Receding glacier causes Canadian river to vanish in four days • Hacker News Board

Re: Receding glacier causes Canadian river to vanish in four days

#41

Post by nostrademons » Mon, Apr 17, 2017, 6:10 PM UTC

OliverJones wrote: post #4

There's another possibility of the event this author calls "river piracy." The Mississippi river is chronically at risk of being grabbed by the Atchafalaya River. John McPhee wrote about this in 1987. http://www.newyorker.com/magazine/1987/02/23/atchafalaya

The Salton Sea is also an example. Its current incarnation was formed through accidental diversion of the Colorado River through an irrigation canal, and its continued existence is sustained through agricultural runoff from diverted Colorado River water. The Colorado River no longer reaches the Gulf of Baja in most years.

http://www.water.ca.gov/saltonsea/documents/history.cfm

Re: Receding glacier causes Canadian river to vanish in four days

#42

Post by dragonwriter » Mon, Apr 17, 2017, 6:19 PM UTC

nostrademons wrote: post #41

OliverJones wrote: post #4

There's another possibility of the event this author calls "river piracy." The Mississippi river is chronically at risk of being grabbed by the Atchafalaya River. John McPhee wrote about this in 1987. http://www.newyorker.com/magazine/1987/02/23/atchafalaya

The Salton Sea is also an example. Its current incarnation was formed through accidental diversion of the Colorado River through an irrigation canal, and its continued existence is sustained through agricultural runoff from diverted Colorado River water. The Colorado River no longer reaches the Gulf of Baja in most years. http://www.water.ca.gov/saltonsea/documents/history.cfm

> The Colorado River no longer reaches the Gulf of Baja in most years.

As your source gets correct, the body of water in question is the Gulf of California, not the "Gulf of Baja".

Re: Receding glacier causes Canadian river to vanish in four days

#43

Post by drt1245 » Mon, Apr 17, 2017, 6:32 PM UTC

Almaviva wrote: post #33

acover wrote: post #31

Earlier quoted context omitted.

The statement should be there is a 99.5% chance that we correctly rejected the null hypothesis. I agree it isn't careful wording. Thanks.

I played a game of Monopoly where I started with a roll of 12. There was a 97% chance I correctly rejected the hypothesis that the dice were fair. Maybe this is true in some sense? But it's still somewhere between misleading and nonsensical to say.

I think a better analogy is that it's like having many pairs of dice, and rolling each pair in turn until you get a roll of 12. Then concluding "this particular pair of dice must be loaded".

Presumably, the researchers did not select rivers at random to study, they selected this river in particular because of the changes it is undergoing.

Re: Receding glacier causes Canadian river to vanish in four days

#44

Post by narrowrail » Mon, Apr 17, 2017, 6:40 PM UTC

dragonwriter wrote: post #42

nostrademons wrote: post #41

Earlier quoted context omitted.

The Salton Sea is also an example. Its current incarnation was formed through accidental diversion of the Colorado River through an irrigation canal, and its continued existence is sustained through agricultural runoff from diverted Colorado River water. The Colorado River no longer reaches the Gulf of Baja in most years. http://www.water.ca.gov/saltonsea/documents/history.cfm

> The Colorado River no longer reaches the Gulf of Baja in most years. As your source gets correct, the body of water in question is the Gulf of California , not the "Gulf of Baja".

O/T: The Baja peninsula is great for camping except June-Aug, and I've spent ~15 weeks along [what we called] the Sea of Cortez. So, I went to wikipedia and apparently, it's gotten somewhat political. I can see both sides, but for other folks who like to lurk talk pages (the first thread is a discussion about what to call this body of water):

https://en.wikipedia.org/wiki/Talk:Gulf_of_California

Re: Receding glacier causes Canadian river to vanish in four days

#45

Post by Almaviva » Mon, Apr 17, 2017, 6:49 PM UTC

acover wrote: post #37

Almaviva wrote: post #33

Earlier quoted context omitted.

I played a game of Monopoly where I started with a roll of 12. There was a 97% chance I correctly rejected the hypothesis that the dice were fair. Maybe this is true in some sense? But it's still somewhere between misleading and nonsensical to say.

Yes, I agree that p-value tests have flaws. If you look at the data to determine your hypothesis it's easy to overfit. Bayes factor appear to solve this issue. I disagree that this is a basic education issue. It is a lack of agreement among scientists as to what statistical analysis is appropriate.

"So it’s 99.5% that it occurred due to warming over the industrial era"

There are at least a couple of statistical fallacies in this conclusion. And there isn't a lack of agreement about that.

One problem with p-value tests is precisely that people misunderstand what the p-value means, which is where basic education comes in. It could save people from believing a lot of things they shouldn't. (Like many health and fitness crazes over the last generation, for instance) Or at the very least, we could train science journalists.

Re: Receding glacier causes Canadian river to vanish in four days

#46

Post by titojankowski » Mon, Apr 17, 2017, 6:49 PM UTC

nickbauman wrote: post #40

titojankowski wrote: post #35

Sweet, so what should we build to change this? Giant carbon-sucking machines, cube-sats pointed at glaciers? (planet labs is doing cool stuff in this space, including a project to count every tree on Earth every day). Solutions welcome!

Plant trees. Lots of them.

Anyone working on new tech to plant trees more efficiently? Or engineering trees optimized for carbon sequestration?

Re: Receding glacier causes Canadian river to vanish in four days

#47

Post by titojankowski » Mon, Apr 17, 2017, 6:51 PM UTC

ocschwar wrote: post #39

titojankowski wrote: post #35

Sweet, so what should we build to change this? Giant carbon-sucking machines, cube-sats pointed at glaciers? (planet labs is doing cool stuff in this space, including a project to count every tree on Earth every day). Solutions welcome!

Train tracks in place of highways, for starters. Windmills and panels everywhere.

Yea totally! Does Hyperloop count as train tracks? I wonder what upcoming inventions in windmills look like...

Re: Receding glacier causes Canadian river to vanish in four days

#48

Post by roughcoat » Mon, Apr 17, 2017, 7:08 PM UTC

titojankowski wrote: post #35

Sweet, so what should we build to change this? Giant carbon-sucking machines, cube-sats pointed at glaciers? (planet labs is doing cool stuff in this space, including a project to count every tree on Earth every day). Solutions welcome!

We should do nothing, because while interesting, this is a nonevent. Parts of that article are wildly exaggerated or outright incorrect, trying to make this sound like some big deal. It's really not.

Sometimes in nature, things happen quickly. Look up glacial surge, for example. Just because a river dried up basically overnight because it got beheaded, it doesn't mean there's some global catastrophe playing out. It just means the glacier receded to a point where the terrain favored the other branch.

Re: Receding glacier causes Canadian river to vanish in four days

#49

Post by kensai » Mon, Apr 17, 2017, 7:12 PM UTC

inetknght wrote: post #9

I'm thinking you're commenting on the wrong article ;) Did you mean -> https://news.ycombinator.com/item?id=14131759

Guys, I seriously do not know wtf happened. I never opened this "Receding glacier" thread. I was commenting on the Intel thread and my comment somehow ended up here. I got aware of it because of all these negative points which came quite unexpected.

Could it have been a glitch in the database?

Re: Receding glacier causes Canadian river to vanish in four days

#50

Post by cjensen » Mon, Apr 17, 2017, 7:14 PM UTC

nostrademons wrote: post #41

OliverJones wrote: post #4

There's another possibility of the event this author calls "river piracy." The Mississippi river is chronically at risk of being grabbed by the Atchafalaya River. John McPhee wrote about this in 1987. http://www.newyorker.com/magazine/1987/02/23/atchafalaya

The Salton Sea is also an example. Its current incarnation was formed through accidental diversion of the Colorado River through an irrigation canal, and its continued existence is sustained through agricultural runoff from diverted Colorado River water. The Colorado River no longer reaches the Gulf of Baja in most years. http://www.water.ca.gov/saltonsea/documents/history.cfm

If you check out Google Maps, you'll see that the Colorado does in fact reach the Gulf of California. Not an impressive amount, but some. Enough that water clarity in the north part of the gulf is significantly worse than the south (a few feet versus tens of feet).