the economics of a blend mandate for biofuels a biofuel blend mandate may increase or decrease consumer fuel prices with endogenous oil prices depending on relative supply elasticities biofuel tax credits always reduce fuel prices tax credits result in lower fuel prices than under a mandate for the same level of biofuel production if tax credits are implemented alongside mandates then tax credits subsidize fuel consumption instead of biofuels this contradicts energy policy goals by increasing oil dependency co 2 emissions and traffic congestion while providing little benefit to either corn or ethanol producers these social costs will be substantial with tax credits costing taxpayers 28 7 billion annually by 2022 copyright 2008 oxford university press

time series econometric analyses of biofuel related price volatility time series econometrics studies have analyzed volatility interactions between biofuel and food and fossil fuel markets we review data modeling techniques and the main findings in the literature and present our latest contributions we identify areas for further research

bayesian estimation and selection of nonlinear vector error correction models the case of the sugar ethanol oil nexus in brazil nonlinear adjustment toward long run price equilibrium relationships in the sugar ethanol oil nexus in brazil is examined we develop generalized bivariate error correction models that allow for cointegration between sugar ethanol and oil prices where dynamic adjustments are potentially nonlinear functions of the disequilibrium errors a range of models are estimated using bayesian monte carlo markov chain algorithms and compared using bayesian model selection methods the results suggest that the long run drivers of brazilian sugar prices are oil prices and that there are nonlinearities in the adjustment processes of sugar and ethanol prices to oil price but linear adjustment between ethanol and sugar prices

market institutions and price relationships the case of coffee in the ethiopian commodity exchange while the ethiopian commodity exchange ecx is widely considered a successful market institution very little rigorous empirical investigation has been done on it this paper contributes to filling this knowledge gap using a unique set of spatially disaggregated prices for five different coffee varieties we examine how the ecx has influenced the dynamics of international and domestic prices for coffee the largest traded commodity in terms of trade value on the exchange floor we follow a multivariate generalized autoregressive conditional heteroscedasticity garch approach to assess the extent of market interdependence conditional correlations and volatility transmission we also evaluate structural changes in price dynamics over time our results suggest that contrary to popular media stories the ecx s success in strengthening coffee price relationships has been limited we discuss the underlying reasons and implications of this finding

how does increased corn ethanol production affect us natural gas prices abstract in recent years there has been a push to increase biofuel production in the united states the biofuel of choice so far has been ethanol produced from corn the effects of increased corn ethanol production on the consumer prices of food and energy continue to be studied and debated this study examines in particular the effects of increased corn ethanol production on us natural gas prices a structural model of the natural gas market is developed and estimated using two stage least squares a baseline projection for the period 2007 2018 is determined and two scenarios are simulated in the first scenario current biofuel policies including eisa mandates tariffs and tax credits are removed in the second scenario we hold ethanol production to the level required only for largely obligatory additive use the results indicate that the increased level of corn ethanol production occurring as a result of the current us biofuel policies may lead to natural gas prices that are as much as 0 25 higher on average than if no biofuel policies were in place a similar comparison between the baseline and second scenario indicates natural gas prices could be as much as 0 5 higher on average for the same period

value at risk estimation with the optimal dynamic biofuel portfolio abstract in the past petroleum companies only paid attention to hedging the variation in the crude oil price and volatility however they have now expanded their analysis to encompass renewable sources such as corn and soybeans under the current low carbon biofuel obligations this paper employs garch 1 1 and arji models to estimate the one day ahead value at risk var of the optimal dynamic biofuel portfolio which consists of crude oil corn and soybeans the optimal blended standard is subject to the dual limitations of minimum production costs and the lowest biofuel using requirements our empirical findings confirm that the arji model is more suitable than the garch 1 1 model and further captures the discontinuous jump behavior from the in the sample data the results of out of sample forecasts also are represented that our models play important roles in var estimation and risk management for biofuel portfolio we therefore suggest that the petroleum companies should simultaneously pay attention to jump risk in hedging material costs in the prices of energy related crops

biodiesel as a motor fuel price stabilization mechanism abstract this article studies the capacity of biofuels to reduce motor fuel price fluctuations for this purpose we study dependence between crude oil and biodiesel blend prices in spain copula models are used for this purpose results suggest that the practice of blending biodiesel with diesel can protect consumers against extreme crude oil price increases

strong sustainability critical natural capital and the capability approach this article is an attempt to conceptually improve the notion of strong sustainability by creating a rapprochement between its core concept critical natural capital and the capability approach we first demonstrate that the capability approach constitutes a relevant framework for analysing the multiple links between human well being and critical natural capital second we demonstrate that the rapprochement between critical natural capital and the capability approach can form both the normative basis and the informational basis for a deliberative approach to human development which embraces a strong sustainability perspective this conceptual rapprochement as illustrated in our case study opens up avenues of research towards the practical implementation of human development projects from a strong sustainability perspective

using a functional approach to test trending volatility in the price of mexican and international agricultural products in this article we extend the traditional garch 1 1 model by including a functional trend term in the conditional volatility of a time series we derive the main properties of the model and apply it to all agricultural commodities in the mexican cpi basket as well as to the international prices of maize wheat swine poultry and beef products for three different time periods that implied changes in price regulations and behavior before the north american free trade agreement nafta 1987 1993 post nafta 1994 2005 and commodity supercycle 2006 2014 the proposed model seems to adequately fit the volatility process and according to heteroscedasticity tests also outperforms the arch 1 and garch 1 1 models some of the most popular approaches used in the literature to analyze price volatility our results show that consistent with anecdotal evidence price volatility trends increased from the period 1987 1993 to 1994 2005 from 1994 2005 to 2006 2014 trends decreased but the persistence of volatility increased for most products especially for international commodities in addition we identify some agricultural products such as avocado beans and chicken that due to their increasing price volatility trends in the 2006 2014 period may present a risk for food inflation in the short run

more than total economic value how to combine economic valuation of biodiversity with ecological resilience abstract the assessment of total economic value has become a pragmatic and popular approach in nature valuation yet criticisms have been raised one major point of critique is that total economic value bases the monetary value of ecosystems purely on the flow of human benefits of services of ecosystems and consequently ignores questions of sustainable use of natural capital per se this paper explains why total economic value by itself is in principle an inadequate concept to guide sustainable use of ecosystems and gives an overview of essential ecological theory that needs to be taken into account in addition to total economic value to fully include ecosystem sustainability the paper concludes with a framework for combining ecological theory with economic valuation the key elements here are theoretical ecological insights about ecosystem resilience and portfolio theory which offers an economic perspective on investment in biodiversity portfolio theory puts total economic value in a framework where investment in biodiversity is expanded to cover functional diversity and mobile link species in order to maintain ecosystem resilience and so fosters sustainable use of ecosystems

price cycles and asymmetric price transmission in the u s pork market economists have proposed several plausible explanations for observed price transmission asymmetries in commodity markets unfortunately the econometric methods commonly used in such studies cannot empirically distinguish pricing behavior under the competing theories we argue that the theories may be classified by firm responses to high and low frequency price cycles and use engle s band spectrum regression to test the symmetry of high and low frequency cycles in weekly pork prices the findings indicate that changes in wholesale prices are asymmetrically transmitted to retail prices in relatively low frequency cycles which does not support search costs and other high frequency explanations conversely wholesale pork prices asymmetrically adjust to changes in farm prices at all frequencies copyright 2001 oxford university press

existence value and intrinsic value abstract in this paper the concept of existence value is related to the notion of intrinsic value current in environmental ethics the methods employed to measure existence value are discussed and thus the question is investigated as to whether these methods are a satisfactory means of taking non use value into account in practical decision making in particular i argue against jonathan aldred that not all bearers of intrinsic value satisfy his definition of existence value plausible counter examples include undiscovered and future bearers of such value section 2 i also raise difficulties for the two proposed measures of existence value willingness to pay and willingness to accept section 3 finally i conclude in section 4 that to base decision making on the valuations of valuers in a free market fails to give value its due a method is instead needed which unlike those associated with existence value more directly takes into account and weighs up the good or the interests of future human beings and of nonhuman entities

complex biofuels related scenarios generated by qualitative reasoning under severe information shortages a review abstract there is a broad spectrum of br biofuel related models however the models are highly specific such models cannot flexibly support complex decision making activities to identify feasible trade offs among many objective functions they represent just one point of view e g engineering company economics therefore cbrms complex biofuel related model are studied in this paper cbrms must cover additional aspects e g macroeconomic ecology sociology and politics such models are inevitably unique partially subjective inconsistent vague and multidimensional ai artificial intelligence has developed a number of tools to solve such problems qualitative reasoning is one of them it is based on the least information intensive quantifiers i e trends there are just three trend qualitative values plus increasing zero constant negative decreasing there are many cbrm items related to soft aspects e g politics taxation etc which cannot be quantified by numbers they are too vague for example if the political sociological sensitivity of land ownership is increasing then the cost of biofuels is increasing such verbal knowledge item cannot be incorporated into a traditional numerical model the paper describes developments of cbrms based on expert knowledge and common sense a consensus among experts is often not reached because of substantial subjectivity of experts knowledge a qualitative intersection of cbrms developed by several experts is simple the case study presents a model based on integration of 10 heuristics using 9 variables e g refinery capacity cost of biofuel production and biofuel demand the result is represented by 13 scenarios the paper is self contained no a prior knowledge of qualitative models is required

building the consensus the moral space of earth measurement abstract we chart the moral space of earth measurement with the aim to develop practical tools to evaluate and improve earth measurement frameworks including environmental economic accounting and ecosystem services based on a survey of environmental ethics we develop four concepts that are fundamentally important to fostering agreement in debates over earth measurement frameworks among stakeholders with diverging belief systems the four concepts can thus be used as criteria to evaluate the completeness and defensibility of existing measurement frameworks the first two concepts the consideration of broad human values and long time frames follow the landmark work by bryan norton we further propose the adoption of the capital approach and precaution as the third and fourth concept respectively we conclude with suggestions for how current frameworks could be rendered more complete defensible and internationally acceptable

do energy prices stimulate food price volatility examining volatility transmission between us oil ethanol and corn markets this paper examines volatility transmission in oil ethanol and corn prices in the united states between 1997 and 2011 we follow a multivariate garch approach to evaluate the level of interdependence and the dynamics of volatility across these markets preliminary results indicate a higher interaction between ethanol and corn markets in recent years particularly after 2006 we only observe however significant volatility spillovers from corn to ethanol prices but not the converse we also do not find major cross volatility effects from oil to corn markets the results do not provide evidence of volatility in energy markets stimulating price volatility in grain markets

on the comovement of commodity prices we present strong evidence against the excess comovement hypothesis that the prices of commodities move together beyond what can be explained by fundamentals prior studies employ broad macroeconomic indicators to explain common price movements and potentially correlated fundamentals are not controlled for we use inventory and harvest data to fit a partial equilibrium model that more effectively captures the variation in individual prices the model explains the majority of the comovements among commodities with high price correlation and all of the comovements among those with marginal price correlation common movements in supply factors appear to play an important role in the observed comovements in commodity prices

effects of tax reform on labor supply investment and saving the u s tax system received two major overhauls during the 1980s the tax cuts of 1981 and the tax reform act of 1986 supporters of both reforms argued that major changes in tax policy could boost saving investment labor supply and entrepreneurship eventually it was argued such changes could reverse the slowdown in economic growth that began in the early 1970s and spur improvements in american living standards the aim of this paper is to assess whether the goals of increased labor supply and capital formation were achieved

payments for ecosystem services as commodity fetishism abstract payments for ecosystem services pes economically reward resource managers for the provision of ecosystem services and are thus characterised by i an ecological function subject to trade ii the establishment of a standard unit of exchange iii and supply demand and intermediation flows between those who sell and buy ecosystem services this paper departs from the term commodity fetishism broadly understood as the masking of the social relationships underlying the process of production to illuminate three invisibilities in the commodification of ecosystem services firstly we argue that narrowing down the complexity of ecosystems to a single service has serious technical difficulties and ethical implications on the way we relate to and perceive nature secondly the commodification of ecosystem services denies the multiplicity of values which can be attributed to these services since it requires that a single exchange value is adopted for trading finally we suggest that the process of production exchange and consumption of ecosystem services is characterised by power asymmetries which may contribute to reproducing rather than addressing existing inequalities in the access to natural resources and services

critical natural capital revisited ecological resilience and sustainable development abstract the maintenance of critical natural capital is an important objective of sustainable development critical natural capital represents a multidimensional concept as it mirrors the different frameworks of various scientific disciplines and social groups in valuing nature this article revisits the concept of critical natural capital and examines its relation to the concept of ecological resilience i propose that ecological resilience can help a great deal in specifying the ecological criticality of specific renewable parts of the natural capital more specifically i suggest that the degree of ecological resilience is inversely related to the degree of threat ecosystems are prone to the concept of ecological resilience may complement other measures such as integrity or vulnerability in estimating the degree of threat specific ecosystems are exposed to the empirical estimates of ecological resilience add a further criterion in order to build a comprehensive and clear conception of critical natural capital

sharp breaks or smooth shifts an investigation of the evolution of primary commodity prices this paper explores the behavior of real commodity prices over a 50 year period attention is given to how the shifting means for various commodity prices have changed with a special emphasis on behavior since the mid 2000s to identify structural changes in commodity prices we estimate shifting mean autoregressions by using the bai and perron 1998 procedure for determining structural breaks low frequency fourier functions and a procedure that specifies shifts to be smooth logistic functions of time we find that the pattern in the timing of shifts is suggestive of the causal factors underlying the recent boom

is there co movement of agricultural commodities futures prices and crude oil even though significant attempts have appeared in literature the current perception of co movement of commodity prices appear inadequate and static in particular we focus on price movements between crude oil futures and a series of agricultural commodities and gold futures a comparative framework is applied to identify changes in relationships through time and various cointegration methodologies and causality tests are employed our results indicate that co movement is a dynamic concept and that some economic and policy development may change the relationship between commodities furthermore we show that biofuel policy buffers the co movement of crude oil and corn futures until the crude oil prices surpass a certain threshold

volatility spillovers between food and energy markets a semiparametric approach previous literature on volatility links between food and energy prices is scarce and mainly based on parametric approaches this article examines these links by using a semiparametric garch model recently proposed by long et al 2011 which is essentially a nonparametric correction of the parametric conditional covariance function the analysis focuses on price links between crude oil ethanol and sugar prices in brazil results suggest strong volatility links between the prices studied parametric approximations of the conditional covariance matrix may lead to misleading results that can be improved upon by using nonparametric techniques

part time work wages and productivity evidence from belgian matched panel data the authors use matched employer employee panel data on belgian private sector firms to estimate the relationship between wage productivity differentials and the firm s labor composition in terms of part time work and gender findings suggest that the groups of women and part timers generate employer rents but also that the origin of these rents differs relatively lower wages for women relatively higher productivity for part timers interactions between gender and part time work suggest that the positive productivity effect is driven by male part timers working more than 25 hours whereas the share of female part timers is associated with wage penalties the authors conclude that men and women differ with respect to motives for reducing working hours and the types of part time jobs available to them women often have to accommodate domestic constraints by downgrading to more flexible jobs whereas male part time work is frequently related to training and collectively negotiated reductions in hours that

divide the hours and conquer the surplus part time workers and pay abstract a theory is presented where the firm strategically over employs part time workers reductions in labor taxes increases in the worker s bargaining strength or reductions in their outside employment opportunities will all increase the level of part time work

commodity prices and unit root tests price theory suggests that commodity prices should be stationary series yet tests for unit roots rather frequently imply that these prices are not stationary this seeming inconsistency is investigated by applying alternative specifications of unit root tests to prices of corn soybeans barrows and gilts and milk the preponderance of evidence suggests that nominal prices do not have unit roots but the results are sensitive to the specification of the test equation accounting for a structural change that shifts the mean appears to be an important issue in unit root tests

on the relation between ecosystem services intrinsic value existence value and economic valuation various attempts have been made to amalgamate the concepts of intrinsic value and ecosystem services often with a stop over at the economic concept of existence value these attempts are based on a confusion of concepts however in this article two types of non use values are distinguished warm glow value related to the satisfaction people may derive from altruism towards nature and existence value related to the satisfaction people may derive from the mere knowledge that nature exists and originating in the human need for self transcendence as benefits to humans warm glow and existence values can be considered ecosystem services neither warm glow value nor existence value represents benefits to nature itself however intrinsic value lies outside the scope of the wide palette of ecosystem services although the concept of ecosystem services does not cover benefits to nature and the intrinsic value of such benefits intrinsic value is not necessarily incompatible with economic valuation although a deontological ethics does not allow economic valuation of nature as an end in itself consequentialism does in consequentialism however intrinsic value is not attributed to nature itself but to benefits to nature these benefits can be economically valued on the basis of benefit transfer

cattle as a consistently resilient agricultural commodity this study compares a range of agricultural commodities over periods of varying economic circumstances these commodities are examined over three categories including returns risk and contributi

short and long run determinants of commodity price volatility to explain price volatility in the u s agricultural energy and metal futures markets we estimate a model of common and commodity specific high and low frequency factors by building on the spline garch model of engle and rangel 2008 a better model fit results from allowing the unconditional variance to slowly change over time moreover the persistence of volatility shocks is shown to be much weaker than what standard garch models imply combining the volatility results with monthly macroeconomic indicator data we find that decomposing realized volatility into high and low frequency components better reveals the impact of slowly evolving aggregate variables on price volatility moreover over the period 1990 2005 most of the macroeconomic variables had similar effects within the same commodity category e g grain but their effects differed across commodity groups e g grain versus livestock over the period 2006 2009 however commodity specific factors dominated common factors copyright 2013 oxford university press

are biofuels the culprit opec food and fuel the food commodity price boom of 2003 2008 was the most notable in the past several decades having a substantial impact on global economic activity it affected developing nations by impacting real output the balance of payments government budgetary positions and most important the well being of the very poor high commodity prices also affected developed countries by transmitting business cycle disturbances and creating inflationary pressures several recent studies tried to identify and quantify the factors that caused the food commodity price boom of 2003 2008 see for instance isabel vansteenkiste 2009 these studies suggest that one key factor is growth in demand which since the 1980s has outpaced growth in supply other studies argued that biofuel is the culprit since it increases demand for staple crops see for instance donald mitchell 2008 all these studies however assumed competitive markets and did not consider the impact of biofuel on energy costs to farmers moreover they ignored the organization of petroleum exporting countries opec these studies leave us perplexed regarding the true impact of biofuel on food commodity prices was it or was it not an important contributor to the recent food commodity boom we believe that to answer this question the interactions between energy and food must be modeled and opec introduced and the impact of biofuels compared with other factors that are argued by the literature to be important this paper aims to analyze the multiple contributions of energy and biofuels to the increase are biofuels the culprit opec food and fuel

oil price agricultural commodity prices and the dollar a panel cointegration and causality analysis abstract this study examines the dynamic relationship between world oil prices and twenty four world agricultural commodity prices accounting for changes in the relative strength of us dollar in a panel setting we employ panel cointegration and granger causality methods for a panel of twenty four agricultural products based on monthly prices ranging from january 1980 to february 2010 the empirical results provide strong evidence on the impact of world oil price changes on agricultural commodity prices contrary to the findings of many studies in the literature that report neutrality of agricultural prices to oil price changes we find strong support for the role of world oil prices on prices of several agricultural commodities the positive impact of a weak dollar on agricultural prices is also confirmed

market interdependence and volatility transmission among major crops this article provides a comprehensive analysis of the dynamics of volatility across major agricultural commodities in the united states volatility interactions across markets may lower the effectiveness of diversification strategies to mitigate price risks and should be taken into account when analyzing the pricing behavior of different agricultural commodities we follow a multivariate garch approach to evaluate the time evolution of conditional correlations and volatility transmission across corn wheat and soybeans price returns on a daily weekly and monthly basis the period of analysis is from 1998 to 2012 the estimation results indicate a lack of lead lag relationships between corn wheat and soybeans price returns at the mean level we find however important volatility spillovers across commodities particularly at the weekly and monthly level wheat and corn seem to play a major role in terms of volatility transmission despite the supposed higher financial market integration of agricultural commodities we do not observe that agricultural markets have become more interdependent in recent years

on the excess co movement of commodity prices a note about the role of fundamental factors in short run dynamics abstract since the influential paper by pindyck and rotemberg 1990 the excess co movement of commodity prices the economic journal 100 1173 1189 there is a common belief that prices of unrelated commodities tend to move together in excess of what can be explained by fundamentals in this paper we consider monthly data of 51 commodities from 1980 to 2008 to confirm that raw resources exhibit co movement at high frequencies nonetheless focusing on oil and six metal prices we present evidence that the high level of correlation between cycles of commodity prices can be explained to a large extent by common shocks to inventory levels once the influences of supply and demand are filtered out it appears that the links between commodity prices are rather loose

assessing the impact of us ethanol on fossil fuel markets a structural var approach abstract despite the growing importance of biofuels the effect of biofuels on fossil fuel markets is not fully understood we develop a joint structural vector auto regression var model of the global crude oil us gasoline and us ethanol markets to examine whether the us ethanol market has had any impact on global oil markets the structural var approach provides a unique method for decomposing price and quantity data into demand and supply shocks allowing us to estimate the distinct dynamic effects of ethanol demand and supply shocks on the real prices of crude oil and us gasoline ethanol demand in the us is driven mainly by government support in the form of tax credits and blending mandates shocks to ethanol demand therefore reflect changes in policy more than any other factor in contrast ethanol supply shocks are driven by changes in feedstock prices a principle finding is that a policy driven ethanol demand expansion causes a statistically significant decline in real crude oil prices while an ethanol supply expansion does not have a statistically significant impact on real oil prices this suggests that even though us ethanol market is small the influence of us biofuels policy on the crude oil market is pervasive we also show that ethanol demand shocks are more important than ethanol supply shocks in explaining the fluctuation of real prices of crude oil and us gasoline

grain price and volatility transmission from international to domestic markets in developing countries summary understanding the sources of domestic food price volatility in developing countries and the extent to which it is transmitted from international to domestic markets is critical to help design better global regional and domestic policies to cope with excessive food price volatility and to protect the most vulnerable groups this paper examines short term price and volatility transmission from major grain commodities to 41 domestic food products across 27 countries in africa latin america and south asia we follow a multivariate garch approach to model the dynamics of monthly price return volatility in international and domestic markets the period of analysis is 2000 through 2013 in terms of price transmission we only observe significant interactions from international to domestic markets in few cases to calculate volatility spillovers we simulate a shock equivalent to a 1 increase in the conditional volatility of price returns in the international market and evaluate its effect on the conditional volatility of price returns in the domestic market the transmission of volatility is statistically significant in just one quarter of the maize markets tested more than half of rice markets tested and all wheat markets tested volatility transmission seems to be more common when trade imports or exports are large relatively to domestic requirements

non parametric and parametric modeling of biodiesel sunflower oil and crude oil price relationships abstract multivariate local linear regression and parametric error correction models are applied to assess price linkages and price transmission patterns between food and energy prices in spain weekly biodiesel sunflower and crude oil prices observed from november 2006 to october 2010 are used in the empirical analysis results suggest the existence of a long run equilibrium relationship between the three prices studied biodiesel is the only variable that adjusts to deviations from this long run relationship local linear regression techniques show that the speed of adjustment of biodiesel prices is faster when biodiesel is relatively cheap than when it is expensive energy prices are also found to influence sunflower oil prices through short run price dynamics

the excess co movement of commodity prices reconsidered this paper provides an empirical reconsideration of evidence for excess co movement of commodity prices within the framework of univariate and multivariate garch 1 1 models alternative formulations of zero excess co movement are provided and corresponding score and likelihood ratio tests are developed monthly time series data for two sample periods 1960 85 and 1974 92 on up to nine commodities are used in contrast to earlier work only weak evidence of excess co movement is found

importance and threat as determining factors for criticality of natural capital abstract an important issue in the debate about the use and conservation of natural ecosystems is the degree to which these ecosystems and their functions should be considered critical this paper presents some guidelines to determine the criticality of natural capital based on two main criteria the first criterion is the importance of natural ecosystems ecological socio cultural and economic and the second is the degree of threat based on the quantity and quality of the remaining natural areas in a given region it is argued that the two criteria are complementary and need to be taken into account simultaneously when determining the criticality of natural capital finally the paper presents and discusses some possibilities for the development of a critical natural capital index for europe