Comovements of ethanol‐related prices: evidence from Brazil and the USA

We use the wavelet coherence methodology to investigate the relations between prices of ethanol and its feedstocks. Our continuous wavelet framework allows for discovering price connections and their evolution in both time and frequency domain in the most important ethanol markets – Brazil and the USA. For both of these markets, we show that the long‐run relationship between prices of ethanol and corn (in the USA) or sugar (in Brazil) is positive, strong and stable in time. Importantly, we show that the prices of feedstock lead the prices of ethanol and not the other way around. The price lead of feedstock is documented for both short‐ and long‐run horizons. Our qualitative results hold true even when the influence of crude oil prices is accounted for by utilizing partial wavelet coherence approach.     

Does corn market uncertainty impact the US ethanol prices?

The growing interest in biofuel as a green energy source has intensified the linkages between corn and ethanol markets, especially in the United States that represents the largest producing and exporting country for ethanol in the world. In this study, we examine the effect of corn market uncertainty on the price changes of US ethanol applying a set of GARCH‐jump models. We find that the US ethanol price changes react positively to the corn market volatility shocks after controlling for the effect of oil price uncertainty. In addition, we document that the impact of corn price volatility on the US ethanol prices appears to be asymmetric. Specifically, only the positive corn market volatility shocks are found to influence the ethanol market returns. Our findings also suggest that time‐varying jumps do exist in the ethanol market.     

Relationship between biomass energy and economic growth in transition countries: panel ARDL approach

In this study, we have investigated the co‐integration and causality relationship between the biomass energy consumption and economic growth in the transition countries by the Panel Auto Regressive Distributed Lag (ARDL) method and Pedroni co‐integration analysis for 1990–2011. Analysed countries are gathered under two groups. For Groups 1 and 2, Pedroni panel co‐integration test and ARDL bound test results show that biomass energy consumption and economic growth are co‐integrated. Fully modified ordinary least squares results suggested that biomass energy consumption has positive effect on the economic growth.     

Estimating the environmental Kuznets curve for Spain by considering fuel oil prices (1874–2011)

We perform a structural analysis on an environmental Kuznets curve (EKC) for Spain by exploiting long time series (1874–2011) and by using real oil prices as an indicator of variations in fuel energy consumption. This empirical strategy allows us to both, capture the effect of the most pollutant energy on carbon dioxide (CO₂) emissions and, at the same time, preclude potential endogeneity problems derived from the direct inclusion of fuel consumption in econometric specification. Knowing the extent to which oil prices affect CO₂ emissions has a straightforward application for environmental policy. The dynamics estimates of the long and short-term relationships among CO₂, economic growth and oil prices are built through an autoregressive distributed lag (ARDL) model. Our test results support the EKC hypothesis. Moreover, real oil prices are clearly revealed as a valuable indicator of pollutant energy consumption.     

Price interconnection of fuel and food markets: Evidence from biodiesel in the United States

The food versus fuel issue has attracted considerable attention with the rapid growth of global biofuel production. The previous literature examining the interconnectedness between biofuel, fossil fuel and agricultural markets employed futures and spot prices. However, food security needs to be discussed with non-financial market prices, such as wholesale prices, since retail companies and households usually do not purchase products directly from financial markets, which encompass speculative activities, making them more volatile than non-financial ones. This paper focuses on non-financial markets in the United States to investigate the price-interconnection of biodiesel, highway diesel, crude oil, and soybean, initially applying partial wavelet coherence and the Diebold-Yilmaz connectedness index to price transmission research on biodiesel, highway diesel, crude oil, and soybean. Our main results are as follows: First, significant coherence between biodiesel and soybean, biodiesel and highway diesel, and highway diesel and crude oil is identified in the short and long term. Second, crude oil and biodiesel prices are found to be net transmitters, while soybean and highway diesel prices are net receivers. Finally, the crude oil market is identified as the source of spillovers among the four markets, and strongly influences the highway diesel market.     

Change in cereal production caused by climate change in Malaysia

This study attempts to estimate the effects of climate change variables, such as average temperature, CO₂ emissions and average rainfall, on cereal production in Malaysia from 1969 to 2018. After preliminary tests on time series data, we employed a novel autoregressive distributed lag (ARDL) method known as the dynamic ARDL simulations technique. The results showed that a long-run co-integration relationship exists between cereal production and climatic and non-climatic factors. All climate variables have a negative impact on cereal yield, while energy consumption and cultivated land have a positive effect on cereal yield in the short- and long-run. Granger causality analyses also showed that a unidirectional causality link exists between rainfall and temperature with cereal production and between CO₂ emissions and cereal production. Energy consumption, as a proxy for technology, has a one-way Granger cause with cereal production. The results of the dynamic ARDL simulations suggest that cereal yield was most sensitive to CO₂ emissions, rainfall and temperature. In the long run, a 1% increase in temperature is associated with a 2.87% and 3.52% decrease in general and predicted estimates of cereal production, respectively. The dynamic ARDL simulations methodology provides a better understanding of the variability of cereal production in Malaysia as a result of climate change.     

Does energy intensity contribute to CO2 emissions? A trivariate analysis in selected African countries

The present study investigates the dynamic relationship between energy intensity and CO₂ emissions by incorporating economic growth in environment CO₂ emissions function using data of Sub Saharan African countries. For this purpose, we applied panel cointegration to examine the long run relationship between the series. We employed the VECM Granger causality to test the direction of causality amid the variables.At panel level, our results validate the existence of cointegration among the series. The long run panel results show that energy intensity has positive and statistically significant impact on CO₂ emissions. There is also positive and negative link of non-linear and linear terms of real GDP per capita with CO₂ emissions supporting the presence of environmental Kuznets curve (EKC). The causality analysis reveals the bidirectional causality between economic growth and CO₂ emissions while energy intensity Granger causes economic growth and hence CO₂ emissions, while across the individual countries, the results differ. This paper opens up new insights for policy makers to design comprehensive economic, energy and environmental policy for sustainable long run economic growth.     

Implications of corn prices on water footprints of bioethanol

Previously reported water footprints (WFPs) of corn ethanol have been estimated based on the assumption that corn ethanol feedstock could be supplied by the same states where the corn is grown. However, ethanol conversion facilities may choose out-of-state feedstock suppliers depending on the total price of feedstock they have to pay including both the corn price and transportation costs. The purpose of this study is to evaluate the WFPs and total water use (TWU) of corn ethanol considering an optimal allocation of corn with heterogeneous corn feedstock prices across states. The results show that the WFPs of corn ethanol are less than 100 l of water per liter of ethanol (Lw/Le) for all ethanol-producing states based on both the 2008 corn price and transportation costs for rail and truck. Results also reveal that WFPs are very sensitive to the market price of corn and that additional greenhouse gas emissions due to corn trade between states are not significant.     

Explaining the reductions in Brazilian sugarcane ethanol production costs: importance of technological change

Over the period 1975–2010, unit production costs of sugarcane ethanol in Brazil declined by 67%, while the per‐unit processing costs decreased by more than 70%. This article examines the role of various factors that lead to these cost reductions, including learning‐by‐doing (LBD), economies of scale, rising input prices, market competitiveness, and exogenous technological changes. Using the aggregate industry‐level data, we show that the traditional experience curve approach will lead to biased estimate of the learning effect when economies of scale, rising input prices, market competitiveness, and exogenous technological changes are excluded as explanatory variables in explaining these cost reductions. With the inclusion of these variables and LBD, we find that the reductions in production/processing costs of Brazilian sugarcane ethanol were primarily driven by autonomous technological changes and unrelated to LBD. Economies of scale, market competitiveness, and rising input prices had insignificant impacts on the reductions in production/processing costs of sugarcane ethanol over the sample period.     

Economic growth,electricity consumption,urbanization and environmental degradation relationship in United Arab Emirates

The present study explores the relationship between economic growth, electricity consumption, urbanization and environmental degradation in case of United Arab Emirates (UAE). The study covers the quarter frequency data over the period of 1975–2011. We have applied the ARDL bounds testing approach to examine the long run relationship between the variables in the presence of structural breaks. The VECM Granger causality is applied to investigate the direction of causal relationship between the variables. Our empirical exercise reported the existence of cointegration among the series. Further, we found an inverted U-shaped relationship between economic growth and CO₂ emissions i.e. economic growth raises energy emissions initially and declines it after a threshold point of income per capita (EKC exists). Electricity consumption declines CO₂ emissions. The relationship between urbanization and CO₂ emissions is positive. Exports seem to improve the environmental quality by lowering CO₂ emissions. The causality analysis validates the feedback effect between CO₂ emissions and electricity consumption. Economic growth and urbanization Granger cause CO₂ emissions.     

Parametric and genetic analysis of Drosophila appetitive long‐term memory and sugar motivation

Distinct forms of memory can be highlighted using different training protocols. In Drosophila olfactory aversive learning, one conditioning session triggers memory formation independently of protein synthesis, while five spaced conditioning sessions lead to the formation of long‐term memory (LTM), a long‐lasting memory dependent on de novo protein synthesis. In contrast, one session of odour–sugar association appeared sufficient for the fly to form LTM. We designed and tuned an apparatus that facilitates repeated discriminative conditioning by alternate presentations of two odours, one being associated with sugar, as well as a new paradigm to test sugar responsiveness (SR). Our results show that both SR and short‐term memory (STM) scores increase with starvation length before conditioning. The protein dependency of appetitive LTM is independent of the repetition and the spacing of training sessions, on the starvation duration and on the strength of the unconditioned stimulus. In contrast to a recent report, our test measures an abnormal SR of radish mutant flies, which might initiate their STM and LTM phenotypes. In addition, our work shows that crammer and tequila mutants, which are deficient for aversive LTM, present both an SR and an appetitive STM defect. Using the MB247‐P[switch] system, we further show that tequila is required in the adult mushroom bodies for normal sugar motivation.     

Assessing the impacts of meteorological factors on soybean production in China: What role can agricultural subsidy play?

Cereal and oilseed crops possess significance in meeting global food security. China, housing the most number of people, remains the top importer of oilseed crops (i.e., soybeans) to produce energy and meet its food needs. With such significance, the present study investigates the impact of meteorological factors on soybean production in China using the annual data from 1978 to 2020. It also incorporated other essential determinants of soybean production, such as agricultural subsidy, cultivated area, and fertilizer use. For data analysis, it employed the autoregressive distributed lag (ARDL) method and the Quantile Regression (QR) technique. The findings from an ARDL model unveiled meteorological factors such as the yearly average temperature and CO₂ emissions declined soybean production in the long–run and short–run analysis, whereas the yearly average precipitation improved soybean production. Besides, agricultural subsidy, cultivated area, and fertilizer use also enhanced soybean production in the long–and short–run analyses. In addition, the findings from the Quantile Regression (QR) technique showed that temperature and CO₂ emissions negatively affected soybean production in each quantile (i.e., 0.1–0.90), while precipitation and agricultural subsidy positively augmented soybean production across all quantiles (i.e., 0.1–0.90). Based on these results, the study provides clear policy implications, such as governments should provide crop-specific subsidies instead of input-based subsidies to embolden the impact of agricultural subsidies. Also, ecological improvement campaigns should be launched to attract farmers' attention to sustainable agriculture practices to meet meteorological challenges.     

Fuel ethanol after 25 years

After 25 years, Brazil and North America are still the only two regions that produce large quantities of fuel ethanol, from sugar cane and maize, respectively. The efficiency of ethanol production has steadily increased and valuable co-products are produced, but only tax credits make fuel ethanol commercially viable because oil prices are at an all-time low. The original motivation for fuel-ethanol production was to become more independent of oil imports; now, the emphasis is on its use as an oxygenated gasoline additive. There will only be sufficient, low-cost ethanol if lignocellulose feedstock is also used.     

收敛交叉映射方法及其在生态学中的应用

收敛交叉映射(CCM)是一种分析非线性系统中时间序列变量间因果关系的方法。其不同于传统的线性系统分析方法,是通过对变量进行状态空间重构来获取变量的历史信息,随着时间序列不断增长,当其估计性能呈现收敛的性质时,可以判断因果关系的存在。本文介绍了CCM的发展史及其较传统的格兰杰因果检验的优点,详细阐明了CCM的原理、算法过程和实现途径。CCM作为一种针对变量间具有弱到中等强度耦合关系的系统分析方法,可以用来有效地解决非线性生态系统多变量间复杂的因果关系问题。将该方法应用于具有空间信息的多点位时间序列变量间因果分析时,应充分考虑点位间的空间自相关性,与可以去除变量及序列间空间相关性的方法相结合,从而确保CCM对变量因果关系的分析更加准确,结果也更具有信服力。     

Climate change and its impacts on Vietnam agriculture: A macroeconomic perspective

Vietnam is an important contributor to the world's food industry as a major exporter of rice, seafood, and coffee. Climate change poses a serious threat to Vietnam's agricultural sector since it adversely affects food security in Vietnam and globally. This study investigates the short- and long-term effects of climate change on Vietnam's agriculture, both in terms of production and values at the macro level. Using the Autoregressive Distributed Lag (ARDL) model and the Toda-Yamamoto (1995) Granger causality test with annual data from 1990 to 2019, we confirm the detrimental impacts of global warming on Vietnam's agricultural performance in both the short and long term. We also reveal the favorable effects of CO₂ emissions, land, and fertilizer on Vietnam's agricultural production and economics. Other factors, including rainfall and labor, however, adversely affect Vietnam's agricultural output and economic performance. Based on the study's results, we provide policy recommendations to assist the government limit the negative effects of climate change on the national economy, thereby promoting poverty alleviation and sustainable development in Vietnam.     

Renewable resources in the chemical industry – Breaking away from oil?

Rising prices for fossil-based raw materials suggest that sooner or later renewable raw materials will, in principle, become economically viable. This paper examines this widespread paradigm. Price linkages like those seen for decades particularly in connection with petrochemical raw materials are now increasingly affecting renewable raw materials. The main driving force is the competing utilisation as an energy source because both fossil-based and renewable raw materials are used primarily for heat, electrical power and mobility. As a result, prices are determined by energy utilisation. Simple observations show how prices for renewable carbon sources are becoming linked to the crude oil price. Whether the application calls for sugar, starch, virgin oils or lignocellulose, the price for the raw material rises with the oil price. Consequently, expectations regarding price trends for fossil-based energy sources can also be utilised for the valuation of alternative processes. However, this seriously calls into question the assumption that a rising crude oil price will favour the economic viability of alternative products and processes based on renewable raw materials. Conversely, it follows that these products and processes must demonstrate economic viability today. Especially in connection with new approaches in white biotechnology, it is evident that, under realistic assumptions, particularly in terms of achievable yields and the optimisation potential of the underlying processes, the route to utilisation is economically viable. This makes the paradigm mentioned at the outset at least very questionable.     

Effects of food price shocks on child malnutrition: The Mozambican experience 2008/2009

A propitiously timed household survey carried out in Mozambique over the period 2008/2009 permits us to study the relationship between shifts in food prices and child nutrition status in a low income setting. We focus on weight-for-height and weight-for-age in different survey quarters characterized by very different food price inflation rates. Using propensity score matching techniques, we find that these nutrition measures, which are sensitive in the short run, improve significantly in the fourth quarter of the survey, when the inflation rate for basic food products is low, compared to the first semester or three quarters, when food price inflation was generally high. The prevalence of underweight, in particular, falls by about 40 percent. We conclude that the best available evidence points to food penury, driven by the food and fuel price crisis combined with a short agricultural production year, as substantially increasing malnutrition amongst under-five children in Mozambique.     

Relationships among carbon emissions,economic growth,energy consumption and population growth: Testing Environmental Kuznets Curve hypothesis for Brazil,China, India and Indonesia

This study examines the impacts of income, energy consumption and population growth on CO₂ emissions by employing an annual time series data for the period 1970–2012 for India, Indonesia, China, and Brazil. The study used the Autoregressive Distributed Lag (ARDL) bounds test approach considering both the linear and non-linear assumptions for related time series data for the top CO₂ emitter emerging countries in both the short run and long run. The results show that CO₂ emissions have increased statistically significantly with increases in income and energy consumption in all four countries. While the relationship between CO₂ emissions and population growth was found to be statistically significant for India and Brazil, it has been statistically insignificant for China and Indonesia in both the short run and long run. Also, empirical observations from the testing of environmental Kuznets curve (EKC) hypothesis imply that in the cases of Brazil, China and Indonesia, CO₂ emissions will decrease over the time when income increases. So based on the EKC findings, it can be argued that these three countries should not take any actions or policies, which might have conservative impacts on income, in order to reduce their CO₂ emissions. But in the case of India, where CO₂ emissions and income were found to have a positive relationship, an increase in income over the time will not reduce CO₂ emissions in the country.     

Drivers leading to higher food prices: biofuels are not the main factor

Since 2007, the overall rise in food prices in the USA was twice that of the overall inflation rate, led by inflation for poultry and dairy products in particular. Prominent studies have indicated that the main drivers associated with the rise in food prices in the past 3 yr are the increased energy costs (and the trickle-down impact on farm input costs) and the devaluation of the US dollar. However, currently, the impact of crude oil as one of the primary drivers in food prices has waned significantly, as crude oil prices have fallen dramatically since late 2008. The data reviewed here debunk the popular myth that food producers, particularly farmers growing corn or soybean for biofuel feedstocks, are making huge profits with high commodity prices. Producers continue to face extraordinary risks in their farming operations, and profit margins have narrowed considerably because of the high input prices driven by high energy costs. One of the primary solutions to the food price inflation is to increase the supply of commodity crops in a responsible way that is both respectful and sustainable regarding economic, social, and environmental aspects. At the center of this solution is implementing and developing new technologies to increase crop yields and nutritional values without increasing the amount of fossil-based inputs used in agriculture. Conventional breeding, molecular breeding, genomics, and biotechnology are pivotal technologies for increasing crop yields to meet these supply needs, combined with the impacts of other new technologies and best management practices in agricultural production.     

Population genetic evidence for sex‐specific dispersal in an inbred social spider

Dispersal in most group‐living species ensures gene flow among groups, but in cooperative social spiders, juvenile dispersal is suppressed and colonies are highly inbred. It has been suggested that such inbred sociality is advantageous in the short term, but likely to lead to extinction or reduced speciation rates in the long run. In this situation, very low levels of dispersal and gene flow among colonies may have unusually important impacts on fitness and persistence of social spiders. We investigated sex‐specific differences in dispersal and gene flow among colonies, as reflected in the genetic structure within colonies and populations of the African social spider Stegodyphus dumicola Pocock, 1898 (Eresidae). We used DNA fingerprinting and mtDNA sequence data along with spatial mapping of colonies to compare male and female patterns of relatedness within and among colonies at three study sites. Samples were collected during and shortly after the mating season to detect sex‐specific dispersal. Distribution of mtDNA haplotypes was consistent with proliferation of social nests by budding and medium‐ to long‐distance dispersal by ballooning females. Analysis of molecular variance and spatial autocorrelation analyses of AFLPs showed high levels of genetic similarity within colonies, and STRUCTURE analyses revealed that the number of source populations contributing to colonies ranged from one to three. We also showed significant evidence of male dispersal among colonies at one site. These results support the hypothesis that in social spiders, genetic cohesion among populations is maintained by long‐distance dispersal of female colony founders. Genetic diversity within colonies is maintained by colony initiation by multiple dispersing females, and adult male dispersal over short distances. Male dispersal may be particularly important in maintaining gene flow among colonies in local populations.