Our Daily Bleg: How Much Does Ice-Making Contribute to Global Warming?

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A reader who works as a research scientist but wishes his name to be kept anonymous — “to avoid any hate mail coming my way” — writes in with a fervent couple of questions.

Being from Europe I have always wondered why Americans drink so much soda. Given the associated health risks, which has been discussed on your website and many others, it just seems ludicrous. Besides this obvious question and the associated health care costs, I was wondering how much energy is actually being wasted each year by making all the ice being added to the sodas. Could you estimate how many metric tons of carbon dioxide are being senselessly generated for making the ice which is added to the beverages which are eroding public health and public funds?

Anyone out there who can tell our curious, timid scientist a) why Americans drink so much soda; and b) how environmentally-unfriendly all that ice is? Back-of-the-envelope calculations welcome.

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  1. Mary S. says:

    No energy is being “wasted” because ice-cold soda is delicious.

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  2. Scott W says:

    Here’s my quick calculation that does not include commercial ice making:

    Assuming an ice maker or ice maker portion of a freezer takes 150W
    Assuming it runs 12 hours/day = 1800 Wh/day = 1.8 kWh/day
    75.11 million housing units in the US (2009 data via Wolfram Alpha)
    Assuming 60% have ice makers in some form = 45 million household ice makers

    45 million households * 1.8kWh/day/household = 81000000 kWh/day

    81000000 kWh/day * 0.0005883 metric tons of CO2/kWh (carbonfund.org) = 47652 metric tons CO2/day

    As to why Americans drink so much soda, it may be to make up for all the smoking we’re not doing anymore (which Europeans don’t seem to mind as much).

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  3. Jessica says:

    a) If soda and wine were the same price (as is often the case for table wine in Europe), I would kick my diet coke habit and pick up a Merlot habit. Duh.

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  4. Rob says:

    Just to give a very rough estimate:
    per capita soda consumption in the US: 789*8oz (http://www.cspnet.com/ME2/Audiences/Segments/Publications/Print.asp?Module=Publications::Article&id=5506D87134B44810A3E2B2ADDBF6C73C) = 6312oz
    Total Soda consumption: 300m*6312=1.9 trillion ounces
    Figure about 15% of total cup’s volume is ice (http://www.sugarstacks.com/beverages.htm) (e.g. ice=.15/.85=.176 of soda volume) this is probably low for restaurants, but compensates somewhat for less ice if drinking from bottles/cans, and assuming ice is same density as soda: .176*1.9t oz= 330 billion ounces of ice
    assuming 1 liquid ounce of water = 1 ounce of mass (it doesn’t, but it’s close), 330 billion oz = 9.4 billion kg
    Energy to produce ice (in Denmark) = .064 kWh/kg (http://www.lcafood.dk/processes/industry/iceproduction.htm): 9.4 billion kg*.064 kWh/kg = 600 million kWh
    US average: 1.297 lbs CO2/kWh: 600m*1.297 (http://www.carbonfund.org/site/pages/carbon_calculators/category/Assumptions) = ****780 million pounds of CO2**** (about 350,000 metric tons)

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  5. Travis T. says:

    Average American drinks 150 quarts of soda a year, so let’s say that’s 400 12 oz servings

    Rough, rough estimation of ice per drink, let’s say 5 oz, roughly 150 mL, so 60 liters of ice per year per American

    300 million Americans: 18 billion liters of ice per year

    Assuming that since 1 calorie (~4.2 joules) is the amount of energy it takes to increase the temperature of 1 mL of water 1 degree, it takes the same amount of energy to decrease the temperature by 1 degree, the amount of energy required to freeze 18 billion liters of water from 22 degrees to 0 degrees is roughly 400 trillion calories (~ 1.7 x 10^12 joules) or about 470,000 kWh

    give it a boost by an order of magnitude for inefficiency of energy and call it 5,000 MWh, using Scott’s CO2/kWh conversion, I get about 3,000 metric tons of CO2/year

    googling “3000 metric tons of CO2″, the second hit says that this is the amount of CO2 that could be saved by having shopping malls stop playing muzak: http://www.grist.org/article/2011-02-03-how-malls-can-save-both-the-earth-and-your-ears

    source for soda consumption: http://fooddemocracy.wordpress.com/2007/11/09/chew-on-this-us-soda-consumption/

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  6. Clark says:

    As a recent convert from soda-drinking American to water-drinking American, I think I can answer part of your first question.

    I grew up with soda as did many of the people my age. Since I wasn’t used to the taste of water growing up, it was hard for me to adapt to its relatively bland taste today. Many Americans aren’t willing to make that switch.
    Also, soda cans are convenient for travel and easily available almost anywhere you go.

    Bottled water is convenient and available too but I don’t see you complaining about bottled water. How much waste is involved in manufacturing the bottles and transporting those bottles to their end users? Water from the tap is imminently cheaper per gallon. Given that Europeans drink a lot more carbonated water than Americans do, can’t we turn the question around to you?

    Besides, now that I’m a water a drinker, I happen to be an ice water drinker. Your initial complaint about making ice for sodas applies to me as well!

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  7. Matthias says:

    I thought that Superfreakonomics showed that global warming from carbon emissions was a total non-issue (if we really cared, we’d eat kangaroos instead of cows which output no methane) and that even if it was an issue we could quickly, effectively, and inexpensively counteract it with the “garden hose to the sky” idea. Maybe I drew incomplete conclusions from the global cooling chapter.

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  8. Elle says:

    I don’t have back-of-the-envelope calculations but I have anecdotal evidence.

    For myself and a lot of my friends, it’s a norm at this point. A lot of them drink soda all the time and I often get soda when I’m out to eat. Around the house I drink a lot of fruit juice (which is just as sugary as soda) but I know I’m exceptional that way. When you go out to restaurants here it seems like you’re offered a plethora of soda choices and only a handful of other non-alcoholic options (water, coffee, tea, sometimes milk and juice).

    I’ve also asked my friends why they always put ice in their drinks (even in winter) and the answer is usually along the lines of they just prefer it that way. I think if their norm was to not have ice in their drinks then they wouldn’t seek out ice from the bin in the freezer. The question for me is where the norm started. Is it from the same one-upping mindset that led to larger portion sizes in restaurants?

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