Global Warming Reduction by Switching to Healthy Diets

by Shelby Long

The consumption of food and beverages accounts for 22–31% of total private consumption greenhouse gas (GHG) emissions in the EU (Tukker et al. 2009). More specifically, the production of meat and dairy products tend to produce greater GHG emissions (Audsley et al. 2009). Saxe et al. (2012) examine how different diets, which are composed of different foods, are associated with varying potential GHG emissions. They use consequential Life Cycle Assessment to compare the emissions, or global warming potential (GWP), from food production for an Average Danish Diet (ADD), the Nordic Nutritional Recommendations (NNR), and a New Nordic Diet (NND), which was developed by the OPUS Project. They determined that the GHG emissions association with NNR and NND were lower than those associated with ADD, by 8% and 7%, respectively. When taking into account the transport of food, NND emissions are 12% less than ADD emissions. With regard to organic versus conventional food production, GHG emissions are 6% less for NND than for the ADD. Saxe et al. adjusted NND to include less beef and more organic produce, and they substituted meat with legumes, dairy products, and eggs, which made the diet more climate-friendly. As a result of this adjustment, the GHG emissions associated with NDD was 27% less than emissions for ADD. Continue reading

The Effect of Climate Change on Prawn Fishing in Bangladesh

by Shelby Long

Nearly 400,000 Bangladeshi people are financially dependent on the fresh water prawn market. Bangladesh offers the natural resources and ideal climate to support prawn farming from wild postlarvae. In 2002, a ban was placed on the fishing of wild postlarvae by the Department of Fisheries in Bangladesh. However, this ban is not strongly enforced, so many locals who rely on the market to make a living continue to fish. Ahmed et al. (2013) examines the effect of climate change on prawn fishing in the Pasur River through variables, including cyclones, salinity, sea level rise, water temperature, flood, rainfall, and drought. The Pasur River ecosystem, more specifically the prawn postlarvae, is highly vulnerable to climate changes because it is only one meter above sea level. Researchers surveyed and interviewed local fishermen, government fisheries officers, policymakers, and non-governmental organization workers. They also conducted focus group discussions with fishers and local community members regarding the various climate-affected variables under study. Ahmed et al. determined that prawn postlarvae catch has gradually decreased by approximately 15% over the past five years, with cyclones being the most significant climatic variable affecting the catch. Decreases in postlarvae prawn catch impact the health and socioeconomic well-being of local fishermen, many of which are women and children. Continue reading

Effect of Climate Change on Australian and Global Food Production

by Shelby Long

Recent droughts associated with climate change have had immense negative effects on food production in Australia. Australia is an important producer and exporter of livestock, dairy, and wheat. Much of the wheat produced is exported to Indonesia, Japan, South Korea, Yemen, Vietnam, and China. The Murray-Darling Basin is one of the main agricultural areas in the country, contributing 40% of Australia’s gross value of agricultural production. Water scarcity is accompanied by a high demand for water for both agricultural irrigation and non-agricultural uses (Quiggin and Chambers 2004). Therefore, it is necessary for crop producers to adopt new strategies to mitigate the impacts of drought. Some of these strategies include land use changes and introducing drought tolerant crop varieties. Qureshi et al. (2013) aim to use the Australian Bureau of Statistics (ABS) data and modeling to explore the possible future effects of Australian water Continue reading

Climate Change Increasing Water Scarcity

by Shelby  Long

The production of food and economic prosperity are highly dependent on a sufficient water supply. Both the demand and supply for water are affected by climate change-induced adjustments of precipitation patterns, temperature, other climate variables, and shifts in population. Much uncertainty remains among climate change models regarding how precipitation levels and patterns, as well as temperature, will change (Meehl et al. 2007). Also, precipitation changes affect other hydrological variables, such as surface or subsurface runoff and river discharge, and, therefore, effective hydrological and climate change modeling takes these variables into account. Schewe et al. (2013) use multiple global hydrological models (GHMs) and greenhouse-gas concentration scenarios to examine how climate change impacts global water resources. They determined that climate change is likely to intensify regional and global water scarcity. They project that a 2°C increase in global temperature will result in approximately 15% more of the global population experiencing a severe decrease in water resources. They also project this 2°C rise in temperature to increase the number of people living under absolute water scarcity by at least 40%, while some models predict a 100% increase. Along with climate change, they expect future population growth to Continue reading

Biofuel Production Using Charcoal and CO2 to Transform Animal Fats

The need for renewable fuels is increasing as the fossil fuel crisis becomes more severe.  Animal fats, an inexpensive source of triglyceride, are a potential cost-effective feedstock for biodiesel production (Kwon et al. 2012).  However, animal fats, which contain up to 6 wt% of free fatty acids (FFA’s), must be pre-treated before undergoing conventional catalytic processes (Crabbe et al. 2001; Naik et al. 2008).  Without pretreatment steps, impurities in the feedstock will react with the catalysts and limit the biofuel yield by producing soap.  Kwon et al. aim to prove that an efficient non-catalytic biodiesel conversion using only charcoal and CO2is possible.  They determined the optimal conditions for this conversion, including temperature, pressure, and feeding ratio of raw materials.  Previous studies on non-catalytic conversion suggest an optimal temperature of 250 °C, a pressure of 10MPa or higher, and a methanol-to-oil molar ratio of 6:1.  In the present study, Kwon et al. determined optimal operating conditions for the conversion of animal fats to biodiesel to be at a temperature of 350500 °C under ambient pressure, and volumetric flow rates of extracted lipid and methanol (MeOH) to be 10 and 3 ml min1, respectively. Shelby Long
Kwon, E. et al., 2012. Transforming animal fats into biodiesel using charcoal and
CO2. Green Chemistry 14, 1799–1804.

                  Kwon et al. analyzed the production process of biodiesel by transforming animal fat into biodiesel using charcoal and CO2.  They obtained cooking oil from a local restaurant, beef tallow and lard from the local slaughterhouse, charcoal from the local market, and MgOCaO/Al2O3 that was generated from magnesium slag from a magnesium-smelting factory.  They determined the acid value (AV), an indicator of oil quality, with the following equation: AV = A x c x 56.11/m (A = volume of KOH solution use to titrate sample; c = concentrations of KOH solution; m = sample mass).  They first examined the non-catalytic biodiesel conversion of used cooking oil to biodiesel using a pressure reactor.  For this experiment they used MgOCaO/Al2O3 as a catalyst.  Kwon et al. carried out the experiment at a temperature of 130–250 °C and maintained pressure by filling the reactor with nitrogen (N2) and CO2.  To further examine the effect of temperature on the conversion process they replicated the previous experiment but varied the temperature from 250–500 °C.  Kwon et al. replicated the same experiment a third time, but added a virgin catalyst, activated Al2O3, in order to examine the catalytic element effect of MgO–CaO on the transesterification reaction.  For their main experiment, Kwon et al. tested the conversion of beef tallow and lard into biodiesel using charcoal.  They packed charcoal into an airtight reactor and maintained the temperature at 250–500 °C while oil feedstock, MeOH, and CO2 reaction medium were continuously added into the reactor.  The mixture was allowed to settle for 2 hours after the reaction before the contents were analyzed.
Kwon et al. achieved an approximately 98% biodiesel conversion rate of used cooking oil after 30 minutes.  This high conversion rate suggests that CO2 can enhance transesterification.  CO2 is believed to enhance the efficiency of the transesterification process by accelerating bond dissociations, also known as thermal cracking (Kwon et al. 2009).  By examining the biodiesel conversion of used cooking oil, Kwon et al. determined that the conversion rate is more responsive to changes in temperature than to pressure.  They also found that non-catalytic biodiesel conversion can be completed using porous materials. The pores, such as those in charcoal, act as small reactors, while the high temperature drives the transesterification reaction.  One of the main findings Kwon et al. observed was that under atmospheric pressure and a relatively high temperature, the conversion cost can be decreased by almost 70%, compared to standard commercial processes.
                  The researchers suggest that the mass decay of lard they observed at the comparatively low temperatures of 120–140 °C may be due to low molecular lipids and moisture in the lard.  Also, the thermal decomposition of lard was observed to be lower than that of beef tallow, which may be attributed to its lower amount of saturated fat.  In addition, they also found that the thermal degradation pattern for animal fats is similar to that of vegetable oil.  The biodiesel conversion efficiency of lard and beef tallow was almost identical at 400 °C.  There was no evidence of thermal cracking taking place in the experiment.
                  Kwon et al. achieved a conversion efficiency of beef tallow and lard into biodiesel of 98.5 (+ 0.5) % under ambient pressure and at temperatures higher than 350 °C.  They determined these to be the optimal operating conditions.  Based on their observations, the researchers assert that the production of biodiesel using charcoal and CO2 has the potential to be a highly cost-effective biofuel conversion process.
Other Sources
Crabbe, E., et al., 2001. Biodiesel production from crude palm oil and evaluation of butanol extraction and fuel properties. Process Biochemistry 37, 65–71.
Naik, M., et al., 2008. Production of biodiesel from high free fatty acid Karanja (Pongamia pinnata) oil. Biomass Bioenergy 32, 354–357.
Kwon, E., et al., 2009.  ASME Conference Proceedings, 231–236. 

The Use of Coffee Grounds for the Production of Biodiesel

In recent decades, the production and consumption of coffee has increased.  As a result of the increased consumption of coffee there is a need for waste management of the spent coffee grounds (SCG).  Spent coffee grounds have a very complex chemical composition, which makes them useful for a variety of applications.  SCG have a 1020 wt% of oil content, and, therefore, they are viable feedstocks for the production of biofuels.  The high amount of sugars in SCG can be used to produce bioethanol through fermentation.  In addition, bioethanol can be used along with lipid fraction extracted from SCG to produce biodiesel through transesterification (Caetano, 2011).  Caetano et al. aims to investigate the use of SCG for the production of biofuels, as well as characterize SCG, the oil they contain, and the biofuels they produce.  They also identify the optimal operating conditions in order to extract oil from SCG, to perform oil transesterification to biodiesel, and to assess the biodiesel quality (Caetano et al. 2012).  Shelby Long
Caetano, N. et al., 2012. Valorization of Coffee Grounds for Biodiesel Production. Chemical Engineering Transactions 26.

Caetano et al. examined the use of SCG for the production of biofuels.  They obtained spent coffee grounds from a local coffee shop and allowed them to air dry for several days.  The SCG then underwent repeated cycles of oven drying at 105 + 5 °C followed by cooling in a desiccator.  The grounds were then weighed, and levels of total carbon (TC), total nitrogen (TN), protein content, ash content, cellulose content, and insoluble and soluble lignin content were taken.  In order to characterize and extract oil from the SCG researchers tested different solvents to determine which would be most effective for the extraction process.  For each treatment, 10 g of oven dried SCG and 200 mL of solvent were placed in a Soxhlet extractor for 2.5 to 9.5 hours.  When three consecutive measurements of the solvent refraction index were constant and close to the pure solvent’s value the extraction process was stopped.  The oil extraction rate was determined.  The oil extracted from the SCG were measured for solvent recoverability for hexane, isopropanol, heptane, octane, ethanol.  In order to recover the oil from the extracting solvent researchers used a rotary evaporator and a vacuum pump.  The extracted oil was characterized and assessed based on its quality.  The iodine number, acid value, water content, kinematic viscosity, density, and higher heating value (HHV) were measured.  In order to produce biodiesel, several esterification steps were performed in an orbital acclimatized shaker.  Researchers monitored the acid value of the product throughout the process and at specific steps added 40% methanol and H2SO4to perform the esterification process.  1% NaOH was used as a catalyst.  The biodiesel was then separated from the glycerol phase and washed with distilled water to achieve a neutral pH.  In order to characterize the biodiesel Caetano et al. accounted for the importance of compliance with standards for the use of biodiesel in vehicles engines.  Therefore, they assessed the biofuel density at 15 ˚C, the kinematic viscosity at 40 ˚C, the acid value, the iodine value, and the methyl esters content, which should all be in accordance with EN biofuel standards.
                  The results of Caetano et al.’s study somewhat differ from what previous studies report.  The moisture content is substantially higher, the higher heating value is lower, and the cellulose content differs from what other studies have indicated (Lago et al. 2001; Bizzo 2003; Mussatto et al. 2011b).  The present study suggests these differences may be due to different coffee extraction procedures, different storage conditions of the grounds, and the use of different types of coffee for the experiment.  The solvent that allowed for the highest oil recovery was octane.  Ethanol and hexane allowed for lower oil recovery.  Hexane had one of the higher recover rates, while ethanol exhibited a lower recovery rate.  Isopropanol had a strong capacity of oil extraction and solvent recovery.  The mixture of hexane and isopropanol at a ratio of 50:50 allowed for high oil extraction, but lower solvent recovery.
                  The extracted coffee oil had iodine values that were too low, too high viscosity to be used in direct combustion engines, and too high acidity to be directly converted into biodiesel without undergoing pre-treatment.  However, the high HHV indicates that the oil extracted may be used for direct combustion.  The biodiesel produced was also characterized, and researchers found that the acid value and viscosity were too high to comply with biofuel EN standards.  They suggest that the high water content in the oil and the high acid value may have hindered the completion of the reaction.  Caetano et al. indicate that more improvements in the SCG biofuel production process must be made in order to improve the quality of biodiesel to meet the EN standards.  Some of these improvements include obtaining a higher methyl ester content by drying the oil, removing water between esterifications, neutralizing excess acid before transesterification, and using different methanol-to-oil molar ratios. 

Effect of Increased Corn Ethanol Production on Food Export and Land Use Changes

The global production of biofuel has greatly increased due to energy security concerns.  Over the past two decades, ethanol production in the United States has grown 15–20% per year to meet the increased demand for renewable fuels (U.S. Energy Information Administration 2011).  The majority of ethanol produced within the United States comes from corn sugars.  Approximately 3% of the corn harvest was needed to meet ethanol demand in 1990, but this percentage grew to 37% by 2010.  Due to the increased demand for more renewable energy sources to replace environmentally harmful fossil fuels, policies have been enacted to promote the increased production of biofuel.  One of these policies is the U.S. Renewable Fuel Standard, which aims to increase biofuel production to 36 billion gallons by 2022.  It has been suggested that not only direct effects, but also indirect effects, of biofuel production should be taken into account (Melillo et al. 2009).  The direct effects of biofuel production include greenhouse gas (GHG) emission reductions, while indirect effects may be evident in land use changes.  It has also been argued that an increase in corn ethanol production will lead to a reduction in food exports and deforestation in other nations (Searchinger et al. 2008).  Due to the increase in the availability of U.S. agricultural data, researchers no longer have to rely on theoretical evidence; rather, now researchers can use real agricultural data to determine the effects of increases in ethanol production.  However, these data may not be sufficient enough to fully assess indirect land use changes in the United States (Wallington et al. 2012).  Shelby Long
Wallington, T. et al., 2012. Corn Ethanol Production, Food Exports, and Indirect Land
Use Change. Environmental Science and Technology 46, 6379–6384.

Wallington et al. analyzed the direct and indirect effects of the United States’ recent increase in biofuel production using available agricultural data through 2010.  They examined data on the global production, import, and export of agricultural commodities published by the United States Department of Agriculture Foreign Agricultural Service (USDA-FAS).  They also analyzed monthly data on energy statistics and production of fuel ethanol published by the United States Energy Information Administration (EIA).  Both sources of information were used by Wallington et al. to gain insight on the history of ethanol production and agriculture exports dating as far back as 1960.  Researchers examined agricultural productivity, corn ethanol production, and agricultural exports of the Unites States.  They acknowledge that between 2000 and 2010 the increase in use of corn for ethanol was accompanied by an increase in corn harvest.  However, researchers do not suggest that the increase in harvest was necessarily due to the increase in corn ethanol production. 
Wallington et al. recommend that future models need to account for increased yields in the United States and other countries due to agriculture technology improvements.  They suggest that these improvements are the result of increased biofuel production in the United States.  If this is the case, then researchers suggest decreases in land use outside of the U.S. would result, therefore, translating into a negative, favorable land use change burden.  In the long term, increases in demand for ethanol could lead to lower costs and higher yields.  In the short run, more intensive land use, investment in new production equipment, weather variability, movement of corn onto the better land, and increases in rotation of higher yielding crops (soy and corn) may take place. 
                  Wallington et al. determined that where there was an increase in ethanol production there were no obvious changes in corn and wheat exports in the past decade.  On the other hand, soybean, chicken, and pork exports have increased significantly over the past decade.  Annual corn exports showed no changes, as they remained at approximately 50 million tonnes.  There has also been a large increase in production and exports of distiller’s dry grains (DDG) over the past 10–15 years.  DDG is a co-product of ethanol production and is used as an animal feed.  Therefore, a reduction in demand for animal feed produced outside of the U.S. could be the result of increased biofuel demand in the U.S.  This reduction in demand for animal feed would lead to a negative indirect land use change.  The corn harvest has exhibited an upward trend over the past 50 years, increasing by about 2% per year.  Along with other factors taking place, the increase in harvest over the past 10 years was accompanied by an increase in use of corn ethanol.  There is no trend in the total harvested area of crops such as corn, soy, wheat, oats, and barley.  This may also indicate that there was no increase in the land devoted to the cultivation of these crops.  There is no significant correlation between U.S. ethanol production and corn exports in the past two decades.  Even if there was a correlation it could not be determined for certain whether one was the cause of the other.  Similarly, data on exports of meat and grains do not support the idea that corn ethanol production affects food exports. 
                  A past study predicted that a 56 billion liter increase in corn ethanol production would lead to a decline in corn, wheat, soybean, pork, and chicken exports by 62%, 31%, 28%, 18%, and 12% (5).  However, these levels of decline in exports were not seen as a result of the 43 billion liter increase in production over the past decade.  Another recent study proposed a model on indirect land use changes associated with an increase in corn ethanol production (Hertel et al. 2010).   The modeled increases in ethanol production were very close to the increase that took place between 2000 and 2010.  The model also predicted a net increase of 0.41% in coarse grain yield and a 17% decrease in coarse grain exports due to increases in ethanol production.  However, the historical 15% increase in ethanol production was 40x greater than the predicted 0.41% increase in yield of corn. 
                  The increases in ethanol production over the past decade have been accompanied by increases in harvest.  These increases in harvest are largely the result of improved yield per acre, increased acreage use, genetic improvements/hybrid plant breeding, and improved crop management (22).  There are two main arguments related to the effect of increased biofuel production on agricultural yields.  The first argument is that the increased market for corn ethanol production has not led to increases in agricultural yields.  This argument may be somewhat supported by the historical trend of corn yields over the past decade, which shows no change.  However, there are many other factors, such as population growth, dietary trends, economic growth, energy price fluctuation, and international export/import policy changes that may have been the cause of any changes in corn yields and demand.  Any changes are not necessarily due to the increases in ethanol production.  The other argument is that increases in demand for corn for ethanol production has made some contribution to changes in agricultural yields.  This argument is plausible because increases in demand and supply for corn, and interest in research and development of hybrid plants and improved agricultural practices are likely to lead to increases in corn yields.  Approximately 12 billion gallons of ethanol are made annually, which requires approximately 100 million tonnes of corn.  Approximately 30 million tonnes of DDG are produced as a result, and 1 tonne of DDG displaces approximately 1.2 tonnes of corn as animal feed (Arora et al. 2010).  If biofuel production does not contribute to increased corn yields, then there would be an indirect land use change due to increased corn ethanol production in the United States.  On the other hand, if biofuel production is responsible for all of the increased corn yields in the U.S., but none of the increased yields observed in the rest of the world, then there would be a small indirect land use change.  If biofuel production was responsible for all of the increases in U.S. corn yields and some of the increased yields in the rest of the world, then there would be negative indirect land use change due to corn ethanol production in the U.S.
                  Such large differences in corn yields of the U.S. and the rest of the world indicate that improved agricultural practices should be adopted by other countries, such as improved soil management, irrigation, fertilizer use, and farm machinery.  Due to the detailed agricultural data now available to researchers, new perspectives can be gained about crop yield changes and their effects.  However, further investigation must be conducted in order to gain a better understanding of the land use changes that may take place as a result of increased ethanol production.  In order to decrease the indirect land use changes in other countries as a result of higher biofuel production in the U.S., intensification of agricultural activities outside of the U.S. should be promoted.  Wallington et al. maintains that further investigation must take place concerning indirect land use changes resulting from ethanol production in order to determine what steps must be taken to decrease the impacts.         
Other Sources
U.S. Energy Information Administration, Monthly Energy Review, 2011.
Melillo, J. et al., 2009.  Science 326, 13971399.
Searchinger, T. et al., 2008.  Use of U.S. croplands for biofuels increases greenhouse
gases through emissions from land-use change.  Science 319, 1238–1240.
Hertel, T. et al., 2010.  Bioscience 60, 223–231.
Arora, S. et al., 2010. Estimated displaced products and ratios of distillers’ co-
products from corn ethanol plants and the implications of lifecycle analysis..  Biofuels 1, 911–922.