Anne van der Veen

Spatial and temporal assessment of drought in the Northern highlands of Ethiopia

With the development of global changes, researchers from all over the world increasingly pay attention to drought detection, and severe droughts that may have resulted from climate change. In this paper, spatial and temporal variability of drought is evaluated based on precipitation data and remotely sensed images. The standard precipitation index (SPI) and vegetation condition index (VCI) are used to evaluate the spatial and temporal characteristics of meteorological and vegetative drought in Tigray, Northern Ethiopia. Based on the drought critical values of SPI and VCI defining drought, the spatial and temporal extent of droughts in the study area is established. We processed 396 decadal images in order to produce the multi-temporal VCI drought maps. The results of the SPI and VCI analysis reveal that the eastern and southern zones of the study region suffered a recurrent cycle of drought over the last decade. Results further show that there is a time lag between the period of the peak VCI and precipitation values obtained from the meteorological stations across the study area. A significant agreement was observed between VCI values with the current plus last two-months of precipitation. The study demonstrates the utility of the vegetation condition index in semi-arid and arid regions.

Land Use Changes in Regional Economic Theory

Land use and land cover changes are a major source of environmental degradation and therefore a serious issue in sustainable development studies and in the integrated assessment of environmental problems. In an attempt to understand part of the complexity of land use change we here aim to explore the ways in which economists deals with the land use issue. We argue that space is one of the forgotten items in economics. Economists often seem to ignore high-resolution spatial dynamics either because they are not considered as an important feature of the problem or out of habit. It seems as though there is a trade-off between spatial resolution and human behaviour in current applications. Certain types of models are capable of capturing the spatial complexity of urban and regional areas, for instance, by using cellular automata. Other types of land use models clearly have shortcomings where it concerns spatial detail. Dynamic modelling approaches do not guarantee a high spatial resolution.We propose to give more attention to agent based modelling as this type of modelling provides a specific connection between processes on micro level and macro-level spatial structures.

Effect of policy interventions on food security in Tigray, Northern Ethiopia

Following the design of a conservation-based agricultural development strategy and food security strategy, the Tigray government has implemented different pro-poor development programs over the past years to address the problems of food security. This study attempts to investigate the effectiveness of government policy interventions at different scales addressed to improve food security. Food security both at the regional and district level was investigated by deriving food balance sheets for the period 2000-2008. An empirical analysis based on a logit model was also employed to analyze household level food security status. The results of the logit model reveal that government policy interventions such as water harvesting schemes, employment generation schemes, and promotion of technology adoption significantly contribute to a higher likelihood of household food security status. The findings of the food balance sheet also indicate that the region has made some impressive development gains in improving regional food self-sufficiency, indicating the importance of government interventions in improving food security both at the household and regional level.

Land market mechanisms for preservation of space for coastal ecosystems: An agent-based analysis

This paper presents an agent-based model of a land market, which is used to explore the effects of land taxes on the land use in a coastal zone. The model simulates the emergence of land prices and urban land patterns from bottom-up via interactions of individual agents in a land market. A series of model experiments helps visualize and explore how economic incentives in a land market may influence the spatial distribution of land prices and urban developments, either leaving space for coastal ecosystems or not. We demonstrate that economic incentives do affect urban form and pattern, land prices and welfare measures. However, they may not always be sufficient to reduce the pressure on coastal ecosystems. Our results show that preservation of ecosystems may involve difficult trade-offs between economic and ecological priorities, as well as between healthy ecosystems and social equity. We also show how conventional economic modelling based on a representative agent, which is usually employed by policy makers, overestimates both environmental benefits and economic costs associated with the tax meant to preserve coastal ecosystems.

Disasters and economic damage: macro, meso and micro approaches

Tsunamis, droughts, earthquakes, hurricanes and floods are a constant threat to society. Where in the past the population at risk had to react on the consequences of disasters, at present society wants to be more in control. Due to the high costs of restoration, of the stress and of the loss of family and friends, a proactive policy in order to prevent disasters or at least to minimize the impact is required. Such a policy asks for a framework to decide on the risk society wants to take. Moreover, it is mandatory to agree on the way instruments preventing disasters are evaluated on their effectiveness. This special issue accounts for the contributions on the methodology of damage estimation by leading European and American economists. Introduces the subject and presents an overview of all papers.

The Effects of Groundwater and Surface Water Use on Total Water Availability and Implications for Water Management: The Case of Lake Naivasha, Kenya

This study discusses the effects of water abstractions from two alternative sources on the available water volume around Lake Naivasha, Kenya: the lake itself and a connected aquifer. An estimation of the water abstraction pattern for the period 1999–2010 is made and its effect on the available water volume in Lake Naivasha and its connected aquifer is evaluated using a simple water balance modeling approach. This study shows that accurate estimates of annual volume changes of Lake Naivasha can be made using a simple monthly water balance approach that takes into account the exchange of water between the lake and its connected aquifer. The amount of water that is used for irrigation in the area around Lake Naivasha has a substantial adverse effect on the availability of water. Simulation results of our simple water balance model suggests that abstractions from groundwater affect the lake volume less than direct abstractions from the lake. Groundwater volumes, in contrast, are much more affected by groundwater abstractions and therefore lead to much lower groundwater levels. Moreover, when groundwater is used instead of surface water, evaporation losses from the lake are potentially higher due to a larger lake surface area. If that would be the case then the overall water availability in the area is more strongly affected by the abstraction of groundwater than by the abstraction of surface water. Therefore water managers should be cautious when using lake levels as the only indicator of water availability for restricting water abstractions.

The Implications of Skewed Risk Perception for a Dutch Coastal Land Market: Insights from an Agent-Based Computational Economics Model

Dutch coastal land markets are characterized by high amenity values but are threatened by potential coastal hazards, leading to high potential damage costs from flooding. Yet, Dutch residents generally perceive low or no flood risk. Using an agent-based land market model and Dutch survey data on risk perceptions and location preferences, this paper explores the patterns of land development and land rents produced by buyers with low, highly skewed risk perceptions. We find that, compared to representative agent and uniform risk perception models, the skewed risk perception distribution produces substantially more, high-valued development in risky coastal zones, potentially creating economically significant risks triggered by the current Dutch flood protection policy.

Coping with food insecurity on a micro-scale: evidence from Ethiopian rural households.

This article examines the main household demographics and economic factors associated with food insecurity and coping behavior of rural households employed during times of food shortages in northern Ethiopia. Using a cost-of-basic-needs approach we estimated the food poverty line. This cut-off value was used to classify households as either food secure or insecure. Then empirical analyses were used, based on respectively a logit regression model and a coping strategy index. The estimated results revealed that household size, size of farm land, livestock ownership, frequency of extension services, and proximity to basic infrastructures are associated with the food security status of farming households in the study area. Moreover, households relied largely on consumption-based coping strategies when faced with food shortages.

Farmers Prone to Drought Risk: Why Some Farmers Undertake Farm-Level Risk-Reduction Measures While Others Not?

This research investigates farmers’ cognitive perceptions of risk and the behavioral intentions to undertake farm-level risk-reduction measures. It has been observed that people who are susceptible to natural hazards often fail to act, or do very little, to protect their assets or lives. To answer the question of why some people show adaptive behavior while others do not, a socio-psychological model of precautionary adaptation based on protection motivation theory and trans-theoretical stage model has been applied for the first time to areas of drought risk in the developing countries cultural context. The applicability of the integrated model is explored by means of a representative sample survey of smallholder farmers in northern Ethiopia. The result of the study showed that there is a statistically significant association between farmer’s behavioral intention to undertake farm-level risk-reduction measures and the main important protection motivation model variables. High perceived vulnerability, severity of consequences, self-efficacy, and response efficacy lead to higher levels of behavioral intentions to undertake farm-level risk-reduction measures. For farmers in the action stage, self-efficacy and response efficacy were the main motivators of behavioral intention. For farmers in the contemplative stage, self-efficacy and cost appear to be the main motivators for them to act upon risk reduction, while perceived severity of consequences and cost of response actions were found to be important for farmers in the pre-contemplative stage.

Simulating Stakeholder Support in a Policy Process: An Application to River Management

The authors present an agent-based model representing a policy process among stakeholders of river management. For evaluating the different river management alternatives, the agent-based model is coupled to an integrated river model that describes the impacts of river management, such as flood risk, nature development, and costs. The model is applied to the case of the ongoing Dutch river management project “Grensmaas.” The authors analyze stakeholder support and reconstruct the observed policy outcomes of the Grensmaas project over the past 15 years to provide a first validation of the model. They then assess how stakeholder support and the policy outcome might change when stakeholders would change their preference structures or take climate change into account. They argue that the main virtue of the developed modeling framework lies in its application within participatory processes, to support stakeholders to reflect on their goals and uncertainty perspectives in a social context.