2 The Climate Footprint of Your Diet 40 points Researchers a

2. The Climate Footprint of Your Diet (40 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/doilabs/10.1021/es702969f that compared the climate impacts of eating local food versus the types of food people typically eat. Use the results oftheir analysis (posted as an Excel file to bCourses) to answer the following questions. Note: Excluded from the researchers\' findings is the global warming potential associated with HFCs a) Calculate the 100-year global warming potential (GWP) (in units of CO2,e) associated with U.S. consumption of the food listed below. Products will be associated with multiple commodity groups! (10 points) I) Red Meat 2) Cereals/Carbs 3) Fruit/Vegetable 4) Dairy Products b) Of these four food types, which is the most carbon-intensive per dollar? (2 points) 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 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, such as beef. (6 points) e) Compare the costs of providing 2,000 kcal of beef (S5/lb) and sweet corn (S2/lb). Then compare the total greenhouse gas footprint (in kg CO2,e) of providing 2,000 kcal of beef (which comes from \"ranching and slaughtering and sweet corn grain farming\"). How do food prices and carbon footprints relate? See USDA, http://ndb nal.usda.gov/ndb/search/list Beef: Use the \"ground beef calculator,\" raw, 10% fat Sweet corn: corn, sweet, yellow, raw (16 points)

Solution

Ans. a) Global warming potential is the determination of the sum of carbon dioxide (CO₂) and methane (CH₄) emissions of a particular population, system or their activity which includes all pertinent sources. It is calculated as carbon dioxide equivalent using the relevant 100-year global warming potential (GWP100). To calculate the GWP, one has to calculate all the GHG emissions per kg of weight from birth until the animal or plant death.

Typically the GWP of milk product is ranges between 0.8 – 1.4 kg co2eq kg-1

b.) Of the mentioned food type, red meet the most carbon intensive per dollar (red meet have high carbon footprint in relation to its economic value).

c.) Low-carbon biological feed are being developed and evaluated in the United States. Nowadays, potential bio feed production systems are examined from a long-term continuous no-tillage corn (Zea mays L.). Corn has been grown for bio-energy and results in net reduction in greenhouse gas (GHG) 29 to 396 grams of CO2 equivalent emissions per megajoule of ethanol per year as a result of straight soil carbon sequestration and from the implementation of integrated bio feed conversion pathways.

d.) There is marked difference in growing these crops (plants) and red meet (animal) as crop plant consumes the CO2 and reduces the greenhouse gas emissions. But on the other hand, red meat production increase the greenhouse gas emissions and thus has a deleterious effect impact on climate change.