Water Scarcity



Grieg-Gran M, Porras I, Wunder S. How can market mechanisms for forest environmental services help the poor? Preliminary lessons from Latin America. World Development [Internet]. 2005;33 :1511-1527. Publisher's VersionAbstract

Market mechanisms for forest environmental services are a new approach for conservation, but there is also an increasing interest in the derived developmental benefits of these mechanisms. We first propose a conceptual framework for future research on the livelihood impacts of environmental service markets. We then review eight Latin American case studies on carbon sequestration and watershed protection market initiatives, finding positive local income effects in most cases, more land tenure security and socioinstitutional strengthening in some cases, but some
negative effects also. We recommend pro-poor policy measures such as reducing smallholders’ transaction costs and removing inappropriate access restrictions.

Pagiola S, Arcenas A, Platais G. Can Payments for Environmental Services Help Reduce Poverty? An Exploration of the Issues and the Evidence to Date from Latin America. World Development [Internet]. 2005;33 :237-253. Publisher's VersionAbstract

This paper examines the main ways in which Payments for Environmental Services (PES) might affect poverty. PES may reduce poverty mainly by making payments to poor natural resource managers in upper watersheds. The extent of the impact depends on how many PES participants are in fact poor, on the poor’s ability to participate, and on the amounts paid. Although PES programs are not designed for poverty reduction, there can be important synergies when program design is well thought out and local conditions are favorable. Possible adverse effects can occur where property rights are insecure or if PES programs encourage less labor-intensive practices.


Weltzin JF, Loik ME, Schwinning S, Williams DC, Fay PA, Haddad BM, Harte J, Huxman TE, Knapp AK, Lin G, et al. Assessing the Response of Terrestrial Ecosystems to Potential Changes in Precipitation. Bioscience [Internet]. 2003;53 :941-952. Publisher's VersionAbstract

Changes in Earth's surface temperatures caused by anthropogenic emissions of greenhouse gases are expected to affect global and regional precipitation regimes. Interactions between changing precipitation regimes and other aspects of global change are likely to affect natural and managed terrestrial ecosystems as well as human society. Although much recent research has focused on assessing the responses of terrestrial ecosystems to rising carbon dioxide or temperature, relatively little research has focused on understanding how ecosystems respond to changes in precipitation regimes. Here we review predicted changes in global and regional precipitation regimes, outline the consequences of precipitation change for natural ecosystems and human activities, and discuss approaches to improving understanding of ecosystem responses to changing precipitation. Further, we introduce the Precipitation and Ecosystem Change Research Network (PrecipNet), a new interdisciplinary research network assembled to encourage and foster communication and collaboration across research groups with common interests in the impacts of global change on precipitation regimes, ecosystem structure and function, and the human enterprise. [ABSTRACT FROM AUTHOR]Copyright of Bioscience is the property of American Institute of Biological Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts)

Gleick PH. Global freshwater resources: soft-path solutions for the 21st century. Science [Internet]. 2003;302 :1524-8. Publisher's VersionAbstract

Twentieth-century water policies relied on the construction of massive infrastructure in the form of dams, aqueducts, pipelines, and complex centralized treatment plants to meet human demands. These facilities brought tremendous benefits to billions of people, but they also had serious and often unanticipated social, economical, and ecological costs. Many unsolved water problems remain, and past approaches no longer seem sufficient. A transition is under way to a "soft path" that complements centralized physical infrastructure with lower cost community-scale systems, decentralized and open decision-making, water markets and equitable pricing, application of efficient technology, and environmental protection.

Oki T, Kanae S. Global Hydrological Cycles and World Water Resources. Science [Internet]. 2006;313 :1068-1072. Publisher's VersionAbstract

Water is a naturally circulating resource that is constantly recharged. Therefore, even though the stocks of water in natural and artificial reservoirs are helpful to increase the available water resources for human society, the flow of water should be the main focus in water resources assessments. The climate system puts an upper limit on the circulation rate of available renewable freshwater resources (RFWR). Although current global withdrawals are well below the upper limit, more than two billion people live in highly water-stressed areas because of the uneven distribution of RFWR in time and space. Climate change is expected to accelerate water cycles and thereby increase the available RFWR. This would slow down the increase of people living under water stress; however, changes in seasonal patterns and increasing probability of extreme events may offset this effect. Reducing current vulnerability will be the first step to prepare for such anticipated changes.

Vidale, P L, Luthi D, Wemann R, Schar C. European summer climate variability in a heterogeneous multi-model ensemble. Climatic Change [Internet]. 2007;81 :209-232. Publisher's VersionAbstract

Recent results from an enhanced greenhouse-gas scenario over Europe suggest that climate change might not only imply a general mean warming at the surface, but also a pronounced increase in interannual surface temperature variability during the summer season (Schär et al., Nature 427:332–336, 2004). It has been proposed that the underlying physical mechanism is related to land surface-atmosphere interactions. In this study we expand the previous analysis by including results from a heterogeneous ensemble of 11 high-resolution climate models from the PRUDENCE project. All simulations considered comprise 30-year control and enhanced greenhouse-gas scenario periods. While there is considerable spread in the models’ ability to represent the observed summer variability, all models show some increase in variability for the scenario period, confirming the main result of the previous study. Averaged over a large-scale Central European domain, the models simulate an increase in the standard deviation of summer mean temperatures between 20 and 80%. The amplification occurs predominantly over land points and is particularly pronounced for surface temperature, but also evident for precipitation. It is also found that the simulated changes in Central European summer conditions are characterized by an emergence of dry and warm years, with early and intensified depletion of root-zone soil moisture. There is thus some evidence that the change in variability may be linked to the dynamics of soil-moisture storage and the associated feedbacks on the surface energy balance and precipitation.

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