I often hear arguments from people around me, about the environmental impact of certain consumer behaviours like:

  • eating meat
  • using plastic bags
  • travelling via car instead of plane

and many others.

However, most of the time things are not as simple and objective data is hard to come by and involves a ton of research on every single item it seems.

Some example of things, which seem to be sustainable or environmentally friendly but actually aren't:

  • Salad has a very high energy usage per calorie
  • cotton bags need thousands of uses, before you can environmentally break even on them
  • cattle's water usage is debated and some numbers seem to be greatly inflated
  • organic food seems like a good idea, but actually requires more space, energy and is most likely not sustainable for the whole world to feed

Is there a somewhat easy and objective source on consumer behaviour regarding environmental impact? What are objectively the most important metrics to watch out for? Energy usage per unit of product? CO2 impact? Water usage? Impact on flora and fauna (not sure, how this can be quantified).

  • 1
    As written, this question is somewhat too broad for an answer that fits here, as it essentially amounts to "how can we measure the sustainability of anything?" Can you narrow it down to one specific issue?
    – krubo
    May 24 '19 at 2:01
  • Also, what is you definition of sustainability? Do you only want to take GHG-emissions into account? Or should reduction of soils, usage of pesticides, fair trade issues etc be taken into account?
    – Erik
    May 24 '19 at 8:32
  • One thing I find is rarely included in such analyses is the impact of transportation - it's no good buying a more sustainable product if it has to be shipped halfway round the world and so ends up with a bigger impact than an otherwise less efficient local product.
    – Nick C
    May 26 '19 at 7:48
  • 2
    @NickC the margins are actually quite small there, especially if a product is literally shipped, as in a boat on the ocean. I looked into it for this answer and found that shipping accounts for less than 3% of the energy use of plastic sent for recycling. Given how efficient ships are at moving cargo (there's a reason why we've been using boats for thousands of years) I doubt the numbers are much different for any standard product category that doesn't require refrigeration.
    – LShaver
    May 26 '19 at 15:11