The Impacts of Food- and Oil Price Shocks on the Namibian Economy: the Role of Water Scarcity

The recent increases in international food and oil prices have raised concerns about how these exogenous shocks will affect the economic activity as well as poverty in developing countries. In this paper, the effects of international food and oil price increases on the Namibian economy are studied by means of a Computable General Equilibrium model. As a corn and oil importing Sub-Saharan African country, Namibia is among the countries considered to be particularly vulnerable to these price shocks. Besides, since Namibia is also one of the driest Sub-Saharan countries, the role of water scarcity is explicitly addressed in this particular context. The results show that the Namibian economy will be negatively affected by the food and oil price increases. In the case where the supply of water is assumed to be constant, it is shown that there will be even less ability to adapt for the economy, thus resulting in a more significant decrease in GDP than in the case where additional water sources are assumed to be available.computable general equilibrium model; food prices; oil prices; water scarcity

Topology and Dark Energy: Testing Gravity in Voids

Modified gravity has garnered interest as a backstop against dark matter and dark energy (DE). As one possible modification, the graviton can become massive, which introduces a new scalar field - here with a Galileon-type symmetry. The field can lead to a nontrivial equation of state (EOS) of DE which is density-and-scale-dependent. Tension between Type Ia supernovae and Planck could be reduced. In voids the scalar field dramatically alters the EOS of DE, induces a soon-observable gravitational slip between the two metric potentials, and develops a topological defect (domain wall) due to a nontrivial vacuum structure for the field.Comment: Revised version, added detail, conclusions unchanged, matches PRL published version in content. 4 pages, 2 figure

Technology Transfers and the Clean Development Mechanism in a North-South General Equilibrium Model

This paper analyzes the potential welfare gains of introducing a technology transfer from Annex I to non-Annex I in order to mitigate greenhouse gas emissions. Our analysis is based on a numerical general equilibrium model for a world economy comprising two regions, North (Annex I) and South (non-Annex I). As our model allows for labor mobility between the formal and informal sectors in the South, we are also able to capture additional aspects of how the transfer influences the Southern economy. In a cooperative equilibrium, a technology transfer from the North to the South is clearly desirable from the perspective of a ‘global social planner’, since the welfare gain for the South outweighs the welfare loss for the North. However, if the regions do not cooperate, then the incentives to introduce the technology transfer appear to be relatively weak from the perspective of the North; at least if we allow for Southern abatement in the pre-transfer Nash equilibrium. Finally, by adding the emission reductions associated with the Kyoto agreement to an otherwise uncontrolled market economy, the technology transfer leads to higher welfare in both regions.Climate Policy, Technology Transfer, Kyoto Protocol, General Equilibrium, Clean Development Mechanism

Reconstructing thawing quintessence with multiple datasets

In this work we model the quintessence potential in a Taylor series expansion, up to second order, around the present-day value of the scalar field. The field is evolved in a thawing regime assuming zero initial velocity. We use the latest data from the Planck satellite, baryonic acoustic oscillations observations from the Sloan Digital Sky Survey, and Supernovae luminosity distance information from Union2.1 to constrain our models parameters, and also include perturbation growth data from the WiggleZ, BOSS and the 6dF surveys. The supernova data provide the strongest individual constraint on the potential parameters. We show that the growth data performance is competitive with the other datasets in constraining the dark energy parameters we introduce. We also conclude that the combined constraints we obtain for our model parameters, when compared to previous works of nearly a decade ago, have shown only modest improvement, even with new growth of structure data added to previously-existent types of data.Comment: 9 pages, 4 figures and 1 table. Version 2 with minor changes to match Physical Review D accepted versio

Essays on Environmental and Development Economics - Public Policy, Resource Prices and Global Warming

This thesis consists of four self-contained papers, which are all related to important environmental and natural resource issues from a developing country perspective. Paper [I] concerns climate policy and addresses the potential welfare gains of introducing a technology transfer from the North (richer countries) to the South (poorer countries). The results largely depend on the environmental policy in the pre- transfer resource allocation and, in particular, whether or not the South abates its own emissions. Although the technology transfer is desirable from a “global social planners” point of view, it is shown that the incentives to use the transfer might be weak from the perspective of the North; at least if the South takes its own measures to reduce emissions. However, in a situation where the North is committed to emission reductions according to the Kyoto protocol, it is shown that there will clearly be incentives for the North to use the technology transfer in order to reach the Kyoto targets in a more cost efficient way. In paper [II], the likely effects of an environmental fiscal reform in Namibia are examined by means of a Computable General Equilibrium (CGE) model. The results show that the introduction of an environmental fiscal reform, where taxes on natural and environmental resources (fish rents, energy and water) are recycled to the economy in different ways might give rise to benefits in terms of GDP, employment and income distribution, in addition to the environmental impacts. While subsidizing unskilled labour would give the most favourable outcome in terms of real GDP and employment impacts, a decrease in food taxes might be a more interesting option if GDP, employment, income distribution and environmental impacts are considered in combination. In paper [III], the value of irrigation water used for different crop alternatives in the Hardap region in Southern Namibia is estimated. The study finds that all crop alternatives that farmers in the region currently choose among, will remain financially viable after the planned increases in user charges. However, if full cost recovery is to be achieved in the future, substantial changes in the agricultural production will most likely be necessary. The method is also extended in order to study the potential effects on total water demand if further increases in user charges are implemented. Paper [IV] studies the likely effects of exogenous international food and oil price shocks on the Namibian economy. This is particularly interesting in a country where the domestic consumption of corn and petroleum products is mainly imported, and where water scarcity represents one of the main constraints to agricultural expansion. The results show that the Namibian economy will be negatively affected from the food and oil price increases, and water scarcity will further limit the ability of the economy to adapt to international oil and food price increases.Climate policy; technology transfer; computable general equilibrium model; environmental fiscal reform; revenue recycling; water scarcity; resource prices

Environmental Fiscal Reform in Namibia – a potential approach to reduce poverty?

In this paper, the likely effects of an environmental fiscal reform in Namibia are examined using a Computable General Equilibrium model. Namibia is a natural resource rich country with poverty alleviation as one important target on the policy agenda. One way for the government of simultaneously ensuring both a sustainable use of the resources and a less skewed income distribution might be to introduce an environmental fiscal reform, where taxes on natural and environmental resources (fish rents, energy and water) are recycled in order to give additional benefits (in terms of GDP, employment and income distribution) to the economy. The results indicate that for some recycling options, there is scope for additional benefits. Subsidizing unskilled labour would give the most favourable result, at least in terms of real GDP and employment. However, poverty might not only be a question of employment; since food constitutes a significant part of poor households’ expenditures, a decrease in taxes on food might be an interesting option if GDP, employment, income distribution and environmental impacts are considered in combination.computable general equilibrium model; environmental fiscal reform; revenue recycling

Observational constraints on thawing quintessence models

We use a dynamical systems approach to study thawing quintessence models, using a multi-parameter extension of the exponential potential which can approximate the form of typical thawing potentials. We impose observational constraints using a compilation of current data, and forecast the tightening of constraints expected from future dark energy surveys, as well as discussing the relation of our results to analytical constraints already in the literature.Comment: 6 pages MNRAS style with 8 figures included. Minor updates to match MNRAS accepted versio

Working memory and referential communication-multimodal aspects of interaction between children with sensorineural hearing impairment and normal hearing peers.

Whereas the language development of children with sensorineural hearing impairment (SNHI) has repeatedly been shown to differ from that of peers with normal hearing (NH), few studies have used an experimental approach to investigate the consequences on everyday communicative interaction. This mini review gives an overview of a range of studies on children with SNHI and NH exploring intra- and inter-individual cognitive and linguistic systems during communication. Over the last decade, our research group has studied the conversational strategies of Swedish speaking children and adolescents with SNHI and NH using referential communication, an experimental analog to problem-solving in the classroom. We have established verbal and non-verbal control and validation mechanisms, related to working memory capacity and phonological short term memory. We present main findings and future directions relevant for the field of cognitive hearing science and for the clinical and school-based management of children and adolescents with SNHI