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The Middle East and North Africa (MENA) region is one of the most water-stressed parts of the world. In just over 25 years, between 1975 and 2001. Looking to the future, MENA's freshwater outlook is expected to worsen because of continued population growth and projected climate change impacts. The region's population is on the way to doubling to 700 million by 2050. Projections of climate change and variability impacts on the region's water availability are highly uncertain, but they are expected to be largely negative. To offer just one more example, rainfall and freshwater availability could decrease by up to 40 percent for some MENA countries by the end of this century. The urgent challenge is how to adapt to the future as illustrated by these numbers and how to turn the region's economy onto a sustainable path. This volume suggests new ways of thinking about the complex changes and planning needed to achieve this. New thinking will mean making better use of desert land, sun, and salt water the abundant riches of the region which can be harnessed to underpin sustainable growth. More mundane, but just as important, new thinking will also mean planning for dramatically better management of the water already available. Right now, water is very poorly managed in MENA. Inefficiencies are notorious in agriculture, where irrigation consumes up to 81 percent of extracted water. Similarly, municipal and industrial water supply systems have abnormally high losses, and most utilities are financially unsustainable. In addition, many MENA countries overexploit their fossil aquifers to meet growing water demand. None of this is sustainable while water resources decline. This volume hopes to add to the ongoing thinking and planning by presenting methodologies to address the water demand gap. It assesses the viability of desalination powered by renewable energy from economic, social, technical, and environmental viewpoints, and it reviews initiatives attempting to make renewable energy desalination a competitively viable option. The authors also highlight the change required in terms of policy, financing, and regional cooperation to make this alternative method of desalination a success. And as with any leading edge technology, the conversation here is of course about scale, cost, environmental impact, and where countries share water bodies plain good neighborly behavior.

Energy efficiency may be an inexpensive way to meet future demand and reduce greenhouse gas emissions, yet little work has been attempted to estimate annual energy efficiency supply functions for electricity planning. The main advantage of using a supply function is that energy efficiency adoption can change as demand changes. Models such as Duke University’s Dynamic Integrated Economy/Energy/Emissions Model (DIEM) have had to rely on simplistic or fixed estimates of future energy efficiency from the literature rather than on estimates from energy efficiency supply curves. This paper attempts to develop a realistic energy efficiency supply curve and to improve on the current energy efficiency modeling. It suggests an alternative approach based on saved-energy cost data from program administrators and explains the methodologies employed to create the supply curve. It illustrates this approach with results from DIEM for various electricity demand scenarios. The analysis suggests that an additional 5–9% of energy efficiency is deployed for every 10% increase in the cost of electricity. Therefore, DIEM “invested” in energy efficiency up to an inelastic point on the energy efficiency supply curve. By contrast, the U.S. Environmental Protection Agency’s energy efficiency approach assumes that realized energy efficiency is fixed, and has no elasticity, regardless of changes to marginal costs or constraints that affect emissions or economics.

The chemical weathering of rocks currently absorbs about 1.1 Gt CO2 a−1 being mainly stored as bicarbonate in the ocean. An enhancement of this slow natural process could remove substantial amounts of CO2 from the atmosphere, aiming to offset some unavoidable anthropogenic emissions in order to comply with the Paris Agreement, while at the same time it may decrease ocean acidification. We provide the first comprehensive assessment of economic costs, energy requirements, technical parameterization, and global and regional carbon removal potential. The crucial parameters defining this potential are the grain size and weathering rates. The main uncertainties about the potential relate to weathering rates and rock mass that can be integrated into the soil. The discussed results do not specifically address the enhancement of weathering through microbial processes, feedback of geogenic nutrient release, and bioturbation. We do not only assess dunite rock, predominantly bearing olivine (in the form of forsterite) as the mineral that has been previously proposed to be best suited for carbon removal, but focus also on basaltic rock to minimize potential negative side effects. Our results show that enhanced weathering is an option for carbon dioxide removal that could be competitive already at 60 US $ t−1 CO2 removed for dunite, but only at 200 US $ t−1 CO2 removed for basalt. The potential carbon removal on cropland areas could be as large as 95 Gt CO2 a−1 for dunite and 4.9 Gt CO2 a−1 for basalt. The best suited locations are warm and humid areas, particularly in India, Brazil, South-East Asia and China, where almost 75% of the global potential can be realized. This work presents a techno-economic assessment framework, which also allows for the incorporation of further processes.

Financial constraints are fundamental to empirical research in finance and economics. We propose two tests to evaluate how well measures of financial constraints actually capture constraints. We find that firms typically classified as constrained do not actually behave as if they were constrained: they have no trouble raising debt when their demand for debt increases exogenously and use the proceeds of equity issues to increase payouts to shareholders. Our evidence suggests that extant findings that have been attributed to constraints may instead reflect differences in the growth and financing policies of firms at different stages of their life cycles.

In carbon capture and storage (CCS), CO2 is captured at power plants and then injected underground into reservoirs like deep saline aquifers for long-term storage. While CCS may be critical for the continued use of fossil fuels in a carbon-constrained world, the deployment of CCS has been hindered by uncertainty in geologic storage capacities and sustainable injection rates, which has contributed to the absence of concerted government policy. Here, we clarify the potential of CCS to mitigate emissions in the United States by developing a storage-capacity supply curve that, unlike current large-scale capacity estimates, is derived from the fluid mechanics of CO2 injection and trapping and incorporates injection-rate constraints. We show that storage supply is a dynamic quantity that grows with the duration of CCS, and we interpret the lifetime of CCS as the time for which the storage supply curve exceeds the storage demand curve from CO2 production. We show that in the United States, if CO2 production from power generation continues to rise at recent rates, then CCS can store enough CO2 to stabilize emissions at current levels for at least 100 y. This result suggests that the large-scale implementation of CCS is a geologically viable climate-change mitigation option in the United States over the next century.

Macroeconomics is the study of the economy as a whole and of work and saving choices of individual economic agents from which macroeconomic activity emerges. This book takes an integrative approach to that topic, showing how short-run and long-run forces operate simultaneously to determine the behavior of key economic indicators such as employment and real, inflation-adjusted GDP.

The Oprah Supply Curve shows the relationship between the quantity of Oprah Winfrey supplied and her income. Although even a Nobel laureate has speculated on the shape of that curve, its shape has not been estimated. We estimate its shape by using variation in the number of new episodes per season of Oprah's television show, The Oprah Winfrey Show. The curve appears to be backward bending. Thus, while Oprah may not be an obvious target for taxation, a higher tax rate might expand the quantity of services she supplies while also increasing tax revenues.

South Africa’s energy network is under severe pressure due to low supply and overwhelming demand. With an increase in renewable energy providers, specifically wind energy, knowing how the supply can satisfy the electricity demand may relieve apprehensions. This research aims to provide insight into the wind energy supply of South Africa and question how well this supply meets the demand of South Africa. The methodology used in this work highlights the importance of access to public datasets to dispel misconceptions in the energy industry. Additionally, the work supports network planning and the arguments for increasing wind energy penetration on the South African grid. Wind profiles and the typical energy production of South African wind farms are compared to electricity demand. The geographical spacing of the operational wind farms is considered. It is observed that wind energy supply assists in the peak electricity hourly demand as well as seasonal peaks. Furthermore, South Africa’s coast is analysed to determine the offshore wind power potential, where shallow and deep waters are considered. It is observed that South Africa has a high potential for offshore wind, even after losses are applied.

By‐products of agricultural and forestry processes, known as residues, may act as a primary source of renewable energy. Studies assessing the availability of this resource offer little insight on the drivers and constraints of the available potential as well as the associated costs and how these may vary across scenarios. This study projects long‐term global supply curves of the available potential using consistent scenarios of agriculture and forestry production, livestock production and fuel use from the spatially explicit integrated assessment model IMAGE. In the projections, residue production is related to agricultural and forestry production and intensification, and the limiting effect of ecological and alternative uses of residues are accounted for. Depending on the scenario, theoretical potential is projected to increase from approximately 120 EJ yr−1 today to 140–170 EJ yr−1 by 2100, coming mostly from agricultural production. To maintain ecological functions approximately 40% is required to remain in the field, and a further 20–30% is diverted towards alternative uses. Of the remaining potential (approximately 50 EJ yr−1 in 2100), more than 90% is available at costs <10$2005 GJ−1. Crop yield improvements increase residue productivity, albeit at a lower rate. The consequent decrease in agricultural land results in a lower requirement of residues for erosion control. The theoretical potential is most sensitive to baseline projections of agriculture and forestry demand; however, this does not necessarily affect the available potential which is relatively constant across scenarios. The most important limiting factors are the alternative uses. Asia and North America account for two‐thirds of the available potential due to the production of crops with high residue yields and socioeconomic conditions which limit alternative uses.

Using unique data from 12 lenders, we examine how equity lending fees respond to demand shocks. We find that, when demand is moderate, fees are largely insensitive to demand shocks. However, at high demand levels, further increases in demand lead to significantly higher fees and the extent to which demand shocks impact fees is also related to search frictions in the loan market. Moreover, consistent with search models, we find significant dispersion in loan fees, with this dispersion increasing in loan scarcity and search frictions. Our findings imply that search frictions significantly impact short selling costs.