GGR107H1 Chapter Notes -Feedlot

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fuchsiamammoth394

27 May 2012

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People do not necessarily need meat but we eat it. Wealth and global commerce have increased in our consumption of meat, milk, eggs and fish. 5. 5. 2 high consumption has led to feedlot agriculture. In traditional agriculture livestock were allowed to graze the grassland. Feedlots/concentrated animal feeding operations (cafos): are hugely designed lots that allow many of animals to live. However there is a lot of waste produced by the animals in feedlots. It could lead to an outbreak in disease. Crowded conditions can lead to the bird flu or mad cow disease. 5. 5. 3 our food choices are also energy choices. We choice certain foods that have energy impacts on the environment. Eating meat requires more energy than eating fruits and vegetables. Scientists have calculated the amount of energy required for food to be made. Growth of meat requires the consumption of plants. Wild fish populations have decreased and now we raise them on farms.

Related Questions

It is currently popular for automobiles to use 10% ethanol / 90%gasoline mixtures (âgasoholâ) as fuel. According to popularconsensus the main benefit of gasohol use is that it âreduces ourdependence upon foreign oil.â We test this assertion by making someelementary calculations. Our analysis will unrealistically ignoreengine maintenance issues associated with older automobiles (suchas gasket and seal hardening), added fuel consumption necessary toproduce grain used as a feedstock in ethanol production,incremental food price increases associated with a reduction ingrain stocks, and many other effects. Gasohol use typically reducesaverage fuel economy by approximately 15% and effectively leavesfuel prices unchanged. This article further debates the wisdom ofethanol use and may be of interest outside the problems:
http://harvardmagazine.com/2006/11/the-ethanol-illusion.html
These concerns and problems have been strongly influenced byconversations with Dr. H.J. Harmon, of the OSU physicsdepartment.

2. Consider a 14.2 mpg 1991 Ford F150 driven 761 miles. Calculatethe pure gasoline consumption of this truck when: a) usinggasoline, and b) when using gasohol (with its attendant economyreduction). Determine the total CO2 emissions for each fuelassuming all fuels produce 20 lbs of CO2 per gallon. Comment uponthe wisdom of using gasohol versus pure gasoline in this vehicle.

Tiny solid and liquid particles suspended in the atmosphere are called aerosols. Windblown dust, sea salts, volcanic ash, smoke from wildfires, and pollution from factories are all examples of aerosols. Depending upon their size, type, and location, aerosols can either cool the surface, or warm it. They can help clouds to form, or they can inhibit cloud formation. And if inhaled, some aerosols can be harmful to people's health.

These maps show average monthly aerosol amounts around the world based on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite. Satellite measurements of aerosols, called aerosol optical thickness, are based on the fact that the particles change the way the atmosphere reflects and absorbs visible and infrared light. An optical thickness of less than 0.1 (palest yellow) indicates a crystal clear sky with maximum visibility, whereas a value of 1 (reddish brown) indicates very hazy conditions.

High aerosol amounts are linked to different process in different places and times of year. High aerosol amounts occur over South America from July through September. This pattern is due to land clearing and agricultural fires that are widespread across the Amazon Basin and Cerrado regions during the dry season. Aerosols have a similar seasonal pattern in Central America (March-May), central and southern Africa (June-September, and Southeast Asia (January-April).

In other cases, however, aerosol concentrations are not related to fires. For example, from May through August each year, aerosol amounts rise dramatically around the Arabian Peninsula and nearby oceans due to dust storms. Elevated aerosol amounts nestle at the foothills of the Himalaya Mountains in northern India in some months, and linger over eastern China for much of the year. These elevated aerosol amounts are due to human-produced air pollution.

What is the most likely source of the high concentration of particulates that appear off the coast of northwestern Africa?

What is the most likely source of the high concentrations of particulates over central Africa and central South America?

What is the most likely source of the high concentrations of particulates over eastern China?

apricottermite85

3. 3 Stratosphere-troposphere exchange

The rate of exchange of air between the troposphere and thestratosphere is critical for determining the potential of variouspollutants emitted from the surface to reach the stratosphere andaffect the stratospheric ozone layer. One of the first estimates ofthis rate was made in the 1960s using measurements of strontium-90(90Sr) in the stratosphere. Strontium-90 is a radioactive isotope(half-life 28 years) produced in nuclear explosions. It has nonatural sources. Large amounts of 90Sr were injected into thestratosphere in the 1950s by above-ground nuclear tests. Thesetests were banned by international treaty in 1962. Following thetest ban the stratospheric concentrations of 90Sr began to decreaseas 90Sr was transferred to the troposphere. In the troposphere,90Sr is removed by wet deposition with a lifetime of 10 days (bycontrast there is no rain, and hence no wet deposition, in thestratosphere). An intensive stratospheric measurement network wasoperated in the 1960s to monitor the decay of 90Sr in thestratosphere. We interpret these observations here using a 2-boxmodel for stratosphere-troposphere exchange with transfer rateconstants kTS and kST (yr-1) between the tropospheric andstratospheric reservoirs. The reservoirs are assumed to beindividually well-mixed.

Let mS and mT represent the masses of 90Sr in the stratosphere andin the troposphere respectively. Observations of the decrease inthe stratospheric inventory for the period 1963-1967 can be fittedto an exponential mS(t) = mS(0)exp(-kt) where k = 0.77 yr-1.

1. Write mass balance equations for mS and mT in the 1963-1967period.

2. Assuming that transfer of 90Sr from the troposphere to thestratosphere is negligible (we will verify this assumption later),show that the residence time of air in the stratosphere is tS =1/kST = 1.3 years.

3. Let m'T and m'S represent the total masses of air in thetroposphere and the stratosphere, respectively. Show that theresidence time of air in the troposphere is tT = tS (m'T/m'S) = 7.4years. Conclude as to the validity of your assumption in question2.

4. Hydrochlorofluorocarbons (HCFCs) have been adopted asreplacement products for the chlorofluorocarbons (CFCs), which werebanned by the Montreal protocol because of their harmful effect onthe ozone layer. In contrast to the CFCs, the HCFCs can be oxidizedin the troposphere, and the oxidation products washed out byprecipitation, so that most of the HCFCs do not penetrate into thestratosphere to destroy ozone. Two common HCFCs have trade namesHCFC-123 and HCFC-124; their lifetimes against oxidation in thetroposphere are 1.4 years and 5.9 years, respectively. There are noother sinks for these species in the troposphere. Using our 2-boxmodel, determine what fractions of the emitted HCFC-123 andHCFC-124 penetrate the stratosphere.

GGR107H1 Chapter Notes -Feedlot

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