Like (Energy-Efficient) Lambs to the Slaughter

The "food miles" concept was almost too good to be true--buying locally-grown food supported neighborhood merchants, preserved scenic farmland, required trips to quaint farmers markets, offered great dinner party bragging rights, and, perhaps most important, slowed global warming by saving all the fossil fuel required to fly produce and meat around the world. As it turns out, the last bit really is too good to be true:

Instead of measuring a product’s carbon footprint through food miles alone, the Lincoln University scientists expanded their equations to include other energy-consuming aspects of production — what economists call “factor inputs and externalities” — like water use, harvesting techniques, fertilizer outlays, renewable energy applications, means of transportation (and the kind of fuel used), the amount of carbon dioxide absorbed during photosynthesis, disposal of packaging, storage procedures and dozens of other cultivation inputs.

Incorporating these measurements into their assessments, scientists reached surprising conclusions. Most notably, they found that lamb raised on New Zealand’s clover-choked pastures and shipped 11,000 miles by boat to Britain produced 1,520 pounds of carbon dioxide emissions per ton while British lamb produced 6,280 pounds of carbon dioxide per ton, in part because poorer British pastures force farmers to use feed. In other words, it is four times more energy-efficient for Londoners to buy lamb imported from the other side of the world than to buy it from a producer in their backyard. Similar figures were found for dairy products and fruit.

Read more on food miles here and here

Editor's Note: We invite comments and request that they be civil and on-topic. We do not moderate or assume any responsibility for comments, which are owned by the readers who post them. Comments do not represent the views of Reason.com or Reason Foundation. We reserve the right to delete any comment for any reason at any time. Report abuses.

  • Grotius||

    Sounds like if you are really interested in this stuff one would have to do a product by product analysis.

  • Timothy||

    I have it on good authority that the "and externalities" piece was inserted by the NYT. I think the intention is that the study looked at both factor inputs, and things that are externalities (run off and other pollution) but the sentence is totally clunky. About what you'd expect from the Times, though, the closest thing they have to an economist is Paul Krugman*!

    *zing!*

    *It should be noted that Krugman is actually a pretty competent economist who did a lot of good work in the 90s and did win the John Bates Clarke medal. It is pretty unfortunate that he's more concerned about being a partisan than economic truth telling in his NYT column, but such is the life of a pundit.

  • ||

    KMW, you have the best photos to accompany your articles.

    Also, Grotius, I agree. Although I would imagine (without being a farming expert) that the math gets simpler (and more pro-local) when you're raising plant life rather than animals. But if you're really concerned about your food's impact (rather than say the suburban light-green version of the hipster doofus,) it's an interesting accounting exercise. As a manufacturing engineer, I can assure you that there are levels of operational complexity that would boggle the minds of most laypeople, even for something as simple as shipping lamb.

    Mmm... lamb...

  • ||

    Very interesting. I've always wondered why it is supposed by lefty environmentalists that economic growth = energy inefficiency, whereas it would seem that using energy more efficiently can easily be part and parcel of economic growth.

  • ||

    Yeah, buying local only really works if the species themselves are local. With enough energy and chemicals, you could grow oranges in Maine. That wouldn't make local oranges a green choice for people in Seattle.

  • thoreau||

    Has anybody done a CO2 analysis of rosemary, olive oil, and pistachios?

    Oh, and garlic and potatoes. And carrots and balsamic vinegar.

    What's the point of analyzing imported lamb if you don't analyze all of the other ingredients as well?

  • ||

    Kenobi,

    Environmentalists have, for the most part, abandoned that thinking for a decade and a half.

    The entire basis of the concept of sustainability is that economic growth is a requirement for environmental quality, just as environmental quality is a requirement for economic growth.

    Don't environmentalists always say that more efficient buildings are good for the bottom line?

  • ||

    Gosh, if only we had some mechanism for conveying information about scarcity, efficiency, and demand, that could operate without the input of our precious bureaucrats...

    -jcr

  • ||

    Kenobi,

    Leftists aren't at all interested in efficiency, freedom, the environment, justice, or any of the other things they purport to care about. They merely use the issue of the moment as yet another premise for increasing government power.

    -jcr

  • ||

    joe,

    I was thinking specifically of the book "Deep Economy," which takes special care to equate economic growth with increased pollution. But, as you and I agree, more energy efficiency is good for the bottom line.

    Don't environmentalists always say that more efficient buildings are good for the bottom line?

    I don't know, I'm clearly out of touch with the environmentalist movement.

    Also, related to KMW's post:

    "Walking to the shops 'damages planet more than going by car'"
    http://www.timesonline.co.uk/tol/news/uk/science/article2195538.ece

  • crap-action-jackson||

    Now if they would just mention the price differences, the results could be very interesting...

  • Timothy||

    RED RED RED
    BLUE BLUE BLUE
    RED RED RED
    BLUE BLUE BLUE

    GO TEAM READ
    GO TEAM BLUE
    GO TEAM RED
    GO TEAM BLUE

    RED RED RED
    BLUE BLUE BLUE
    RED RED RED
    BLUE BLUE BLUE

    There, I just saved us the trouble of this whole thread. RTFA instead.

  • thoreau||

    Timothy, if we don't have this thread, how will we discuss the proper ingredients to accompany imported lamb?

  • Timothy||

    Ah, true...I like your suggestions earlier, thoreau.

    What about some nice cheese and maybe some pepper corns?

  • ||

    A nice chutney?

  • ||

    JCR,

    Leftists aren't at all interested in efficiency, freedom, the environment, justice, or any of the other things they purport to care about. They merely use the issue of the moment as yet another premise for increasing government power.

    I wouldn't quite go as far as saying they don't care about justice. In fact, I don't think there's a person on the planet who actively advocates systemic injustice (at least along their idea of justice). I agree, though, that things we traditionally associate with leftism like modern feminism and advocates of government laws to 'protect' the environment are more about extending government power than about those specific issues.

  • ||

    So the market moves capital to the most effecient use.Imagine that.

  • Bee||

    Instead of "preserved scenic farmland", perhaps we could consolidate farming where it is efficient, and return less-efficient farmland to its original prairie or forest state.

    I keep hearing rumors that cleared land is reverting in places back east, as housing or agricultural need for it diminishes. That concept fairly boggles the mind of this Southern Californian!

  • VM||

    "the proper ingredients to accompany imported lamb?"

    Mary?

  • thoreau||

    Chutney, cheese, and peppercorns are all good ideas. A nice sharp cheese melted atop the potatoes could be good. I'm a big fan of sharp cheeses.

    Maybe some parmesan mixed in with the pistachio crust on the lamb?

    Call me crazy, but I think a confit of duck hash could make the perfect appetizer before the lamb.

  • ||

    New Zealand's farming industry has become incredibly efficient since the gov't stopped farm subsidies. While food miles alone are not enough to measure a food's green-ness (is one factor ever enough to measure anything?), the study is comparing one of the world's most efficient, free-market systems with Britain's clunker of a subsidy-based system.

  • ||

    Hey, I think this article and thread has lead me to discover an unknown economic principle:

    Specialization based on talents and readily available resources leads to efficiencies.

    (I want a Nobel Prize.)

    Now, if only greenies and liberals could be convinced that it decreases greenhouse gasses and does not cause alienation.

  • SIV||

    shipped 11,000 miles by boat to Britain

    Mandate the New Zealand lambs fly in supersonic jets then the local lambs will be greener.
    Problem solved!

    Why did Gaia curse us to be able to thrive as a walking graveyard of dead animals while to perish on a diet of clover?

  • Allen||

    Seriously, when are those crazy non-shaving hippies going to learn about productivity?

  • ||

    After all these years we learn that, instead of
    "In vino veritas,"
    it should have been
    "In computer formulas veritas"

    The future is bright!

  • ||

    Hey, I think this article and thread has lead me to discover an unknown economic principle:

    Specialization based on talents and readily available resources leads to efficiencies.


    Ah, but NoStar, you forget that if people are allowed to meet their needs efficiently there won't be any jobs! Silly capitalist.

  • ||

    Rosemary smoked grilled lamb with truffle mashed potatoes dotted with fleur vert goat cheese. I would start with enoki mushrooms wrapped in bacon.

    But that's just me.

    By the way, deboning a leg yourself can save a lot of money, and you have the bone for stock, of course.

  • ||

    I'm sure North Koreans do everything locally!

  • ||

    I see I took too much time to post and now I will have to share the Nobel prize in economic with Michael Pack.

  • ||

    Give me enough money, trucks and fuel and I could produce an excellent chardonnay in Alaska.

  • ||

    If only we had a means of conveying to John C. Randolph the fact that different parties can have different interests.

    It doesn't matter how well you convey to a builder that his buyers will save a great deal of money over the next decades if he provides them with a better-designed building. It still isn't in his interest to spend the extra money.

    But, hey, you got to insult those terrible, awful people who don't agree with you about politics, so don't let facts and logic get in your way.

  • SIV||

    I'm sure North Koreans do everything locally!

    They eat leaves and sticks-or as the Dear Leader's minions label it "substitute food".
    Can't get much greener than that!

  • ||

    Nice projection, Kenobi and Randolph.

    Since the scope of government is the primary motivator of your own political beliefs, by golly, it just has to be the primary motivator of everyone elses.

    That's how I know that libertarians are all racists. Since my support for laws forbidding discrimination in private transactions is based on opposition to racism, everyone who disagrees with me must be motivated by support for racism.

    This has the twin advantages of eliminating a great deal of effort that used to go to thought, and giving me a warm sensation of self-righteousness in my tummy.

  • ||

    joe, if you believe its better to grow foods where they grow best naturally rather than using artificial means to get them to grow in hostile environments, I sure hope you support free trade--particularly with our neighbors to the south.

  • ||

    joe, you presume too much

    Since the scope of government is the primary motivator of your own political beliefs, by golly, it just has to be the primary motivator of everyone elses.

    That's how I know that libertarians are all racists. Since my support for laws forbidding discrimination in private transactions is based on opposition to racism, everyone who disagrees with me must be motivated by support for racism.


    Clearly you were unaware of the reasoning I used, so I'll forgive you snarkiness towards myself (but your hostility to Randolph is justified). My reasoning is thus:
    Feminism (the mainstream of the modern variety, not all feminism) advocates government intervention in society to ensure material equality for women

  • ||

    Accidentally submitted previous post before finishing, will finish it in a few minutes

  • dhex||

    is there anything that rosemary doesn't improve? (well aside from like, coffee)

    also: is it time for a "conservatarians fuck off" t-shirt yet? perhaps with a picture of that douche from instapundit in the middle.

    go go gadget illustrator!

  • thoreau||

    Kenobi-

    OK, so you have strong opinions on feminism? What does this have to do with lamb?

    What, you're too macho to cook for yourself or something? Maybe Gordon Ramsey should whip your ass.

    dhex, I'd like one of those t-shirts, please.

  • ||

    You know,they used to grow grapes and make wine in England before the little iceage.Global warming could make wine for London 'green' again.

  • ||

    Cesar,

    I very much support the elimination of trade barriers on agricultural products, although I won't go as far as to express support for Free Trade, Inc.

    Better still is buying locally-grown species that are either native to the local climate, or were able to thrive there in the pre-industrial farming era.

  • ||

    Kenobi,

    I was responding to advocates of government laws to 'protect' the environment are more about extending government power than about those specific issues, but you did say that feminists, too, were primarily interested in expanding government power.

  • ||

    To continue,

    Feminism advocates government intervention in society to ensure material equality between women and men via no-discrimination laws, proposed laws to ensure equal pay even between professions, etcetera.
    Most environmentalists advocate government intervention in society to curb pollution and protect furry critters, arguing that if these things are not regulated by the government the market will go wild and destroy the planet, etcetera.

    Oddly enough, lots of the latter also sympathize with the former, and both share the underlying assumption that the unhampered market generates systematically negative results. Hence, their advocates are really aiming at something else, specifically increased government power over society and the economy.

    Your "all libertarians are racist" analogy doesn't follow from this reasoning, since some libertarians favor the free market because it allows them to racially discriminate but others favor it because they think it most effectively eliminates such racial bigotry (or at least the effects thereof). However, if libertarians of the former variety advocated state-mandated segregation, we could conclude that their real preferred aim was segregation of the races, rather than reducing the scope of government (that would be markedly unlibertarian, however).

  • dhex||

    thoreau: draft 1 (NSFW, really)
    http://dhex.org/pics/grylliade/conservatarians.png

  • ||

    I was responding to advocates of government laws to 'protect' the environment are more about extending government power than about those specific issues, but you did say that feminists, too, were primarily interested in expanding government power.

    Many feminists of the modern variety. I believe I made that clear. I am aware that feminism is not the exclusive domain of this type, but if you asked the average person on the street I think the characteristics of feminism they would provide would force one to conclude that it is a form of gender-based socialism.

  • dhex||

    uh guys nearly everyone is into expanding state power - that what makes us such special snowflakes. us and the anarchists.

  • ||

    is one factor ever enough to measure anything?

    Price is the best one to start with.

    It doesn't matter how well you convey to a builder that his buyers will save a great deal of money over the next decades if he provides them with a better-designed building. It still isn't in his interest to spend the extra money.

    Why not? The present value of the occupancy cost for the life of the building is a component of the price he can get for it today. People have clearly shown there is a market for energy efficient appliances, even when it means paying more up front. Fuel economy is part of the decision when purchasing a car, why is it different with a building?

  • ||

    Kenobi,

    Oddly enough, lots of the latter also sympathize with the former, and both share the underlying assumption that the unhampered market generates systematically negative results. does not lead to

    Hence, their advocates are really aiming at something else, specifically increased government power over society and the economy.

    Because they support government power to achieve X, it's the government power that really motivates them, and not X? Does not follow. I used a scrubby to clean my dishes last night, and no, getting to use the scrubby was not what I was "really aiming at."

    dhex,

    I don't care one way or the other about expanding state power. No, check that, all else being equal, I'd rather have less state power than more.

    It's merely a means to an end.

  • ||

    swillfredo,

    The present value of the occupancy cost for the life of the building is a component of the price he can get for it today.

    It's a small component, and not for all buyers. Say a builder sells to a buyer, who intends to flip it in a few years to another buyer. That's a lot of steps in which everyone has to agree that energy efficiency is worth an up-front investment.

  • SIV||

    Hey lets not let the spat between libertarians and libertarian-conservatives get out of hand.
    Can't we all be happy out here on the far right?


    Wouldn't want it to turn into something like that
    Communist/Nazi tiff they had over on the Left last mid century.

  • Doctor Duck||

    Green? Hah. When I was growing up all we had to eat was green, and we liked it. Frozen green in the winter. Green for breakfast, lunge, and dinner. Lunge wasn't even really a meal. If we ran out at the end of the month we had to eat yellow. Nasty, that yellow. Smells of wool.

  • ||

    Because they support government power to achieve X, it's the government power that really motivates them, and not X? Does not follow. I used a scrubby to clean my dishes last night, and no, getting to use the scrubby was not what I was "really aiming at."

    Right, I should say that it's not using the tool of government but of getting rid of the free market that is their central goal. One seems to be inherent in the other, though, does it not?

  • ||

    It's a small component, and not for all buyers. Say a builder sells to a buyer, who intends to flip it in a few years to another buyer. That's a lot of steps in which everyone has to agree that energy efficiency is worth an up-front investment.

    If I want to sell an apple to steve and if I have to buy fruit from bob, I'm not going to buy an orange from bob, am I? More analagously, if steve wants larger apples I'm going to want to buy larger apples from bob in the first place.

  • dhex||

    "It's merely a means to an end."

    i'm no traditionalist but there are definitely good things about a classic jesuit education.

    har har no really, hence my "nearly all" qualifier above. i know plenty of young liberal types (we buy lattes together) in this great city of ours and the last eight years have certainly opened their minds to narratives like "wow the government is fucking scary."

    however, i fear that such memories will fade once the correct boot is on the correct jack-foot.

  • ||

    Right, I should say that it's not using the tool of government but of getting rid of the free market that is their central goal. One seems to be inherent in the other, though, does it not?

    Gee, you don't think that achieving something that has to do with gender relations and environmental quality might be their real goal?

  • ||

    Look, we don't have to skylark on whether energy efficiency sells itself. If it did, all buildings would be constructed to energy star standards.

    They're not. We know this. Ergo, the existence of cost savings from energy efficiency does not reliably translate into greener buildings being built.

  • ||

    Gee, you don't think that achieving something that has to do with gender relations and environmental quality might be their real goal?

    If it were, I would expect we wouldn't see so many people cluster around the particular strategy of using the government to 'solve' such problems.

  • ||

    Most environmentalists advocate government intervention in society to curb pollution and protect furry critters, arguing that if these things are not regulated by the government the market will go wild and destroy the planet, etcetera.


    I think the root of your problem lies in the opening assumption. Green's don't actually advocate increases in government power, they advocate changing practices of living. This will include changing the way business and government interact with the environment. Sometimes that means increased regulation, sometimes that means decreased regulation... motivated by concern the impact on the environment.

    The Fair Trade movement, which has its roots and most of its support in the environmental movement, is an example of how the movement implements ideas in the real world. It is a very libertarian idea. A private regulatory regime that meets the needs of those that are interested in the environmental impact/labor practices that went into making their product. No government involved.

    False premises lead to poor conclusions.

  • ||

    Look, we don't have to skylark on whether energy efficiency sells itself. If it did, all buildings would be constructed to energy star standards.

    They're not. We know this. Ergo, the existence of cost savings from energy efficiency does not reliably translate into greener buildings being built.


    That reasoning assumes a free market in housing and a free market in energy. I think we have either right now, what with the subsidies that go into the oil companies and the housing market.

  • ||

    Neu Mejican,

    Consider me corrected. I guess almost every non-libertarian I talk to about the "free market" idea going on about how private industry is going to run the world into the ground had me fooled.

  • The Wine Commonsewer||

    Besides all that somebody needs to explain to me how people living in Buffalo NY are going to get locally grown produce in January.

  • Grotius||

    thoreau,

    As far as the rosemary, garlic, potatoes and carrots are concerned, that's in part why one grows a garden.

  • ||

    A good restaurant for lamb is Avra's in Atlanta, Georgia. Medium rare, it's to die for.

  • lunchstealer||

    Besides all that somebody needs to explain to me how people living in Buffalo NY are going to get locally grown produce in January.

    You'll eat your hardtack, and you'll love it. Also, rickets will be renamed "vitamin fun deficiency!".

  • ||

    Kenobi,

    If it were, I would expect we wouldn't see so many people cluster around the particular strategy of using the government to 'solve' such problems.

    You haven't noticed feminists and environmentalists using media events and personal interactions to try to change people's minds? You've never heard of fair trade products, organic foods, or "I Am Not A Plastic Bag" bags? You've never heard of carbon offsets and hippies on bikes?

    How odd.

  • ||

    joe,

    I have noticed those things, but I have also noticed the underlying assumption that the free market is systematically negative. The fact that they don't realize that such methods fall entirely within the free market is their mistake.

  • thoreau||

    I'm pretty sure I could grow rosemary in a pot in my kitchen, and I could retask the...commerce operation in the basement to grow garlic. But roots like potatoes and carrots sound like too much work, Grotius.

  • dhex||

    hey guys how about we all agree to use "some" when discussing population groups, as in "some environmentalists prefer government solution xyz" or "some* conservatarians need to get shot out of a cannon into the sun" rather than pulling an all or nothing?

    (*this "some" means "all")

    also basically rosemary is perfect and i think we can all agree on that. i like rosemary, fresh basil, some oregano and a bay leaf as the bottom of a hearty beef stew. (along with cumin, black pepper, chili powder, cayenne powder and a little bit of salt)

    sadly tonight's tofu will have no rosemary.

  • Grotius||

    thoreau,

    For the latter one might to have to join a community garden if one is city folk. Anyway, I grow most of my own herbs in pots (so I can move them inside on frosty days) and it saves a lot of money.

  • ||

    You haven't noticed feminists and environmentalists using media events and personal interactions to try to change people's minds? You've never heard of fair trade products, organic foods, or "I Am Not A Plastic Bag" bags? You've never heard of carbon offsets and hippies on bikes?

    Heh, I've also noticed people who dislike illegal immigration and outsourcing starting "buy american" campaigns, but that doesn't mean they don't favor protectionism.

  • Grotius||

    dhex,

    One of the nice things about rosemary is that it is a woordy plant that deals with winter well (well, not New England winters, but mid-Atlantic and going south winters). It can grow big of course too. Several feet high.

  • Grotius||

    Er, woody plant.

  • thoreau||

    Kenobi, some of us are trying to talk about lamb and rosemary here.

    I totally need to get some of those pots of rosemary plants from Trader Joe's.

  • dhex||

    i've never seen a rosemary plant several feet high. that sounds pretty awesome.

    huh, according to wikipedia the oil is a powerful convulsant.

    ROSEMARY: DARK SIDE OF THE HERB?

  • dhex||

    oh but anyway rosemary is great as a coating for steaks for grilling, along with some cracked black pepper and a bit of salt.

  • ed||

    rosemary is great as a coating for steaks for grilling,
    along with some cracked black pepper and a bit of salt.


    Indeed. Don't forget the garlic.

    http://www.youtube.com/watch?v=Lsj2LmBCpuQ

  • Grotius||

    dhex,

    Yeah, it can look almost like a hedge bush. In the U.S. sometimes you see them in restarants that way.

  • Vermont Gun Owner||

    Yeah, buying local only really works if the species themselves are local. With enough energy and chemicals, you could grow oranges in Maine. That wouldn't make local oranges a green choice for people in Seattle.

    Shouldn't that have been Portland instead of Seattle?

  • ||

    Doctor Duck | August 6, 2007, 2:55pm |
    Green? Hah. When I was growing up all we had to eat was green, and we liked it. Frozen green in the winter. Green for breakfast, lunge, and dinner.


    But, but, It's made of *people*!


    The Wine Commonsewer | August 6, 2007, 3:34pm |
    Besides all that somebody needs to explain to me how people living in Buffalo NY are going to get locally grown produce in January.


    You get it from your cellar. Or your greenhouse. Or you eat lamb.....!

  • Ellis Hollow||

    This whole food miles thing isn't new. Was done by Rodale's Cornucopia Project circa 1980. One recollection I had of their studies: The least efficient step energy-wise in the whole farm-to-table chain was hopping in the car to bring home 33 pounds of groceries.

  • Paul||

    Incorporating these measurements into their assessments, scientists reached surprising conclusions. Most notably, they found that lamb raised on New Zealand's clover-choked pastures and shipped 11,000 miles by boat to Britain produced 1,520 pounds of carbon dioxide emissions per ton while British lamb produced 6,280 pounds of carbon dioxide per ton, in part because poorer British

    Like, duh. Didn't we cover this already in a previous H&R post? I seem to remember getting into the tit-for-tat with other posters who drank the "food miles" koolaid where I postulated that the "carbon footprint" and efficiency of strawberries shipped from Venezuela were less than the 12 pounds of strawberries transported by Organic Farmer Brown to the quaint local farmers market in his red '56 Chevy Pickup which got 9 mpg?

    Part of the reason that Venezuelan strawberries are cheaper than Organic Meadow's Strawberries is partially because it's more efficient to bring them to market.

  • Paul||

    What's the point of analyzing imported lamb if you don't analyze all of the other ingredients as well?

    'cause everybody uses different ingredients? I mean, sure, though, we can certainly calculate the carbon footprint of your raw garlic, your raw onions, and then add them all together if need be.

  • ||

    Kenobi,

    I guess almost every non-libertarian I talk to about the "free market" idea going on about how private industry is going to run the world into the ground had me fooled.

    I was going to say, essentially, what dhex posted at 3:52pm...but instead I'll just add...

    Environmentalists are, probably, even more diverse in their views than libertarians...

    This is particularly true when it comes to the role of government and the free market in providing solutions to environmental problems.

  • ||

    And by the way...

    What the fuck is wrong with you people?
    A discussion of what ingredients go with lamb and no one even brings mint up? Mint people...Mint.


    Last night I made an amazing New Zealand lamb tenderloin with ginger, garlic, honey, and lemon ...yum...

    Didn't have any mint on hand.
    8~)

  • ||

    Vermont Gun Owner,

    Yes, Portland. Oops.

    Kenobi,

    Heh, I've also noticed people who dislike illegal immigration and outsourcing starting "buy american" campaigns, but that doesn't mean they don't favor protectionism.

    Perhaps they do. And now, for the $25,000 question: are people who support "Buy American" campaigns AND protectionism motivated by a) a desire for bigger government or b) a desire to maintain a large pool of domestic manufacturing jobs?

    Also, Rosemary is my favorite spice as well.

GET REASON MAGAZINE

Get Reason's print or digital edition before it’s posted online

  • Video Game Nation: How gaming is making America freer – and more fun.
  • Matt Welch: How the left turned against free speech.
  • Nothing Left to Cut? Congress can’t live within their means.
  • And much more.

SUBSCRIBE

advertisement