CIV ENG 11 Chapter Notes - Chapter 1: Global Warming Potential, Emission Intensity, Life-Cycle Assessment

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Published on 11 Oct
School
Berkeley
Department
Civil And Environmental Engineering
Course
CIV ENG 11
Professor
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DEPARTMENT OF CIVIL AND ENVIRONMENTAL ENGINEERING
UNIVERSITY OF CALIFORNIA, BERKELEY
CE11 ENGINEERED SYSTEMS AND SUSTAINABILITY, SPRING 2020
HOMEWORK 4: LIFE-CYCLE ASSESSMENT
DUE FRIDAY, MARCH 6, 2020 (100 POINTS)
*****SOLUTIONS*****
1. The Climate Footprint of Your Diet (32 points)
Researchers at Carnegie Mellon University published a paper, “Food-Miles and the Relative Climate
Impacts of Food Choices in the United States” (http://pubs.acs.org/doi/abs/10.1021/es702969f), that
compared the climate impacts of eating local food versus the types of food people typically eat. Use the
results of their analysis (posted as an Excel file, “Food_LCA_Data, on bCourses) to answer the following
questions. Note: Excluded from the researchers’ findings is the global warming potential associated with
HFCs.
a) Calculate the global warming potential (GWP100) (in units of CO2,e) associated with U.S.
consumption of the foods listed below. Products will be associated with multiple commodity groups!
(8 points)
1) Red Meat
2) Chicken/Fish/Eggs
3) Fruit/Vegetable
4) Beverages
Food Type GWP
(1000 mtCO2) $M Demand kg CO2/$
Red Meat 181,753 43,033 4.22
Chicken/Fish/Eggs 43,118 31242 1.38
Fruit/Vegetable 42,719 35,396 1.21
Beverages 23,323 30,426 0.77
b) Of these four food types, which is the most carbon-intensive per dollar? (2 points)
Red Meats (4.2 kg CO2 / $)
c) Corn (mainly for its carbohydrates content) and soybeans (as protein) are often found in many food
products in the United States. Draw a life-cycle diagram of the different phases associated with
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providing either (dry) corn (as animal feed) or edamame. Label all life-cycle phases and note major
input resources. (6 points)
d) List three major differences between producing these crops and producing red meats (beef). (6 points)
1) Cattle give off methane
2) It takes corn and other food crops to feed cattle
3) Cattle must be processes before entering into local markets
4) Beef must be refrigerated after processing
5) Producing crops requires fertilizer use
e) Compare the costs of providing 2,000 kcal of beef ($5/lb) and soybeans ($2/lb). Then compare the
total greenhouse gas footprint (in kg CO
2
,e) of providing 2,000 kcal of beef (which comes from
“animal, except poultry, slaughtering”) and soybeans (“grain farming”). How do food prices and
carbon footprints relate? (10 points)
See the USDA: https://fdc.nal.usda.gov/ and search using the following keywords:
Beef: Beef, ground, 90% lean meat / 10% fat, raw
Soybeans: soybeans, green, raw
Beef: 176 kCal / 100 g; Soybeans: 147 kCal / 100 g)
Beef: 2000 kcal x (100 g beef / 176 kcal) x (2.2lb / 1000 g) x ($5 / lb) = $12.5
Soybeans: 2000 kcal x (100 g soybeans / 147 kcal) x (2.2lb / 1000 g) x ($2 / lb) = $6
Beef: $12.5 x (~5.3 kg CO2e/$) = ~66 kg CO
2
,e
Soybeans: $6 x (~4.7 kg CO2e/$) = ~28 kg CO
2
,e
Beef is ~100% more expensive and ~2.5 times more CO
2
-intensive than soybeans.
2. The Carbon Footprint of Your Activities (23 points)
Please calculate your carbon footprint at http://footprint.wwf.org.uk.
a) What percent is “your share,” and how many tons? What is the breakdown of your carbon footprint?
Copy the chart into your homework. (6 points)
NOTE: Specific answers will vary for this problem. The following answers are an example.
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Share: 8.6 tonnes
Carbon Footprint: 82% of target impact on the world
Representative chart
b) What tips does the calculator give you to reduce your carbon footprint? Do you agree that these tips
would indeed reduce your footprint? Put forward two arguments pro and two contra. (6 points)
Tips are divided by the 4 categories (Food, Home, Travel, Stuff).
Travel
Ride a bicycle instead of driving a car (as this takes cars off the road)
Take public transport (b/c fewer cars on road and the remaining cars have quicker journeys and
thus emit less CO2)
If you drive: (1) make sure you are not carrying excess weight; (2) have good air pressure in
your tires; (3) drive 10% slower
Food
Eat seasonal food (as this reduces packaging, transporting, and other farming processes)
Eat less meat and dairy (as these food products have the most GHG emissions)
Eat a variety of foods (as continuing to plant one crop over and over again is bad for the
ecosystem)
Home
Switch to an energy provider that uses renewable sources in their mix
Use energy-efficient bulbs
Use SMART technology
Stuff
Buy one expensive item rather than continuing to replace cheaper alternatives (so that you
reduce waste)
Buy secondhand (so as to reduce waste)
Two Pro Arguments
Riding a bicycle to campus rather than driving would reduce your personal emissions.
If you switched to energy-efficient lightbulbs and did not use them at a rate higher than if you
used standard lightbulbs, you might also reduce your personal footprint.
Two Contra Arguments
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Document Summary

*****solutions****: the climate footprint of your diet (32 points) Researchers at carnegie mellon university published a paper, food-miles and the relative climate. Impacts of food choices in the united states (http://pubs. acs. org/doi/abs/10. 1021/es702969f), that compared the climate impacts of eating local food versus the types of food people typically eat. Use the results of their analysis (posted as an excel file, food_lca_data, on bcourses) to answer the following questions. Note: excluded from the researchers" findings is the global warming potential associated with. Hfcs: calculate the global warming potential (gwp100) (in units of co2,e) associated with u. s. consumption of the foods listed below. Products will be associated with multiple commodity groups! (8 points: red meat, chicken/fish/eggs, fruit/vegetable, beverages. 0. 77: of these four food types, which is the most carbon-intensive per dollar? (2 points) Red meats (4. 2 kg co2 / $: corn (mainly for its carbohydrates content) and soybeans (as protein) are often found in many food products in the united states.

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