Estimate Greenhouse Gas Emissions Research Articles

Estimation of Greenhouse Gas Emissions from Remote Sensing and Field Data in the Wari-Maro Forest Reserve and Its Periphery (Benin)

Land use affects the structure and functioning of forest ecosystems, thus affecting greenhouse gas fluxes. Greenhouse gas emissions were assessed in the Wari-Maro Forest Reserve (FCWM) and its periphery between 2005 and 2020. To achieve this, the methodological approach applied is based on the use of activity data (AD) from 2005 and 2020 land use and land cover maps derived from satellite images and emission factors (EF) from forest inventory data conducted in 2005 and 2020. The analysis of the results shows that the peripheral zone has the highest emission factor evaluated at 87.22 t.eq-CO2 /ha/year against 47.37 t.eq-CO2/ha/year recorded in the Forest Reserve. The total CO2 emissions due to deforestation in the Forest Reserve are 5106.78 t.eq-CO2/ha/year against a global emission of 65402.23 t.eq-CO2/ha/year for the periphery. This high emission of the peripheral area is due to the result of the high anthropogenic pressure in this area. Those due to degradation are 2880.53 t.eq-CO2/ha/year in the Forest Reserve against 1049.67 t.eq-CO2/ha/year in the periphery. The amount of CH4 and N2O increases progressively from the Forest Reserve (319.49 t.eq-CO2/ha/year and 26.80 t.eq-CO2/ha/year) to the periphery (2658.08 t.eq-CO2ha/year and 222.99 t.eq-CO2/ha/year) probably due to the extent of agricultural and livestock production activities in this area.

Comparative evaluation of data requirements and level of decision support provided by decision support tools for reducing livestock-related greenhouse gas emissions

Quantifying and mitigating the environmental impact of livestock sector is of global interest as it has an important role in the global climate change. Although accurate estimation of greenhouse gas (GHG) emissions from livestock production systems is complex, there are several available tools to assist with the emissions estimation. These tools differ in many ways, such as in terms of accessibility, methodology, assumptions, and scope. Such tools are important because they help farmers know where their farms and livestock production processes stand in terms of sustainability. This information also helps farmers in devising and implementing mitigation strategies. In this paper, we review and assess popular and available open-access decision-support tools (DSTs) for estimating farm-level GHG emissions from livestock production systems. We noted that most of the available tools are built based on the Intergovernmental Panel on Climate Change (IPCC) Tier 2 guidelines, and relevant region- and product-specific assumptions. Only a very few tools, such as GLEAM and CFT, are suitable for all geographic locations. Apart from GHG emissions estimation, some tools, such as AgRECalc, provide static general recommendations to support decision-making in GHG emissions mitigation, and other tools, such as Holos, include scenario analysis. We also observed that most of the tools are lacking concrete recommendation provisions to assist in developing mitigation strategies. Such recommendation engines can be of great help to farmers in identifying potential focus areas to prioritize while developing mitigation strategies. We, furthermore, present a high-level framework of a decision support system that addresses the discovered gaps and can be adopted for sustainable livestock farming.

Methods applied to the estimation of Greenhouse Gases in hydroelectric reservoirs

Introduction/objective: Emissions of naturally occurring greenhouse gases (GHG) have increased due to anthropogenic actions, threatening the planet with environmental imbalance. Reservoirs for storing water, which is later used to drive the turbines of hydroelectric power plants, accumulate sediments generating GHGs. This paper analyzes the methods used to estimate GHG emissions in reservoirs, classifying the scientific publications found in the ScienceDirect and Google Scholar search engines. Methodology: The analytical method uses a Boolean expression to collect information in the indicated search engines and extract the relevant literature considering factors such as water temperature, geographic location, type and surface area of the reservoir, type of gas and technology, attributing a relevance value to each characteristic to elaborate a matrix of results. Results: The results show that more than 50% are based on GHG estimates and the rest on direct measurements in the reservoirs. In addition, the contribution of artificial intelligence as an estimation technique is less than 6 %. Conclusions: Finally, the world regions where studies are conducted are proportionally distributed and the analysis of scientific literature indicates versatility in GHG estimation methods in hydropower reservoirs.

Spatially resolved inventory and emissions modelling for pea and lentil life cycle assessment

Pulses are an increasingly popular source of plant-based protein among food manufacturers, food service providers, and retailers globally. Canada is currently a global leader in pulse production and exports. Given the large geographical scope of their production within Canada, pulses are produced under a variety of conditions reflecting differences in soil, climate, and characteristic management practices. In order to understand the influence of regional factors on the impacts of pulse production, high-resolution, regionalized life cycle assessments (LCAs) were carried out using both region-specific input/output data and emissions modelling. Six hundred Canadian pea and lentil farmers were surveyed to collect detailed data regarding characteristic farm inputs, yields and management practices at the reconciliation unit level of spatial resolution, which reconciles Canadian provincial borders with terrestrial ecozones based on soil and climate factors. The process-based model DeNitrification DeComposition (DNDC) was used to estimate regionally specific N emissions. This was compared to emissions estimates generated using the IPCC Tier II empirical models, which are typically used to estimate greenhouse gas emissions for national inventory reports. The main contributors to the life cycle environmental impacts of pea and lentil production were fertilizer and fuel use. This was consistent across all levels of regional aggregation including the total Prairie province average, as well as ecozone and provincial levels. There was variation in the magnitude of the impacts in each region assessed, which was mainly attributable to differences in yield, as well as reported fertilizer application rates and related emissions and fuel use for field operations. Significant differences were found in N emissions estimates between the DNDC and IPCC models, the magnitude of which varied by region and by the N emissions model employed. DNDC was found to provide better-resolved emissions estimates at the ecozone scale. This demonstrates the relevance of regionally specific emissions modelling since local soil and climate conditions had a large impact on the emissions estimates. In addition, the levels of uncertainty in the models were generally higher at the provincial and prairie province scale than at the ecozone scale. This may indicate that farming practices and associated resource/environmental impacts are more strongly influenced by soil and climate conditions than by provincial standards and guidelines. These results underscore the necessity of spatially resolved data collection and modelling to provide accurate estimates of the environmental impacts of crop production and to support more sustainable management of arable crop production.

Estimating Greenhouse Gas Emissions from Road Construction by Considering the Regional Differences in Carbon Emission Factors of Cement: The Case of China

Rapid road construction and expansion in China resulted in massive GHG emissions. The carbon emission factors of raw materials, particularly cement, have a significant influence on the calculation of GHG emissions from road construction. This study estimates GHG emissions from road construction by taking into account regional differences in cement carbon emission factors. The results indicate that (1) total GHG emissions from road construction have a “U” shape from 2009 to 2019, with the highest level being 437 million t CO2e 2009 and the lowest level being 184 million t CO2e in 2017; (2) Class-Ⅳ roads account for roughly 80% of total GHG emissions from road construction; and (3) GHG emissions from road construction are shifting from east to west regions. This is the first paper to calculate GHG emissions from road construction by taking into account both road type and cement carbon emission factors. The findings of this study could provide references for transportation agencies to better understand the impacts of road construction to climate change and improve policymaking, especially for the development of road construction technologies and raw material production technologies.

Estimation of nitrous oxide emissions from rice paddy fields using the DNDC model: a case study of South Korea.

The Denitrification-Decomposition (DNDC)-Rice is a mechanistic model which is widely used for the simulation and estimation of greenhouse gas emissions [nitrous oxide (N2O)] from soils under rice cultivation. N2O emissions from paddy fields in South Korea are of high importance for their cumulative effect on climate. The objective of this study was to estimate the N2O emissions and biogeochemical factors involved in N2O emissions such as ammonium (NH4+) and nitrate (NO3-) using the DNDC model in the rice-growing regions of South Korea. N2O emission was observed at every application of fertilizer and during end-season drainage at different rice-growing regions in South Korea. Maximum NH4+ and NO3- were observed at 0-10 cm depth of soil. NH4+ increased at each fertilizer application and no change in NO3- was observed during flooding. NH4+ decreased and NO3- increased simultaneously at end-season drainage. Minimum and maximum cumulative N2O emissions were observed at Chungcheongbuk-do and Jeju-do regions of South Korea, respectively. The simulated average cumulative N2O emission in rice paddies of South Korea was 1.37 kg N2O-N ha-1 season-1. This study will help in calculating the total nitrogen emissions from agriculture land of South Korea and the World.

The impact of changing toward higher welfare broiler production systems on greenhouse gas emissions: a Dutch case study using life cycle assessment

In the Netherlands, the Dutch Retail Broiler (DRB) and Better Life one Star (BLS) production systems have been introduced with the aim to improve broiler welfare. Simultaneously, retailers set targets for reduction of greenhouse gas (GHG) emissions in the whole broiler production chain. The GHG emissions of DRB and BLS may differ from conventional systems because of differences in slaughter age, feed intake, and diet composition. The aim of this study was to estimate GHG emissions of the conventional, DRB, and BLS production systems. A deterministic, spreadsheet based model was developed that included the breeder, hatchery, and broiler farm stages. First, the model calculates feed intake of different diets and energy use, based on performance objectives and literature. Selection of feed ingredients for the different types of diets was based on least cost formulation with nutritional constraints for each diet. Second, GHG emissions were estimated from cradle to broiler farm gate for processes along the broiler production chain by using life cycle assessment, and expressed as kg CO2-equivalents per kg live weight (kg CO2-eq/kg LW). Results showed that BLS (3.55 kg CO2-eq/kg LW) had lower GHG emissions compared to conventional (3.65 kg CO2-eq/kg LW) and DRB (3.98 kg CO2-eq/kg LW) at the broiler farm gate. Emissions from land use change (LUC) from feed production, mainly from soybean products, had highest impact on total GHG emissions (>50%) for the systems and these soybean products had the lowest inclusion in the diets of the BLS production system. Sensitivity analyses showed that variation in slaughter weight and feed intake could result in overlap of GHG emissions between systems. When soybean products were sourced from a country with low LUC emissions, conventional (1.37 kg CO2-eq/ kg LW) had the lowest GHG emissions and BLS (1.79 kg CO2-eq/kg LW) the highest. This study showed that origin of and including or excluding LUC emissions from soybean production results in different conclusions for achieving the GHG emissions reduction targets set by retailers.

Thermophilic biological fluidized bed reactor in sludge line reduces greenhouse gas emissions in wastewater treatment system

Greenhouse gas (GHG) emissions represent one of the main drawbacks of wastewater (WW) treatment. However, results of a detailed estimation of the emissions can be a valid tool to define optimal solutions for minimizing impact of WW treatment system on the environment. Thermophilic biological fluidized bed reactor (TBFBR) has been recently proposed as an alternative solution for biological sludge minimization in wastewater treatment plant (WWTPs). In this work, 5 diverse scenarios of sludge line composition were studied and combined with 5 diverse sludge disposal options. GHG emissions in 25 combinations were fully investigated to define optimal sludge treatment and disposal option. Results suggested that TBFBR help to reduce net emitted GHGs with respect to scenario with conventional stabilization treatment in sludge line (anaerobic digestion) (−32.3 ± 3.55 %) thanks to (i) the reuse in water line of the aqueous residue of TBFBR as alternative carbon source, (ii) the significant minimization of sludge production, and (iii) the contained impact of gross GHG emissions due to the energy consumption of this process. The strong minimization of sludge also led to a decisive reduction in GHG emissions in the subsequent phases of transport, additional treatments, and final disposal making the choice of the disposal option indifferent on the overall GHG emission estimation. Moreover, the coupling of processes for the simultaneous and preventive maximization of energy recovery (TCH, and AnaD) before sludge minimization in TBFBR determined a limited reduction of GHG emission compared to scenario with TBFBR alone (−3.71 ± 1.47 %).

Assessment of Struvite as an Alternative Sources of Fertilizer-Phosphorus for Flood-Irrigated Rice

Phosphorus (P) recovery from wastewaters as struvite (MgNH4PO4·6H2O) may be a viable alternative fertilizer-P source for agriculture. The objective of this study was to evaluate the economic and environmental implications of struvite as a fertilizer-P source for flood-irrigated rice (Oryza sativa) relative to other commonly used commercially available fertilizer-P sources. A field study was conducted in 2019 and 2020 to evaluate the effects of wastewater-recovered struvite (chemically precipitated struvite (CPST) and electrochemically precipitated struvite (ECST)) on rice yield response in a P-deficient, silt–loam soil in eastern Arkansas relative to triple superphosphate, monoammonium and diammonium phosphate, and rock phosphate. A life cycle assessment methodology was used to estimate the global warming potentials associated with rice produced with the various fertilizer-P sources. Life cycle inventory data were based on the field trials conducted with and without struvite application for both years. A partial budget analysis showed that, across both years, net revenues for ECST and CPST were 1.4 to 26.8% lower than those associated with the other fertilizer-P sources. The estimated greenhouse gas emissions varied between 0.58 and 0.70 kg CO2 eq kg rice−1 from CPST and between 0.56 and 0.81 kg CO2 eq kg rice−1 from ECST in 2019 and 2020, respectively, which were numerically similar to those for the other fertilizer-P sources in 2019 and 2020. The similar rice responses compared to commercially available fertilizer-P sources suggest that wastewater-recovered struvite materials might be an alternative fertilizer-P-source option for flood-irrigated rice production if struvite can become price-competitive to other fertilizer-P sources.

Blue revolution for food security under carbon neutrality: A case from the water-saving and drought-resistance rice

Blue revolution for food security under carbon neutrality: A case from the water-saving and drought-resistance rice

Financial Viability and Environmental Sustainability of Fecal Sludge Treatment with Pyrolysis Omni Processors.

Omni Processors (OPs) are community-scale systems for non-sewered fecal sludge treatment. These systems have demonstrated their capacity to treat excreta from tens of thousands of people using thermal treatment processes (e.g., pyrolysis), but their relative sustainability is unclear. In this study, QSDsan (an open-source Python package) was used to characterize the financial viability and environmental implications of fecal sludge treatment via pyrolysis-based OP technology treating mixed and source-separated human excreta and to elucidate the key drivers of system sustainability. Overall, the daily per capita cost for the treatment of mixed excreta (pit latrines) via the OP was estimated to be 0.05 [0.03–0.08] USD·cap–1·d–1, while the treatment of source-separated excreta (from urine-diverting dry toilets) was estimated to have a per capita cost of 0.09 [0.08–0.14] USD·cap–1·d–1. Operation and maintenance of the OP is a critical driver of total per capita cost, whereas the contribution from capital cost of the OP is much lower because it is distributed over a relatively large number of users (i.e., 12,000 people) for the system lifetime (i.e., 20 yr). The total emissions from the source-separated scenario were estimated to be 11 [8.3–23] kg CO2 eq·cap–1·yr–1, compared to 49 [28–77] kg CO2 eq·cap–1·yr–1 for mixed excreta. Both scenarios fall below the estimates of greenhouse gas (GHG) emissions for anaerobic treatment of fecal sludge collected from pit latrines. Source-separation also creates opportunities for resource recovery to offset costs through nutrient recovery and carbon sequestration with biochar production. For example, when carbon is valued at 150 USD·Mg–1 of CO2, the per capita cost of sanitation can be further reduced by 44 and 40% for the source-separated and mixed excreta scenarios, respectively. Overall, our results demonstrate that pyrolysis-based OP technology can provide low-cost, low-GHG fecal sludge treatment while reducing global sanitation gaps.

Seasonal Variations in Grain Yield, Greenhouse Gas Emissions and Carbon Sequestration for Maize Cultivation in Bangladesh

Rationale: Greenhouse gas (GHG) emissions from crop agriculture are of great concern in the context of changing climatic conditions; however, in most cases, data based on lifecycle assessments are not available for grain yield variations or the carbon footprint of maize. The current study aimed to determine net carbon emissions and sequestration for maize grown in Bangladesh. Methods: The static closed-chamber technique was used to determine total GHG emissions using data on GHG emissions from maize fields and secondary sources for inputs. A secondary source for regional yield data was used in the current study. GHG emission intensity is defined as the ratio of total emissions to grain yield. The net GHG emission/carbon sequestration was determined by subtracting total GHG emissions (CO2 eq.) from net primary production (NPP). Results: Grain yields varied from 1590 to 9300 kg ha−1 in the wet season and from 680 to 11,820 kg ha−1 in the dry season. GHG emission intensities were 0.53–2.21 and 0.37–1.70 kg CO2 eq. kg−1 grain in the wet and dry seasons, respectively. In Bangladesh, the total estimated GHG emissions were 1.66–4.09 million tonnes (MT) CO2 eq. from 2015 to 2020, whereas the net total CO2 sequestration was 1.51–3.91 MT. The net CO2 sequestration rates were 984.3–5757.4 kg ha−1 in the wet season and 1188.62–5757.39 kg ha−1 in the dry season. This study observed spatial variations in carbon emissions and sequestration depending on growing seasons. In the rice–maize pattern, maize sequestered about 1.23 MT CO2 eq. per year−1, but rice emitted about 0.16 MT CO2 eq. per year−1. This study showed potential spatiotemporal variations in carbon footprints. Recommendation: Special care is needed to improve maize grain yields in the wet season. Fertiliser and water use efficiencies need to be improved to minimise GHG emissions under changing climatic conditions. Efforts to increase the area under cultivation with rice–maize or other non-rice crop-based cropping systems are needed to augment CO2 sequestration. The generation of a regional data bank on carbon footprints would be beneficial for combating the impact of climate change.

Elaboration of Energy Flow Sankey Diagrams for the Central American Region to Improve National Energy Planning

This article addresses the development of energy flow diagrams for the Central American region, based on the World Energy Balance for the year 2019. The main objective of this work is to provide a diagnosis of the efficiency of the energy systems, as well as the components that integrate them, which help to identify the improvement areas for the reduction of energy consumption. The development of the energy flow diagrams follows a model stablished by the International Energy Agency, divided in: primary energy resources, conversion technologies, and sectors of demand. In addition to the model stated before, energy flow diagrams shown in this article contain energy services and energy losses, calculated through the efficiencies found for each sector of demand. Six energy flow diagrams were developed to represent the energetic outlook of the region in regards to energy efficiency, primary energy resource consumption, and final energy consumption by the sectors of demand, as well as the estimation of greenhouse gases (GHG) emissions. This work can serve as a guide for energy planning, by tracking the energy flows to reduce energy losses and CO2 emissions by improving the low efficiency areas.

Greenhouse Gas Emission Reduction Potential of European Union’s Circularity Related Targets for Plastics

Current rising concerns about environmental and climate impacts in production, consumption and end-of-life of plastics have led to efforts to switch from linear to circular economy of plastics in Europe. Greenhouse gas emissions are likely to decrease with a transition to a circular system; however, a systematic and integrated perspective on plastics and the carbon cycle is currently missing in the debate on plastics.In this study, a model to estimate greenhouse gas emissions of the current mostly linear plastics value chain of the EU in 2018 and a future scenario, 2025 model, were created. By 2025 if current policy targets are reached, the plastic packaging recycling rate should be 50%, PET-based drinking bottles should include 25% recycled content, 77% collection target for plastic bottles, 10 Mt recyclates should enter the markets, uptake of bio-based plastics is estimated by European bioplastics to increase from current 1 to 1.32% and landfilling will continue to decrease according to the current trend at 3.85%.Total greenhouse gas emissions caused by the current plastics value chain are estimated at 208 million tonnes of CO2-eq. The 2025 model estimates that total plastics value chain emissions will be 182 Mt of CO2-eq. Reduction potential is approximately 26 Mt of CO2-eq or 13%.

Socioeconomic and Environmental Aspects of Traditional Firewood for Cooking on the Example of Rural and Peri-Urban Mexican Households

Firewood is a solid biofuel that is widely used for cooking in Mexico’s residential sector. This study seeks to identify relevant factors in firewood consumption patterns, and their implications for climate change, gender, and health, and for energy poverty in Mexico, by climate region and socioeconomic level. For this purpose, a statistical analysis was conducted of recently published official information. We estimate that a total of 31.3 million Mexicans—26% of the total population—use firewood, and we have identified three main types of users: (i) exclusive firewood users (30%); (ii) mixed firewood users using firewood as their primary fuel (18%) and (iii) mixed firewood users using firewood as their secondary fuel source (52%). Total consumption of firewood was estimated at 116.6 PJ, while estimated greenhouse gas emissions were 8.1 million tCO2e. Out of all the households studied, 53% were in the tropical climate region; 59% were categorized as being in the “low” socioeconomic level; and 75% were in population centers comprising fewer than 2500 inhabitants. Some 68% of households do not pay for the acquisition of firewood, and for those households that do pay for the resource, estimated transactions total USD 286.9 million. Expenditures on firewood for energy represent up to 10% of household income. Finally, it was estimated that 15.7 million direct users of firewood are women who use the resource in three-stone fires, in which they expose themselves to health risks in doing so. In conclusion, main universal findings, the study’s limitations, and future research are presented.

Estimating greenhouse gas emissions arising from the maintenance of sewer networks

As the push to reduce global carbon dioxide emissions intensifies, infrastructure managers are rethinking how maintenance is planned and executed to minimise greenhouse gases (GHGs) without sacrificing the performance of their infrastructure networks. This paper addresses this need. The work includes a detailed description of the estimation of GHG emissions that arise from common sewer maintenance interventions. These detailed estimates were subsequently used to project emissions from three maintenance scenarios for a large sewer network. The study found that emissions from maintenance mainly originate from materials and that emissions from transport, traffic congestion and machinery were of secondary importance. The current practice promises the lowest emissions up to 2035 but does not address the ageing pipe network. As a consequence, the network condition and performance deteriorate further as failures rapidly accumulate. Embracing preventive maintenance coupled with circular economy thinking is shown to be an effective solution to improve the network condition and performance while at the same time offering savings of 6222 t carbon dioxide a year. These findings provide infrastructure managers with a detailed example of the potential of circular economy thinking in reducing long-term emissions along with insights into the expected trade-offs that arise with network performance and resource utilisation.

Basin‐scale estimates of greenhouse gas emissions from the Mara River, Kenya: Importance of discharge, stream size, and land use/land cover

AbstractGreenhouse gas fluxes (CO2, CH4, and N2O) from African streams and rivers are under‐represented in global datasets, resulting in uncertainties in their contributions to regional and global budgets. We conducted year‐long sampling of 59 sites in a nested‐catchment design in the Mara River, Kenya in which fluxes were quantified and their underlying controls assessed. We estimated annual basin‐scale greenhouse gas emissions from measured in‐stream gas concentrations, modeled gas transfer velocities, and determined the sensitivity of up‐scaling to discharge. Based on the total annual CO2‐equivalent emissions calculated from global warming potentials (GWP), the Mara basin was a net greenhouse gas source (294 ± 35 Gg CO2 eq yr−1). Lower‐order streams (1–3) contributed 81% of the total fluxes, and higher stream orders (4–8) contributed 19%. Cropland‐draining streams also exhibited higher fluxes compared to forested streams. Seasonality in stream discharge affected stream widths (and stream area) and gas exchange rates, strongly influencing the basin‐wide annual flux, which was 10 times higher during the high and medium discharge periods than the low discharge period. The basin‐wide estimate was underestimated by up to 36% if discharge was ignored, and up to 37% for lower stream orders. Future research should therefore include seasonality in stream surface areas in upscaling procedures to better constrain basin‐wide fluxes. Given that agricultural activities are a major factor increasing riverine greenhouse gas fluxes in the study region, increased conversion of forests and agricultural intensification has the possibility of increasing the contribution of the African continent to global greenhouse gas sources.

Individual dietary structure changes promote greenhouse gas emission reduction

Reducing greenhouse gas (GHGs) emission in the food system, which has contributed one third of the total GHGs emissions from human activities, is crucial to achieve the Paris Agreement Announcement to limit global warming to 1.5 °C or 2 °C above pre-industrial levels. The intensity of GHGs emissions from different food varies significantly, so dietary structures will certainly lead to different global warming impacts. Adjusting people's diet structure, reducing red meat and other high carbon emission foods in the production process, and increasing low carbon healthy foods such as vegetables and seafood, can not only meet people's health needs, but also reduce GHG emissions in the food production process and promote the development of cleaner production. This study estimated GHGs emissions from human food consumption at a global scale and analyzed the driving factors. To explore the reducing path of GHGs emission from individual diets, two scenarios (a plant-rich diet and a diet with mussels replacing some of the traditional carbon intensive meat) of different diet structure were evaluated. Results suggest that the cumulative GHGs emissions caused by food consumption in 2020–2060 are 374 Gt CO2 equivalent. Furthermore, the plant-rich diet can reduce total GHGs emissions by 41%, and the mussels-replacing diet can have a reduction of 4.5%, 13.6%, and 22.4%, by replacing the traditional meat by 10%, 30% and 50%, respectively. Therefore, diet structure optimization has huge potential in GHGs emission mitigation, and such affordable and effective reduction measure can provide new insights for policy makers to control emissions from the food system.

The Importance of Lake Emergent Aquatic Vegetation for Estimating Arctic‐Boreal Methane Emissions

AbstractAreas of lakes that support emergent aquatic vegetation emit disproportionately more methane than open water but are under‐represented in upscaled estimates of lake greenhouse gas emissions. These shallow areas are typically less than ∼1.5 m deep and can be detected with synthetic aperture radar (SAR). To assess the importance of lake emergent vegetation (LEV) zones to landscape‐scale methane emissions, we combine airborne SAR mapping with field measurements of vegetated and open‐water methane flux. First, we use Uninhabited Aerial Vehicle SAR data from the NASA Arctic‐Boreal Vulnerability Experiment to map LEV in 4,572 lakes across four Arctic‐boreal study areas and find it comprises ∼16% of lake area, exceeding previous estimates, and exhibiting strong regional differences (averaging 59 [50–68]%, 22 [20–25]%, 1.0 [0.8–1.2]%, and 7.0 [5.0–12]% of lake areas in the Peace‐Athabasca Delta, Yukon Flats, and northern and southern Canadian Shield, respectively). Next, we account for these vegetated areas through a simple upscaling exercise using paired methane fluxes from regions of open water and LEV. After excluding vegetated areas that could be accounted for as wetlands, we find that inclusion of LEV increases overall lake emissions by 21 [18–25]% relative to estimates that do not differentiate lake zones. While LEV zones are proportionately greater in small lakes, this relationship is weak and varies regionally, underscoring the need for methane‐relevant remote sensing measurements of lake zones and a consistent criterion for distinguishing wetlands. Finally, Arctic‐boreal lake methane upscaling estimates can be improved with more measurements from all lake zones.

Climate COP-up, COP-out and hyCOPrisy

The complexities of climate science, of estimates of global greenhouse gas emissions and of their implications for climate change have not prevented widespread acceptance that global warming is a reality and its consequences potentially catastrophic for our planet and its peoples. But the convoluted processes of international negotiations and the political and economic context of their implementation mean that few have any confidence that national undertakings and international targets will be met. COP26 was a watershed, revealing the lack of progress on the most critical challenge of our time, the hypocrisy and double-speak of capitalist states and corporations, and the co-option of some conservation organisations through a deceptively ‘green’ narrative. A critical, materialist, Marxist approach can break through the greenwash of official discourse, reveal the need for systemic change, and potentially serve as a focus for growing public awareness and environmental activism.