70% of the emissions attributable to CO2, 23% to CH4, and 5% to N2O (2% to other gases). When divided by sectors, we found agreement across emission estimates from various sources for fossil fuels, cattle, agriculture, and waste for all GHGs. However, considerable discrepancies were identified in the fluxes from terrestrial ecosystems. The disagreement was particularly large for the land CO2 sink, where net biome production estimations from the national inventory were double those from any other observational product. Extensive knowledge gaps exist, mainly related to aquatic systems (e.g., outgassing in rivers) and the lateral fluxes (e.g., wood trade). In addition, limited information is available on CH4 emissions from wetlands and soil CH4 consumption. We expect these results to guide future research to reduce estimation uncertainties and fill the information gaps across Mexico.

Mitigating greenhouse gases emissions in processing fossil carbon containing industrial waste

The article assesses the Best Available Techniques for the methods of reduction of greenhouse gases (GHG) emissions in the waste treatment sector, that includes oil, plastic and rubber materials. The certain GHG emissions sources were shown and an attention is paid to the economic feasibility of specified methods in different places. It was shown, that for GHG mitigation policy, waste-management should be complied with the product life-cycle optimization, while recycling is considered as initially the best available method. The article is based on methods of scaling and statistical generalization. The data was obtained from official resources, including Reference Documents on the Best Available Techniques, National Inventory of GHG and from scientific publications. It was intended with full agreement, that resource efficiency enhancement relevantly should be in top priority of environmental and economic regulation.

The Bees of Costa Rica and its Representation in two National Collections

For decades, scientific studies related to wildlife have been little reviewed for national inventories, with birds and mammals being the only faunal groups that have official lists and specific numbers. Although it is true that species of insects and other invertebrates appear constantly, this is not an excuse for not having official lists of species reported for science. In this review, a total of 507 were found for Costa Rica, 7 of Andrenidae, 299 of Apidae, 30 of Colletidae, 106 of Halictidae and 65 of Megachilidae. Any other species outside of this list that has been found, collected in Costa Rican territory and is not on this list is a new report.

Evaluation of the Larvicidal Activity of Marigold (Tagetes erecta) Flower Extracts in Mixed Cultured Mosquitoes

For decades, scientific studies related to wildlife have been little reviewed for national inventories, with birds and mammals being the only faunal groups that have official lists and specific numbers. Although it is true that species of insects and other invertebrates appear constantly, this is not an excuse for not having official lists of species reported for science. In this review, a total of 507 were found for Costa Rica, 7 of Andrenidae, 299 of Apidae, 30 of Colletidae, 106 of Halictidae and 65 of Megachilidae. Any other species outside of this list that has been found, collected in Costa Rican territory and is not on this list is a new report.

A Sensitivity Study of a Bayesian Inversion Model Used to Estimate Emissions of Synthetic Greenhouse Gases at the European Scale

To address and mitigate the environmental impacts of synthetic greenhouse gases it’s crucial to quantify their emissions to the atmosphere on different spatial scales. Atmospheric Inverse modelling is becoming a widely used method to provide observation-based estimates of greenhouse gas emissions with the potential to provide an independent verification tool for national emission inventories. A sensitivity study of the FLEXINVERT+ model for the optimisation of the spatial and temporal emissions of long-lived greenhouse gases at the regional-to-country scale is presented. A test compound HFC-134a, the most widely used refrigerant in mobile air conditioning systems, has been used to evaluate its European emissions in 2011 to be compared with a previous study. Sensitivity tests on driving factors like—observation selection criteria, prior data, background mixing ratios, and station selection—assessed the model’s performance in replicating measurements, reducing uncertainties, and estimating country-specific emissions. Across all experiments, good prior (0.5–0.8) and improved posterior (0.6–0.9) correlations were achieved, emphasizing the reduced sensitivity of the inversion setup to different a priori information and the determining role of observations in constraining the emissions.The posterior results were found to be very sensitive to background mixing ratios, with even slight increases in the baseline leading to significant decrease of emissions.

Greenhouse Gas Emissions Efficiency in Polish Agriculture

Analysis of the efficiency of greenhouse gas emissions in agriculture is an important part of agricultural and environmental economics research. The theme is extremely important due to the deepening problem of climate change and the simultaneous need to ensure food security. However, counteracting climate change cannot be achieved at the expense of reducing agricultural productivity. Due to the need to study the economic-environmental relationship in agriculture, the main purpose of this study was to assess the changes in the level and structure of agricultural greenhouse gas emissions and to examine the changes in efficiency of agricultural greenhouse gas emissions. The authors also estimated the relative efficiency of emissions, which allowed for comparing the efficiency of emissions between agriculture and other sectors of the national economy. Analyzing the changes in agricultural emissions efficiency, as well as changes in relative efficiency of emissions, is an indirect way of assessing whether the ongoing trends are consistent with the sustainable development concept and if the country is effective enough in mitigating climate change in relation to its economic performance. The research conducted showed that agriculture has a significant share of greenhouse gas emissions among all sectors of the Polish economy. However, greenhouse gas emissions from agriculture decreased by a total of 23.5% in the years studied. The most significant changes occurred in the context of greenhouse gas emissions from intestinal fermentation. The research also shows that the efficiency of emissions from agriculture more than doubled in the years examined. However, it decreased compared to other sectors of the economy in the country. This study was based on emissions data retrieved from National Inventory Reports prepared by the National Center for Emissions Management and on the Agricultural Statistical Yearbooks of the Central Statistical Office. This paper also proposes some examples of measures that could be taken to reduce agricultural emissions. Some of them include reducing food losses, sustainable use of fertilizers, increasing energy efficiency, and greater use of renewable energy.

Using Atmospheric Inverse Modelling of Methane Budgets with Copernicus Land Water and Wetness Data to Detect Land Use-Related Emissions

Climate change mitigation requires countries to report their annual greenhouse gas (GHG) emissions and sinks, including those from land use, land use change, and forestry (LULUCF). In Finland, the LULUCF sector plays a crucial role in achieving net-zero GHG emissions, as the sector is expected to be a net sink. However, accurate estimates of LULUCF-related GHG emissions, such as methane (CH4), remain challenging. We estimated LULUCF-related CH4 emissions in Finland in 2013–2020 by combining national land cover and remote-sensed surface wetness data with CH4 emissions estimated by an inversion model. According to our inversion model, most of Finland’s CH4 emissions were attributed to natural sources such as open pristine peatlands. However, our research indicated that forests with thin tree cover surrounding open peatlands may also be a significant source of CH4. Unlike open pristine peatlands and pristine peatlands with thin tree cover, surrounding transient forests are included in the Finnish GHG inventory if they meet the criteria used for forest land. The current Finnish national GHG inventory may therefore underestimate CH4 emissions from forested organic soils surrounding open peatlands, although more precise methods and data are needed to verify this. Given the potential impact on net GHG emissions, CH4 emissions from transitional forests on organic soils should be further investigated. Furthermore, the results demonstrate the potential of combining atmospheric inversion modelling of GHGs with diverse data sources and highlight the need for methods to more easily combine atmospheric inversions with national GHG inventories.

Measurements of methane and nitrous oxide in human breath and the development of UK scale emissions

Exhaled human breath can contain small, elevated concentrations of methane (CH4) and nitrous oxide (N2O), both of which contribute to global warming. These emissions from humans are not well understood and are rarely quantified in global greenhouse gas inventories. This study investigated emissions of CH4 and N2O in human breath from 104 volunteers in the UK population, to better understand what drives these emissions and to quantify national-scale estimates. A total of 328 breath samples were collected, and age, sex, dietary preference, and smoking habits were recorded for every participant. The percentage of methane producers (MPs) identified in this study was 31%. The percentage of MPs was higher in older age groups with 25% of people under the age of 30 classified as MPs compared to 40% in the 30+ age group. Females (38%) were more likely to be MPs than males (25%), though overall concentrations emitted from both MP groups were similar. All participants were found to emit N2O in breath, though none of the factors investigated explained the differences in emissions. Dietary preference was not found to affect CH4 or N2O emissions from breath in this study. We estimate a total emission of 1.04 (0.86–1.40) Gg of CH4 and 0.069 (0.066–0.072) Gg of N2O in human breath annually in the UK, the equivalent of 53.9 (47.8–60.0) Gg of CO2. In terms of magnitude, these values are approximately 0.05% and 0.1% of the total emissions of CH4 and N2O reported in the UK national greenhouse gas inventories.

Missing methane emissions from urban sewer networks

Methane emissions from sewer networks are an important source of anthropogenic greenhouse gases (GHGs) but are not currently reflected in the national GHG inventory. We found significant CH4 emissions of approximately 573 [395–831] CH4 t y−1 from sewer networks in the old residential and commercial areas of Seoul (Gwanak district) using an electric vehicle-based atmospheric GHG monitoring platform. The majority of ethane-to-methane ratios (<0.005) from the observations further suggest that distinctive CH4 emissions from sewer networks are likely related to microbial activity rather than to simple natural gas leakage. Because over 90% of the sewer network in Seoul is a gravity drain type of combined sewer network, where both wastewater and stormwater flow through the same pipes, resulting in the generation of methane emissions from the microbial activity and the manholes and rain gutters, which are directly connected to the combined sewer networks are major sources of atmospheric methane emissions. This study suggests that appropriate treatment of sewer networks can mitigate missing methane emissions in cities that were not originally included in GHG inventory of South Korea.