[HN Gopher] Transporting food generates whopping amounts of carb...
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Transporting food generates whopping amounts of carbon dioxide
Author : mgl
Score : 35 points
Date : 2022-07-03 20:29 UTC (2 hours ago)
(HTM) web link (www.nature.com)
(TXT) w3m dump (www.nature.com)
| xyst wrote:
| yet another reason why vertical farming will become the future.
|
| Build the vertical farms in cities and skip the CO2 intensive
| process of transportation from the traditional farm to the
| grocery store/distributor/farmers market.
|
| Imagine living in a building where a vertical farm exists below
| grade. Retail, restaurants, and bodegas on the street level.
| Finally, residences and commercial in the upper floors.
|
| Literally straight from "farm" to table.
| chroem- wrote:
| Yeah, just burn terawatts of fossil fuels to generate light for
| growing your crops instead of using solar energy and natural
| photosynthesis.
| jka wrote:
| I don't know much about the power consumption and efficiency
| of vertical farm lighting and heating; can you share any
| references about them?
|
| One thing that does occur to me is that artificial lighting
| wouldn't be limited by the passage of the sun, so crop growth
| could potentially continue 24 hours a day.
| jaegerpicker wrote:
| Vertical farming is far less resource intensive, using LEDS
| powered by solar or wind and gravity flow designs. I posted
| this in another comment but here is very brief video
| talking about it.
| https://www.youtube.com/watch?v=5clOYWsNhhk
|
| I have other resources should you wish and I ton of
| personal experience. I have 3 Hydroponic systems (1 off the
| shelf, 2 custom designed by me) and 2 Aquaponics systems.
| The custom ones took 3 months to recoup the costs of
| materials vs the cost of produce, though the liquid
| fertilizer is a cost and input that I don't love. I've
| switched most of my effort to Aquaponics (Aquaculture -
| raising fish, which provides a natural fertilizer), I have
| 1 microsetup growing herbs and microgreens that has been
| running for 1 year. Only inputs are water and fish food, I
| clean it 1 once every 3 months since the plants act as a
| natural filter to clean the water.
| zdragnar wrote:
| The original comment suggested putting the farm below
| apartment buildings ("below grade" means underground).
|
| It's extremely costly to provide sufficient light to grown
| plants, as photosynthesis isn't terribly efficient. Natural
| sunlight is significantly stronger than what people tend to
| expect.
|
| Not only that, but you would need to move massive amounts
| of air to keep the plants happy, plus the humidity from
| being underground and all the water they need. Beyond that,
| you need to go quite a bit underground to feed a sufficient
| number of people, which isn't always feasible depending on
| the type of soil and water table, etc
|
| Final note, most plants do better not getting 24 hours of
| light. They can only grow just so fast and need to
| photosynthesize just so much.
|
| That's a lot of work (meaning higher prices for people who
| need to eat) for very little gain.
| jaegerpicker wrote:
| Below ground has trade offs, it's easier to use gravity
| flow designs but you lose all natural sunlight. Most of
| the time rain catchment systems on roof top vertical
| farms or free standing green houses are easier to design.
| There are already a bunch of vertical farms in commercial
| operation. The Netherlands in particular is leading the
| science here but in the US a number of farms exist.
| Vertical farming uses around 90% less water and
| solar/wind/hydro power for LED's is extremely doable. You
| are wholly incorrect about the amount of work required
| and amount of resources. It does take smart design to
| work however.
| crummy wrote:
| What's the efficiency loss for light>solar
| panel>LED>plants vs light>plants?
| jaegerpicker wrote:
| Wrong question to ask, PPFD's is the correct measure.
| It's not a direct energy comparison. Photosynthesis is a
| chemical reaction of Chlorophyll reacting to certain but
| not all light wavelength's (Red and Blue being the major
| ones) plus the distance from the light source. The amount
| of watts the the sun generates is NOT what grows plants.
| LED's can produce the same light wavelength's but much
| closer and with no obstructions. The question isn't about
| LED's power generation, it's how much power does it take
| for an LED to cover an area. Obviously a LED can't
| compare to pure Solar efficiency on a watt by watt basis
| but it doesn't need to.
| verve_rat wrote:
| What's the CO2 output by the concrete used to build the
| building that houses the farm?
| jaegerpicker wrote:
| That's actually a good question, I have no experience
| with underground systems. Most are free standing
| greenhouses (about 10x more efficient (water and yield)
| that traditional farming per square foot). Electric is
| only a major cost for the pumping of water, LED light
| coverage is very cheap and we don't need to compete with
| the power of the sun.
| zdragnar wrote:
| Where I live, people already struggle with eliminating
| excess moisture from their basements. Putting growing
| plants there requires a significant upgrade to air
| ventilation and dehumidification, as it is the perfect
| breeding ground for mold.
|
| As for LED grow lights, you typically use about 30-40
| watts / square foot. That's a not insignificant added
| cost compared to growing above ground.
|
| The added challenges to growing underground simply make
| it irrational.
| jaegerpicker wrote:
| This is completely misinformed, there are tons of vertical
| Hydroponic and aquaponic farms already in production that are
| thriving at much lower resource costs. Solar panels powering
| LED's and gravity flow water make a massive difference. For
| example:
|
| One is being built minutes from my house
| https://verticalharvestfarms.com/locations/westbrook-maine/
|
| Also The Netherlands are leading the world at this type of
| farming, here is a short video about it
| https://www.youtube.com/watch?v=5clOYWsNhhk
| chroem- wrote:
| US farmland occupies 895 million acres (3.6M km^2) [1].
| Average solar irradiance on most US farmland is about 200
| W/m^2 [2]. By being generous and assuming vertical farming
| is 100x more efficient than natural photosynthesis, the
| energy requirements come out to 7.2 terawatts of generating
| capacity. In contrast, the US currently has 1.1 terawatts
| of generating capacity. [3] Vertical farming isn't just
| uneconomical: _it 's completely absurd_.
|
| [1] https://www.statista.com/statistics/196104/total-area-
| of-lan...
|
| [2] https://en.wikipedia.org/wiki/Solar_irradiance
|
| [3] https://www.eia.gov/energyexplained/electricity/electri
| city-...
| mensetmanusman wrote:
| Thanks for doing the numbers, it's interesting that in 50
| years people are predicting annual TW installs of global
| solar capacity. So maybe a technology for the future if
| storage and distribution gets solved.
| jaegerpicker wrote:
| Except none of that matters, Solar Irradiance has very
| little to do with actual photosynthesis. You are
| measuring Watt's as a pure energy source, that's useless
| in this case. Photosynthetic photon flux density (PPFD's)
| are what's important, that's the amount of light
| wavelengths that the plant needs to absorb to power
| photosynthesis. Here is a definition from another source,
| I'll post the link at the bottom:
|
| PPFD is a measure of photosynthetic active radiation, PAR
| for short. PAR is not a measure of anything itself but is
| more of a description. PAR light is all the visible
| wavelengths of light which cause photosynthesis, found
| within the 400-700 nanometer range. PPFD is a 'spot'
| measurement that tells you how many photons from the PAR
| range hit a specific area of your canopy over time. It is
| expressed as micro moles per square meter per second
| (mmol/m2/s). For this reason, PPFD is the most accurate
| measure of light power. First, unlike other measures, it
| considers the entire spectrum of light that plants see.
| PPFD also takes into account the amount of light that
| will actually reach the plant instead of focusing only on
| the point of origin. A light source can be very bright
| and powerful, but if it is too away from the plant, or
| obstructed in some way, the plant won't be getting all
| the light it needs for photosynthesis. PPFD controls for
| this kind of inaccuracy.
|
| With LED's you can place the plants much closer to the
| light source and control the color spectrum along with
| the obstructions 24/7. It allows you to grow indoors at
| an extremely efficient rate. Your formula has almost
| nothing to do with indoor farming.
|
| https://www.freightfarms.com/blog/indoor-grow-
| lights#:~:text....
|
| Here are some additional sources:
| https://archipel.uqam.ca/1619/1/1998_025_Gendron.pdf http
| s://www.ncbi.nlm.nih.gov/pmc/articles/PMC1066711/pdf/pln.
| .. https://www.researchgate.net/profile/Paul_Hanson7/publ
| icatio... https://www.horti-growlight.com/en-gb/par-ppf-
| ypf-ppfd-dli#:....
| https://www.sciencedirect.com/topics/medicine-and-
| dentistry/...
|
| Quick summary: PPFD measures the amount of light
| wavelengths that the plant captures that kicks off the
| chemical reaction of Chlorophyll. Red and Blue lights are
| the vast majority of wavelengths that interact with
| Chlorophyll. That's a major reason why the solar
| irradiance measure of pure Wattage is irrelevant.
| chroem- wrote:
| Are you able to achieve a 10000x efficiency improvement
| vs natural photosynthesis by using those technologies? If
| not, the idea is still completely unfeasible.
| jaegerpicker wrote:
| IT'S COMPLETELY IRRELEVENT, the efficiency at generating
| electricity is not what powers photosynthesis. It's a
| chemical reaction to light wavelengths (ie the absorbing
| of Red and Blue light) that powers it. More watt's
| doesn't equal more growth, it equals more heat which
| allows longer growing seasons. LED's and Sunlight have
| EXACTLY the same level of photosynthesis, none of the
| math you did matters at all. For LED's you need to
| calculate coverage of the area not pure power. If you
| produce Red or Blue wavelength's that's all that matters,
| the Sun does that and a hell of a lot more but we don't
| need the power of the sun or even a tiny faction of it's
| power for photosynthesis, we need to heat and cool and
| creat weather which effect plant growth but Watt's is
| irrelevant.
| nathanaldensr wrote:
| You drastically, drastically overestimate just how many
| calories are derived from vegetables. You also drastically
| underestimate the amount of protein humans need to survive and
| thrive. If meat were so easy to replace with agriculture,
| humans would've already adapted to do that because meat is, as
| everyone likes to remind us, energy-intensive to raise.
| cosmolev wrote:
| Why living in a city in the first place? Imagine living in a
| small town near the farm.
| mistrial9 wrote:
| watch out for a few thousand guys on horses though; more
| recently, ranchers vs. farmers; this decade in North America,
| pay rent to Lord Gates, farm-meister
| cgb223 wrote:
| Because if everyone moves to the small town, it won't be a
| small town anymore
| hurril wrote:
| So sad there's only the one small town.
| lm28469 wrote:
| I doubt the maths check out, you'd have to grow shit extremely
| fast to feed people year round. In ultra dense cities I really
| doubt it's possible.
| jaegerpicker wrote:
| Aquaponics and Hydroponics average 3-4x the growth rate and
| grow 24/7 (though you do need to provide lightless hours for
| proper fruiting). It's 100% viable and there are commercial
| operations right now.
| jaegerpicker wrote:
| Especially when you use Hydroponics and Aquaponics, which are
| MUCH more efficient than traditional farming. Fresh
| fish/seafood and produce minutes after harvest is are
| completely different and better class of food!
| JamesBarney wrote:
| You have to use really weird definitions of efficiency for
| that to be the case.
| jaegerpicker wrote:
| In what way? Photosynthesis is about light wavelength's and
| water is easy to be more efficient since the plants are in
| water instead of soil. There are numerous successful
| commercial operations already. Also I've posted a ton of
| detail on the measurements elsewhere in this thread. When
| people measure efficiency most measure Wattage from the Sun
| and that's completely irrelevant.
| gruez wrote:
| There was a recent story on a vertical strawberry farm in New
| Jersey: https://news.ycombinator.com/item?id=31454883. The
| quoted price (from the comments), is $20 for 8 strawberries.
| That's an order of magnitude higher than the strawberries at
| the supermarket. That does not bode well for the future of
| vertical farming, unless there's some miraculous breakthrough
| in cost effectiveness expected. As it stands right now you're
| better off buying conventional strawberries and spending the
| rest on carbon offsets.
| MrRobotics wrote:
| Once robotics develops further, it would be interesting to have
| an organization that uses small mobile farming robots to tend
| gardens in people's yards and produce fruits and vegetables for
| personal or local consumption.
|
| This could enable people during certain times of the year to eat
| food that is local, fresher, cheaper, and more environmentally
| friendly.
|
| I know a lot of people that have personal gardens but don't grow
| much since it's too time consuming for them.
| drewcoo wrote:
| What would they pay for these robots?
|
| What would it cost to hire a part-time gardener now?
| 29athrowaway wrote:
| That's why having something like the rehydration machine from
| bttf would be great. Water = volume and weight.
| goldforever wrote:
| _Microft wrote:
| The bar chart "food transport and production emissions" is
| misleading. If they had shown the charts at the same scale, the
| bars in the left one would only be 40% as long as they are now
| (range: 0-0.8 vs 0-2).
| ajkjk wrote:
| yeah what the heck was the point of that? just undermines the
| whole article.
| shafyy wrote:
| Here's Hannah Ritchie from Our World in Data debunking this
| claim:
| https://twitter.com/_HannahRitchie/status/153893755867520204...
|
| Basically, they make up a non-standard definition of food miles
| to include everything like fertilizers, pesticides and machinery.
|
| Emissions from food transport are negligible for most foods
| (except for foods that is transported by planes for long
| distances, because of very short shelf life, but that's rarely
| the case) [0].
|
| The best way to cut GHG emissions from food is and will always be
| to cut out meat and dairy.
|
| 0: https://ourworldindata.org/environmental-impacts-of-
| food#foo...
| api wrote:
| I'm really starting to dislike studies that use artificial
| synthetic stand-in metrics. It's trivial to cook these to mean
| anything you want.
| epistasis wrote:
| From that thread:
|
| > If we want to count these emissions from moving fertilizers,
| tractors etc. around as 'food miles' then the logical
| conclusion would not be 'eat local'.
|
| > Instead, 'eat from countries that manufacture fertilisers &
| pesticides' so they don't have to export elsewhere.
|
| When I walk to the farmer's market by my house, I always
| shudder at all the cars that have driven there and parked. The
| quantity of emissions from driving a personal gasoline vehicle
| is really staggering compared to any food related emissions.
|
| And it's really shocking that people are so ignorant of the
| toll their personal vehicles take. I think that if people had
| to manually lift all the fuel that they pumped into their cars,
| maybe even for one filling per year, they would get a better
| feel for just how bad driving is. And the CO2 is far heavier
| than even the fuel, pre combustion. A 20 gallon refill of a
| tank is 400 pounds of CO2, a fifth of a ton.
|
| If we even legalized corner stores for US neighborhoods, we
| could probably start driving down emissions.
| nathanaldensr wrote:
| Not everyone can have a garden in their backyard--if they
| _have_ a backyard. If people driving to buy food makes you
| shudder, I wonder what a nation of shut-ins eating their
| government-allotted-and-delivered-by-vehicle bread would do.
| scrose wrote:
| I think the OP was talking about the benefits of improving
| walkability as a way to reduce emissions, not locking
| yourself at home.
| twoxproblematic wrote:
| staplers wrote:
| This contradicts data from the EPA.
|
| https://www.epa.gov/ghgemissions/global-greenhouse-gas-emiss...
| galangalalgol wrote:
| I have never been able to find any consistency in the data
| around food sustainability in general. Some meta studies
| using the same data rank GHG per 100g of protein vastly
| differently. Milk in particular moves pretty far up or down
| the list. Somehow cheese always stays at the bad end. Shrimp
| moves up and down a lot too. Fish and chicken swap around a
| lot. Pork is usually right above those two. And eggs are
| always at the bottom of the animal proteins as far as impact.
| Beans and pulses are always at the bottom. I keep meaning to
| get some red lentils, I have troubles with all the beans and
| pulses I've tried, but red lentils supposedly lack whatever
| it is that messes with some people.
| verve_rat wrote:
| That link doesn't seem to contain any information about food
| miles, it is irrelevant to this discussion.
| qwertyuiop_ wrote:
| This coordinated PR seems to be leading to let's eat bugs from
| our backyard.
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