A glitch in our present system is the disconnect between those who are good at solving our problems (e.g. engineers) and those who are good at drawing attention to their solutions (e.g. celebrities). Case in point: Sheryl Crow, who appears to have nothing but good intentions here, has made headline news (albeit in the entertainment section, but it's still headline news) calling for a reduction in toilet paper consumption as a means of mitigating climate change. I suppose this action would help somewhat, but upon closer inspection, it's not a top priority. Below, I've got details of the story plus an analysis of both her proposal and a counter-proposal. Ms. Crow, if you're listening, I'd be glad to work with you on this, but there are much better folks than me out there, such as the good people at the Rocky Mountain Institute.
Update: From comments, I learn that Ms. Crow was joking with her TP comments. Still, several media outlets made the same mistake I did in taking her words seriously.
I first saw this on Google News (retrieved ~11:00AM, Monday, April 23, 2007):
Here's one article on the topic; here's a "blog post" (no comment thread) on Ms. Crow's website. She writes:
I have spent the better part of this tour trying to come up with easy ways for us all to become a part of the solution to global warming. Although my ideas are in the earliest stages of development, they are, in my mind, worth investigating. One of my favorites is in the area of conserving trees which we heavily rely on for oxygen. I propose a limitation be put on how many sqares of toilet paper can be used in any one sitting. Now, I don't want to rob any law-abiding American of his or her God-given rights, but I think we are an industrious enough people that we can make it work with only one square per restroom visit, except, of course, on those pesky occasions where 2 to 3 could be required. When presenting this idea to my younger brother, who's judgement I trust implicitly, he proposed taking it one step further. I believe his quote was, "how bout just washing the one square out."
I'm having a hard time finding numbers on the per-piece energy consumption of toilet paper. (Imagine that!) So, I hacked together what numbers I could find and came up with (see calculations below) 0.12 kg CO2 per piece of toilet paper. Meanwhile, 1 gallon of gasoline produces 8.7 kg CO2. So, you could save one gallon of gas, or you could save 72 pieces of toilet paper. In other words, your decision of how you get to the store to buy toilet paper (walk vs transit vs driving a more or less efficient car, and how long the trip is) is much more important than how many pieces you wipe with. Moreover, many of us use more gallons of gas each day than we do squares of TP. (Not me! No car!) Bottom line: Conserving TP can't hurt, but our attention should be focused elsewhere. However, if Ms. Crow's goal is to get us conserving wherever we can and not just when, err, wiping, then maybe we're giving her to hard of a time here.
Update: Thanks to a measurement made by a commenter, I learn I've underestimated the mass of a piece of TP by a factor of 100. The above should read 7200 pieces of TP per gallon of gasoline.
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Note: The work presented here has not been thoroughly checked. If you can point out any errors, that'd be awesome.
I start the analysis with this report (1.4MB PDF) produced by Jacobs Engineering and the Georgia Tech Institute of Paper Science and Technology for the Department of Energy and the American Institute of Chemical Engineers. From p.3(4) (Executive Summary):
In 2002 the U.S. Paper Industry produced 99.5 million tons of pulp and paper products while consuming 2,361 trillion Btus... It should be noted that since 2002, the Pulp and Paper Industry has reduced its energy consumption, primarily through the use of waste energy streams, i.e. capturing the energy in waste heat streams, both air and liquid, as well as installing energy saving devices such as variable speed motors and more efficient lighting.
Let's use these 2002 numbers even though they're over-estimates. Using the fabulous OnlineConversion.com site for unit conversions, we get 99.5M ton ~ 10^11kg and 2,361T Btu ~ 2.4*10^18J. Ah, metric units. That feels so much better now! With these numbers, we get 2.4*10^7J per kg of paper.
So how much does a piece of toilet paper weigh? Looking at this, we have about 4000g per 200 pieces, or 20g = 0.02kg per piece. That sounds reasonable. That means about 5*10^5 J per piece of toilet paper.
Assuming most of this energy comes from coal and some from natural gas (see Fig. 2.1 on p.3(4) of the paper industry pdf), that gives us about 2 lbs CO2 per kilowatt hour. (See Table 2.1 of this DoEn report and note that coke is a form of coal.) That means 2.5*10^-7 kg CO2 per J or 0.12 kg CO2 per piece of toilet paper.
This covers the production of the toilet paper. However, it does not factor in the transportation of the toilet paper from production to bathroom. This will vary substantially depending on how far the store you buy it at is from the production facility and any intermediate warehouses, etc. and it will also, as mentioned above, vary substantially with how you get to and from the store. I don't have time to do the analysis now, but some starting points are (both are pdfs):
http://www.alan-whitehead.org.uk/...
http://www.greenhouse.gov.au/...
I also didn't factor in the loss of trees, although if tree farms are used, that could be negligible. Either way, I think it's fair to say that transportation is a bigger concern than toilet paper. Other big sectors include agriculture (reduce your meat consumption) and buildings (smaller residences, 'green' building, fluorescent light bulbs, etc).
The numbers for gasoline come from this analysis on Felicifia.