Greenhouse Gases Flashcards
1
Q
Greenhouse Gasses (GHGs)
A
- 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
2
Q
Livestock’s Long Shadow (2006) – UN Food and Agriculture Organization (UN FAO)
A
- “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
3
Q
Life Cycle Assessment
A
- 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
4
Q
Number of Fridges in US with Animal-Sourced Foods
A
- 98%
5
Q
Percent of Protein Sales that are Plant-Based Alternatives
A
- 0.3% plant-based
- 99.7% animal-sourced
6
Q
Global GHG Emissions by Sector
A
- energy = 73.2% of all GHGs in the world (fossil fuel burning)
- agriculture and forestry = 18.4%
7
Q
US
A
- 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
8
Q
Global Warming Potential of GHGs (GWP 100)
A
- 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
9
Q
Global Methane Budget
A
- 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
10
Q
Methane Sinks
A
- 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
11
Q
Half-Life of Main Greenhouse Gasses
A
- 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
12
Q
Biogenic Carbon Cycle
A
- 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
13
Q
Soil-Carbon Sequestration
A
- 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
14
Q
Fossil Fuels
A
- 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
15
Q
Stock Gas CO2
A
- 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
16
Q
Flow Gas Methane
A
- 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
17
Q
Reducing CO2 and CH4
A
- if you decrease CO2, warming continues until the plant producing CO2 is shut down, then warming plateaus
- if you decrease CH4, warming decreases
18
Q
Plant-Based Diet Issue
A
- 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
19
Q
CA Methane Sources
A
- dairy = 45% of methane emissions
- non-dairy livestock = 10%
20
Q
Methane Law
A
- 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)
21
Q
Covered Lagoons
A
- 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
22
Q
Feed Additives
A
- rumen modifiers
- methane inhibitors
23
Q
Rumen Modifiers
A
- change microbial composition in rumen
24
Q
Methane Inhibitor
A
- 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
25
Genetic Methane Management
- 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
26
CA Progress
- should overachieve 40% reduction by 2030
- due to attrition, alternative manure management, dairy digesters, feed additives
27
Attrition
- herd size reduction of 0.5% per year bcs individuals are more productive
- less belching
28
Dairy Digesters
- 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)
29
Meat Consumption in US
- steady rates of beef, red meat consumption
- poultry consumption incr by 500%
30
Diet Changes
- 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
31
True Stats
- 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)
32
FAO
- now says livestock produces 11% of all anthro GHGs
33
Getting Rid of all Livestock and Poultry
- 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
34
Food Waste
- 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
35
Developed Countries
- food wasted by consumer is greatest loss out of production, postharvest, handling, storage, processing, packaging, distribution, retail, and consumer losses
36
Developing Countries
- food loss: occurs before food reaches consumer
- occurs on farms/ag production systems before consumption
37
Items Lost
- meat and milk lost at relatively small amounts (least wasted)
- 50-60% of all fruits and veggies are never eaten and are thrown away
