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So the thing is that that iceberg lettuce, even if traveling 5,000 miles, with all that plastic packaging etc etc... actually is more green in that it results i

• OrvalWintermute 4y ago
  Basically you are counting GHG emissions as anything emitting, but, you are actually discounting the fossil fuel perspective which is heavily utilized for one, but not the other. This data is also being based on comparing conventional produce raising vice feedlot style farming > to put these figures into perspective, when combined with the fact that the average household consumes around 5 kg of food per day (29), average final delivery of food is 1640 km (1020 mi), and the total supply chain requires movement of 6760 km (4200 mi). Food groups vary in these average distances from a low of beverages (330 km delivery, 1200 km total) to a high of red meat (1800 km delivery, 20 400 km total). and is heavily biased based on over-generalization which does not apply to many types of food production, as this assumes heavy fertilization, grain-feeding, etc. > We estimate the average household’s climate impacts related to food to be around 8.1 t CO2e/yr, with delivery “food-miles” accounting for around 0.4 te CO2e/yr and total freight accounting for 0.9 t CO2e/yr. To put these figures into perspective, driving a 25 mi/gal (9.4 L/100 km) automobile 12 000 miles/yr (19 000 km/yr) produces around 4.4 t CO2/yr. Expressed in this manner, a totally “localized” diet reduces GHG emissions per household equivalent to 1000 miles/yr (1600 km/yr) driven, while shifting just one day per week’s calories from red meat and dairy to chicken/fish/eggs or a vegetable-based diet reduces GHG emissions equivalent to 760 miles/yr (1230 km/yr) or 1160 miles/yr (1860 km/yr), respectively. Shifting totally away from red meat and dairy toward chicken/fish/eggs or a vegetable-based diet reduces GHG emissions equivalent to 5340 mi/yr (8590 km/yr) or 8100 mi/yr (13 000 km/yr), respectively. Which of these options is easier or more effective for each climate-concerned household depends on a variety of factors, though given the difficulty in sourcing all food locally, shifting diet for less than one day per week may be more feasible. > Within food production, which totaled 6.8 t CO2e/household-yr, 3.0 t CO2e(44%) were due to CO2 emissions, with 1.6 t (23%) due to methane, 2.1 t (32%) due to nitrous oxide, and 0.1 t (1%) due to HFCs and other industrial gases. Thus, a majority of food’s climate impact is due to non-CO2 greenhouse gases. Nitrous oxide (N2O) emissions, mainly due to nitrogen fertilizer application, other soil management techniques, and manure management, are prevalent in all food groups but especially in animal-based groups due to the inefficient transformation of plant energy into animal-based energy. Methane (CH4) emissions are mainly due to enteric fermentation in ruminant animals (cattle, sheep, goats) and manure management, and are thus concentrated in the red meat and dairy categories. Similarly, other of these are all about dense feedlot operations >We obtain animal feed requirements using the database from Herrero et al. (2013). This data set provides feed requirements for 30 world regions, which are mapped to the country level. Aggregated feed concentrate requirements per animal production system are distributed into individual crops, such as oil crops to rapeseed and others, based on feed crop consumption statistics (Food and Agriculture Organisation of the United Nations FAO, 2017). For consistency, feed use numbers from Herrero et al. (2013) are rescaled to match country-level feed use totals in FAOSTAT 2009–2011 (Food and Agriculture Organisation of the United Nations FAO, 2017). Feed crop emissions are then added to the consumption emissions of animal products. As I have worked on a ranch like this that did not regularly use fuel, did not fertilize, basically grass pastured cattle, I found this material to be incredibly skewed. Maybe it is accurate talking about feedlot commercial cattle production. Maybe. For smaller organic pastured husbandry that is not fuel intensive, and not grain fed, I don't find this to be true. I do know the source of much of the cattle I consume. Given my location, I can also tell you that much of the produce where I shop is from at least >~2300 miles distant Consequently, I call into question much of the data you provided, as an example of over generalization and data skew. I doubt this was intentional, since the articles didn't even suggest it was possible to eat anything meat based in a green manner. What Chutzpah!
  • virgildotcodes 4y ago
    >This data is also being based on comparing conventional produce raising vice feedlot style farming Given that 96%[5] of beef sold in the US is grain fed, it seems as if it would make sense to base the data on that. Not only is it the norm, but it's apparently the best case scenario in terms of emissions. If you're trying to make an argument for beef being less emission intensive, you want to use CAFO numbers as grass fed numbers are worse. According to these studies, grain fed cattle are slaughtered at 14 - 22 months of age, while grass fed cows are kept alive longer because they gain weight more slowly, leading them to be slaughtered at 20 - 26 months of age.[4] Their extended lifespans lead to greater emissions even if they were to emit the same amount of CO2 + methane per day, but a diet of grass itself leads to higher methane emissions than grain, resulting in overall methane emissions being about 43% higher for grass-fed beef.[1] Methane traps about 80 times more heat than CO2 over the first 20 years, before it degrades into CO2 and then overall ends up trapping about 25 times more over the first 100 years.[2] Now, some of that may be offset by by soil carbon sequestration in the grass fed beef, but according to the Oxford study below - “This report finds that better management of grass-fed livestock, while worthwhile in and of itself, does not offer a significant solution to climate change as only under very specific conditions can they help sequester carbon. This sequestering of carbon is even then small, time-limited, reversible and substantially outweighed by the greenhouse gas emissions these grazing animals generate.”[3] Finally, grass fed beef not only grow more slowly but they end up at a lower final weight when they’re slaughtered, ~1100 lbs vs ~1300 lbs. After they’re butchered, this leaves 638 lbs vs 832 lbs of beef per animal. This means that to meet the same amount of demand, we’d require increasing the total number of cattle raised by about 30%, further increasing emissions and overall environmental impacts.[4] Further - “The required 30% increase in the overall cattle population must be accompanied by large increases in the productivity of existing pastures, on the order of 40%–370%, to avoid clearing additional native vegetation or competition with the human food supply.”[1] [1] https://iopscience.iop.org/article/10.1088/1748-9326/aad401 https://iopscience.iop.org/article/10.1088/1748-9326/aad401 [2] https://climate.mit.edu/ask-mit/why-do-we-compare-methane-carbon-dioxide-over-100-year-timeframe-are-we-underrating https://climate.mit.edu/ask-mit/why-do-we-compare-methane-ca... [3] https://tabledebates.org/sites/default/files/2022-04/fcrn_gnc_report.pdf https://tabledebates.org/sites/default/files/2022-04/fcrn_gn... [4] https://extension.okstate.edu/fact-sheets/carbon-footprint-comparison-between-grass-and-grain-finished-beef.html https://extension.okstate.edu/fact-sheets/carbon-footprint-c... [4] https://extension.okstate.edu/fact-sheets/carbon-footprint-comparison-between-grass-and-grain-finished-beef.html https://extension.okstate.edu/fact-sheets/carbon-footprint-c... [5]https://extension.sdstate.edu/grass-fed-beef-market-share-grass-fed-beef#:~:text=About%204%25%20of%20U.S.%20beef,value%20of%20roughly%20%244%20billion https://extension.sdstate.edu/grass-fed-beef-market-share-gr....