Greater Greenhouse Gas Emissions Research Articles

Understanding Life-Cycle Greenhouse-Gas Emissions of Shared Electric Micro-Mobility: A Systematic Review

In recent years, the implementation of shared electric micro-mobility services (SEMMS) enables short rentals of light electric vehicles for short-distance travel. The fast expansion of SEMMS worldwide, promoted as a green mobility service, has raised a debate about its role in urban mobility, especially in terms of environmental impacts such as climate change. This article presents a systematic review of the current knowledge on the environmental impacts of SEMMS, with a special focus on the use of life-cycle assessment (LCA) methods. The study offers a detailed analysis of the global warming potential of SEMMS and its critical phases. It is found that shared e-scooters have the greatest greenhouse-gas emissions during their life cycle, while emissions from shared e-mopeds and shared e-bikes tend to be lower. The literature reveals that the materials and manufacturing phase is the most important one for the environmental impact of shared e-scooters, followed by the daily collection of vehicles for charging. The article also identifies influential factors in the sensitivity analysis and the potential for net-impact reduction accounted for mode substitution. Finally, the article identifies further research areas aimed at contributing to the adoption of environmentally responsible practices in the rapidly expanding field of shared services in cities.

The environmental impact of fossil fuel subsidy policies

The environmental impact of fuel subsidy policies is an important but understudied issue. This paper makes use of country-level panel data of 139 countries from 1998 to 2015 and the STIRPAT model to investigate the relationship between fuel subsidy policies and environmental emissions. Our estimations indicate that high fossil fuel subsidies are associated with greater greenhouse gas (GHG) emissions. We find that countries pursuing high-subsidy policies emit approximately 11.4% more GHG emissions than those pursuing high-tax policies. In the unlikely event that crude oil prices would remain at around $120 per barrel and all countries pursuing high-subsidy policies would switch to high-tax policies, we project that global GHG emissions could decline by about 1.28%. We find that while fuel subsidy reform can help reduce global GHG emissions and tackle climate change by improving fuel efficiency, it is far from being a silver bullet and, as a result, only represents a small tool to be used among others to achieve emission reduction goals.

Environmental impacts of eco-nutrition swine feeding programs in spatially explicit geographic regions of the United States.

This study was conducted to determine greenhouse gas (GHG) emissions, water consumption, land use, as well as nitrogen (N), phosphorus (P), and carbon (C) balance of five diet formulation strategies and feeding programs for growing-finishing pigs (25-130 kg body weight) in the three spatially explicit geographic regions where the majority of U.S. pork production occurs. Feeding programs evaluated consisted of 1) standard corn-soybean meal (CSBM) diets, 2) CSBM containing 15% corn distillers dried grains with solubles (DDGS), 3) CSBM with 8.6% thermally processed supermarket food waste (FW), 4) low crude protein CSBM diets supplemented with synthetic amino acids (SAA), and 5) CSBM with phytase enzyme (PHY) added at 600 FTU (phytase units)/kg of diet. An attributional Life Cycle Assessment approach using a highly specialized, spatially explicit Food System Supply-Chain Sustainability (FoodS3) model was used to quantify GHG emissions, water consumption, and land use of corn, soybean meal, and DDGS based on county level sourcing. The DDGS, FW, and SAA feeding programs had less estimated N and P intake and excretion than CSBM, and the PHY feeding program provided the greatest reduction in P excretion. The FW feeding program had the least overall GHG emissions (319.9 vs. 324.6 to 354.1 kg CO2 equiv./market hog), land use (331.5 vs. 346.5 to 385.2 m2/market hog), and water consumption (7.64 vs. 7.70 to 8.30 m3/market hog) among the alternatives. The DDGS feeding program had the greatest GHG emissions (354.1 kg CO2 equiv./market hog) among all programs but had less impacts on water consumption (7.70 m3) and land use (346.5 m2) per market hog than CSBM and PHY. The SAA feeding program provided a 6.5-7.4% reduction in land use impacts compared with CSBM and PHY, respectively. Regardless of feeding program, the Midwest had the least contributions to GHG emissions and land use attributed to feed and manure among regions. Water consumption per market hog associated with feeding programs was much greater in the Southwest (59.66-63.58 m3) than in the Midwest (4.45-4.88 m3) and Mid-Atlantic (1.85-2.14 m3) regions. Results show that diet composition and U.S. geographic region significantly affect GHG emissions, water consumption, and land use of pork production systems, and the potential use of thermally processed supermarket food waste at relatively low diet inclusion rates (<10%) can reduce environmental impacts compared with other common feeding strategies.

EVALUATION OF GGE OF DIFFERENT PROCESS FOR DRYING ORANGE SLICES

Just because of burning fossil fuels and the fact that renewable energy sources (solar, wind, hydraulic, geothermal, biomass, tidal, wave etc.) have not become widespread globally, many parallel environmental problems such as global warming, climate change and carbon emissions have been emerged. In the present study, two different orange cultivars (Valencia and Washington Navel) were dried under different air-convective conditions (50, 55 and 60°C). Samples were sliced three different thickness as 5, 7 and 9 mm, respectively. In addition, three different drying time was selected for orange drying as 8, 9 and 10 h, respectively. The effects of a single unit air convective drying of 1 kg product on greenhouse gas emissions (GGE) of different types of power plants (wind, solar, hydroelectric, and geothermal) were investigated. Present findings revealed that while the greatest GGE were obtained from the geothermal power plant, the lowest values were obtained from the wind power plant. Besides, increasing CO2 emissions were encountered with increasing drying time and sample thickness. Additionally, CO2 emissions had a decreasing trend at higher temperatures.

Performance, meat quality, profitability, and greenhouse gas emissions of suckler bulls from pasture-based compared to an indoor high-concentrate weanling-to-beef finishing system

CONTEXTDemand for environmentally sustainable produced beef, especially ‘grass-fed’, is rising. Bull-beef production is a desirable alternative to steers due to large inherent growth and feed efficiency advantages. Compared to conventional indoor high-concentrate diets, pasture-finishing of bulls is low-cost, but carcass fat cover may not meet market requirements. OBJECTIVEWe evaluated the performance, meat quality, profitability, greenhouse gas (GHG) emissions, and human-edible protein (HEP) efficiency of pasture-based purchased suckler bull ‘weanling’-to-beef finishing systems compared to an indoor high-concentrate system. METHODSSuckler bulls, initially offered grass silage and supplementary concentrates during a ‘backgrounding’ phase, were assigned to one of four finishing systems: grazed grass with three levels of barley-based concentrate, 0 (G-0), 0.25 (G-25), and 0.50 (G-50) of predicted dietary dry matter intake, or ad libitum concentrates and grass silage (ALC). The experimental data generated were used to parameterise a whole-farm systems model and the output, profitability and GHG emissions of ‘purchased weanling’-to-beef finishing systems were evaluated. RESULTS AND CONCLUSIONSTotal daily dry matter intake was highest for ALC and lowest for G-0. Carcasses from ALC were heavier (406 kg) than all grazing systems; G-50 was heavier (387 kg) than G-25 and G-0 (367 kg). Carcass fat score was higher for ALC (8.3, scale 1–15) than the grazing systems, which were similar (5.0–5.6). Meat eating quality did not differ between systems. Although carcass output per hectare increased by 50% for G-50 and almost-doubled for ALC compared to G-0, gross and net margins were similar for G-0 and G-50, and considerably less for ALC. The GHG emission per animal were lowest for G0 and highest for G50; however, when expressed relative to live-, carcass-, and especially meat weight, emission intensities (kg CO2eq) were lowest for ALC (5.4, 14.9, and 12.2, respectively) and highest for G-0 and G-25 (~9.6, 19.4, and 20.8, respectively). The HEP efficiency ratio was highest for G-0 (0.67) and lowest for ALC (0.21). Compared to a high-concentrate indoor bull finishing system, temperate pasture-based systems had lighter, ‘under-finished’ carcasses but similar meat eating quality, were more profitable, had superior HEP efficiency, but greater GHG emissions when expressed relative to live-, carcass-, and meat weight gain. SIGNIFICANCEAlthough carcasses were ‘under-finished’ for the grazing systems compared to the high-concentrate indoor system, meat eating quality was similar, implying that, potentially, there is greater scope for beef producers to operate relatively more profitable pasture-based bull-beef finishing. In view of the inverse relationships between profitability, HEP efficiency, and GHG emissions per unit of product among different suckler weanling-to-beef finishing systems, consideration of unavoidable trade-offs is necessary from a beef production, policy and future-research perspective.

Future Prospects of Spent Coffee Ground Valorisation Using a Biorefinery Approach

In the UK, half a million tonnes of spent coffee ground (SCG) waste are generated annually. Current SCG management practices of landfill and energy-from-waste (EfW) facilities either underutilise its valuable constituents or have negative environmental impacts. This study investigates the prospects of SCG-based biorefineries by assessing the impact of biorefinery size, location and products on economic and environmental performances. Two biorefinery design configurations are proposed. Configuration I produces biodiesel and electricity whilst Configuration II produces biodiesel and high-value chemicals. From these configurations, four biorefinery scenarios are analysed at a 10% discount rate with 2019 as the reference year. Configuration I using SCG from London coffee establishments yields a negative net present value (NPV) of −£3.9 million and 22% greater greenhouse gas (GHG) emissions than conventional rapeseed biodiesel production. Changing the SCG source to a coffee factory increases biorefinery size by 2.3 times but still produces a negative NPV. Using Configuration II to process SCG from coffee shops significantly improves NPV. However, without on-site energy generation, its GHG emissions are greater than those from conventional production methods of the high-value chemicals. An on-site Configuration I using SCG from the coffee factory yields the best performance. It produces a NPV of £3.1 million and GHG emissions 85% and 13% lower than that of SCG landfilling and conventional biodiesel. Overall, these findings demonstrate the potential of extracting value from SCG waste using a biorefinery approach, revealing a strong likelihood that future SCG biorefineries will be large scale and on-site of SCG production.

Reduction of Energy Intensity in Broiler Facilities: Methodology and Strategies.

Broiler facilities consume a lot of energy resulting in natural source depletion and greater greenhouse gas emissions. A way to assess the energy performance of a broiler facility is through an energy audit. In the present paper, an energy protocol for an energy audit is presented covering both phases of data collection and data elaboration. The operational rating phase is analytically and extendedly described while a complete mathematical model is proposed for the asset rating phase. The developed energy audit procedure was applied to poultry chambers located in lowland and mountainous areas of Epirus Greece for chambers of various sizes and technology levels. The energy intensity indices varied from 46 to 89 kWh/m2 of chamber area 0.25–0.48 kWh/kg of produced meat or 0.36–1.3 kWh/bird depending on the chamber technology level (insulation, automation, etc.) and the location where the unit was installed. The biggest energy consumer was heating followed by energy consumption for ventilation and cooling. An advanced technology level can improve energy performance by ~ 27%−31%. Proper insulation (4–7 cm) can offer a reduction of thermal energy consumption between 10 and 35%. In adequately insulated chambers, the basic heat losses are due to ventilation. Further energy savings can be achieved with more precise ventilation control. Automation can offer additional electrical energy saving for cooling and ventilation (15–20%). Energy-efficient lights can offer energy saving up to 5%. The use of photovoltaic (PV) technology is suggested mainly in areas where net-metering holds. The use of wind turbines is feasible only when adequate wind potential is available. Solar thermal energy is recommended in combination with a heat pump if the unit's heating and cooling systems use hot/cold water or air. Finally, the local production of biogas with anaerobic fermentation for producing thermal or electrical energy, or cogenerating both, is a choice that should be studied individually for each farm.

How does soil carbon sequestration affect greenhouse gas emissions from a sheep farming system? Results of a life cycle assessment case study

A life cycle assessment (LCA) study of a transition from semiintensive to semi-extensive Mediterranean dairy sheep farm suggests that the latter has a strong potential for offsetting greenhouse gas (GHG) emissions through the soil C sequestration (Cseq) in permanent grasslands. The extensification process shows clear environmental advantage when emission intensity is referred to the area-based functional unit (FU). Several LCA studies reported that extensive livestock systems have greater GHG emissions per mass of product than intensive one, due to their lower productivity. However, these studies did not account for soil Cseq of temporary and permanent grasslands, that have a strong potential to partly mitigate the GHG balance of ruminant production systems. Our LCA study was carried out considering the transition from a semiintensive (SI) towards a semi-extensive (SE) production system, adopted in a dairy sheep farm located in North-Western Sardinia (Italy). Impact scope included enteric methane emissions, feed production, on-farm energy use and transportation, infrastructures as well as the potential C sink from soil Cseq compared to emission intensity. In order to provide a more comprehensive analysis, we used the following FUs: 1 kg of fat and protein corrected milk (FPCM) and 1 ha of utilised agricultural area (UAA). We observed that the extensification of production system determined contrasting environmental effects when using different FUs accounting for soil Cseq. When soil Cseq in emission intensity estimate was included, we observed slightly lower values of GHG emissions per kg of FPCM in the SI production system (from 3.37 to 3.12 kg CO2 equivalents – CO2-eq), whereas a greater variation we observed in the SE one (from 3.54 to 2.90 kg CO2-eq). Considering 1 ha of UAA as FU and including the soil Cseq, the emission intensity in SI moved from 6257 to 5793 kg CO2-eq, whereas values varied from 4020 to 3299 kg CO2-eq in SE. These results indicated that the emission intensity from semi-extensive Mediterranean dairy sheep farms can be considerably reduced through the soil Cseq, although its measurement is influenced by the models used in the estimation. Highlights - Extensification of dairy sheep systems provides an environmental benefit when soil C sequestration is considered. - Extensification of dairy sheep systems determines lower environmental impact per hectare of utilized agricultural area. - Enteric methane emissions are the main source of GHG emissions of the sheep milk life cycle. - Carbon sequestration in permanent grasslands can considerably contribute to climate change mitigation.

Life Cycle Perspectives of Using Non-Pelleted vs. Pelleted Corn Stover in a Cellulosic Biorefinery

Cellulosic biorefineries have attracted interest due to the growing energy security and environmental concerns related to fossil fuel-based energy and chemicals. Using pelleted biomass as a biorefinery feedstock can reduce their processing inputs while improving biomass handling and transportation. However, it is still questionable whether energy and emission savings from feedstock transportation and processing can justify pelletization. A life cycle assessment approach was used to compare energy consumption and greenhouse gas (GHG) emissions from pelleted and non-pelleted corn stover as a biorefinery feedstock. Operations considered were pelleting, transportation, and soaking in aqueous ammonia (SAA) pretreatment. Despite greater GHG emissions (up to 25 times higher than the transportation) generated from the pelleting process, the model showed a significant opportunity to offset and even reduce overall GHG emissions considering the pretreatment process benefits. Our process energy analysis showed that SAA pretreatment of pelleted biomass required significantly lower energy inputs (56%) due to the lower-severity pretreatment’s effectiveness. Higher pretreatment solid loadings are allowed when pelleted biomass is used and this reduces the process chemicals and water requirements by 56% and 49%, respectively. This study demonstrated that the SAA pretreatment of pelleted biomass might be a feasible option as the cellulosic biorefinery feedstock.

How a carbon tax will affect an emission-intensive economy: A case study of the Province of Saskatchewan, Canada

A carbon tax has been proposed or applied in many countries and regions around the world to reduce greenhouse gas (GHG) emissions. In this study, a Computable General Equilibrium (CGE) model for the Province of Saskatchewan is first developed to examine and analyze a series of direct and indirect socio-economic impacts of a carbon tax. The energy sector is further disaggregated based on the production structure and energy use pattern to obtain robust results. Different carbon tax rates are simulated to quantify the inter-relationships of the carbon tax, GHG emission reduction, and economic growth. In-depth examinations are also conducted to investigate some other macroeconomic impacts and responses from specific economic sectors. The results show that the GDP change is mainly caused by consumption reduction and import increases, due to the income decline and relatively low tariff rates. Changes in coal and petroleum product production and processes result in the greatest GHG emissions among all sectors. This suggests that clean coal and petroleum technologies may be the crucial issues for realizing both national and provincial environmental and economic objectives. It is expected that the results will provide a solid basis for supporting the application of an effective Pan-Canadian carbon pricing strategy.

Greenhouse gas emissions from dairy manure management in a Mediterranean environment

Livestock agriculture is a major source of anthropogenic greenhouse gas (GHG) emissions, with a substantial proportion of emissions derived from manure management. Accurate estimates of emissions related to management practices and climate are needed for identifying the best approaches to minimize, and potentially mitigate, GHG emissions. Current emissions models such as those of the IPCC, however, are based on emissions factors that have not been broadly tested against field-scale measurements, due to a lack of data. We used a diverse set of measurements over 22months across a range of substrate conditions on a working dairy to determine patterns and controls on soil-based GHG fluxes. Although dairy soils and substrates differed by management unit, GHG fluxes were poorly predicted by these or climate variables. The manure pile had the greatest GHG emissions, and though temperature increased and O2 concentration decreased following mixing, we detected almost no change in GHG fluxes due to mixing. Corral fluxes were characterized by hotspots and hot moments driven by patterns in deposition. Annual scraping kept the soil and accumulated manure pack thin, producing drier conditions, particularly in the warm dry season. Summed over area, corral fluxes had the greatest non-CO2 global warming potential. The field had net CH4 consumption, but CH4 uptake was insufficient to offset N2 O emissions on an area basis. All sites emitted N2 O with a similar or greater climate impact than CH4 . Our results highlight the importance of N2 O emissions, a less commonly measured GHG, from manure management and present potential opportunities for GHG emissions reductions.

1194 Including corn in crop rotations is profitable for dairy farms and does not result in greater greenhouse gas emissions at the whole-farm level

1194 Including corn in crop rotations is profitable for dairy farms and does not result in greater greenhouse gas emissions at the whole-farm level

Dryland Soil Greenhouse Gases and Yield‐Scaled Emissions in No‐Till and Organic Winter Wheat–Fallow Systems

Core Ideas Dryland organic and no‐till wheat‐fallow systems impact GHG and wheat yields. The organic system produced more wheat grain yield than the no‐till system in a dry year. The organic system had greater GHG emissions during the fallow period. Concerted effort toward reducing tillage is needed to reduce overall GHG emission in dryland organic wheat–fallow systems. In the semiarid central Great Plains of the United States, cropping intensification beyond the traditional winter wheat (Triticum aestivum L.)–fallow rotation along with reduced tillage can lead to soil organic matter (SOM) conservation and offset greenhouse gas emission. Here, we quantified (i) soil greenhouse gas (GHG) carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes, and (ii) yield‐scaled GHG emissions from dryland no‐till (NT) and organic production systems in western Nebraska over a 2‐yr period. The systems evaluated were no‐till winter wheat–proso millet (Panicum miliaceum L.)–fallow (NT 3 yr), no‐till winter wheat–millet–fallow–winter wheat–sunflower (Helianthus annuus L.)–fallow (NT 6 yr), and organic winter wheat–millet or sunflower–fallow (Organic 3 yr). In 2012 and 2013, CO2 and N2O fluxes in the winter wheat phase were generally higher in the no‐till systems relative to the Organic 3‐yr system. In the fallow phase, however, these fluxes were higher in the Organic 3‐yr system than in the NT 6‐yr system, suggesting greater mineralization under the former. In 2013, fluxes of CH4 in the winter wheat phase tended to be higher in the Organic 3‐yr system than in the no‐till systems. Compared with the NT 6‐yr system, the Organic 3‐yr system had lower yield‐scaled emission in the winter wheat phase in 2012 (0.026 vs. 0.014 Mg [CH4 + N2O] in CO2 equivalent Mg−1 yield). More effort toward reducing tillage‐caused soil disturbance intensity is needed to further reduce CO2 and N2O emissions and SOM depletion in dryland organic winter wheat–fallow production systems.

Modelling the influence of soil carbon on net greenhouse gas emissions from grazed pastures

Sequestering carbon (C) in soil organic matter in grassland systems is often cited as a major opportunity to offset greenhouse gas (GHG) emissions. However, these systems are typically grazed by ruminants, leading to uncertainties in the net GHG balance that may be achieved. We used a pasture model to investigate the net balance between methane (CH4), nitrous oxide (N2O) and soil C in sheep-grazed pasture systems with two starting amounts of soil C. The net emissions were calculated for four soil types in two rainfall zones over three periods of 19 years. Because of greater pasture productivity, and consequent higher sheep stocking rates, high-rainfall sites were associated with greater GHG emissions that could not be offset by C sequestration. On these high-rainfall sites, the higher rate of soil organic carbon (SOC) increase on low-SOC soils offset an average of 45% of the livestock GHG emissions on the modelled chromosol and 32% on the modelled vertosol. The slow rate of SOC increase on the high-SOC soils only offset 2–4% of CH4 and N2O emissions on these high-rainfall sites. On low-rainfall sites, C sequestration in low-SOC soils more than offset livestock GHG emissions, whereas the modelled high-C soils offset 75–86% of CH4 and N2O emissions. Greater net emissions on high-C soils were due primarily to reduced sequestration potential and greater N2O emissions from nitrogen mineralisation and livestock urine. Annual variation in CH4 and N2O emissions was low, whereas annual SOC change showed high annual variation, which was more strongly correlated with weather variables on the low-rainfall sites compared with the high-rainfall sites. At low-soil C concentrations, with high sequestration potential, there is an initial mitigation benefit that can in some instances offset enteric CH4 and direct and indirect N2O emissions. However, as soil organic matter increases there is a trade-off between diminishing GHG offsets and increasing ecosystem services, including mineralisation and productivity benefits.

Pasture-derived greenhouse gas emissions in cow-calf production systems.

There is a lack of information regarding carbon dioxide (CO), methane (CH), and nitrous oxide (NO) emissions from pasture soils and the effects of grazing. The objective of this study was to quantify greenhouse gas (GHG) fluxes from pasture soils grazed with cow-calf pairs managed with different stocking rates and densities. The central hypothesis was that irrigated low-density stocking systems (SysB) would result in greater GHG emissions from pasture soils than nonirrigated high-density stocking systems (SysA) and grazing-exclusion (GRE) pasture sites. The nonirrigated high-density stocking systems consisted of 120 cow-calf pairs rotating on a total of 120 ha (stocking rate 1 cow/ha, stocking density 112,000 kg BW/ha, rest period of 60 to 90 d). The irrigated low-density stocking systems consisted of 64 cow-calf pairs rotating on a total of 26 ha of pasture (stocking rate 2.5 cows/ha, stocking density 32,700 kg BW/ha, rest period of 18 to 30 d). Both systems consisted of mixed cool-season grass-legume pastures. Static chambers were randomly placed for collection of CO, CH, and NO samples. Soil temperature (ST), ambient temperature (temperature inside the chamber; AT), and soil water content (WC) were monitored and considered explanatory variables for GHG emissions. GHG fluxes were monitored for 3 yr (2011 to 2013) at the beginning (P1) and at the end (P2) of the grazing season, always postgrazing. Paddock was the experimental unit (3 pseudoreplicates per treatment), and chambers (30 chambers per paddock) were considered multiple measurements of each experimental unit. A completely randomized design considered the term year × period as a repeated measure and chamber nested within paddock and treatment as the random term. Generally, SysB had greater CO emissions than SysA and GRE pasture sites across years and periods ( < 0.01). Soil temperature, AT, and WC had effects on CO emissions. Methane and NO emissions were observed from pasture sites of the 3 systems, but the effect of grazing was not constantly significant for CH and NO emissions. In addition, ST, AT, and WC did not conclusively explain CH and NO emissions. No clear trade-offs between GHG were observed; generally, GHG emissions increased from 2011 to 2013, which was likely associated with weather conditions, such as higher daily temperature and precipitation events. The central hypothesis that SysB would result in greater GHG emissions from pasture soils than SysA and GRE was not confirmed.

Future energy loads for a large-scale adoption of electric vehicles in the city of Los Angeles: Impacts on greenhouse gas (GHG) emissions

Using plug-in electric vehicles (PEVs) has become an important component of greenhouse gas (GHG) emissions reduction strategy in the transportation sector. Assessing the net effect of PEVs on GHG emissions, however, is dependent on factors such as type and scale of electricity generation sources, adoption rate, and charging behavior. This study creates a comprehensive model that estimates the energy load and GHG emissions impacts for the years 2020 and 2030 for the city of Los Angeles. For 2020, model simulations show that the PEV charging loads will be modest with negligible effects on the overall system load profile. Contrary to previous study results, the average marginal carbon intensity is higher if PEV charging occurs during off-peak hours. These results suggest that current economic incentives to encourage off-peak charging result in greater GHG emissions. Model simulations for 2030 show that PEV charging loads increase significantly resulting in potential generation shortages. There are also significant grid operation challenges as the region׳s energy grid is required to ramp up and down rapidly to meet PEV loads. For 2030, the average marginal carbon intensity for off-peak charging becomes lower than peak charging mainly due to the removal of coal from the power generation portfolio.

Vegetation Restoration and Its Effects on Carbon Balance in Guangdong Province, China

Abstract The significance of the regional carbon (C) balance of vegetation restoration to global change was studied in Guangdong Province, one of the most populated provinces in China. The percentage of the province in forestland cover increased steadily from 26.23% in 1979 to 50.11% in 1998 owing to restoration of forests. During this period, the area increase in the conifer forest was 424.83 × 104 ha, whereas the area in broad‐leaved, mixed, and other forests increased by 68.82 × 104, 18.94 × 104, and 60.46 × 104 ha, respectively. C sequestration by forest soils from 1979 to 1998 was 389.36 Mt, equivalent to 1.43 Pg fixed carbon dioxide (CO2). The total annual CO2 sequestration by forests and the soils was 118.05 Mt, which was about half of the annual CO2 emission in Guangdong. The role of forest management and restoration in improving the carbon balance is discussed.