It's a Micro World after all is a blog dedicated to discussing pretty much whatever I feel like. When I delve into scientific matters it will primarily be discussing microbiology (agricultural, bioenergy, and environmental focus). Otherwise, I'll probably ramble on about sports and life.
My posts are presented as opinion and commentary and do not represent the views of LabSpaces Productions, LLC, my employer, or my educational institution.
Please wait while my tweets load
Welcome to my first Research Blogging post here at LabSpaces! I'm not sure if this is a first for LabsSpaces, or simply a first for It's a Micro World after all, but regardless ... you're here now and you may as well stay for the fun! I grabbed a paper which caught my eye, and certainly generated a fair amount of buzz in the news, probably because it highlights the wasteful nature we've overlooked for far too long. As of the time of me writing this entry, the manuscript is available for download free from Environmental Science & Technology (link at bottom of page), but I have no idea how long this will last. So accordingly, here is the abstract for the manuscript:
This work estimates the energy embedded in wasted food annually in the United States. We calculated the energy intensity of food production from agriculture, transportation, processing, food sales, storage, and preparation for 2007 as 8080 ± 160 trillion BTU. In 1995 approximately 27% of edible food was wasted. Synthesizing these food loss figures with our estimate of energy consumption for different food categories and food production steps, while normalizing for different production volumes, shows that 2030 ± 160 trillion BTU of energy were embedded in wasted food in 2007. The energy embedded in wasted food represents approximately 2% of annual energy consumption in the United States, which is substantial when compared to other energy conservation and production proposals. To improve this analysis, nationwide estimates of food waste and an updated estimate for the energy required to produce food for U.S. consumption would be valuable.
Notice, we're talking in the trillions of BTUs. For reference, a BTU (British Thermal Unit) is the amount of energy needed to heat one pound of water 1°F. As an additional reference, it takes approximately 136 BTU to keep a 40 watt lightbulb lit for an hour. So when we're talking 2030 trillion BTUs wasted over the course of the year 2007 (and 2010 trillion BTU wasted in the year 2004) we're talking a lot of lit lightbulbs, for a really long time.
So the authors talk about a dearth of information on exactly how much energy is wasted in the United States when it comes to food. They cite several numbers which are pretty alarming (i.e., USDA estimated that 27% of available food was wasted in 1995), and also state that it takes roughly 10% of the US energy supply to produce the food that is consumed (and wasted) each year. Ergo, if over a quarter of the food produced each year is wasted, and it takes a tenth of our energy supply to produce that wasted food ... we're looking at a pretty darn sizeable portion of energy that is -- in turn -- simply wasted each year. Here is the money paragraph out of their Introduction which states the problem they wish to address, and their objectives for the manuscript.
Because of the desire to reduce greenhouse gas emissions, concerns about fossil fuel availability, and the expected increase in population, the reliance of food on fossil energy sources has become more scrutinized. In order to better understand the relationship between food and energy, a current estimate for the energy embedded in food production is needed as well as a calculation of the energy that is lost in wasted food. No such study using current data has been identified in the literature. Consequently this work seeks to fill that knowledge void and provide important data that will quantify both the energy required to produce food in the U.S. in 2007 and the energy embedded in wasted food.
Pretty straightforward, and honestly I'm surprised that such a study (or studies) had not already been performed. The authors then launch themselves into going about their business and determining just how wasteful the United States is when it comes to its available food supply.
Now, I should note that the authors are forced to make some concessions to come up with these numbers because they've got to get data sets which were not constructed with other past/future data sets in mind to "come together" (so to speak). Also, there is an inherent set of uncertainty to the data they're working with but I felt that they were pretty straightforward in explaining the issue and their workarounds/concessions to come up with a workable estimate. This isn't my field of expertise, so while their justifications seemed more than adequate to me, perhaps people who are better "in the know" could comment (if they read this blog entry) on the approaches taken by Cuéllar and Webber. I do like this comment by them in their manuscript though which they use to bolster their case.
Ultimately, the 20% error bars we use are arbitrary, since they rely on two varying estimates of error for nitrogenous fertilizer production and food transportation. We expect our energy estimate to have some range of error because of the assumptions and estimates we make throughout our analysis. Nonetheless, we rely on methodologies published in the scientific literature and data sets from the U.S. government, which we consider reliable sources. Therefore we use the 20% error bars not to overstate the accuracy of our estimate but also to note undermine the validity of our work in estimating the energy required to produce the food consumed in the U.S.
I'm not going to pour over the data they present in the seven tables shown in the manuscript, but I'll summarize the first six which lead up to the main thrust of the manuscript (Table 7). Table 1 discusses the total energy requirement to produce food in the United States for the year 2002. They break it down as follows:
Energy Spent on Agriculture: 1240 ± 70 trillion BTU
Energy Spent on Transportation: 1650 ± 520 trillion BTU
Energy Spent on Processing: 1120 ± 220 trillion BTU
Energy Spent on Food Handling: 3780 ± 460 trillion BTU
That comes out to a grand total of 7790 ± 730 trillion BTU. Scaled to 2007 estimates, that value rises to 8080 ± 760 trillion BTU. The authors state that this estimate to produce the food consumed in the US accounts for approximately 8% of the energy consumed by the US annually, and they're on the low end of that estimate. Other studies have put the numbers at anywhere from 10.5% to 15.7%. Granted each study was done a bit differently, with additional factors being considered (or not), but it's safe to say that regardless of what study you look at, we can all come to the conclusion that food production is a good chunk of the US energy budget each year.
So from here they launched into several other sets of calculations and reports which are featured in Tables 2 through 6. And they did the following ...
Oh great, they did math.
... yep, they did math. Ok yeah, they were doing it all along, but they started putting equations into the manuscript.
Table 2 lists the USDA estimates on edible food waste in 1995, which was estimated at 96.3 billion pounds (of a total of 356 billion pounds), for a total loss of 27%. These numbers are based on a report by Kantor et al. entitled "Estimating and addressing America's food losses" which was published in 1997 (PDF, 11 pages). This table is important because lists the amounts wasted of each food category and will be used in Table 7 (see below)
From here we start building up to Table 7. Table 3 highlights the energy required for the production of various agricultural food categories for a total expenditure of 1270 trillion BTU. Table 4 highlights the energy required for transportation for a total energy expenditure of 1690 trillion BTU. Table 5 highlights the energy required for processing the US food supply, and reports a total energy expenditure of 1150 trillion BTU, and Table 6 lists the energy expenditure required for food handling and comes up with a total of 3880 trillion BTU.
So, taking the reported USDA waste values (listed in Table 2), and using the energy expenditures sunk into food production from all the measured sources (production, transportation, processing, and handling) listed in Tables 3 through 6, the authors calculate the total energy expenditure that was wasted in the years 2004 and 2007. Wasted. Lost. Benefited nobody. Came to no good end.
Here is how it broke down (I constructed the following graph using the 2004 values for total energy expended and energy lost). You can right click and open the image for a bigger/better look at the graph.
US Food Energy Expenditures for 2004
You can't really see the dry beans, peas and lentils, or the tree nuts and peanuts categories on the graph but they total up to 12.17 trillion BTU lost in 2004 (a total of 15.9% wasted). Dairy is the biggest offender with over 436 trillion BTU lost in 2004, followed closely by vegetables (381 trillion BTU lost), and meat, poultry, and fish (312 trillion BTU lost). The total energy value of the food wasted in 2004 amounts to 2010 ± 160 trillion BTU lost. That number is adjusted to 2030 ± 160 trillion BTU for 2007. I know I related this energy loss to lightbulbs earlier in the entry, but let me put it in terms of calories. 1 BTU is roughly .250 food calories, so 8000 BTU translates into a single day caloric intake for your average person (assuming 2000 calories). If I'm doing my math correctly*, that wasted energy, if it could be converted entirely into food could feed 690 million people for an entire year (690, 247, 252 to be exact). We waste, in food production alone, the equivalent to feed roughly a tenth of the worlds population! Now obviously we can't really translate all that energy into food production, but it is a number that should grab your attention.
It's something to seriously consider. The food collecting mold on your counter top, or the milk spoiling in your fridge. It's not just a few pulls of the udder that you're wasting when that milk goes bad. You're wasting the energy spent collecting it, pasteurizing it, transporting it from the farm to eventually your grocery store, and the energy spent packaging it. That's a lot to consider. A lot of us cry (and we should) about our energy dependence which threatens our national security. Yet, we usually don't recognize that even the little things we do contribute to this insecurity. So, the next time you're out at your favorite restaurant and they give you that heaping plate of food, make sure you take home the leftovers and eat them the following day. Be aware of what you consume on a daily, weekly, and monthly basis and adjust your budgets accordingly. Not only will you be doing your part to decreasing the amount of energy the US wastes each year, you'll be saving yourself a significant amount in savings. Not only that but better management of our food and cash budgets should have an effect on the markets and could save us even more money in the long run. I'm sure that's something all of us could get behind. Eat smart folks, in more ways than one.
*That's a big "if", and if someone wants to come behind me and check it, I'd appreciate it. I did a simple "back of the napkin calculation" and applied some "PI math".
Cuéllar, A., & Webber, M. (2010). Wasted Food, Wasted Energy: The Embedded Energy in Food Waste in the United States Environmental Science & Technology, 44 (16), 6464-6469 DOI: 10.1021/es100310d
This post has been viewed: 3057 time(s)
"It's not just a few pulls of the udder that you're wasting when that milk goes bad."
After breastfeeding, one can never again look at dairy spoilage the same way. "Just".
Wow! Great article, fascinating stuff! In years to come mothers will be printing out your blog, showing it to their children and ranting about BTUs rather than telling them there are starving children in Africa if they don't finish their dinners!
Seriously though, it really makes you think about what a wasteful society we are. It's not just the big, obvious things we do that are wasteful and harmful to the environment, but simple things like buying too much food and letting it go off in the fridge, something I am particularly guilty of when it comes to fruit and veg, it just seems to go off so damn quickly!
I also meant to comment that I was really surprised that we wasted more fruit and veg than meat, for some reason I had it in my head that meat would be the big issue. But actually when I relate it to myself I can understand that.
I also read a really interesting piece recently in the Best American Science and Nature Writing 2009. It was about the fallacy of the recent trend, particularly in the UK, to drive people to buy local produce, and how, for example, the energy required to grow things in an environment that isn't necessarily ideal far outweighs that required to ship the produce in from further away. I thought that was also very interesting.
Jane, if this blog entry has such a lifespan, I'll be proud beyond words! We are truly a wasteful society, and I think outreach is partly to blame. I doubt I'll solve the nations problems with this single blog post, but I really do think that we all need to consider our actions and then spread the word. I'll have to take a look at the article you've mentioned as well, it sounds like an interesting read (especially as someone who tries his best to buy local and at the farmers market, which is next door to where I work).
becca, welcome to my blog. Nice to see you commenting here! :)
As a parent I cringe at the amount of food my children waste, especially when they take cold lunch to school. But I must admit, stuff goes bad in the frig sometimes, partly because we in the US make big grocery runs instead of going to the market daily to buy the food to be consumed that day. Sometimes the efficiency of the US food system is not as efficient as we think.
You might not solve the nations problems, but you given people something to think about at least. I'll be pointing people in the direction of this blog as well, it's definitely an important topic. Do check out that article, the book as a whole is a good read, but that one stuck with me. I don't mean to say that local produce is all bad, it definitely has many advantages, not least supporting local farmers, but it's definitely something to bear in mind. As with everything in society it should be everything in moderation, we have this real tendency (driven by the media) to swing hard one way or the other. It's interesting to hear the other side of the story, though I think if you take every point of view into account when trying to be environmentally friendly and aware, then I think you would go slowly insane!
Jane, but damned if the local stuff doesn't sometimes have more intense flavors than the stuff shipped and stored under nitrogen. Shipping is definitely more economic than local, but local flavors are just so much more intense (and in NorCal more varied).
This is just a great article as far as food production goes, and I doubt there's any great solution on this other than stop wasting food. It's just more convenient to stop at the supermarket one day a week vs most every night, and a good green market isn't available regularly everywhere. I wonder what Alice Waters would say?
JaySeeDub - Having had my mind blown by the produce in the local farmer's shop when we first arrived in California from England, I am 100% with you on the intense flavours thing. I never knew fruit and veg could taste so good!
make sure you take home the leftovers and eat them the following day
but what about all the extra energy it takes for the packaging, the refrigeration, the re-heating? is it a net save in energy, or would it actually be more energy efficient to trash the leftover food? (which of course also takes energy)
whahahaha. I am everywhere on teh internets!
@JohnF- I remember being a kid, and stuffing my sandwiches into my empty milk carton... it was just sad how much food I wasted...
I wonder if you can recoup any significant energy loss by composting (if you avoid using nitrogen based fertilizers, it might very well add up if you grow a bunch of stuff).
As far as the flavors of local food issue- I think that's likely a big plus in California. And, in fairness, where I am in Pennsylvania, maybe for apples or the like (things that grow really well here). But I get the impression when reading rave reviews of farmers market foodies that either 1) they are comparing the WORST supermarket food to the farmers markets (an out of season walmart tomato is an abomination, no question) or 2) there is some "i'm paying more, it must be better" or even a direct "i'm buying local it must be better" cognitive enhancement- the former definitely happens with things like wine, I don't see why it wouldn't with produce. The later is the one I've never seen a study on, but I really want to.
JohnF, yes we're a wasteful nation. Unfortunately. I'm just as guilty of this as the next person, but I'm really trying to curb my wasteful habits. For example I literally don't buy/drink milk anymore because I know I waste usually 50% of whatever I buy. I have bought UHP milk on a rare occasion, or soy milk (both of which have much better shelf lives) but I've more or less just cut it out of my consumption list and budget.
JaySeeDub and Jane, yes local produce is a much different beast. I think part of that is that things need to be pulled prior to fully ripening so they can withstand the shipping and storage times, which drastically reduces their flavor. Also, I know (anecdotal evidence) some cases where the producers will keep the "better crops" for local sale (and their own consumption) while shipping off the less desirable stuff "up north". :P
Jason, I don't know. I was originally going to write "ask for smaller portions". Of course, if you're going out to eat, you could always bring your own tupperware container with you (some people bring their own shopping bags with them to the grocery store nowadays). Since the tupperware container is reusable, every use offsets the manufacture costs (compared to the styrofoam manufacturing costs). And who heats up their leftovers? I know I personally love cold pasta, and think it is MUCH better the day after it was prepared fresh and served hot! Then, as long as you keep your fridge well stocked (making sure not to waste anything therein), the energy used to keep that one item cool for an additional 24 hours shouldn't come as much of a cost.
becca, I think composting definitely could be used to offset some of the energy costs. A lot of energy is put into producing nitrogen-based fertilizers. So either composting, or perhaps anaerobic digestion would be good options. I've toyed with the idea of a home-made, home-use anaerobic digestion system with the biogas being used to offset the energy I draw off the grid. Doubt I'd be able to get the permits to build such a system where I live, but I don't think the concept I have in mind is in use anywhere. Perhaps I should patent it ...
becca, I've never noticed much difference in price between green market & supermarkets when comparing an "organic" cucumber from either. There are some things that are noticeable that I won't touch (giant beefsteak tomatoes that have too waxy and firm a skin at Safeway/WalMart). But, I also buy several things from the growers and the stands will knock down the price a bit. You walk away with 10lbs of fresh fava beans and see if the next day the guy won't knock down the price of a couple peaches and watermelons. I get the wine thing, though. I see that a lot with Whole Foods and SF's Ferry Building Marketplace (not everything there is wow enducing. And certainly not for $5/lb).
TJ, totally. I know a lot of local farmers who contract to sell to the larger wholesalers keep their better stuff for local resale than ship it off. A farm out near UC Davis I like treats the acreage they designate "local" better irrigated and rotated than the stuff they sell to whatever wholesale outfit they supply.
Jason, a couple restaurants I like encourage bringing your own container. No idea about direct analysis of trashing vs packaging, though. I know several restaurants now compost left overs that diners don't wish to take home, with their suppliers taking the compost. I do wonder about restaurants that have their own large gardens that supply their stuff now, though.
Also, on the subject of food energy, I thought Chris Cosentino's take on eating the whole animal was appropos to the topic - http://eatocracy.cnn.com/2010/10/07/chef-chris-cosentino-thinks-you-should-eat-the-whole-beast/
Thanks for the link JaySeeDub. I'm also pretty serious about bringing my own container with me when I eat out from now on. Every little bit helps, I hope.