South America's second-largest river retreats to lowest levels in 77 years
graphics.reuters.com
graphics.reuters.com
Is it really fair to blame global warming for this 2 year massive change? I find that hard to believe.
At the bottom of the article it's stated:
> “It is a twice in a century event,” said Sierra, who is an advisor to the Buenos Aires grains exchange, adding that a long-term weather cycle had converged with a double hit from the La Niña phenomenon which lowers precipitation.
So perhaps next year the river could be up at 2019 levels again?
Not everything is a simple linear effect. There are all kinds of interactions that do not have a simple linear correlation between the amount of cause and the degree of effect.
Climate and the effects on various things we care about are particularly complex and full of these sorts of interactions. There is no inherent reason to doubt global warming is a plausible cause for something just because it took place (relatively) suddenly.
Is global warming the cause in this specific instance? I have no idea. But discounting the idea just because the river didn't slowly get lower over the past decade or two is not reasonable.
There are quite a few tipping points that are only fully definable in hindsight. Attempting to anticipate them still has value.
For example, I might see latency creeping up on my webserver over several weeks. At some point, that's likely to become a problem, but the exact date/time when I get Pingdom alerts from a downed server may not be something I can determine.
Are there unknowns that are likely huge threats? Maybe, maybe not. Who's to say?
You can say "when we mess with massively, inherently chaotic systems, things tend to go in unexpected directions very rapidly", though.
> Who's to say?
Climatologists, who've been saying so for decades?
I'm certainly not saying tipping points aren't a threat, but who would claim to know the greatest threat inside of climatology? I mean we have dozens of unaccounted for nuclear warheads from the cold war era and you'd have me believe there are qualified people stating they know what the greatest threat is and it's some tipping point that will set off global warming?
I'm not sure why you want me citing something entirely different - opposite, really - that I haven't claimed.
Of course climatologists are pointing to some very serious issues, but they also understand those to be modeled projections and potential outcomes. The most dire models are indeed alarming and of course it is their job to sound the alarm. It's everyone else's job to use their relevant experience to decide just how important those alarms are. If we've learned anything from this pandemic it should be that alarmist models can very well make every headline but still fail to predict the future.
I'm unaware of continental slope failure being commonly attributed to global warming.
That is true; on the other hand, you can't just say "complex interaction" and still call this a consequence of climate change when the causation is absolutely unclear beyond "less water = warm = bad". It might possibly be, yes, but the fact that 2019 had a lot of water (when climate change was arguably worse since there was no dent in emissions by lockdowns) needs some explanation.
> But discounting the idea just because the river didn't slowly get lower over the past decade or two is not reasonable
The grandparent explicitly asked whether climate change is the reason in this specific instance, neither I nor they doubt climate change in general (I assume). And if your observation doesn't match your thesis, simply saying "complex interaction" is not sufficient - in fact, it helps skeptics, since they can - correctly! - point out holes.
I am not an expert on any of this, but my understanding is that climate change is dependent on the TOTAL level of CO2 in the atmosphere, not the rate of adding CO2. Thus, as 2020 was obviously not net-zero, 2021 is worse than 2020 is worse than 2019. I think many people misunderstand this fundamental point, maybe because they link CO2 to air pollution, which reacts much faster (because of wind, rain, etc.).
Therefore we are actually in a much better situation than we think. If increase C02 levels by say 5% in the next 50 years, temperates won't rise 5%
The greenhouse effect is significantly more complicated, but at 0.04% it seems likely we are in a fairly linear range.
I went out of my way - several times - to mention I was not presenting an opinion on the actual cause here. I don't know if global warming caused this. Hopefully the third time will be the charm.
I was arguing that the dismissal of global warming being a possible cause on the basis of it changing too fast was unreasonable.
> The grandparent explicitly asked whether climate change is the reason in this specific instance
No, they very specifically said they found it hard to believe climate change could be a cause because just a year or two ago it wasn't a problem. They did not ask if climate change could be a reason, but said that due to the timing they thought it made climate change significantly unlikely to be a possible cause.
> It might possibly be, yes, but the fact that 2019 had a lot of water (when climate change was arguably worse since there was no dent in emissions by lockdowns) needs some explanation.
In fact, you continued with the same mistake they made, so I apparently did not make a clear argument the first time. Hopefully I can rectify that.
Let's start with a much simpler example. A bowl of ice sitting out at room temperature. Now graph the temperature over time. You'll see it rise for a bit, then stop at 0 C for a fair while, and then start to rise again.
You can't look at just the temperature to determine the total energy the bowl is gaining. Just because the temperature rise stopped at 0 C doesn't mean the temperature won't continue to rise in the future. The fact the temperature stopped at 0 C is just a result of the physical nature of the system. Similarly, the nature of the ice changes suddenly. It's solid until it's not.
These effects aren't nice and linear, or even particularly smooth. You can't just take two arbitrary points in time and come to any great conclusions about the system.
It's also important to realize that this is a single very simple hypothetical. In reality there are many changes that weren't relevant due to the simplicity. Take the change from solid to liquid. In a bowl, not a big deal. But what if it's a permanent glacier on a mountain? As ice it'll basically sit there. As water, it leaves. Now the mountain is in a very different state, and won't behave the same as it did in the past. The area around the mountain also gained a bunch of water, which will change the systems there too, and then that just spirals outward. Classic butterfly situation, except instead of a butterfly flapping it's wings we just melted and moved however many millions or billions of metric tons of water.
And water can get involved in all sorts of fun stuff. Ice looks positively boring in comparison.
There's a reason I can't find a better way to sum this up than "complex interaction." I agree that's not a reason to blame climate change for anything in particular, but it's absolutely a good reason not to dismiss it as a possible cause out of hand just because some simple correlation didn't happen the way you thought.
It's not simple, so you can't expect it to behave simply. Coming up with a simple correlation and demanding it be true is just not reasonable.
> (when climate change was arguably worse since there was no dent in emissions by lockdowns)
This is just not true. Emissions are not directly causing heating, but causing more heat from the sun to be trapped. Think of it like putting on blankets. If you've thrown on three blankets already and then take a few minutes to decide to grab a fourth, you aren't suddenly colder. You're still just as warm as before, and warming up just as fast. You're just slightly cooler than you'd be if you'd grabbed the fourth blanket faster.
So even if there was a simple and direct relationship between temperature and river level, you really would not expect any kind of year-to-year response to emissions levels. No explanations are required.
> And if your observation doesn't match your thesis, simply saying "complex interaction" is not sufficient
I hope by now what I was trying to say is clear. You can't assume your thesis is correct, even if it seems nice and simple. It's not a safe assumption when you're dealing with such a complex and chaotic system.
We don't know what kind of variable the water level is, or how to expect it to behave. Does it have jumps and halts in it, like the temperature of water/ice? Is there some threshold effect and it'll appear to just suddenly change nature like ice turning to water?
And something like the water level of a river is not going to be as simple as an ice cube melting. It's going to be a combination of other systems that also influence each other. But the root causes - if you trace them back far enough - will be things like how ice melts. So you expect to - and do - see effects like you see there. Sometimes things don't change much until they change suddenly. Sometimes something seems to stop changing, even though the cause of the change is still happening.
But without knowing those details, what kind of thesis can you come up with that even has a shot of being halfway decent?
You can't. That's my point. The thesis is no good, and shouldn't be used. The thesis is assuming the ice changes temperature smoothly, and is doing so a hundred or thousand times over. It's so oversimplified that it has no power. When the observation doesn't match expectations, it tells you nothing. There was never a good reason to expect the observation to match in the first place.
As I understood to the text and the map, most of the land that dried are the “marshes, lagoons and meandering streams” mentioned. You can still clearly make out the main stream of the river, which presumably carries the majority of the volume, at the bottom of both images.
The rest of the article makes it clear the water levels have been declining for decades.
Yeah, when you cut out what you don't want to read you'll draw just the conclusions you want to have.
If you were to read the whole article you'd understand that it refers to several causes compounding and working together, deforestation and global warming are not the only ones. But most people just like to read the convenient parts.
Which, of course, means that centuries ago those rivers were low too, in a period that climate change wasn't a thing and the Amazon forest wasn't even known.
https://www.nytimes.com/2021/09/04/world/americas/drought-ar...
"Experts say deforestation in the Amazon, along with rain patterns altered by a warming planet, are helping fuel the drought. Much of the humidity that turns into the rain that feeds tributaries of the Paraná originates in the Amazon rainforest, where trees release water vapor in a process scientists call “flying rivers.”
Rampant deforestation has disrupted this flow of humidity, weakening the streams that feed the larger rivers in the basin"
Looking into various photos, movies, etc. of 193x it looks to me like it was kind of "sunny" compare to for example very bleak 198x, and it is not surprising - the mid 194x was the warm peak of the 80 years cycle while the 198x were the cold peak (thus for example hit to USSR agriculture in those years which combined with the low oil of the 198x brought the USSR down (and the conditions due to the low peak of the 190x - also pretty bleak years - were a major factor causing the first Russian Revolution in 1905)). The cycle-wise we seems to be coming to the next warm peak which on top of the global warming promises very hot temperatures and droughts for the next decade and even lower water levels for the rivers and the lakes.
It seems plausible that Amazon rainforest will affect the North tributaries. And the Parana state with its deforestation is about midway of the river.
Similar issues are occurring with floodplain harvesting in Australia where cotton farms are damming rivers which has dried up river beds downstream.
Was it man made intervention?
How could its location now have anything to do with the systemic economic problems that caused her job to disappear, since it's been there before?
And the images at the bottom show the river in flood stage in 2019 and then "normal" in 2020. It gives a very misleading impression.
Thanks again, Captain Chainsaw. You are a f*ing genius.
Santa, less ads and more of this creativity/innovations for 22.