Greenhouse Gases

Question 1

Greenhouse Gasses (GHGs)

Answer 1

• gasses that trap heat emitted from the sun
• CO2, methane, nitrous oxide, CFCs (chlorofluorocarbons), ozone
• sun radiates solar radiation to Earth’s surface
• GHGs act like blanket over atmosphere and trap that heat to prevent it from escaping
• without greenhouse gasses, life would be impossible because it would be too cold
• GHGs are increasing because of human activities that contribute to the formation of these gasses
• too much heat from the sun is being retained by the Earth

Question 2

Livestock’s Long Shadow (2006) – UN Food and Agriculture Organization (UN FAO)

Answer 2

• “livestock and poultry are responsible for 18% of global GHG emissions measured in CO2e. This is a higher share than transportation”
• has been proven wrong
• FAO used one methodology to look at impact of livestock and different methodology to look at impact of transportation

Question 3

Life Cycle Assessment

Answer 3

• all aspects of product or service are analyzed
• the feed, soil, animal emissions, product processing, transport, refrigeration, cooking, all the way until you put that animal product in your mouth
• didn’t use LCA on transportation, only looked at tailpipe/direct emissions
• UN FAO acknowledged that mistake was made, but no media running that story made corrections to the story accordingly

Question 4

Number of Fridges in US with Animal-Sourced Foods

Answer 4

• 98%

Question 5

Percent of Protein Sales that are Plant-Based Alternatives

Answer 5

• 0.3% plant-based
• 99.7% animal-sourced

Question 6

Global GHG Emissions by Sector

Answer 6

• energy = 73.2% of all GHGs in the world (fossil fuel burning)
• agriculture and forestry = 18.4%

Question 7

US

Answer 7

• all livestock combined contributes to 4% of total greenhouse gas emissions
• beef is about 2% (1/2) of this
• fossil-fuel consuming sectors are the largest source of greenhouse gas emissions

Question 8

Global Warming Potential of GHGs (GWP 100)

Answer 8

• CO2: 1x (basically like the beer of GHGs)
• CH4: 28x CO2 (wine)
• NO2: 265x CO2 (vodka)
• GWP 100 assumes everything else is the same, but that’s not true
• using this assertion for constant source of methane overblows effect of methane by factor of 4
• GWP 100: how these gasses will affect warming over 100 years

Question 9

Global Methane Budget

Answer 9

• globally, all sources of methane amount to 558 (from fossil fuel, agriculture and waste, biomass burning, wetlands, other natural emissions)
• methane is different from other GHGs because it is produced but also destroyed naturally by sinks

Question 10

Methane Sinks

Answer 10

• destroy 548/558 teragrams of methane released into atmosphere
• major sink is from chemical reactions in the atmosphere
• takes 10-12 years for methane molecules to meet a hydroxyl radical molecule in the atmosphere
• hydroxyl radicals destroy methane during hydroxyl oxidation
• during this decade, methane is still a potent GHG
• there’s enough hydroxyl radicals in the atmosphere as long as methane is a constant source
• methane is not 28x more powerful than CO2

Question 11

Half-Life of Main Greenhouse Gasses

Answer 11

• 1000 yrs for CO2
• 12 yrs for methane
• 110 yrs for nitrous oxide
• if we stopped all GHG emissions/fossil fuel burning, we wouldn’t stop global warming
• we would just plateau because these gasses are still in the atmosphere

Question 12

Biogenic Carbon Cycle

Answer 12

• carbon in methane comes from atmospheric CO2
• plants take in CO2 and produce carbs (cellulose, starch)
• animals (ruminants) eat carbs
• they release methane
• that C in CH4 has been in atmosphere before
• C released by livestock in methane isn’t new
• after 10 yrs, hydroxyl oxidation results in CO2 → this isn’t good or bad
• not new CO2, was there before
• while it is in form of methane, it is potent GHG
• but doesn’t add additional warming
• majority of C goes into soil during soil-carbon sequestration

Question 13

Soil-Carbon Sequestration

Answer 13

• soil microbes sequester 1/3 of the carbon that humanity puts into the atmosphere back into the soil
• carbon stays there unless soil is plowed
• if land is grazed, carbon stays in soil

Question 14

Fossil Fuels

Answer 14

• oil, coal, and gas – originally plants and animals – dinosaurs, trees, grasses (100-200M yrs ago)
• 70 yrs ago, humans extracted fuels to burn it
• humanity has extracted ½ of fossil fuels and burned it into the atmosphere
• not a short-lived cycle
• one-way street from soil → atmosphere

Question 15

Stock Gas CO2

Answer 15

• burning fossil fuels incr stock gasses over time bcs they stay in environment
• can’t go down in concentration of CO2, can only go up

Question 16

Flow Gas Methane

Answer 16

• flow gasses stay stagnant, as they are destroyed at the same rate of emission
• equal amt of what’s put in vs what’s put out
• if you put in less, methane levels will decr
• there is a destruction of methane

Question 17

Reducing CO2 and CH4

Answer 17

• if you decrease CO2, warming continues until the plant producing CO2 is shut down, then warming plateaus
• if you decrease CH4, warming decreases

Question 18

Plant-Based Diet Issue

Answer 18

• retention rate of people who stay on plant-based diets is very low
• 84% of people who start on plant-based diets stop after 1 year
• for every person who eats a vegan diet, 5 have given up

Question 19

CA Methane Sources

Answer 19

• dairy = 45% of methane emissions
• non-dairy livestock = 10%

Question 20

Methane Law

Answer 20

• mandatory for all methane sources to reduce their methane emissions by 40% by 2030
• dairy had to reduce to 7.2 MMT
• carrot approach of economically incentivizing farmers because taxes and fines don’t work
• CA dairies have reduced 4.4 MMT (over half of the sector’s methane reduction goal)

Question 21

Covered Lagoons

Answer 21

• traps biogas (renewable natural gas) from manure
• biogas is 60-70% methane
• methane is extracted and used to power heavy-duty trucks/transportation sector
• methane is converted to CO2 in this process, but not adding more CO2 to the atmosphere

Question 22

Feed Additives

Answer 22

• rumen modifiers
• methane inhibitors

Question 23

Rumen Modifiers

Answer 23

• change microbial composition in rumen

Question 24

Methane Inhibitor

Answer 24

• seaweed, 3NOP
• need 12 enzymatic steps to produce methane
• methane inhibitors disrupt one of these steps so that methane can’t be produced –> reduces methane

Question 25

Genetic Methane Management

Answer 25

• how much methane animal belches is a heritable trait
• you can test cow for being high methane producer and take that into account along w/ milk production quantity, etc.
• you could replace herd in a way that has lower methane-producing cows
• this trait is not linked to other traits (i.e., low-methane cow isn’t necessarily low-milk cow)
• ome cows just have different eructation rates based on their digestive system
• different gut healths, rumen conditions might not be conducive to the methane-producing microbes

Question 26

CA Progress

Answer 26

• should overachieve 40% reduction by 2030
• due to attrition, alternative manure management, dairy digesters, feed additives

Question 27

Attrition

Answer 27

• herd size reduction of 0.5% per year bcs individuals are more productive
• less belching

Question 28

Dairy Digesters

Answer 28

• most effective way to reduce methane
• reduces emissions on the farm and in transportation
• the methane from biogas doesn’t go directly into atmosphere
• methane replaces diesel (fossil fuels)

Question 29

Meat Consumption in US

Answer 29

• steady rates of beef, red meat consumption
• poultry consumption incr by 500%

Question 30

Diet Changes

Answer 30

• omnivore to vegan per person = 0.8 tons/year
• one trans-Atlantic flight per passenger = 1.6 tons/yr
• Meatless Monday (US) = 0.3% of US GHG reduction

Question 31

True Stats

Answer 31

• livestock produces 4% of all anthro GHGs globally
• 70% of all ag land is used for livestock and poultry (bcs that’s marginal land that can’t be used for crops)

Question 32

FAO

Answer 32

• now says livestock produces 11% of all anthro GHGs

Question 33

Getting Rid of all Livestock and Poultry

Answer 33

• if we just got rid of livestock and poultry, we wouldn’t reduce 4% of GHGs
• we still need to eat plants
• we’d have to compensate for animal-sourced nutrients w/ plant-based foods
• we would produce 2.6% GHGs as a vegan US
• whole world can’t sustain veganism
• underdeveloped countries rely heavily on animal agriculture because rainfall for plant growth unpredictable
• also have bad malnutrition problem in developing countries
• the people in these countries benefit greatly from even the smallest supplementation of animal-sourced foods

Question 34

Food Waste

Answer 34

• the main issue in our food system
• 40% of all food we buy is never eaten (1/3 calories)
• dates on food are sell-by, not expiration

Question 35

Developed Countries

Answer 35

• food wasted by consumer is greatest loss out of production, postharvest, handling, storage, processing, packaging, distribution, retail, and consumer losses

Question 36

Developing Countries

Answer 36

• food loss: occurs before food reaches consumer
• occurs on farms/ag production systems before consumption

Question 37

Items Lost

Answer 37

• meat and milk lost at relatively small amounts (least wasted)
• 50-60% of all fruits and veggies are never eaten and are thrown away