Short-term CO2 Emissions Research Articles

Analysis for Decarbonization Pathways for Shipping

As regulations and goals for reducing carbon emissions in shipping become increasingly clear, decarbonization will become the top priority for the development of shipping industry in the coming decades. Currently, the main source of CO2 emissions from marine engines comes from the combustion of fossil fuels, while the operation of merchant ships typically requires striking a balance between equipment investment costs and the efficiency of CO2 emissions reduction. Thus, choosing a more suitable approach for ships is a hot topic of concern. This article summarizes three decarbonization methods, including reduction of energy consumption by speed reduction and air lubrication, using low-carbon and carbon-free fuels to substitute conventional marine fuels, and carbon capture. These methods are analysed for their technical feasibility, decarbonization capacity, safety, economy, and technical readiness. To achieve the short-term CO2 emissions reduction goal, there are various technologies to be applied, individually or in combination. Carbon-free fuels internal combustion engines can meet the long-term goal and its fuel cells will be the ultimate choice for net-zero scenario.

Prediction of Carbon Dioxide Emissions in China Using Shallow Learning with Cross Validation

Accurately measuring carbon dioxide (CO2) emissions is critical for effectively implementing carbon reduction policies, and China’s increased investment in reducing CO2 emissions is expected to significantly impact the world. In this study, the potential of shallow learning for predicting CO2 emissions was explored. Data included CO2 emissions, renewable energy consumption, and the share of primary, secondary, and tertiary industries in China from 1965 to 2021. These time-series data were converted into labeled sample data using the sliding window method to facilitate a supervised learning model for CO2 emission prediction. Then, different shallow learning models with k-fold cross-validation were used to predict China’s short-term CO2 emissions. Finally, optimal models were presented, and the important features were identified. The key findings were as follows. (1) The combined model of RF and LASSO performed best at predicting China’s short-term CO2 emissions, followed by LASSO and SVR. The prediction performance of RF was very fragile to the window width. (2) The sliding window method is used to convert time series predictions into supervision learning problems, and historical data can be used to predict future carbon dioxide emissions. To ensure that the feature data are real, the model can predict CO2 emissions for up to six years ahead. (3) Cross-validation and grid search were critical for optimizing China’s CO2 emissions prediction with small datasets. (4) By 2027, carbon dioxide emissions will continue to grow and reach 10.3 billion tons. It can be seen that the task of China to achieve its carbon peak on schedule is very heavy. The results indicate that an increase in renewable energy consumption and adjustments in industrial structure will continue to play an important role in curbing China’s CO2 emissions.

Impacts of a bunker levy on decarbonizing shipping: A tanker case study

The pressure on shipping to reduce its carbon footprint is increasing. Various measures are being proposed at the International Maritime Organization (IMO), including Market-Based Measures (MBMs). This paper investigates the potential of a bunker levy in achieving short-term CO2 emissions reductions. The analysis focuses on the tanker market and uses data from the latest IMO GHG studies and a variety of other sources. The connection between fuel prices and freight rates on the one hand and vessel speeds on the other is investigated for the period 2010–2018. A model to find a tanker’s optimal laden and ballast speeds is also developed and applied to a variety of scenarios. Results show that a bunker levy, depending on the scenario, can lead to short-term CO2 emissions reductions of up to 43%. Policy implications are also discussed, particularly vis-à-vis recent IMO and European Union (EU) action on MBMs.

Pengaruh Industrialisasi Terhadap Emisi CO2 Di Indonesia

Developing countries such as Indonesia have the ambition to carry out structural transformations in order to increase their economic growth. The structural transformation of the economy from low-productivity agriculture to high-productivity industrialization is seen as a prerequisite for achieving sustainable economic growth, but there are concerns about the impact of industrialization on the environment, especially in the context of carbon emissions and climate change. This study aims to analyze the effect of industrialization on long-term and short-term CO2 emissions in Indonesia, using the Vector Error Correction Model (VECM) method on time series data in Indonesia for the period 1974-2016. The variables used in this study are CO2 emissions, carbon intensity, energy intensity, Gross Domestic Product (GDP) and industrial value added, where the CO2 emission variable is the endogenous variable and the industrial value added variable is a proxy for industrialization. The other variables refer to the rich identity theory which describes the similarity of the relationship between human activities and the environment. The results of the study indicate that there is a significant positive effect of carbon intensity, energy intensity and GDP on CO 2 emission in Indonesia in the long term, meanwhile the value added industry show a significant negative effect in the long term. These variables further show no significant effect on CO 2 emissions in the short term. Keywords: Industrialization, CO 2 Emissions, Structural Transformation, Vector.Error, Correction Model (VECM), Granger Causality Test

Short-Term and Long-Term Effects of Natural and Artificial Carbonaceous Substrates on Greenhouse Gas Fluxes

The emissions of two greenhouse gases (GHG), carbon dioxide (CO2) and nitrous oxide (N2O), from six substrates with different carbonaceous content were compared in short and long-term incubation experiments. Three natural soils and three artificial chars were mixed with carbon (C) poor soil (Cambisol) to simulate real conditions after application of char to farmland. The natural soils were a Cambisol, an Anthrosol and a Histosol with C contents of 1.3%, 4.4% and 13.2%, respectively. The three chars produced through thermal conversion of wood chips by hydrothermal carbonisation (HTC), fluidized bed gasification and pyrolysis had C contents of 56.9%, 75.4% and 79.9%, respectively. Emission rates of CO2 and N2O from the rewetted substrates were measured by gas chromatography over a short time of 72 h and over a long period of nearly two years. The short-term CO2 emissions from the natural soils showed a clear relationship to their C content. The emission rate for the Histosol/Cambisol mixture was three times higher than that for the pure Cambisol, 77.1 vs. 23.5 mg CO2-C kg−1 organic matter (OM) per hour. The C emission rates for the char/Cambisol mixtures were much lower, ranging between 3.0 and 9.1 mg CO2-C kg OM−1 h−1 , and did not correspond to their total C contents. Comparison between the two incubation lengths showed that the long-term CO2 emission rates were generally one order of magnitude lower than the short-term rates. The final emission rates for natural substrates over a period of two years were still twice those for artificial char substrates, between 2.2–3.5 mg CO2-C kg OM−1 h−1 and 1.3–1.8 mg CO2-C kg OM−1 h−1 , respectively. Although the contents of total nitrogen (Ntot) and extractable nitrogen (Nmin) were considerable in the chars under study, enhanced N2O release was not observed in the incubation experiments. Instead, N2O emission rates in the three mixtures of chars and Cambisol were lower by one to two orders of magnitude compared to the pure Cambisol in short-term incubations. Even long-term N2O emissions were 5 to 9 times lower. The highest degree of N2O reduction was found for the HTC char. Because of the high global warming potential of N2O, this positive effect of chars may play an important role in mitigating emissions of CO2 equivalents. Both CO2 and N2O must be taken into account when balancing GHG emitted after chars (biochar, gasifier char, HTC char) are applied to soil.

Soil organic carbon accumulation and carbon dioxide emissions during a 6-year study in irrigated continuous maize under two tillage systems in semiarid Mediterranean conditions

Aim of study: To evaluate the effects of conventional tillage (CT) and no tillage (NT) systems on the soil organic carbon (SOC) changes, CO2 emissions and their relation with soil temperature and grain yield in a monoculture of irrigated maize during six years.Area of study: In Zamadueñas experimental field in the Spanish province of Valladolid, from 2011 to 2017.Material and methods: The SOC content was determined by collecting soil samples up to 30 cm in November at two years interval. Short-term CO2 emissions were measured simultaneously with soil temperature using a respiration chamber and a hand-held probe immediately before, after every tillage operation and during the maize cycle.Main results: The SOC stock of the top 30 cm soil layers was 13% greater under NT than CT. Short-term CO2 emissions were significantly higher under CT ranging from 0.8 to 3.4 g CO2 m-2 h-1 immediately after tillage while under NT system, soil CO2 fluxes were low and stable during this study period. During the first 48 h following tillage, cumulative CO2 emissions ranged from 0.6 to 2.4 Mg CO2 ha-1 and from 0.2 to 0.3 Mg CO2 ha-1 under CT and NT systems, respectively. Soil temperature did not show significant correlation with CO2 emissions; however, it depended mostly on the time of measurement.Research highlights: No tillage increased the SOC accumulation in the topsoil layer, reduced CO2 emissions without decreasing maize grain yield and minimized the impact on climate change compared to CT system.

Short-term CO[formula omitted] emissions forecasting based on decomposition approaches and its impact on electricity market scheduling

The world is facing major challenges related to global warming and emissions of greenhouse gases is a major causing factor. In 2017, energy industries accounted for 46% of all CO2 emissions globally, which shows a large potential for reduction. This paper proposes a novel short-term CO2 emissions forecast to enable intelligent scheduling of flexible electricity consumption to minimize the resulting CO2 emissions. Two proposed time series decomposition methods are developed for short-term forecasting of the CO2 emissions of electricity. These are in turn bench-marked against a set of state-of-the-art models. The result is a new forecasting method with a 48-hour horizon targeted the day-ahead electricity market. Forecasting benchmarks for France show that the new method has a mean absolute percentage error that is 25% lower than the best performing state-of-the-art model. Further, application of the forecast for scheduling flexible electricity consumption is studied for five European countries. Scheduling a flexible block of 4 h of electricity consumption in a 24 h interval can on average reduce the resulting CO2 emissions by 25% in France, 17% in Germany, 69% in Norway, 20% in Denmark, and just 3% in Poland when compared to consuming at random intervals during the day.

Effect of energy and CO2 consumption on the economy in Sub-Sahara Africa

The study focused on the long-term related effect among energy consumption (EC), CO2 production and economy growth (EG) of 12 randomly selected countries in sub-Saharan Africa. We used validation and causality tests in the 2008-2018 annual record. Special effects vary from country to country, in the long term, strong consumption of energy and economy growth in many countries has been linked with an increment in air pollution. The observation of the longitudinal study showed economic growth resulting in short-term CO2 emissions in Benin, the Democratic Republic of Congo, Ghana, Nigeria and Senegal, reflecting a lack of economy. This would not be possible without affecting the environment. The effect between CO2 and EG in Gabon, Nigeria and Togo has shown that environmental policies aimed at reducing pollution can be harmful. economic growth. In addition, long-term economic and CO2 production in Nigeria has been closely linked to the long-term links to Congo and Gabon. In the long-run, greenhouse gas emissions are the result of EC, EG and CO2 emission in Benin, Ivory Coast, Nigeria, Senegal, South Africa and Togo.

Tillage frequency affects microbial metabolic activity and short-term changes in CO2 fluxes within 1 week in karst ecosystems

Tillage disturbance can significantly affect soil microbial metabolic activity and CO2 fluxes. Nevertheless, the influence of different tillage frequencies on microbial metabolic activity and short-term temporal changes of CO2 fluxes remains unclear. We established an in situ experiment with the following treatments: no tillage (T0), semiannual tillage (T1), tillage every 4 months (T2), bimonthly tillage (T3), and monthly tillage (T4). The microbial metabolic activity (Biolog EcoPlate), short-term (hours to days) temporal changes in CO2 fluxes within 1 week, and soil properties were measured after 1 year of treatment. The highest CO2 emissions occurred in the first 72 h after tillage treatment and were significantly higher in T3 and T4 than in T0, T1, and T2 within 1 week. Average well color development (AWCD) values reflect microbial metabolic activity and were significantly higher in the tillage treatments (T1, T2, T3, and T4) than under no tillage. There was no significant difference in the Shannon diversity index under all treatments. A higher Simpson diversity index was observed under high tillage frequency in T2, T3, and T4 compared with T0 and T1, while the highest was observed in T2. The highest utilization of carboxylic acids, amino acids, and polymers occurred in T3 and T4 soils, whereas T2 had the highest utilization of carbohydrates, amines, and miscellaneous carbon sources. AWCD values and short-term CO2 fluxes were significantly correlated with annual changes in soil organic carbon (△SOC), annual changes in dissolved organic carbon (△DOC), microbial biomass carbon (MBC), and large macroaggregates (> 1 mm). These results suggest that frequent tillage disturbance increases microbial metabolic activity, which can stimulate short-term CO2 emissions through changes in soil aggregates, SOC, DOC, and MBC.

A global analysis of terrestrial plant litter dynamics in non-perennial waterways

Perennial rivers and streams make a disproportionate contribution to global carbon (C) cycling. However, the contribution of intermittent rivers and ephemeral streams (IRES), which sometimes cease to flow and can dry completely, is largely ignored although they represent over half the global river network. Substantial amounts of terrestrial plant litter (TPL) accumulate in dry riverbeds and, upon rewetting, this material can undergo rapid microbial processing. We present the results of a global research collaboration that collected and analysed TPL from 212 dry riverbeds across major environmental gradients and climate zones. We assessed litter decomposability by quantifying the litter carbon-to-nitrogen ratio and oxygen (O2) consumption in standardized assays and estimated the potential short-term CO2 emissions during rewetting events. Aridity, cover of riparian vegetation, channel width and dry-phase duration explained most variability in the quantity and decomposability of plant litter in IRES. Our estimates indicate that a single pulse of CO2 emission upon litter rewetting contributes up to 10% of the daily CO2 emission from perennial rivers and stream, particularly in temperate climates. This indicates that the contributions of IRES should be included in global C-cycling assessments.

Cover crop rotations in no-till system: short-term CO2 emissions and soybean yield

In addition to improving sustainability in cropping systems, the use of a spring and winter crop rotation system may be a viable option for mitigating soil CO2 emissions (ECO2). This study aimed to determine short-term ECO2 as affected by crop rotations and soil management over one soybean cycle in two no-till experiments, and to assess the soybean yields with the lowest ECO2. Two experiments were carried out in fall-winter as follows: i) triticale and sunflower were grown in Typic Rhodudalf (TR), and ii) ruzigrass, grain sorghum, and ruzigrass + grain sorghum were grown in Rhodic Hapludox (RH). In the spring, pearl millet, sunn hemp, and forage sorghum were grown in both experiments. In addition, in TR a fallow treatment was also applied in the spring. Soybean was grown every year in the summer, and ECO2 were recorded during the growing period. The average ECO2 was 0.58 and 0.84 g m2 h–1 with accumulated ECO2 of 5,268 and 7,813 kg ha–1 C-CO2 in TR and RH, respectively. Sunn hemp, when compared to pearl millet, resulted in lower ECO2 by up to 12 % and an increase in soybean yield of 9% in TR. In RH, under the winter crop Ruzigrazz+Sorghum, ECO2 were lower by 17%, although with the same soybean yield. Soil moisture and N content of crop residues are the main drivers of ECO2 and soil clay content seems to play an important role in ECO2 that is worthy of further studies. In conclusion, sunn hemp in crop rotation may be utilized to mitigate ECO2 and improve soybean yield.

Surface organic carbon enrichment to explain greater CO2 emissions from short-term no-tilled soils

The impact of agricultural practices on CO2 emissions from soils needs to be understood and quantified to enhance ecosystem functions, especially the ability of soils to sequester atmospheric carbon (C), while enhancing food and biomass production. The objective of this study was to assess CO2 emissions in the soil surface following tillage abandonment and to investigate some of the underlying soil physical, chemical and biological controls. Maize (Zea mays) was planted under conventional tillage (T) and no-tillage (NT), both without crop residues under smallholder farming conditions in Potshini, South Africa. Intact top-soil (0–0.05m) core samples (N=54) from three 5×15m2 plots per treatment were collected two years after conversion of T to NT to evaluate the short-term CO2 emissions. Depending on the treatment, cores were left intact, compacted by 5 and 10%, or had surface crusts removed. They were incubated for 20 days with measurements of CO2 fluxes twice a day during the first three days and once a day thereafter. Soil organic C (SOC) content, soil bulk density (ρb), aggregate stability, soil organic matter quality, and microbial biomass and its activity were evaluated at the onset of the incubation. CO2 emissions were 22% lower under NT compared with T with CO2 emissions of 0.9±0.10 vs 1.1±0.10mg C–CO2gC−1 day−1 under NT and T, respectively, suggesting greater SOC protection under NT. However, there were greater total CO2 emissions per unit of surface by 9% under NT compared to T (1.15±0.03 vs 1.05±0.04g C–CO2m−2 day−1). SOC protection significantly increased with the increase in soil bulk density (r=0.89) and aggregate stability (from 1.7±0.25mm to 2.3±0.31, r=0.50), and to the decrease in microbial biomass and its activity (r=−0.59 and −0.57, respectively). In contrast, the greater NT CO2 emissions per m2 were explained by top-soil enrichment in SOC by 48% (from 12.4±0.2 to 19.1±0.4gkg−1, r=0.59). These results on the soil controls of tillage impact on CO2 emissions are expected to inform on the required shifts in agricultural practices for enhancing C sequestration in soils. In the context of the study, any mechanism favoring aggregate stability and promoting SOC allocation deep in the soil profile rather than in the top-soil would greatly diminish soil CO2 outputs and thus stimulate C sequestration.

Crop residues on short-term CO2 emissions in sugarcane production areas

The proper management of agricultural crop residues could produce benefits in a warmer, more drought-prone world. Field experiments were conducted in sugarcane production areas in the Southern Brazil to assess the influence of crop residues on the soil surface in short-term CO2 emissions. The study was carried out over a period of 50 days after establishing 6 plots with and without crop residues applied to the soil surface. The effects of sugarcane residues on CO2 emissions were immediate; the emissions from residue-covered plots with equivalent densities of 3 (D50) and 6 (D100) t ha-1 (dry mass) were less than those from non-covered plots (D0). Additionally, the covered fields had lower soil temperatures and higher soil moisture for most of the studied days, especially during the periods of drought. Total emissions were as high as 553.62 ± 47.20 g CO2 m-2, and as low as 384.69 ± 31.69 g CO2 m-2 in non-covered (D0) and covered plot with an equivalent density of 3 t ha-1 (D50), respectively. Our results indicate a significant reduction in CO2 emissions, indicating conservation of soil carbon over the short-term period following the application of sugarcane residues to the soil surface.

Tillage Intensity and Tillage-Induced CO2Loss

Field experiments were done to measure the effect of different primary tillage methods on the CO2 flux from soil and to evaluate the effect of conservation tillage tools on short-term CO2 emissions. The experiments were conducted on a clay loam soil winter wheat field and a corn field. The three tillage treatments included stubble mulching (disc harrow, mulch tiller, chisel plough), primary tillage (disc harrow, moldboard plough, and chisel plough) and secondary tillage (combined seedbed maker). The control treatment was no-till with soil and residues left by the harvester. The CO2 flux from the tilled soil surface was measured by a portable closed-chamber tester. Moldboard ploughing produced the roughest soil surface and the highest initial CO2 flux and maintained the highest flux throughout the experiment. The moldboard ploughing caused higher CO2 loss than less intensive tillage such as chisel ploughing, mulch cultivating, or disc harrowing. Primary tillage caused higher CO2 emission in the fall than s...