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Ritz S.P.,University of Bern | Stocker T.F.,University of Bern | Grimalt J.O.,The Water Council | Menviel L.,University of Sydney | Timmermann A.,University of Hawaii at Manoa
Nature Geoscience | Year: 2013

The Atlantic meridional overturning circulation affects the latitudinal distribution of heat, and is a key component of the climate system. Proxy reconstructions, based on sedimentary 231Pa/230Th ratios and the difference between surface- and deep-water radiocarbon ages, indicate that during the last glacial period, the overturning circulation was reduced during millennial-scale periods of cooling1-5. However, much debate exists over the robustness of these proxies6-8. Here we combine proxy reconstructions of sea surface and air temperatures and a global climate model to quantitatively estimate changes in the strength of the Atlantic meridional overturning circulation during the last glacial period. We find that, relative to the Last Glacial Maximum, the overturning circulation was reduced by approximately 14 Sv during the cold Heinrich event 1. During the Younger Dryas cold event, the overturning circulation was reduced by approximately 12 Sv, relative to the preceding warm interval. These changes are consistent with qualitative estimates of the overturning circulation from sedimentary 231Pa/230Th ratios. In addition, we find that the strength of the overturning circulation during the Last Glacial Maximum and the Holocene epoch are indistinguishable within the uncertainty of the reconstruction. Copyright © 2013 Macmillan Publishers Limited. Source


Climate change and rainfall variability poses serious risks to rainfed farming communities in the semi-dry agro-ecological zones of Zimbabwe. Its impacts include erratic and unpredictable seasonal rainfall, floods and cyclones. These impacts are more magnified in marginal rainfed agricultural areas characterized by low and erratic precipitation leading to low and unpredictable levels of crop production. Adaptation to these impacts is increasingly being advocated as a more sustainable response that enhances livelihoods. Through an examination of key debates from climate-science scholars, this paper examines the social research and action priorities that can be pursued in order to build the resilience of rural communities who rely on rainfed agriculture for their livelihoods. The paper examines the nature of adaptation processes and subsequently identifies research themes, action priorities and approaches that can generate more robust responses to climate change at various levels. The study found out that despite the weaknesses identified in Zimbabwean water and agricultural policies, there are a number of specific actions that researchers, policy-makers and communities can take to enhance adaptation capacity. Systematic assessment of rural risk and vulnerability and participatory identification of possible solutions can enable the rural poor to get better access to options, assets and the services they require to improve their livelihoods. This also enables the identification and improvement of more adaptation options that the farmers themselves have already been trying out for many years. © 2010 Elsevier Ltd. Source


Trade in energy products and services and investments in the energy sector are central to energy security. Despite the rhetoric of energy independence, the world's leading economies inhabit a complex world of energy flows and institutions that seek to govern them. This article asks: how is energy governed by international trade and investment institutions and agreements; and how would it be governed by these institutions depending on alternative governance preferences? Drawing on recent developments, it outlines three sets of tensions - between emerging multipolarity and existing regimes, between states and markets, and a structural imperative between energy and climate - that are shaping the context for energy governance. The article then analyses, from the perspective of energy exporters, importers and firms, how the landscape of multilateral, plurilateral and regional agreements manages these challenges. The current institutional configuration reveals partially overlapping memberships, incoherent rules governing state-driven policies and market-led interventions, and inconsistent rules between energy and environmental concerns. In pursuit of coherence in this complex milieu, the article ends by outlining a schematic framework for institutional design. The design choices depend on countries' preferences for greater or lesser consistency in rules and on more integrated versus fragmented governance across institutions. © 2011 London School of Economics and Political Science and John Wiley & Sons Ltd. Source


Giordano R.,The Water Council | Liersch S.,Potsdam Institute for Climate Impact Research
Environmental Modelling and Software | Year: 2012

The increasing awareness of the complexity and uncertainty of environmental processes is changing the role of information production to support decision-making. Monitoring systems need to gather reliable information, adopting a multi-scale and integrated approach. Using exclusively technical monitoring methods to collect the information could result in unsustainable monitoring costs. In order to minimize the costs and to address the scale issue, the integration of local and technical knowledge is proposed in this work. For the implementation of this approach, a tool based on the use of fuzzy logic and geographic information system (GIS) technologies was developed. The willingness of the local community to participate in monitoring activities was ensured by keeping these activities as simple and close to local knowledge as possible. The fuzzy GIS-based system enhances both the comprehensibility of the local knowledge for the decision-makers and its reliability, making it usable for the decision-making process. The tool was developed to support soil salinity monitoring in the lower Amudarya River Basin in Uzbekistan. © 2011 Elsevier Ltd. Source


Abdel-Dayem S.,The Water Council
International Journal of Water Resources Development | Year: 2011

One of the greatest water-related challenges facing Egypt is the pollution of its surface and ground water resources from agricultural, domestic and industrial sources. The cost of environmental degradation due to water quality deterioration is relatively high with serious health and quality-of-life consequences. The closed water system of the country makes it more vulnerable to quality deterioration in a northward direction. The water quality of Lake Naser upstream of the High Aswan Dam and the main stem of the River Nile from Aswan to Cairo is good and traces of pollutants, if any, are far below the levels set in the quality standards set by Law 48. However, water quality in the irrigation and drainage canals deteriorates downstream and reaches alarming levels in the Delta. Monitoring water quality of the Nile system (Lake Naser, the main Nile and its branches, irrigation canals, drains and groundwater aquifers) started as early as the 1980s. The complexity of water quality management required the development of other mechanisms including policies, institutional and governance arrangements, infrastructure for monitoring and analytic laboratories, awareness and skilled human resources. This paper describes the different aspects of water quality management in Egypt and the current state as it stands by the end of the first decade of the 21st century. It also presents the methodology used in turning several monitoring programmes managed by different institutions into one national integrated system. It argues that water quality management is multifaceted and while progress along one aspect could be significant, other aspects could be lacking due to multiple reasons, the high cost involved in pollution reduction at the source is not the least. © 2011 Taylor & Francis. Source

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