A comparison of two algorithms for estimating carbon dioxide emissions after forest clearing

<p>Air-sea exchange of heat, freshwater, and carbon dioxide in the Southern Ocean exhibits large anomalies on decadal time scales. In particular, anomalies in the exchange of carbon-dioxide between the atmosphere and the ocean are dominated by decadal fluctuations. Since known modes of Southern Ocean climate variability, like the Southern Annular Mode, cannot explain these fluctuations, previous studies have suggested a strong link to decadal variability in the tropics. Here, we show that these fluctuations mainly arise from zonal sea-level pressure gradients between 35°S and 63°S that only correlates with tropical climate variability on regional scales. An atmospheric state of increased zonal pressure gradients leads to a stronger meridional exchange of heat and moisture. Such an enhanced meridional exchange favors air-sea fluxes either through a direct modification of the air-sea temperature and humidity gradients, or through resulting changes in ocean mixing and water-mass transformation. The latter changes have profound influences on the surface partial pressure of carbon dioxide in the surface ocean, which controls the surface carbon-dioxide flux. In order to capture this decadal mode of variability in the atmospheric circulation, we define a Southern Decadal Oscillation (SDO) index that is based on the zonal sea-level pressure gradients. This index explains more than two thirds of the variance in the total Southern Ocean carbon-dioxide flux and also dominates the variance in the surface heat and freshwater fluxes on time scales longer than five years. Our results provide an important step in understanding variations in the Southern Ocean surface climate on decadal time scales and imply that the surface ocean buoyancy forcing may control decadal variations in the water masses formed in this region.</p>

’s (2012) conclusion that observed climate change is comparableto projections, and in some cases exceeds projections, allows further inferences ifwe can quantify changing climate forcings and compare those with projections.The largest climate forcing is caused by well-mixed long-lived greenhouse gases.Here we illustrate trends of these gases and their climate forcings, and we discussimplications. We focus on quantities that are accurately measured, and we includecomparison with fixed scenarios, which helps reduce common misimpressionsabout how climate forcings are changing.Annual fossil fuel CO

The growing demand for bioenergy increases pressure on peatlands. The novel strategy of wet peatlands agriculture (paludiculture) may permit the production of bioenergy from biomass while avoiding large greenhouse gas emissions as occur during conventional crop cultivation on drained peat soils. Herein, we present the first greenhouse gas balances of a simulated paludiculture to assess its suitability as a biomass source from a climatic perspective. In a rewetted peatland, we performed closed‐chamber measurements of carbon dioxide, methane, and nitrous oxide exchange in stands of the potential crops Phragmites australis, Typha latifolia, and Carex acutiformis for two consecutive years. To simulate harvest, the biomass of half of the measurement spots was removed once per year. Carbon dioxide exchange was close to neutral in all tested stands. The effect of biomass harvest on the carbon dioxide exchange differed between the 2 years. During the first and second year, methane emissions were 13–63 g m−2 a−1 and 2–5 g m−2 a−1, respectively. Nitrous oxide emissions lay below our detection limit. Net greenhouse gas balances in the study plots were close to being climate neutral during both years except for the Carex stand, which was a source of greenhouse gases in the first year (in CO2‐equivalents: 18 t ha−1 a−1). Fifteen years after rewetting the net greenhouse gas balance of the study site was similar to those of pristine fens. In addition, we did not find a significant short‐term effect of biomass harvest on net greenhouse gas balances. In our ecosystem, ~17 t ha−1 a−1 of CO2‐equivalent emissions are saved by rewetting compared to a drained state. Applying this figure to the fen area in northern Germany, emission savings of 2.8–8.5 Mt a−1 CO2‐equivalents could possibly be achieved by rewetting; this excludes additional savings by fossil fuel replacement.

Land use has a very close relationship with transportation. Transportation is formed as a result of the interaction between land use and its support system. Good land use supported by good infrastructure will result in good movement as well. Accessibility is one of the supporting factors for good interaction between transportation and land use—the better the land use conditions in an area, the greater the movement in that area. However, the interaction between land use and transportation can cause one of the problems: the increase in carbon dioxide emissions due to the more significant movement of motorized vehicles. Motor vehicles are the most significant contributor to carbon dioxide (CO2) emissions in the world. The further the route traveled by motorized vehicles, the more carbon dioxide (CO2) emissions will increase. This study aims to analyze the average total emission of carbon dioxide (CO2) resulting from transportation activities in Pekanbaru City into two parts, namely: (1) Based on Travel Time (2) Based on the type of vehicle. Vehicle Kilometers of Travel (VKT) and Emission Factors are the primary data in calculating Carbon Dioxide (CO2) Emissions. The research area consists of 12 zones involving 1,342 households in Pekanbaru City. Based on travel time, 52% of community motorized vehicle movement activities are carried out in the morning. Private cars contribute 65% of carbon dioxide (CO2) emissions in Pekanbaru City based on the type of vehicle. This study found that a high number of motorized vehicles cannot be used as a benchmark that the resulting emissions will also be high. However, the emission of carbon dioxide (CO2) depends on the fuel consumption of each vehicle. The higher the fuel consumption, the higher the amount of carbon dioxide (CO2) emissions released by motorized vehicles.

Growing season carbon dioxide and methane exchange at a restored peatland on the Western Boreal Plain

In agricultural systems, soil carbon dioxide emissions and physical properties are thought to depend largely on management practices. This field study was carried out in a semi-arid region of eastern Tunisia to evaluate the effects of tillage management on soil carbon dioxide emissions and related physical properties; bulk density (BD), penetration resistance (PR), total porosity (TP) and air-filled porosity (AFP). Tillage management treatments included plowing with a moldboard plow or a disk plow to different depths, described here as shallow (10 cm), medium (15 cm) and deep (25 cm). No-tillage was also considered as a control plot. Correlation analysis was used to explore how soil carbon dioxide emissions (CO2) were related to the other studied properties. The results showed higher carbon dioxide (CO2) emissions (p < .05) from tilled soil compared to no-till (NT), regardless of the tillage management. No significant differences in carbon dioxide (CO2) emissions were found between moldboard and disk plow tillage at the same tillage depth. Soil carbon dioxide release was the highest after deep tillage (moldboard = 0.101 t ha−1 and disk plow = 0.107 t ha−1) suggesting that deeper tillage to 25 cm promoted higher carbon dioxide (CO2) emissions. Significant differences with tillage were observed in bulk density (BD) and penetration resistance (PR) compared to no-tillage. Correlations of carbon dioxide emissions to soil physical properties across all the tillage treatments indicated significant negative relationships between carbon dioxide (CO2) emissions and soil bulk density (BD) and penetration resistance (PR) and significant positive relationships between carbon dioxide (CO2) and total porosity (TP) and air-filled porosity (WFP) suggesting that these soil attributes are important controlling factors of carbon dioxide (CO2) emissions.

Carbon dioxide exchange at four intensively managed grassland sites across different climate zones of Japan and the influence of manure application on ecosystem carbon and greenhouse gas budgets

Inorganic carbon dynamics in coastal marine systems

Population growth and trends are centrally important to the environment because it helps to determine the environmental impact of human activities. In this study, the World Bank database has been used. Here, carbon dioxide (CO2) emissions, and energy intensity (EI) are considered as environmental indicators. The population indicators are the proportion of the population aged 15-64 years, and the percentage of the urban population. The Gross Domestic Product (GDP) is considered a development indicator in a country. This study tries to identify the association between population environment and development. Correlation analysis has been employed to know association and Path analysis is used to determine the important factors for environmental impacts such as carbon dioxide (CO2) emissions. The result presents that the zero-order correlation exists among energy intensity (EI), the proportion of the population aged 15-64 (P15-64), urbanization (UR), gross domestic product (GDP) per capita (US$), total population (P) ) and carbon dioxide (CO2) emission in Bangladesh and India. It is observed that 8 paths for Bangladesh and 7 paths for India out of each 12 hypothesized paths are found to be statistically significant. In Bangladesh, the total effects of exogenous variables like as energy intensity (X1) and population aged 15-64 (X2) are observed negative direction on carbon dioxide emissions (X6) and the remaining variable like as urbanization (X3) is observed as positive direction on carbon dioxide emissions. However, in India total effects of these two exogenous variables population aged 15-64 (X2) and urbanization (X3) are observed positive direction on carbon dioxide emissions (X6) and the remaining variable like as energy intensity (X1) is observed negative direction on carbon dioxide emissions (X6). The total effects of endogenous variables like as GDP per capita (X4) show a negative direction on carbon dioxide emissions and population (X5) shows a positive direction on carbon dioxide emissions. The study demonstrates that CO2 emission is important for environmental impact in Bangladesh and India. There is a strong association between population, GDP per capita, energy consumption and urbanization and CO2 emission in Bangladesh and India. The factors of CO2 emissions play an important role in environmental degradation. Thus, attention should be focused on using low energy consumption, and proper urbanization, particularly on modern technology which assures fewer uses of CO2 emissions in Bangladesh and India.

Better information on greenhouse gas (GHG) emissions and mitigation potential in the agricultural sector is necessary to manage these emissions and identify responses that are consistent with the food security and economic development priorities of countries. Critical activity data (what crops or livestock are managed in what way) are poor or lacking for many agricultural systems, especially in developing countries. In addition, the currently available methods for quantifying emissions and mitigation are often too expensive or complex or not sufficiently user friendly for widespread use.The purpose of this focus issue is to capture the state of the art in quantifying greenhouse gases from agricultural systems, with the goal of better understanding our current capabilities and near-term potential for improvement, with particular attention to quantification issues relevant to smallholders in developing countries. This work is timely in light of international discussions and negotiations around how agriculture should be included in efforts to reduce and adapt to climate change impacts, and considering that significant climate financing to developing countries in post-2012 agreements may be linked to their increased ability to identify and report GHG emissions (Murphy et al 2010, CCAFS 2011, FAO 2011).

Management and estimation of thermal comfort, carbon dioxide emission and economic growth by support vector machine

The role of the ocean as a sink for anthropogenic carbon dioxide is a subject of intensive investigation and debate. Interest in this process is driven by the need to predict the rate of future increase of atmospheric carbon dioxide and subsequent global climatic change. Although estimates of the magnitude of the oceanic sink for carbon dioxide appear to be converging on a value of ∼2 (Gt) C yr−1 for the 1980s, a detailed understanding of the temporal and spatial variability in the rate of exchange of carbon dioxide between the ocean and the atmosphere is not available. For example, recent modeling work and direct measurements of air‐sea carbon dioxide flux produce very different estimates of the air‐sea flux in the northern hemisphere. As a consequence, it has been suggested that a large unidentified oceanic carbon dioxide sink may exist in the North Pacific. As a part of our time series observations in the North Pacific Subtropical Gyre, we have measured dissolved inorganic carbon and titration alkalinity over a four‐year period. These measurements constitute the most extensive set of observations of carbon system parameters in the surface waters of the central Pacific Ocean. Our results show that the ocean in the vicinity of the time series site is a sink for atmospheric carbon dioxide. On the basis of these observations, we present a mechanism by which the North Pacific Subtropical Gyre can be a potential sink for ∼0.2 Gt C yr−1 of atmospheric carbon dioxide. Although our observations indicate that the North Pacific Subtropical Gyre is a sink for atmospheric carbon dioxide, the magnitude of this oceanic sink is relatively small. Our data and interpretations are therefore consistent with the argument for a relatively large sink during the 1980s in northern hemisphere terrestrial biomass. Another possibility is that the net release of carbon dioxide to the atmosphere owing to land use activities in tropical regions has been overestimated.

In relation to global warming and the role of carbon dioxide, the atmospheric residence-time of carbon dioxide from industrial emissions, and the carbon dioxide fixation capacity by photosynthesis in forests, land areas and oceans is considered, for the decades 1960 to 2010. Carbon dioxide fixation in forests, annually and worldwide, is estimated to be larger than the annual and global carbon dioxide emissions from industrial and land use activities, for the decades 1960 to 2010. Observations of the Keeling curve for the period 1960 to 2010, imply slow and rate-limiting steps for the atmospheric carbon dioxide cycle from industrial emissions, namely the transfer of carbon dioxide from the atmosphere to the Earth’s surface, forests, land areas and oceans. It is proposed that these carbon dioxide emissions have a long residence-time with significant accumulation in the atmosphere. Carbon dioxide emissions from natural-biological sources, namely respiration of organisms and passive emissions from the land and oceans, remain close to the Earth’s surface, with short atmospheric residence-times, rapid conversion into biomass and no significant accumulation in the atmosphere. This is known as the natural carbon dioxide cycle. Research and development are proposed as follows; (a) determination of the atmospheric residence times of industrial, urban and natural carbon dioxide emissions, (b) effective cooling of flue gases from industrial emissions to direct these emissions to lower atmospheric altitude(s), and thereby decrease the atmospheric residence-time(s) of carbon dioxide and (c) synthetic hydrocarbon fuels for aircraft, which are low-carbon in the complete cycle, developed with public-funded research. Global, public-funded research and development programs are proposed for achieving these goals, involving national and international organisations and industries.

A dynamic STIRPAT model used in the current study is based on panel data from the eight most populous countries from 1975 to 2020, revealing the nonlinear effects of urbanization routes (percentage of total urbanization, percentage of small cities and percentage of large cities) on carbon dioxide (CO2) emissions. Using “Dynamic Display Unrelated Regression (DSUR)” and “Fully Modified Ordinary Least Squares (FMOLS)” regressions, the outcomes reflect that percentage of total urbanization and percentage of small cities have an incremental influence on carbon dioxide emissions. However, square percentage of small cities and square percentage of total urbanization have significant adverse effects on carbon dioxide (CO2) emissions. The positive relationship between the percentage of small cities, percentage of total urbanization and CO2 emissions and the negative relationship between the square percentage of small cities, square percentage of total urbanization and CO2 emissions legitimize the inverted U-shaped EKC hypothesis. The impact of the percentage of large cities on carbon dioxide emissions is significantly negative, while the impact of the square percentage of large cities on carbon dioxide emissions is significantly positive, validating a U-shaped EKC hypothesis. The incremental effect of percentage of small cities and percentage of total urbanization on long-term environmental degradation can provide support for ecological modernization theory. Energy intensity, Gross Domestic Product (GDP), industrial growth and transport infrastructure stimulate long-term CO2 emissions. Country-level findings from the AMG estimator support a U-shaped link between the percentage of small cities and CO2 emissions for each country in the entire panel except the United States. In addition, the Dumitrescu and Hulin causality tests yield a two-way causality between emission of carbon dioxide and squared percentage of total urbanization, between the percentage of the large cities and emission of carbon dioxide, and between energy intensity and emission of carbon dioxide. This study proposes renewable energy options and green city-friendly technologies to improve the environmental quality of urban areas.

Power lines