statistics and applied probability

national university of singapore

Dodgy statistics about vegetarianism and climate change?

I got an interesting, attractively designed (though poorly edited) booklet through my letter box last week, entitled the Survival of the World is in Your Hands.  It seems to be the work of the Supreme Master Ching Hai, and there are related ads appearing on bus stops around about Singapore.  The basic argument is that we can avert climate change by becoming “veg”, which seems to indicate adopting a vegetarian diet.  (Conflict of interest declaration: I don’t eat meat, although I do eat fish.)

The argument is supported by impressive sounding statistics alongside charts like this bizarre pie chart:

Greenhouse gas in perspective

Not quite sure what the things protruding from the charts are.  (I edited out the extra text, if you want to read it, check out the original on the loving hut webpage.)

Here are some of the claims:

  • At least 51% of global greenhouse gas emissions come from livestock.
  • Natural disasters have doubled in the last 20 years.
  • There is a 99% correlation between the number of pig factory farms and the number of people getting influenza A (H1N1-2009) in Canadian provinces.

Having just read Lomborg’s the Skeptical Environmentalist, and having been working on H1N1 a bit, these claims seem far-fetched. The 51% claim comes from a publication of the Worldwatch Institute, and is much higher than the estimate from the FAO (of 18%), but the latter has recently been been criticised as being too high (which the authors of the FAO report conceded).   The doubling of natural disasters is to me fairly convincingly dismissed by Lomborg.  The 99% correlation claim comes from some newspaper reports by Alex Roslin in Canada, but while I could get the data on the number of pig farms, the number of cases at the time of the report seems to be no longer available, alas.  But it seems far more likely that there is a high correlation between the number of pig farms and the number of people (infected or no) and that that’s driving this correlation.  After all, didn’t we get H1N1 in Singapore?  Not too many pigs here…

It’s a shame the author had to resort to scare-mongering.  I think she’d have done better by providing more of the recipes that appear in the middle of the booklet: asparagus wrap, pasta with mariana sauce, etc.  Yum!


  1. Hi Prof alex! Sadly, depite all the dodgy stats pointed out, the cult seems to have garnered quite a substantial amount of followers especially in China.

  2. Alex

    2010/04/13 at 16:08

    Hi Yaoyuan,

    Well, I’m not saying the Supreme Master has made this up, after all, these are all claims that have appeared in various, semi-official sources. Nor am I saying that eating meat is good for the environment: it clearly takes a lot of kg of plant mass to make a single kg of animal mass. But I think the argument in favour of eating less meat and for trying to minimise our impact on the planet is weakened by presenting false arguments.

  3. I agree. They should have been more critical and thorough in their analysis instead of 断章取意; i.e. looking at the context of 1 sentence instead of the whole passage.

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