"Is x more sustainable than y" questions?

Question

Naturally there are quite a few of questions of the type "Which one is more sustainable, x or y?" or "What is best for the environment, a or b?" - the most recent being

Steel vs plastic bottles,

Olive vs sunflower oil and

Transport mode to cross the Atlantic

As far as I understand a lot of these questions can only be answered with thoroughly conducted life cycle assessments which are not necessarily available.

But nevertheless, a lot of information is very specific to one system (in terms of the geographic location, temporal aspects, the state of technology, recycling strategies of countries, the nature and composition of in- and outputs of the system, the legislation and so on) and may not be transferred to other systems of similar nature.

This is probably even more difficult if the person asking the question does not specify several aspects like "sustainability" (which can basically mean anything) or several methodological parameters commonly defined in life cycle assessment studies (the boundaries of a system, the impact categories chosen, etc).

My questions therefore are;

Should we demand more specifications (especially when the question is asking for sustainability) or leave this up to the person answering? and

Should we be more technical (such as referring to how representative a cited study is in the context of the question) when answering, pointing out the limitations of such studies? (for my understanding it seems that most people are not necessarily aware of that - which is not surprising given the complexity of production systems and even the life cycle methodology).

Answer 1

I agree with the direction I think you're trying to go, but only cautiously.

If the suggestion is that we demand more precise questions/answers, then my opinion is no. If the suggestion is to encourage people to be more precise, then my opinion is yes.

• First of all, I don't think we want to make "the perfect the enemy of the good". A perfectly precise question may be better, but I don't think that means that a more general question isn't useful.

• The general Stack Exchange network has this concept that questions should be narrowly defined, but also that there is the concept of Too Localized, which is in fact a reason that a question may be closed. The point is that no Q+A site succeeds if the questions are so localized as to only be useful to the person asking the question. They have to be more broadly useful, too. So, I think it is possible to force questions to be too specific.

• Sustainable Living may be a little different than some of the sites that Stack Exchange started with. For example, Stack Overflow is a giant site used by all kinds of software developers. There's 100,000 active participants (200+ rep), and millions of questions. For Stack Overflow, it makes sense to work hard to narrow the questions a bit, because there's still enough to keep the site strong. I'm not sure Sustainable Living is going to have so many questions, so I'd be very concerned if this suggestion turns into a reason to close/censor questions that don't get posed precisely enough for some peoples' liking.

• I certainly do agree that questions and answers are better if they clarify which sustainability criterion (e.g. climate change, energy use, resource depletion, waste production, biodiversity, etc.) is being discussed. I'm going to make a note to edit some of my existing answers, because I know I've been a little sloppy in that regard.

• I do want to express my opinion that this is not a science site, per se, and if questions get treated with the rigor of a scientific journal, I don't think as many people will be interested. I believe the best way to be most useful to the widest range of people is to provide practical, but fairly short, answers to common sustainability-related questions people have. Links to good sources of more in-depth data are great to provide, but I tend to favor sources that are targeted at the layman. Solely providing original scientific sources may lose the average site viewer.

Conclusion

Basically, any comparisons like the three questions you cited are going to depend on lots and lots of factors, and it's hard to imagine providing one correct answer if Choice X and Choice Y differ in some sustainability criterion by less than about 20%.

I think we want to help identify major issues with everyday choices people have, and help them with low hanging fruit. Help avoid the really unsustainable choices we make, explain why they're unsustainable, and nudge the common knowledge base in the right direction. To me, that's an achievable goal.

Answer 2

It's easy for such questions to be not-so-great. They're easy to ask, hard to research if you don't know the answer, and often, when asking, one doesn't even know which factors are important and which are trivial. So that can make it hard for a question to be technically specific.

But great answers to them can make them really valuable.

So I think there's lots of scope for answerers to make the most of the opportunity that these questions provide, to fill in the gaps left by the questioner: either by asking for clarifications in comments, or by explicitly stating your assumptions in the answer.