Comment by lsd5you | Hacker News Reader

Comment by lsd5you | Hacker News Reader

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There have always been droughts though, and things have varied from location to location. This effect you are invoking needs actually quantifying, and then comparing to the change in population. Would these regions coped if their populations hadn't drastically increased? Has water supply actually even decreased?

e.g. Yemen, population has gone up x4 in 40 years (or something like this). They have wars, and water shortages. What is the relative contribution of climate change?

So, see this article.

https://climateandsecurity.org/2016/08/03/a-storm-without-ra...

It is fairly balanced and fact filled, but when it comes to reduced rainfall and climate change, they are invoked, but left completely unquantified. No source, no estimate, no numbers (let alone a nice impartial unmanipulated graph). Did it decrease 10%, 1%. So if they have absolutely no handle on the quantification how can they make the claim at all? If there is a large uncertainty then that should be expressed.

This is what I mean, we are being primed to accept climate change as an explanation. When we have other massive, dominating factors - massive population growth and running out of acquifer runway (i.e. they have been in deficit for a long time).

Literally in the first paragraph of the article you cite as problematic it says:

> Like other unstable situations in the region, climate change may be an exacerbating factor in the country’s instability, not a primary cause, and to what extent is uncertain.

It's simply a hard question to quantify the impact of climate change on rainfall. Major effort in the IPCC report just goes into adequately representing the uncertainty in precipitation changes. And this is not hidden it's front and center in the Summary for Policymakers:

https://www.ipcc.ch/site/assets/uploads/2018/02/AR5_SYR_FINA...

Figure SPM.7

So yeah, people now look for the contribution of climate change to all sorts of things. It will often not be a dominating driver, and often hard to quantify, but I don't see anything terribly problematic here in the sense that the dominant reasons are ignored. (Population growth in this context is often also indirectly taken into account through land change uses, which mostly means turning nature into farmland.)

Which is problematic.

They are citing it as a cause but have no quantative basis for it what so ever apparently. The effect could be 0, or negative, they've apparently just brought feelings on the situation.

So figure SPM.7 looks pretty serious. It is 60-80 years in the future (probably further at the time of the models) and based on models (albeit on the agreement of presumably independent models). However current shortages are being attributed to climate change. To do this it should be possible to a) show a long term drop in precipitation and b) show climate related causality somehow. This should be easier than accurately predicting the future - but of course is less easy than innaccurately predicting the future.

So what you show I would say reenforces my point. We have predictions based on models (which we can take seriously or not), but then we also have current events which are being attributed to climate change with no quantifiable basis for doing so - despite the fact it should be possible to come up with some kind of proxy for climate induced problems(other than just a shortage happened).

Actually it's just the opposite.

But literally SPM.7 is the summary of the summary of the summary. There is so so much research published on precipitation, the vast majority of which is careful and precise in giving uncertainties.

It's also actually harder to attribute causality to long term trenda for individual current events than to look at model based predictions for the future. The entire extreme events due to climate change business is incredibly tricky to quantify, even though there are some good heuristic reasons to think it might hold.

So you won't conceed that this is problematic that there is according to you presumably relevant data they could cite - even if it doesn't directly apply to yemen in that particular perioud, but they chose not to? I mean what ever happened to 'citation needed'.

I mean uncertainties is a bit of an umbrella term. You should be able to be certain about predictions if you make the error bars big enough. If you still can't come up with a reliable assertion doing this then things are spurious.

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