Maximize Carbon Sequestration Research Articles

Boundaries matter: Greenhouse gas emission reductions from alternative waste treatment strategies for California's municipal solid waste

How waste is managed – whether as a nuisance to be disposed of, or as a resource to be reused – directly affects local and global environmental quality. This analysis explores the GHG benefits of five treatment options for residual municipal solid waste (MSW) in California: Business As Usual (landfilling), Anaerobic Digestion, Incineration, 40% Reduction, and MaxEnergy (both incineration and anaerobic digestion). Because recycling efforts in California are already strong, this analysis focuses on non-recyclables and asks what else can be done with the material fractions that are currently reaching landfills. Using two different waste LCA models, EASEWASTE (a Danish model) and WARM (a U.S. model), we find that improved biogenic waste management through anaerobic digestion and waste reduction can lead to life-cycle GHG savings when compared to Business As Usual. The magnitude of the benefits depends strongly on a number of model assumptions: the type of electricity displaced by waste-derived energy, how biogenic carbon is counted as a contributor to atmospheric carbon stocks, and the landfill gas collection rate. Assuming that natural gas is displaced by waste-derived energy, that 64% of landfill gas is collected, and that our system boundary begins when waste is thrown away and ends with disposal or conversion to air emissions, reducing California's residual waste by 40% can lead to a savings of 6 Mt (million metric tonnes) of CO 2-e per year, and digesting California's biogenic waste could save 0.6 Mt CO 2-e per year. Source reduction is the most robust means to mitigate GHG emissions from waste, though either increasing landfill gas capture rates within the current management plan or digesting biogenic waste (and designing landfills to maximize carbon sequestration) provide two other important means for greenhouse gas mitigation from waste management.

Using ecological criteria to develop CDM projects in Zhifanggou Valley, Loess Plateau, China

This study investigates the development of forestry Clean Development Mechanism projects on the Loess Plateau in China and analyzes its feasibility using Zhifanggou Valley as an example. The study considers the unique ecological environment and socio-economic situation of the project site, and applies the tree-shrub-grass model with the purpose of maximizing carbon sequestration in the area without compromising the quality of its environment. Income generation analysis and GIS analysis were applied in the research. Possible social and economic impacts of these projects are also discussed. Additional income opportunities for backward rural areas are explored, also in order to find new perspectives for conflicts between limited compensation periods to farmers involved in CDM projects and sustainable agro-forestry development. In particular, the study focuses on the impacts of forestry projects in rural areas on the Loess Plateau, from the perspectives of poverty reduction and, at the same time, ecological conservation policies. Results reveal that forestry CDM projects could generate CNY 140,000 annually for local residents or CNY 1240 per household when carbon sequestration of grasslands can be credited. Therefore, revenues generated by forestry CDM could make a significant contribution to vegetation conservation in these rural areas.

Soil organic carbon stocks in Laos: spatial variations and controlling factors

AbstractSurface soils, which contain the largest pool of terrestrial organic carbon (C), may be able to sequester atmospheric C and thus mitigate climate change. However, this remains controversial, largely due to insufficient data and knowledge gaps in respect of organic C contents and stocks in soils and the main factors of their control. Up to now and despite numerous evaluations of soil organic carbon (SOC) stocks worldwide, the sloping lands of southeast Asia, one of the most biogeochemically active regions of the world, remain uninvestigated. Our main objective was to quantify SOC stocks and to evaluate the impact of various environmental factors. We, therefore, selected Laos with 230 566 km2of mostly forested steep slopes, and where cultivation is still mainly traditional, i.e. a system of shifting cultivation without fertilization or mechanical tillage. Analytical data from 3471 soil profiles demonstrated that the top 1 m of soil depth holds an estimated 4.64 billion tons of SOC, 65% of which is in the first 0.3 m. SOC stocks to 0.3 m exhibit a high coefficient of variation (CV=62%) with values from 1.8 to 771 Mg C ha−1and a mean at 129 Mg C ha−1. Furthermore, these stocks are significantly (atP<0.05 level) affected by land use as shown by principal components analysis andt‐tests with the largest amount being found under forest, less under shifting cultivation and the smallest under continuous cultivation. Moreover, SOC stocks correlated regionally to total annual rainfalls and latitude, and locally at the hill‐slope level to the distance to the stream network and the slope angle. It is hypothesized that this correlation is through actions on mineral weathering, soil clay content, soil fertility and SOC redistributions in landscapes. These relationships between SOC stocks and environmental factors may be of further use in (1) predicting the impact of global changes on future SOC stocks; and (2) identifying optimal strategies for land use planning so as to minimize soil C emissions to the atmosphere while maximizing carbon sequestration in soils.

Effect of forest management on future carbon pools and fluxes: A model comparison

Currently, there is a strong demand for estimates of the current and potential future carbon sequestration in forests, the role of management practices, and the temporal duration of biotic carbon sinks. Different models, however, lead to different projections. Model comparisons allow us to assess the range of potential ecosystem responses, and they facilitate the detection of the strengths and weaknesses of particular models. In this study, the empirical, individual-based forest models MASSIMO, the semi-empirical individual-based forest models SILVA – both combined with the soil model YASSO – and the process-based, biogeochemical model Biome-BGC were used to assess the above- and belowground carbon pools and net fluxes of several forested regions in Switzerland for the next 100 years under four different management scenarios: (1) the current harvest amounts were used, (2) harvest was intensified by reducing the amount of large tree dimensions, (3) harvest was reduced to a minimum by only maintaining the protection function in mountain forests and avoiding pests and diseases, and (4) harvest was adjusted to achieve maximum sustainable growth. The results show that the three models projected similar patterns of net carbon fluxes. The models estimated that in the absence of large-scale disturbances the forest biomass and soil carbon can be increased, particularly under scenario 2, and therefore, forests can be used as carbon sinks. These sinks were estimated to last for a maximum of 100 years. Differences between the management scenarios depend on the time period considered: either net carbon fluxes are maximized at a short term (30–40 years) or at a longer term (100 years or more). In contrast to the similar carbon fluxes, some carbon pools projected by the models differed strongly. These differences in model behaviour can be attributed to model-specific responses to the strongly heterogeneous Swiss climate conditions and to different model assumptions. To find the optimum strategy in terms of not only maximizing carbon sequestration but climate protection, it is essential to account for wood-products and particularly substitution of fossil fuel in the model simulations.

Climate Change Effects on Mediterranean Forests and Preventive Measures

This paper synthesizes and reviews literature concerning climate change effects on Mediterranean forest ecology and management as well as the restorative techniques necessary to maintain forest health, forest yield and biodiversity. Climate change compounded with trends of rural abandonment are likely to diminish forested areas within the Mediterranean basin that will be replaced by fire prone shrub communities. This could be favoured by outbreaks of pathogens, fire and other large-scale disturbances. Landscape fragmentation is expected to impede species migration. Annual increments and subsequent income from forests are expected to decrease. Reafforestations are necessary to ensure the presence of propagules of forest species and their site-specific varieties best adapted to future climatic conditions even though they may be different from the present forest-plant community. Current challenges in biodiversity conservation can only be met by afforestations whose main objective is to maintain ecosystem functioning. A new silviculture must emerge encompassing these habitat displacement and economic concerns while maximizing carbon sequestration.

Optimizing Forest Management for Atmospheric Carbon Sequestration

Forest disturbances from logging activities in Canada’s boreal forest influence forest structure and nutrient cycling. Understanding the effect of Canadian forest industry practices on carbon uptake, storage, and release is important for forest management. Forest management is an important component of climate change mitigation through the removal of carbon from the atmosphere. Changes to forest structure and soil nutrient storage can have significant impacts on primary productivity. Primary productivity is a measure of the rate of carbon sequestration in forest biomass. Reviewing the literature on forest ecosystem carbon dynamics will inform on how to maximize carbon sequestration in forest management. Identifying forest industry practices that result in the highest rates of carbon sequestration is an important step for sustainable forest management.