Joseph Alcamo

United Nations Environment Programme, Nairoba, Nairobi Area, Kenya

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Publications (114)125.95 Total impact

  • Klara Reder, Martina Flörke, Joseph Alcamo
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    ABSTRACT: Information on fecal coliform (FC) concentrations in European rivers is scarce. The objective of this study was to identify hotspots of water pollution in Europe and provide information on the different FC sources and their contributions to the loads that lead to concentrations in rivers. Model simulations were carried-out with the large-scale water quality model WorldQual to assess the calculated loads regarding to its associated sources and to further estimate the related in-stream concentration. For the year 1995, model results indicated that FC loadings were higher in central Europe with 500 to above 2000 1010 cfu km−2 a−1 than in northern and eastern Europe where loadings ranged between 0 and 200 1010 cfu km−2 a−1. Major sources of FC loadings are domestic sewage, followed by scattered settlements (private treatment), urban surface runoff and manure application. Concentrations showed similar regional patterns as loadings, with high concentrations in central Europe and low concentrations in northern and eastern Europe.
    Environmental Modelling and Software 11/2014; · 3.48 Impact Factor
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    ABSTRACT: To address the continental and large‐scale aspects of water quality assessments, new modelling approaches are required. This paper describes the development of a continental‐scale model of river water quality – WorldQual. Simple equations, consistent with the availability of data on the continental‐scale, are used to simulate the response of biochemical oxygen demand (BOD5) and total dissolved solids (TDS) to anthropogenic loadings and flow dilution. A methodology is developed that is appropriate for scenario analysis on the continental and global scale. Average monthly river water quality is modelled on a 5 arcmin grid covering all Europe. Loadings are derived from assumptions about water use, return flows and other variables. The model WorldQual is tested against measured longitudinal gradients and time series data at specific river locations. The model performance on European scale shows that a good fit can be reached when using concentration classifications as a measure: For BOD5, 51% of the simulated data is in the same quality class as the measurements and 30% differ only by one water‐quality class; for TDS, the respective values are 35% and 41%. WorldQual was applied to investigate the impact of climate change on resulting changes of in‐stream concentrations. The results for Europe show that future climate changes only have a small impact on European in‐stream concentration levels of BOD5, except for the Eastern part and the Black Sea region. This effect is stronger for the IPCM4‐A2 scenario than for the MIMR‐A2 scenario. Copyright © 2012 John Wiley & Sons, Ltd.
    Hydrological Processes 07/2012; 26(16):2370-2384. · 2.50 Impact Factor
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    ABSTRACT: AbstractA methodology for estimating the loading of pollutants to water courses across all of pan‐Europe, an area reaching to the River Don in the east and including some Mediterranean rim countries in the near east and North Africa is presented. Loadings come from point (domestic effluent, manufacturing discharge and urban runoff) and diffuse (scattered settlements and land use) sources. The loads have been calculated on a countrywide basis using readily available data held by national and international bodies. These loads are downscaled to the grid cells (5 × 5′) used in the model. The paper illustrates the general framework for making these calculations using biochemical oxygen demand (BOD) and total dissolved solids (TDS), and estimated loads for periods representing 1990, 1995, 2000 and 2005 are presented as maps.According to the model, in 2005, annual BOD loads came mostly from domestic effluent (3 Mt) and diffuse sources (5 Mt, mainly attributed to livestock). Manufacturing, urban runoff and scattered settlements contributed annual loads of 0.33, 0.15 and 1.2 Mt, respectively. For TDS, annual manufacturing loads were 65 Mt and annual domestic loads 28 Mt. Diffuse loadings (36 Mt) came from irrigated land and therefore showed a different spatial pattern from BOD. The total annual diffuse load of TDS was 56 Mt. Scattered settlements contributed only 9.6 Mt to the total pan‐European load. Some limited comparison of the loads estimated in this study for BOD with those estimated by others for countries and large catchments in the area has been carried out. Copyright © 2012 John Wiley & Sons, Ltd.
    Hydrological Processes 07/2012; 26(16):2395-2410. · 2.50 Impact Factor
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    ABSTRACT: Highlights ► An approach to model variable river flow velocity in large scale models is presented. ► The approach is based on the Manning–Strickler formula. ► The representation of lateral transport has been improved. ► Climate change impacts on flow velocity, and on residence time of water were assessed.
    Journal of Hydrology 03/2012; s 424–425:238–251. · 2.96 Impact Factor
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    ABSTRACT: The global integrated land use model, LandSHIFT, is evaluated by testing its performance against available data sets, by analyzing the sensitivity of model parameters and structure, and by conducting a scenario analysis of future land use change in Africa. Despite the paucity of suitable data sets, a range of different tests were designed to make best use of available data and to examine the model’s ability to compute cropland suitability, extent of cropland area, and location of deforestation. The model showed more ability to calculate the spatial distribution of cropland suitability and continental average deforestation rates than to compute the spatial distribution of deforestation. LandSHIFT was found to be particularly sensitive to assumptions about future climate change for simulations extending over several decades through the influence of climate on cropland and grassland productivity. With regards to the scenario analysis, the model was applied to two scenarios for Africa that cover a wide range of assumptions about future driving forces. Results showed that cropland land may expand greatly up to 2050 (34–40%, depending on the scenario) because of increasing food demand and despite expected increases in crop yield. This expansion comes largely at the expense of forested land, although the average continental deforestation rate computed from 2000 to 2050 is lower than the computed rate for the 1990s. The testing and scenario analysis showed the ability of the model to develop consistent scenarios of land use change on the continental scale by combining the effects of driving forces and competition between land uses in a single spatially-explicit framework.
    Environmental Modelling & Software. 01/2011; 26:1017-1027.
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    ABSTRACT: India’s growing population and economy generate an increasing demand for energy. Facing the decline of global fossil fuel resources, the Indian government and energy industry are considering the long-term expansion of biofuel production in order to increase energy security. This development leads to a strong competition of energy crops versus food crops for land and may result in an increasing pressure on natural resources. In a pilot scenario study, the LandSHIFT model is applied to assess the impact of biofuel production on land-use change in India up to the year 2030. The model aims at the spatially explicit simulation of land-use change and its relation to other global change processes on the national up to the global scale. It explicitly addresses competition between land-use activities such as human settlement, biofuel production and food production as well as the resulting effects on the spatial extent of natural land. Baseline of the study is a simulation with drivers from the “Order from Strength” scenario of the Millennium Ecosystem Assessment. To illustrate the consequences of expanded biofuel production for the extent of natural land, we calculate three scenarios of bioethanol production to substitute 5%, 10% and 20% of the expected petrol demand in 2030. In the simulations shown, a comprehensive linkage is made between driving forces (such as population change) and policies (such as biofuel usage) that will affect land-use change over the coming decades.
    Biomass and Bioenergy 01/2011; 35(6):2401-2410. · 3.41 Impact Factor
  • Earth Interactions 01/2011; · 1.71 Impact Factor
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    ABSTRACT: available at:
    International Association for Sharing Knowledge and Sustainability (IASKS). 01/2011; 3(1):25-31.
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    ABSTRACT: In order to develop pathways to increase the benefits from regional water resources for humans and ecosystems, the GLOWA Jordan River project comprises the elaboration of regional development scenarios for Israel, Jordan and the Palestinian Authority. Since land-use change strongly affects water quantity and quality as well as biodiversity and ecosystem functioning, land-use change scenarios form an essential part of these regional development scenarios. We have applied the spatially explicit land-use change model LandSHIFT.R as integration tool within the scenario analysis of GLOWA Jordan River in order to develop land-use change scenarios for Israel, Jordan and the Palestinian Authority up to 2050. The objective of this paper is to present the four resulting spatially explicit land-use change scenarios. All four scenarios show an increase in urban and built-up area and agricultural area by 2050. Two of these scenarios stand out due to strong rangeland expansion. Reasons are a large increase in livestock numbers and the application of a sustainable rangeland management strategy, respectively. We discuss possible future environmental problems and potential subsequent applications of the land-use change scenarios in form of environmental impact studies. Furthermore, we highlight necessary enhancements of the land-use change scenarios.
    International Journal of Sustainable Water and Environmental Systems. 01/2011; 3(1):25-31.
  • Martina Weiß, Joseph Alcamo
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    ABSTRACT: Making use of ensemble climate modeling systems and multimodel simulations of climate projections calls for a systematic approach in impact studies. In this study the response surface method is introduced to systematically, consistently, and objectively examine impacts of climate change on water availability, subject to selected impact thresholds. The response surface hereby represents the sensitivity of water availability to a broad range of possible climatic change, onto which vulnerability thresholds are superimposed. Their exceedance is assessed by additionally superimposing climate change projections onto the surface. With this method, 18 European river basins are ranked according to their sensitivity to climate change (analyzing the response surface itself). The use of climate change projections from six regional climate models for the year 2100 under the Intergovernmental Panel on Climate Change A1B emissions scenario in combination with societal vulnerability thresholds then enables a vulnerability ranking of these basins. Overall, a strong climate sensitivity of the Nordic basins is found on the basis of their mainly snow-dominated flow regime. When looking at the vulnerability, however, southern European basins together with some central European basins are highest in the ranking because of the violation of both low flow and water stress thresholds.
    Water Resources Research 01/2011; 47(2). · 3.15 Impact Factor
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    ABSTRACT: Land-use and land-cover change are important drivers of global environmental change, affecting the state of biodiversity, the global carbon cycle, and other aspects of the earth system. In this article we describe the development of the land-use model LandSHIFT, which aims to simulate land-use and land-cover change on the continental and global scale. The model is based on a “land-use systems” approach, which describes the interplay between anthropogenic and environmental system components as drivers of land-use change. LandSHIFT’s modular structure facilitates the integration of different components that cover key parts of land-use systems. The model prototype combines a module for the simulation of land-use change dynamics with a module for calculating crop yields and net primary productivity of grassland. LandSHIFT is driven by country-level model inputs including time-series of socio-economic variables as well as agricultural production data. This information is regionalized to land-use grid maps with a cell size of 5 arc-minutes. Here, the model clearly differentiates between the land-use activities settlement, crop cultivation and grazing. By using standardized input–output formats, LandSHIFT can be combined with other models for conducting complex simulation studies.
    Environmental Modelling & Software. 01/2011; 26:1041-1051.
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    ABSTRACT: Abstract available at:
    International Journal of Sustainable Water and Environmental Systems. 01/2011; 3(1):25-31.
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    ABSTRACT: Future changes in water availability with climate change and changes in water use due to socio-economic development are to occur in parallel. In an integrated analysis we bring together these aspects of global change in a consistent manner, and analyse the water stress situation in Europe. We find that today high water stress exists in one-fifth of European river basin area. Under a scenario projection, increases in water use throughout Eastern Europe are accompanied by decreases in water availability in most of Southern Europe – combining these trends leads to a marked increase in water stress in Europe.
    Integrated Assessment 08/2010; March 2002(Vol. 3):15-29.
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    ABSTRACT: The planned expansion of biofuel plantations in Brazil could potentially cause both direct and indirect land-use changes (e.g., biofuel plantations replace rangelands, which replace forests). In this study, we use a spatially explicit model to project land-use changes caused by that expansion in 2020, assuming that ethanol (biodiesel) production increases by 35 (4) x 10(9) liter in the 2003-2020 period. Our simulations show that direct land-use changes will have a small impact on carbon emissions because most biofuel plantations would replace rangeland areas. However, indirect land-use changes, especially those pushing the rangeland frontier into the Amazonian forests, could offset the carbon savings from biofuels. Sugarcane ethanol and soybean biodiesel each contribute to nearly half of the projected indirect deforestation of 121,970 km(2) by 2020, creating a carbon debt that would take about 250 years to be repaid using these biofuels instead of fossil fuels. We also tested different crops that could serve as feedstock to fulfill Brazil's biodiesel demand and found that oil palm would cause the least land-use changes and associated carbon debt. The modeled livestock density increases by 0.09 head per hectare. But a higher increase of 0.13 head per hectare in the average livestock density throughout the country could avoid the indirect land-use changes caused by biofuels (even with soybean as the biodiesel feedstock), while still fulfilling all food and bioenergy demands. We suggest that a closer collaboration or strengthened institutional link between the biofuel and cattle-ranching sectors in the coming years is crucial for effective carbon savings from biofuels in Brazil.
    Proceedings of the National Academy of Sciences 02/2010; 107(8):3388-93. · 9.81 Impact Factor
  • R. Schaldach, J. Koch, J. Alcamo
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    ABSTRACT: In many cases land-use activities go hand in hand with substantial modifications of the physical and biological cover of the Earth's surface, resulting in direct effects on energy and matter fluxes between terrestrial ecosystems and the atmosphere. For instance, the conversion of forest to cropland is changing climate relevant surface parameters (e.g. albedo) as well as evapotranspiration processes and carbon flows. In turn, human land-use decisions are also influenced by environmental processes. Changing temperature and precipitation patterns for example are important determinants for location and intensity of agriculture. Due to these close linkages, processes of land-use and related land-cover change should be considered as important components in the construction of Earth System models. A major challenge in modelling land-use change on the global scale is the integration of socio-economic aspects and human decision making with environmental processes. One of the few global approaches that integrates functional components to represent both anthropogenic and environmental aspects of land-use change, is the LandSHIFT model. It simulates the spatial and temporal dynamics of the human land-use activities settlement, cultivation of food crops and grazing management, which compete for the available land resources. The rational of the model is to regionalize the demands for area intensive commodities (e.g. crop production) and services (e.g. space for housing) from the country-level to a global grid with the spatial resolution of 5 arc-minutes. The modelled land-use decisions within the agricultural sector are influenced by changing climate and the resulting effects on biomass productivity. Currently, this causal chain is modelled by integrating results from the process-based vegetation model LPJmL model for changing crop yields and net primary productivity of grazing land. Model output of LandSHIFT is a time series of grid maps with land-use/land-cover information that can serve as basis for further impact analysis. An exemplary simulation study with LandSHIFT is presented, based on scenario assumptions from the UNEP Global Environmental Outlook 4. Time horizon of the analysis is the year 2050. Changes of future food production on country level are computed by the agro-economy model IMPACT as a function of demography, economic development and global trade pattern. Together with scenario assumptions on climatic change and population growth, this data serves as model input to compute the changing land-use und land-cover. The continental and global scale model results are then analysed with respect to changes in the spatial pattern of natural vegetation as well as the resulting effects on evapotranspiration processes and land surface parameters. Furthermore, possible linkages of LandSHIFT to the different components of Earth System models (e.g. climate and natural vegetation) are discussed.
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    ABSTRACT: This article was submitted without an abstract, please refer to the full-text PDF file.
    IOP Conference Series Earth and Environmental Science 02/2009; 6(34).
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    ABSTRACT: This article was submitted without an abstract, please refer to the full-text PDF file.
    IOP Conference Series Earth and Environmental Science 02/2009; 6(18).
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    Regional Environmental Change 01/2009; 9(2):137-138. · 1.95 Impact Factor
  • Joseph Alcamo
    Regional Environmental Change 12/2008; 8(4):135-136. · 1.95 Impact Factor

Publication Stats

2k Citations
125.95 Total Impact Points


  • 2012
    • United Nations Environment Programme
      Nairoba, Nairobi Area, Kenya
  • 1996–2012
    • Universität Kassel
      • Center for Environmental Systems Research (CESR)
      Cassel, Hesse, Germany
  • 2011
    • Helmholtz-Zentrum für Umweltforschung
      Leipzig, Saxony, Germany
  • 1994–1995
    • National Institute for Public Health and the Environment (RIVM)
      Utrecht, Utrecht, Netherlands