Some of the World's Biggest Lakes Are Drying Up • Hacker News Board

Re: Some of the World's Biggest Lakes Are Drying Up

#41

Post by spodek » Sun, Mar 04, 2018, 1:02 PM UTC

You can look for causes all you want. They all lead to human population growth.

Talking about it could possibly lead to finding something to do about it, which would mean deliberately lowering the birth rate. How? I don't know, but the alternatives are 1) hoping we get lucky and don't overshoot Earth's carrying capacity or 2) letting nature lower our population for us.

Regarding option 1, everyone knows population growth rates in many places (not everywhere) are declining, but the rates have nothing to do with Earth's carrying capacity, so it would only be luck if we stabilized below the carrying capacity. If we've already overshot it, lowering rates won't prevent option 2.

Option 2 means people dying prematurely from disease, famine, war, pestilence, etc.

Are there meaningful third options? Going to space or Mars doesn't lower the population here, and it presupposes that people could manage population growth on the spacecraft and early colonies. If we can there, we can elsewhere.

So however challenging figuring out how to lower the birth rate is, it seems the best option of the three. It seems like talking to you kids about birth control. It's easier not to talk about it, but the parents who don't do it end up with grandchildren sooner than they expect, and less cohesive families since they were chosen by circumstance, not deliberate choice.

Re: Some of the World's Biggest Lakes Are Drying Up

#42

Post by mikeash » Sun, Mar 04, 2018, 1:19 PM UTC

spodek wrote: post #41

You can look for causes all you want. They all lead to human population growth. Talking about it could possibly lead to finding something to do about it, which would mean deliberately lowering the birth rate. How? I don't know, but the alternatives are 1) hoping we get lucky and don't overshoot Earth's carrying capacity or 2) letting nature lower our population for us. Regarding option 1, everyone knows population gr…

A third option is to increase Earth’s carrying capacity. I don’t know how, but the capacity depends on technology and resource use, so it should be possible.

Re: Some of the World's Biggest Lakes Are Drying Up

#43

Post by graeme » Sun, Mar 04, 2018, 1:39 PM UTC

mikeash wrote: post #42

spodek wrote: post #41

You can look for causes all you want. They all lead to human population growth. Talking about it could possibly lead to finding something to do about it, which would mean deliberately lowering the birth rate. How? I don't know, but the alternatives are 1) hoping we get lucky and don't overshoot Earth's carrying capacity or 2) letting nature lower our population for us. Regarding option 1, everyone knows population gr…

A third option is to increase Earth’s carrying capacity. I don’t know how, but the capacity depends on technology and resource use, so it should be possible.

We have been doing that. But one problem is that it's easy to fool ourselves: you can temporarily raise carrying capcity by eating capital.

So, we catch many more fish now, for example. But we are catching at faster than replacement rate, depleting the natural capital stock.

Carbon energy + space in the atmosphere for CO2 is another variety of capital stock which we have used for temporary carrying capacity gains.

There are also long run carrying capacity improvements in the mix. General efficiency improvements fall in this category.

Re: Some of the World's Biggest Lakes Are Drying Up

#44

Post by majos » Sun, Mar 04, 2018, 1:56 PM UTC

spodek wrote: post #41

You can look for causes all you want. They all lead to human population growth. Talking about it could possibly lead to finding something to do about it, which would mean deliberately lowering the birth rate. How? I don't know, but the alternatives are 1) hoping we get lucky and don't overshoot Earth's carrying capacity or 2) letting nature lower our population for us. Regarding option 1, everyone knows population gr…

I'm in the camp that says the earth's carrying capacity is much higher than anything we're likely to reach.

I also believe that fertility rates are strongly tied to development, so that this problem will sort itself out if global development continues (especially in sub-Saharan Africa -- see maps [1] and [2]).

[1] https://en.m.wikipedia.org/wiki/Total_fertility_rate

[2] https://en.m.wikipedia.org/wiki/List_of_countries_by_GDP_(PP...

Re: Some of the World's Biggest Lakes Are Drying Up

#45

Post by vim_wannabe » Sun, Mar 04, 2018, 2:55 PM UTC

DennisP wrote: post #37

bilbo0s wrote: post #28

Earlier quoted context omitted.

Maybe someone gave you water as a newly made up excuse for China taking Tibet? But make no mistake about it, on October 7, 1950, the Chinese were not thinking about water. I'm fairly certain most historians would agree on that point.

Here are two comments on r/askhistorians saying water was one of the reasons [1], along with natural resources in general [2]. Of course that's not the only reason; other answers make clear there were a lot of factors. Now though, Tibetan water is a huge issue, including for other countries downstream of Tibet including India and Pakistan [3]. There are no water treaties between these countries; China has been buildi…

Anyone else feel like [3-5] should be a bigger issue? Desertification is scary as hell already but this is even more immediate.

Re: Some of the World's Biggest Lakes Are Drying Up

#46

Post by verelo » Sun, Mar 04, 2018, 3:11 PM UTC

oldcynic wrote: post #20

verelo wrote: post #15

I have to admit i know nothing about this, so i want to ask what feels like a dumb question: What stops water from evaporating into space? I feel like the answer is something simple like "gravity", or "condensation", but we seem to think Mars once had water, so where is it now, and will that happen here too?

There are tiny losses from the upper atmosphere, but not enough to matter. If you look at the water cycle[0], you'll see that as the water vapour rises it condenses - it gets quite cold a few miles up. Clouds consist of tiny droplets of liquid water and ice, not vapour. [0] https://en.wikipedia.org/wiki/Water_cycle

Right, that makes sense, and i should have considered the extreme cold of the upper atmosphere. Thanks!

Re: Some of the World's Biggest Lakes Are Drying Up

#47

Post by libertine » Sun, Mar 04, 2018, 3:11 PM UTC

mseebach wrote: post #38

libertine wrote: post #35

Earlier quoted context omitted.

I know the difference - but when a pattern of similar weather is noticed in the past 5-10 years, it's more than just weather, I believe it's climate. What worries the most isn't how warm or cold it guets, it's precisely how dry it is.

No, you don't know the difference when you talk about climates and then link to the weather for a single day as supporting evidence.

The day was an example among a period of years of extreme drought.

Drought is the outcome of years of low precipitation - it's not one day, one week,one month or one year. The recovery won't come in the same time period I said in the previous sentence. It will take years of rain to refill what was lost, not to mention there might be erosion already that have made some riverbeds/lakes permeable again, so water will not be held there.

The spring of the main river in the Iberian Peninsula has dried. Many other springs of secondary rivers have dried as well.

It's not weather. It's climate change.

Re: Some of the World's Biggest Lakes Are Drying Up

#48

Post by verelo » Sun, Mar 04, 2018, 3:12 PM UTC

cstejerean wrote: post #16

verelo wrote: post #15

I have to admit i know nothing about this, so i want to ask what feels like a dumb question: What stops water from evaporating into space? I feel like the answer is something simple like "gravity", or "condensation", but we seem to think Mars once had water, so where is it now, and will that happen here too?

Gravity and a magnetic field. Gravity keeps the atmosphere from floating away, and the magnetic field protects it from getting stripped by solar radiation. The problem on mars is he magnetic field.

Magnetic field, ah! Right so, interestingly does that mean a polar shift (that every now and again people rave about) might have larger implications than breaking electronics? Ie massive water loss? I feel like it would depend what the poles look like after the shift, is it likely the field could be weakened or would it just flip? I should probably try learn more about this.

Re: Some of the World's Biggest Lakes Are Drying Up

#49

Post by IntronExon » Sun, Mar 04, 2018, 3:36 PM UTC

candiodari wrote: post #34

IntronExon wrote: post #23

Earlier quoted context omitted.

I’m curious who do you think is suffering now as a result of drought and diminishing ecological resources? Who is going to suffer through famine and drought? Your point is valid, but only insofar as people who can’t defend themselves always suffer. Every course of action hurts the group you’re concerned about, but the most likely to succeed and least damaging is conservation.

Well the problem is the large cities taking up all capacity in the rivers and the people who suffer are the people on the coastlines of those lakes. The capacity in the rivers, by and large, is not taken up by people on those coastlines. And conservation, I bet, "somehow" misses this reality. So it attempts to protect things like tourism income at the further expense of the victims. But nobody, absolutely nobody is t…

You didn’t even come close to addressing my question. I pointed out that your concern for the helpless is an obvious canard in this context, and you took that as a opportunity to engage in more ideological chatter.

Re: Some of the World's Biggest Lakes Are Drying Up

#50

Post by joncrane » Sun, Mar 04, 2018, 3:48 PM UTC

anvandare wrote: post #31

joncrane wrote: post #7

Where is the water going, though? Isn't water a zero-sum game in the sense that Earth is a closed system?

Just like energy and entropy, it becomes harder to harvest efficiently. There's still just as much water, it's just not easily accessible. The difference between the water in your glass and the water in the cubic foot of earth after you spill your glass on it. You can't drink from the latter. The water cycle does the collection for us (lakes, rivers, aquifers) but we're draining them faster than they can recharge, pa…

Thank you.