Bilateral intralobar pulmonary sequestration : a case report

Bronchopulmonary sequestration is a congenital lung malformation consisting of a non-functioning lung segment. Arterial supply to such a segment is found to be systemic rather than pulmonary, and by definition there is no communication with the tracheobronchial tree. It accounts for about 6% of all congenital pulmonary malformations. Bilateral bronchopulmonary sequestration is yet more uncommon. These malformations can be classified as either intralobar sequestration (the commoner type), or extralobar sequestration (in 14- 25%).peer-reviewe

Potential for soil organic carbon sequestration in grasslands in East African countries: A review

Grasslands occupy almost half of the world's land area. Soil organic carbon (SOC) is a key indicator of soil fertility and grassland productivity. Increasing SOC stocks (so‐called SOC sequestration) improves soil fertility and contributes to climate change mitigation by binding atmospheric carbon dioxide (CO2). Grasslands constitute about 70% of all agricultural land, but their potential for SOC sequestration is largely unknown. This review paper quantitatively summarizes observation‐based studies on the SOC sequestration potential of grasslands in six East African countries (Burundi, Ethiopia, Kenya, Rwanda, Tanzania and Uganda) and seeks to identify knowledge gaps related to SOC sequestration potential in the region. In the studies reviewed, SOC stocks in grasslands range from 3 to 93 Mg C/ha in the upper 0.3 m of the soil profile, while SOC sequestration rate ranges from 0.1 to 3.1 Mg C ha‐1 year‐1 under different management strategies. Grazing management is reported to have a considerable impact on SOC sequestration rates, and grassland regeneration and protection are recommended as options to stimulate SOC sequestration. However, a very limited number of relevant studies are available (n = 23) and there is a need for fundamental information on SOC sequestration potential in the region. The effectiveness of potential incentive mechanisms, such as payments for environmental services, to foster uptake of SOC‐enhancing practices should also be assessed

The optimal carbon sequestration in agricultural soils : does the dynamics of the physical process matter ?

The Kyoto Protocol, which came in force in February 2005, allows countries to resort to «supplementary activities» consisting particularly in carbon sequestration in agricultural soils. Existing papers studying the optimal carbon sequestration recognize the importance of the temporality of sequestration, but overlook the fact that it is a dissymmetric dynamic process. This paper takes explicitely into account the temporality of sequestration. Its first contribution is technical : we solve an optimal control problem with two stages and a dissymmetric dynamic process. The second contribution is empirical : we show that the error made when sequestration is supposed immediate can be very significant, and we exhibit numerically the optimal path of sequestration/de-sequestration for specific benefit, damage and cost functions, and a calibration that mimics roughly the world conditions.Environment, agriculture, carbon sequestration, Kyoto Protocol, optimal control.

Sequestering atmospheric CO₂ inorganically:a solution for Malaysia's CO₂ emission

Malaysia is anticipating an increase of 68.86% in CO2 emission in 2020, compared with the 2000 baseline, reaching 285.73 million tonnes. A major contributor to Malaysia's CO2 emissions is coal-fired electricity power plants, responsible for 43.4% of the overall emissions. Malaysia's forest soil offers organic sequestration of 15 tonnes of CO2 ha(-1) year(-1). Unlike organic CO2 sequestration in soil, inorganic sequestration of CO2 through mineral carbonation, once formed, is considered as a permanent sink. Inorganic CO2 sequestration in Malaysia has not been extensively studied, and the country's potential for using the technique for atmospheric CO2 removal is undefined. In addition, Malaysia produces a significant amount of solid waste annually and, of that, demolition concrete waste, basalt quarry fine, and fly and bottom ashes are calcium-rich materials suitable for inorganic CO2 sequestration. This project introduces a potential solution for sequestering atmospheric CO2 inorganically for Malaysia. If lands associated to future developments in Malaysia are designed for inorganic CO2 sequestration using demolition concrete waste, basalt quarry fine, and fly and bottom ashes, 597,465 tonnes of CO2 can be captured annually adding a potential annual economic benefit of (sic)4,700,000.</p

CARBON DIOXIDE SEQUESTRATION: WHEN AND HOWMUCH?

We analyze carbon dioxide (CO sequestration as a strategy to manage future climate change in an optimal economic growth framework. We approach the problem in two ways: first, by using a simple analytical model, and second, by using a numerical optimization model which allows us to explore the problem in a more realistic setting. CO sequestration is not a perfect substitute for avoiding CO2 production because CO2 leaks back to the atmosphere and hence imposes future costs. The “efficiency factor” of CO2 sequestration can be expressed as the ratio of the avoided emissions to the economically equivalent amount of sequestered CO2 emissions. A simple analytical model in terms of a net-present value criterion suggests that short-term sequestration methods such as afforestation can be somewhat ( 60 %) efficient, while long term sequestration (such as deep aquifer or deep ocean sequestration) can be very ( 90%) efficient. A numerical study indicates that CO2 sequestration methods at a cost within the range of present estimates reduce the economically optimal CO2 concentrations and climate related damages. The potential savings associated with CO2 sequestration is equivalent in our utilitarian model to a one-time investment of several percent of present gross world product.

Optimal use of carbon sequestration in a global climate change strategy : is there a wooden bridge to a clean energy future ?

s. Whether it should be part of a global climate mitigation strategy, however, remains controversial. One of the key issues is that, contrary to emission abatement, carbon sequestration might not be permanent. But some argue that even temporary sequestration is beneficial as it delays climate change impacts and"buys"time for technical change in the energy sector. To rigorously assess these arguments, the authors build an international optimization model in which both sequestration and abatement can be used to mitigate climate change. They confirm that permanent sequestration, if feasible, can be overall part of a climate mitigation strategy. When permanence can be guaranteed, sequestration is equivalent to fossil-fuel emissions abatement. The optimal use of temporary sequestration, on the other hand, depends mostly on marginal damages of climate change. Temporary sequestration projects starting now, in particular, are not attractive if marginal damages of climate change at current concentration levels are assumed to be low.Montreal Protocol,Environmental Economics&Policies,Climate Change,Economic Theory&Research,Global Environment Facility,Energy and Environment,Environmental Economics&Policies,Montreal Protocol,Carbon Policy and Trading,Climate Change

Ultra High Energy Cosmic Rays from Sequestered X Bursts

Assuming that there is no GZK (Greisen-Zatsepin-Kuzmin) cut-off and that super-GZK cosmic rays correlate with AGN (Active Galactic Nuclei) at cosmological distances, it is speculated that a relic superheavy particle (X) has its lifetime enhanced by sequestration in an extra dimension. This sequestration is assumed to be partially liberated by proximity of merging supermassive black holes in an AGN, temporarily but drastically reducing the lifetime, thus stimulating an X burst. Based on sequestration of the decay products of X, a speculative explanation of the observed $\gamma/N$ ratio is proposed.Comment: 12 pages LaTe

Great SCO2T! Rapid tool for carbon sequestration science, engineering, and economics

CO2 capture and storage (CCS) technology is likely to be widely deployed in coming decades in response to major climate and economics drivers: CCS is part of every clean energy pathway that limits global warming to 2C or less and receives significant CO2 tax credits in the United States. These drivers are likely to stimulate capture, transport, and storage of hundreds of millions or billions of tonnes of CO2 annually. A key part of the CCS puzzle will be identifying and characterizing suitable storage sites for vast amounts of CO2. We introduce a new software tool called SCO2T (Sequestration of CO2 Tool, pronounced "Scott") to rapidly characterizing saline storage reservoirs. The tool is designed to rapidly screen hundreds of thousands of reservoirs, perform sensitivity and uncertainty analyses, and link sequestration engineering (injection rates, reservoir capacities, plume dimensions) to sequestration economics (costs constructed from around 70 separate economic inputs). We describe the novel science developments supporting SCO2T including a new approach to estimating CO2 injection rates and CO2 plume dimensions as well as key advances linking sequestration engineering with economics. Next, we perform a sensitivity and uncertainty analysis of geology combinations (including formation depth, thickness, permeability, porosity, and temperature) to understand the impact on carbon sequestration. Through the sensitivity analysis we show that increasing depth and permeability both can lead to increased CO2 injection rates, increased storage potential, and reduced costs, while increasing porosity reduces costs without impacting the injection rate (CO2 is injected at a constant pressure in all cases) by increasing the reservoir capacity.Comment: CO2 capture and storage; carbon sequestration; reduced-order modeling; climate change; economic

Land-Use Change and Carbon Sinks

When and if the United States chooses to implement a greenhouse gas reduction program, it will be necessary to decide whether carbon sequestration policies — such as those that promote forestation and discourage deforestation — should be part of the domestic portfolio of compliance activities. We investigate the cost of forest-based carbon sequestration. In contrast with previous approaches, we econometrically examine micro-data on revealed landowner preferences, modeling six major private land uses in a comprehensive analysis of the contiguous United States. The econometric estimates are used to simulate landowner responses to sequestration policies. Key commodity prices are treated as endogenous and a carbon sink model is used to predict changes in carbon storage. Our estimated marginal costs of carbon sequestration are greater than those from previous engineering cost analyses and sectoral optimization models. Our estimated sequestration supply function is similar to the carbon abatement supply function from energy-based analyses, suggesting that forest-based carbon sequestration merits inclusion in a cost-effective portfolio of domestic U.S. climate change strategies.abatement; carbon; climate change; costs; forestry; greenhouse gases; land use; landuse change; sequestration

Estimating the costs of atmospheric carbon reductions in Mexico

Trading in carbon emissions is a means of ensuring that supplies with the lowest marginal costs of emissions reduction are commissioned first. To analyse the potential for Mexican suppliers to participate in an emissions trading market, the relative cost-effectiveness of a carbon sequestration project and carbon abatement project is assessed. The marginal costs of emission reductions for each project are estimated and compared using standardised data. The results show that the carbon sequestration project has lower marginal costs for carbon emissions reductions than the technology-based abatement. Factors such as timescale, discounting implementation costs, transaction costs, and technical assumptions are considered in this comparison. The high transaction costs to set up carbon sequestration projects and weak institutional capacity to monitor and enforce agreements are relevant factors. Even though the carbon sequestration project is more cost-effective than the renewable energy power plant, both projects may allow Mexican suppliers to enter a potential international carbon emissions trading market depending on demand and supply conditions and the rules of the market