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This paper develops a strategy for the continuing and improved supply of woodfuels to urban and industrial consumers in Sub-Sahara Africa. It argues that continued use of these fuels is not only a necessity, but is also in the best economic interest of most of the countries in this region. It shows that intensified and more orderly utilization of woodfuels can help to enhance, rather than impinge upon environmental parameters. Some examples are provided that illustrate how such strategies can be put into practice.

We utilize a variety of climate datasets to examine impacts of two mechanisms on precipitation in the Greater Horn of Africa (GHA) during northern-hemisphere summer. First, surface-pressure gradients draw moist air toward the GHA from the tropical Atlantic Ocean and Congo Basin. Variability of the strength of these gradients strongly influences GHA precipitation totals and accounts for important phenomena such as the 1960s–1980s rainfall decline and devastating 1984 drought. Following the 1980s, precipitation variability became increasingly influenced by the southern tropical Indian Ocean (STIO) region. Within this region, increases in sea-surface temperature, evaporation, and precipitation are linked with increased exports of dry mid-tropospheric air from the STIO region toward the GHA. Convergence of dry air above the GHA reduces local convection and precipitation. It also produces a clockwise circulation response near the ground that reduces moisture transports from the Congo Basin. Because precipitation originating in the Congo Basin has a unique isotopic signature, records of moisture transports from the Congo Basin may be preserved in the isotopic composition of annual tree rings in the Ethiopian Highlands. A negative trend in tree-ring oxygen-18 during the past half century suggests a decline in the proportion of precipitation originating from the Congo Basin. This trend may not be part of a natural cycle that will soon rebound because climate models characterize Indian Ocean warming as a principal signature of greenhouse-gas induced climate change. We therefore expect surface warming in the STIO region to continue to negatively impact GHA precipitation during northern-hemisphere summer.

Individual trees have been shown to exhibit strong relationships between DBH, height and volume. Often such studies are cited as justification for forest volume or standing biomass estimation through remote sensing. With resolution of common satellite remote sensing systems generally too low to resolve individuals, and a need for larger coverage, these systems rely on descriptive heights, which account for tree collections in forests. For remote sensing and allometric applications, this height is not entirely understood in terms of its location. Here, a forest growth model (SERA) analyzes forest canopy height relationships with forest wood volume. Maximum height, mean, H₁₀₀, and Lorey's height are examined for variability under plant number density, resource and species. Our findings, shown to be allometrically consistent with empirical measurements for forested communities world-wide, are analyzed for implications to forest remote sensing techniques such as LiDAR and RADAR. Traditional forestry measures of maximum height, and to a lesser extent H₁₀₀ and Lorey's, exhibit little consistent correlation with forest volume across modeled conditions. The implication is that using forest height to infer volume or biomass from remote sensing requires species and community behavioral information to infer accurate estimates using height alone. SERA predicts mean height to provide the most consistent relationship with volume of the height classifications studied and overall across forest variations. This prediction agrees with empirical data collected from conifer and angiosperm forests with plant densities ranging between 10²-10⁶ plants/hectare and heights 6-49 m. Height classifications investigated are potentially linked to radar scattering centers with implications for allometry. These findings may be used to advance forest biomass estimation accuracy through remote sensing. Furthermore, Lorey's height with its specific relationship to remote sensing physics is recommended as a more universal indicator of volume when using remote sensing than achieved using either maximum height or H₁₀₀.

AbstractChina is under pressure to improve its agricultural productivity to keep up with the demands of a growing population with increasingly resource‐intensive diets. This productivity improvement must occur against a backdrop of carbon intensity reduction targets, and a highly fragmented, nutrient‐inefficient farming system. Moreover, the Chinese government increasingly recognizes the need to rationalize the management of the 800 million tonnes of agricultural crop straw that China produces each year, up to 40% of which is burned in‐field as a waste. Biochar produced from these residues and applied to land could contribute to China's agricultural productivity, resource use efficiency and carbon reduction goals. However competing uses for China's straw residues are rapidly emerging, particularly from bioenergy generation. Therefore it is important to understand the relative economic viability and carbon abatement potential of directing agricultural residues to biochar rather than bioenergy. Using cost‐benefit analysis (CBA) and life‐cycle analysis (LCA), this paper therefore compares the economic viability and carbon abatement potential of biochar production via pyrolysis, with that of bioenergy production via briquetting and gasification. Straw reincorporation and in‐field straw burning are used as baseline scenarios. We find that briquetting straw for heat energy is the most cost‐effective carbon abatement technology, requiring a subsidy of $7 MgCO2e−1 abated. However China's current bioelectricity subsidy scheme makes gasification (NPV $12.6 million) more financially attractive for investors than both briquetting (NPV $7.34 million), and pyrolysis ($−1.84 million). The direct carbon abatement potential of pyrolysis (1.06 MgCO2e per odt straw) is also lower than that of briquetting (1.35 MgCO2e per odt straw) and gasification (1.16 MgCO2e per odt straw). However indirect carbon abatement processes arising from biochar application could significantly improve the carbon abatement potential of the pyrolysis scenario. Likewise, increasing the agronomic value of biochar is essential for the pyrolysis scenario to compete as an economically viable, cost‐effective mitigation technology.

The basins of the Indus and Ganges rivers cover 2.20 million km2 and are inhabited by more than a billion people. The region is under extreme pressures of population and poverty, unregulated utilization of the resources and low levels of productivity. The needs are: (1) development policies that are regionally differentiated to ensure resource sustainability and high productivity; (2) immediate development and implementation of policies for sound groundwater management and energy use; (3) improvement of the fragile food security and to broaden its base; and (4) policy changes to address land fragmentation and improved infrastructure. Meeting these needs will help to improve productivity, reduce rural poverty and improve overall human development.

This chapter uses data on Intended Nationally Determined Contributions (INDCs) to examine the nature of climate change mitigation and adaptation actions being pursued in African countries and assesses the extent to which preferred mitigation and adaptation priorities advance the cause of sustainable development on the continent. The prospective synergies between mitigation and adaptation approaches and sustainable development are assessed. Also, the pathways through which resource constraints and institutional and policy environment affect Africa’s ability to mitigate and adapt to climate change are examined, as well as the degree to which these constraints are being addressed. It is argued that Africa’s ability to benefit from sustainable development synergies embedded in the mitigation and adaptation strategies in the INDCs will be greatly limited by institutional and policy environment that hinders funding, capacity building, and technological innovation systems development. The slow pace of efforts to address these impediments further erodes confidence that climate adaptation in Africa will be effective at sufficiently contributing to a reduction in climate change risks to the continent.

Abstract Sweet sorghum, a C4 plant, is known to be a unique, versatile, and potential energy crop that can be separated into starchy grains, soluble sugar juice, and lignocellulosic biomass. The fermentable sugars in the juice (53–85% sucrose, 9–33% glucose, and 6–21% fructose) can be directly fermented into ethanol. The grain is primarily starch (62–75%), which can be hydrolyzed and fermented into ethanol. The bagasse, a fibrous lignocellulosic material, can be used to produce cellulosic ethanol, heat and/or power co-generation. In this review, the potential of sweet sorghum for bioenergy production (of various forms) using recently developed cultivars with improved agronomic performance was discussed. In addition, sweet sorghum was compared with other starch, sugar, and lignocellulosic feedstocks. Studies have been conducted on alternative pathways to convert whole sweet sorghum stalks and bagasse into bioenergy. However, very little review of the techno-economic analysis of bioenergy production and co-products from sweet sorghum has been published. The aim of this research was to review the current knowledge of agronomic requirement for cultivating sweet sorghum, the productivity of recently developed cultivars for bioenergy production, and pathways of converting sweet sorghum crop into bioenergy as well as the techno-economic feasibility of using sweet sorghum for bioenergy.

Abstract A hydrocarbon miscible flood was initiated in the Wizard Lake D-3A pool in late 1969. The scheme involved placing a slug of LPG at the gas-oil interface, and displacing it vertically downward with dry gas while injecting water to stabilize the oil-water contact. Ultimate recovery is expected to be 323 million stock tank barrels, 84per cent of the original oil-in-place and 69 million stock tank barrels higher than under primary depletion. The Wizard Lake D-3A pool, located in central Alberta, is one of nine Devonian reef pools connected to the Cooking Lake aquifer. It is a dolomitized bioherm reef with a maximum original oil zone of 648 feet. The pool was considered an ideal candidate for a miscible displacement process because of its vertical relief, small areal extent and the absence of any barriers that would be detrimental to displacement of the slug. This paper reviews the implementation, monitoring techniques and performance of the miscible flood scheme. Introduction The Wizard Lake D-3A pool, located 55 kilometres (35 miles) southwest of Edmonton, as shown in Figure 1, was discovered in April 1951 with the drilling of Texaco Wizard Lake Crown 'B-I in 12-22-48-27-W4M. The pool, drilled on 4D-acre spacing, was fully delineated by the late nineteen fifties. The reservoir is a dolomitized bioherm reef of Devonian age which is part of a prolific chain of Leduc member reefs appropriately known as the Golden Trend. The productive horizon attained a maximum recorded height of 197.5 metres (648 feet) above the Cooking Lake aquifer in which reef growth was initiated. The Cooking Lake aquifer pinches out to the west, but is extensive in the other three directions. This aquifer is very active and is common to other oil and gas accumulations which give rise to interference between pools (Figures 2 and 3). The oil column covered an area of 1,507 hectares (3,725 acres) at the original oil-water contact of 1,230 metres subsea (4,034 feet subsea). Figure 4 presents a structure contour map of the top of the pool based on the gross reef section. The initial oil-in-place is estimated to be 61,200,000 m3 (385 MMSTB), with some 6.5 × 109 m3 (231 bcf) of solution gas dissolved in it. The primary recovery mechanism, identified as a combination of gas expansion, water drive and gravity segregation, was allowed to continue until 1969, when a slug-type hydrocarbon miscible scheme was initiated (Fig. 5). In 1965, a secondary gas cap began to form and by the end of 1969 there existed a 24-metre (78-foot) gas column containing approximately 152 × 106 m3 (5.4 Bcf). Also, by 1969 the oil-water contact had risen by 15 metres (50 feet); leaving an relatively small quantity of available core and thus a method had to be developed to Overcome this shortcoming and also handle the edge effect on porosity that is characteristic of reef pools(1).