So 2000 years ago people also had access to this part of the river. They must have experienced the climate changing too.
A lot of climate science has been dumbed down to "it's getting warmer" in popular media, which isn't wrong, but people misunderstand this as "winters get less cold and summers get warmer" which isn't necessarily the case in every place.
There's more energy in the system. Imagine an intricate network of tiny machines all working in unison (heck, think of a road network with driverless cars if you want) and then making everything run much faster with no regard for physical constraints and mechanical properties. Eventually there will be collisions and those will have effects on other parts of the network and the more complex the initial system is the harder it becomes to predict what will happen exactly but even if you stop increasing the speed and allow for the system to stabilize, it will be very different from how you started and even if you slow it down back to the original speed, the system will look different. If you imagined this as a road network, humanity and other animals are the pedestrians trying to cross the streets and there are no traffic lights. I hope this metaphor also demonstrates how historical changes effectively just slowed down and sped up the traffic a tiny bit (say, going slightly above or under the speed limit). The implications for the system overall and for the pedestrians within are very different.
However, your answer has 'climate change' baked in. What evidence is there in this article to suggest climate change, rather than an intermittent event that has probably occurred numerous times in the past 2000 years? Why does the article say 'climate change'? Why do you think it? Why was the river low 2000 years ago, in pre-climate change times?
The thing is that there have always been droughts, floods, etc - these were recorded in biblical times. That most people frame 'changing weather' in terms of climate change is a question of psychology and education - but has nothing to do with any evidence anyone can see and verify. We have to simply told to accept the provided 'climate change' explanation.
The weather has always changed - its not running faster now, or at least I don't have any reason to this it is. What is running faster is the level of information being provided on weather.
The article is not about climate change, it's about a drought. It doesn't try to present evidence for climate change.
> The weather has always changed
The plural of weather is not climate. Weather is an emergent effect of the climate. I don't have a collection of references to dump on you to demonstrate climate change because it's the scientific consensus, even within the United States. At this point, if you're scientifically literate enough to be on HN, you're scientifically literate enough to look up scientific explanations for why your intuitions and concerns about climate change maybe not being a thing after all are wrong. I'm not going to spend my finite lifetime trying to argue this with a person on the Internet, especially someone who might be religiously motivated.
Eg: the pictured carvings are on collapsed rock shelves, presumeably these were above normal river level when carved and in a two thousand year period the river has undercut the rock shelf and they've colapsed to below the usual river level.
In fact there are many possible reasons why your apparent smug bad faith poo poo climate change comment isn't well considered.
> the pictured carvings are on collapsed rock shelves, presumeably these were above normal river level when carved and in a two thousand year period the river has undercut the rock shelf and they've colapsed to below the usual river level.
You presume something that is not expressed in the article. There's nothing about the river undercutting the rock shelf and causing a collapse - that's an act of imagination on your part.
If you simply take out the political, environmental slant (out of the article, and your mind) and just look at what is stated, the most obvious conclusion is that every so often this river drops lower than usual. And that droughts, floods, etc have always been part of life on earth.
No idea, I was also downvoted by someone, it's not something I fuss about; you'd have to ask the downvoters.
> You presume something that is not expressed in the article.
It's right there in the pictures, layered strata, rock shelf, carvings on rock collapsed off of the shelf.
It's a pretty basic geological observation.
> I'm simply making the obvious observation - that the river got this low 2000 years ago,
That's a shallow conclusion, geologically speaking .. a leap of "can't think of anything else".
There are many possible reasons strata | water relationships might alter over the course of two thousand years. I've fleshed out one.
> take out the political, environmental slant (out of the article, and your mind)
There you go with the poor reasoning and shoddy conclusions based on projected assumption again.
My background is geophysics and my two comments are related to geology and timescales.
It isn't.
The article says:
> The rock carvings are not usually visible because they are covered by the waters of the Negro River, whose flow recorded its lowest level in 121 years last week.
There is no mention of "collapse", "strata" or "shelf". Are we looking at the same info?!?
The article ties climate change into this, when it says:
> According to experts, the dry season has worsened this year due to El Niño, an irregular climate pattern over the Pacific Ocean that disrupts normal weather, adding to the effect of climate change.
but there is no reason to think climate change has anything to do with this. The article itself also says:
> The rock carvings are not usually visible because they are covered by the waters of the Negro River, whose flow recorded its lowest level in 121 years last week.
ie 121 years ago, the river was recorded as being this low. ie before climate change.
For me this is another 'climate change' article, but is interesting as not all the claims the article makes can all be true.