This whole "if cows eat seaweed that'll vastly reduce their carbon footprint" is based on a single study with 12 cows.
If you take into consideration that especially small, never replicated studies often don't hold up to scrunity the next thing to do is not to ask how to produce the seaweed. The next reasonable step would be to try to replicate this study in a larger sample (and probably also with a larger variety of cow breeds).
Its not - most often "skeptical science remarks" although popular, are poorly informed and misleading.
A quick scholar search shows numerous studies broadly agreeing with the one featured here, including the seaweeds effects on sheep digestion and microbial and metabolic details:
It's more of an "intellectually lazy ego indulgence" than true skepticism. It's a false skepticism. Not that there's anything wrong with it, it's part of being human. I'm often guilty of it and I don't think there are people who aren't.
Getting a really rich definition of skepticism helped me make what I came to understand is a very important distinction. Link, In case anybody is interested: https://www.youtube.com/watch?v=5kzZdps9PG4
I love when you get people complaining about sample sizes, yet the effect is huge and significance levels are minuscule.
Yes, significance testing has some flaws, but they mostly show up at the margins, and complaining about sample sizes has nothing to do with that anyway.
I would prefer being skeptical instead of blindly accepting things. This behavior will instigate another to provide evidence or a counter-argument. This makes for great discussion, in most cases I think it is healthy.
It's easy for what passes for a skeptical attitude to actually _be_ a blind acceptance. Whether of another implicit and unexamined paradigm that one is operating from, or just a dissonance-triggered knee-jerk. It's a very sneaky self-deception, false skepticism.
OP's comment casts doubt on the validity of the article's conclusions. Maybe OP didn't look into it as much as others. The response to OP reaffirms the validity and sways my skeptical mind. I enjoyed both comments; indeed good discussion.
Its not about skeptical remarks being poorly informed. It's about taking a thought that could occur to anyone thinking about the issue at hand without having all the information, presenting it, and having an informed reply. It's part of the dialog, and shouldn't be demonized!
Effects of nutrition on livestock methane production have been studied for over 20 years now. We have methane reduction results from both in-vivo and in-vitro research. What varies is the numbers (99%, 50%, 15%?). Replication is always welcome but I believe we have enough sound science to move into more industry/engineering efforts.
I agree, we need to slowly study other groups of cows to see if this is a viable solution.
I'm reading Factfulness by Hans Rosling at the moment. He had a great point about "single numbers" - the jist was to always be skeptical of just a single number or metric.
Here's an example [1]. During WWII, soliders were dying in their own vomit because they were laying prone on the battlefield, in sick beds, etc and left unattended. Doctors tried using the Recovery Position [2] and saw a decrease in those types of deaths by about 99% (this is in the book).
Sounds like it should work for other types of people, right? First aid organizations quickly updated their "best recommendations" for all types of people: sick, drunk, young, old. This position was the best possible position for increased airway access, thereby decreasing preventable patient deaths.
It wasn't until the 1980's that this idea was challenged. A few health organizations noticed an increase in infant deaths. Hong Kong's group was the first to investigate this [3]. Other groups joined in and realized that infants, when turned on their stomach, do not have the strength to tip their heads after they vomit. As a result, infant deaths increase when they are placed into the Recovery Position.
The recommendation was quickly updated in the late 1980's / early 1990's. Now the recovery position is recommended for people ages 5 and up.
Between 1940 - 1985, there was a larger number of infant deaths because one group of well-meaning people took some knowledge they gained for one group and quickly applied it to all other groups.
I think this study (cows reducing methane based on diet) is a great idea. But we need to be cautious about applying this quickly to all cows, else we could kill half the cow population and cause the cost of beef to skyrocket.
My impression is that farmers generally areconservative about how they change their feed for their livestock. I don’t think there is any risk that they will “kill half the cow population” in a hurry.
Having a small sample and a large effect doesn't mean you're guaranteed at least some effect on a large sample. If anything, a very large effect is more likely to indicate a flaw in your method.
Yes, but effect sizes are relatively harder to hack/screw up (knowingly or otherwise) than p-values. My totally anecdotal impression is that findings showing large effect sizes seem to replicate better than findings showing highly significant effects.
It could be an example of publication bias, from the wiki article on effect size [1]:
An example of this is publication bias, which occurs when scientists report results only when the estimated effect sizes are large or are statistically significant. As a result, if many researchers carry out studies with low statistical power, the reported effect sizes will tend to be larger than the true (population) effects, if any.
Excessively large effect sizes are a warning sign in and of themselves. A good article on this is here: [0] -- simply if the effect is too huge, it becomes incumbent on the researcher to explain why no-one has noticed this before. Methane is a gas with a distinct and noticeable smell. Seaweed is plentiful in many places cows are kept. If the effect was really as dramatic as claimed you'd expect that it'd be well known that letting cows eat seaweed made them less smelly, and the authors of the original study make no attempt to explain why this might be the case.
Interesting, thank you! I was surprised by this, as it's the major component of natural gas (as used widely for cooking here), and this has a distinct smell. I went looking however, and discovered that's actually because Ethyl Mercaptan is added specifically to make it detectable by humans. I never realised this, and does indeed explain why it's plausible no-one would have noticed such a large effect.
If I'm not mistaken the original inspiration for this research was precisely that farmers noticed their cattle (or perhaps it was sheep) were happier when allowed to graze in fields which happened to be along the shore, allowing them to naturally eat quantities of sea weed.
In a small sample, the observed effect needs to be large in order to cross the threshold for statistical significance. It could still be a fluke and the true effect zero or even negative.
It depends. If the original study was published only because it had a positive result (significance filter, usually true), we expect the effect to be smaller in a larger replication. It's called Type M error, with M for magnitude. And, yes, large scale replications typically show smaller effects or no effects. See this paper for details: https://journals.sagepub.com/doi/full/10.1177/17456916145516...
Further food for thought: the lower the statistical power of a study which meets a given significance threshold, the more exaggerated the effect size will be.
So our default posture to evidence like this, even assuming we find it broadly credible, should be that the real-world effect is very likely to be smaller than this, and very unlikely to be larger.
Yup. There's plenty of boutique dairy farms within easy driving distance of rich colleges in the northeast (some of whom already have existing relationships with said colleges). I'm sure anyone who seriously wants to replicate the study would be able to find a farmer that will work with then to get an n value of a few hundred. It's not like you have to go somewhere remote to study cow farts.
I went to a college like that. Most colleges with big ag programs aren't spending big resources on cow emissions. Their flagship researchers that get the money are going to be studying things that are of more immediate importance to the farming industry and farming in general. At present those things are usually along the lines of how to minimize negative impacts and/or leverage the current and future changes in climate.
Anecdotally, taking in a little chlorophyll per day dramatically reduces how much gas I produce. So in my experience, it’s at least possible the effect may be large. Worthy of more research.
> "It contains chemicals that reduce the microbes in the cows’ stomachs that cause them to burp when they eat grass."
Apparently, they are comparing this to eating grass. I'm a little skeptical of that statement, though. Grass-fed vs. grain-fed have wildly different outcomes for the health of the animal.
This whole "if cows eat seaweed that'll vastly reduce their carbon footprint" is based on a single study with 12 cows.
If you take into consideration that especially small, never replicated studies often don't hold up to scrunity the next thing to do is not to ask how to produce the seaweed. The next reasonable step would be to try to replicate this study in a larger sample (and probably also with a larger variety of cow breeds).