Given the long-running chronic nature of the coastline change, I'm surprised this is being raised as an "emergency." Given that the principal cities of government and commerce in Louisiana would likely be extremely negatively affected by an honest root cause analysis (without the Mississippian waters, they won't work so well as ports), I'd bet the powers that be will play up climate change and ask for lots of money to be pointlessly dumped in the gulf.
Just because it's not a new situation doesn't mean it's not an emergency.
Having lived on the west bank, south of New Orleans, if there is anything I expect from Louisiana politicians, it's a keen pursuit of their personal, short-term self-interest. If they can each make $50,000 by dumping 50B in the Gulf, they vote "yea" before their sclerotic arteries see another hypertensive heartbeat.
* I might be uninformed on this point. If anyone knows about some poor money-handling from his office, feel free to correct me
"As the mouth advances southward and the river lengthens, the gradient declines, the current slows, and sediment builds up the bed. Eventually, it builds up so much that the river spills to one side."
I'm having a little trouble understanding it. What does it mean for the mouth of the river to move southward? Does sediment build up and create new land near what used to be the mouth?
Yes, exactly right. This is what the entire southern coast of Louisiana is.
Envision the river like a wiggling hose spewing out water and sediment. As the sediment piles up in one area, that eventually is no longer the easiest path to the Gulf, and the hose jigs off to one side, finding a better path. When it does, it leaves behind huge, flat, fertile floodplains, bayous, and marshes. Then the new course too eventually fills up and it picks a new course again, often one of the previous ones which is now relatively more appealing.
It's been doing that for thousands of years, wandering around the southern coast of Louisiana, piling up sediment that flowed south into the great bayous and swamps.
That was until the Mississippi River became a giant trade path and New Orleans its terminus. If the Mississippi were allowed to change course and allow most of its water to reach the Gulf by going through the Atchafalaya River, the ports of Baton Rouge and New Orleans would be left dry. Meanwhile, Morgan City would be washed into the Gulf.
To prevent that, the Army Corps of Engineers has, for decades built barriers along the sides of the Mississippi to force the water to stay in that channel. Those barriers in turn reduce friction and cause the River to flow faster and faster. That means that instead of building up sediment at the current end of the river, that stuff is getting washed farther out into the Gulf.
Meanwhile, the Atchafalaya Basin and other areas which would have gotten their "turn" and had their own deltas built up have been left to erode with little new sediment coming into them.
This has been a well-known problem for longer than most of us have been alive. In the early 90s, I did a science project as a kid on it. But New Orleans has never been known for its long term planning. ("Laissez les bon temps rouler.") See also: Hurricane Katrina, which was an infrastructure failure more than a weather disaster.
So here we are.
Prediction: The only intended goal of this measure is to suck more federal cash into Louisiana which will be used to line political pockets. No real substantive ecological or infrastructure changes will come of it.
Over time this creates an underwater mound that acts like a barrier to the current. So it deflects to one side or the other (or both). Then the sediment builds up in that new location until the current deflects again.
Over time this builds up a fan-shaped extension of the shoreline called a delta. The river might flow out through any number of channels through the delta, and it might change often.
The bigger the river, the bigger the delta. The Mississippi has a huge one... which New Orleans sits on top of.
Here is some more info.
At some point, the river is going to go back to the way it's supposed to be, Army Corps of Engineers be damned.
I don't think it's an either-or, though. The delta's generally pretty close to sea level (NOLA averages about 5ft below IIRC) as is, and when the seas rise, that means more Gulf and less Louisiana Delta. It'll just vanish quicker because we haven't been letting the river refresh the land for a few centuries.
Ultimately it becomes a question of how much money anyone is willing to dump into this; I wouldn't be that surprised to see the city I was born and raised in become either New Atlantis or New Venice in my lifetime.
EDIT: added source link
Your link doesn't support your claim. It says region has a higher-than-average relative change. The sea doesn't rise locally, but the ground can sink downward locally.
EDIT: I gave you an upvote for at least reading my source, thank you.
Nowhere have I claimed that the issue in LA is solely AGW.. only that the sizable portion of the problem that is caused by AGW is going to fall on deaf ears in that region because of the amount of oil money there.
Interesting tidbit: check out Wikipedia's timeline of party strength in Louisiana https://en.wikipedia.org/wiki/Political_party_strength_in_Lo...
2.) It is a combination of both. To put a number to it. 5–6 mm per year because of land subsidence and about 3 mm per year because of rising sea levels . So, about 30 % is due to rising sea levels, which is pretty significant in my opinion. Especially because this effect appears to be accelerating. These numbers seem small, but their effect is devastating.
3.) I have also lived in LA for a year :)
I'm not sure how that informs you on the cause.
What is that based on?
If the coastline changes were significantly caused by climate change/rising sea levels then the other Gulf coast states would have problems too. The link between the control humans have exerted on Louisiana rivers, additional artificial waterways and loss of coastline is fairly well established. If you'd like more information, the below medium work seems a reasonable introduction--I scanned over it and it seems to have the main points, some nice maps, doesn't avoid the problem of sea level changes, and has some human interest stuff:
How I wish that were true. Many problems of humanity are very predictable - climate change is an easy one, but probably we can all think of some problems in the tech industry - and yet people do it anyway. If it were true, we wouldn't fight any wars.
> If the coastline changes were significantly caused by climate change/rising sea levels then the other Gulf coast states would have problems too.
That's not how it works. There is a lot of coastline in the world and the effect of climate change varies greatly. Look at just the East Coast of the U.S.: Miami is facing big problems; New Jersey is seeing some problems; New York is not (yet). Holland, with its low-lying reclaimed land, is likely to face problems long before the cliffs of Dover.
There is a pretty wide literature on this also.
An incredible overview of the problem was written 20 years ago by John McPhee, as part of his book "The Control of Nature". Unfortunately, solving the problem in the long term means essentially undermining the entire economy of South Louisiana, and leaving the City of New Orleans destitute.
I served in Baton Rouge for 3 years and spent a lot of time on the Mississippi River. It's an extraordinary resource that much of America silently takes for granted. I with there were better solutions to save it and protect the people of Louisiana, but I don't feel like I have better answers to these questions that anyone else. It's a tough situation.
It's the parts of the delta which are fed by the Old Mississippi which are disappearing, and this is a totally natural process. The same river is what serves the port of New Orleans. The natural course of the river can only be temporarily stayed; it will find a way around the ORCS eventually. If the river is allowed to flow naturally, the majority of Southeast Louisiana, including New Orleans and Lake Ponchartrain, will disappear under the ocean.
I often cynically wonder if the true aim of some of these "emergencies" is boosting the local economy and adding jobs which presumably allows the governor to claim economic growth.
A lot of the Louisiana marshes have disappeared
This godly redneck can tell yearly temprature average fluctuations by 0.1 degrees, and using it as anecdotal proof that climate change is a fraud.
>"The climate is exactly the same as when I was a kid. Summers hot, winters cold."
We bear responsibility for our actions, me too.
Sounds like a terrible plan to me. Treating symptoms instead of the disease won't solve the problem. Just because we humans are "determined" doesn't mean fighting nature like this will be successful. I'm sure the locals will feel better about their politicians for a few years and probably just long enough to 'forget' until the next time this exact problem needs to be solved.
The true options in this case are: 1) prevent rising sea levels, 2) move away from the coast. Wasting money "rebuilding" barrier islands is just folly.
If someone has a broken bone, you want to fix that, but you'll also want to give them some painkillers if they're in a lot of pain.
It is actually your position which makes no sense. "Hey 4.6 million Louisianans, sure you're only 0.00063% of world population, but protecting yourself and your land from what the other 99.9994% do is futile, you must instead convince the other ~7.1 billion humans to change so your land will be safe!"
Sure, we could probably engineer building up the coastline with higher land to maintain the current coastline, but at what expense? At what point do we just decide that the coastline is moving inland and we should just follow suit?
All of these things occurred long before there was any discussion of global warming. The state can be blamed for excessive dredging and cutting canals, but hindsight is 20/20. Putting in river control structures was considered the right thing to do back then (Mississippi River levees were built in 1800s), and certainly was not only done by those in LA.
Now comes global warming/climate change and it complicates the picture even more. The solutions to all of these problems are not mutually exclusive. Coastal erosion exacerbates the problem of rising seas for coastal areas.
Another tricky factor is where people should and should not live. It's easy (and logical) to say people shouldn't live in areas prone to heavy flooding, and if they do they should accept the possibility of flooding as a consequence of their decision. For example, the lower 9th ward in New Orleans that was completely flooded in Hurricane Katrina was known to be susceptible to major flooding (it had happened at least once before in the 1920's or thereabouts). The majority of the people that live there are poor, their families have been there all their lives, and most probably don't have the means to pick up and go someplace else.
Of course LA residents are responsible for many of these things that have occurred over very long periods of time. But when you consider the full story and where they are today, it's not like the problems in the coastal areas are only the result of global warming.
To suddenly be concerned and have a change of heart about one historical cause of damage to your coast (dredging, etc), but completely ignore for ideological reasons another major ongoing cause that will make any fixes you do to the prior destruction pointless, is, well, bad, dumb, stupid? What should we call it?
Unfortunately that's not practical for most people. Also, we overinvest in our highways and cars because there seems to be almost no collective will to build a national transportation network beyond that.
And I don't want to completely rag on one side of the political spectrum because if we could build a whole bunch more nuclear reactors we could solve a lot of this very quickly in the short-term.
Finally we could all eat a whole lot less beef. But I don't see any of this happening even if the current crop of leaders is kicked out the next round of elections.
There are solutions to a lot of the problems we face here in America but many of them are going to annoy both sides of the political fence differently therefore they're not going to happen. I'd love to see that change but I'm not holding my breath.
(Although the total difference in carbon emissions from diet are subsumed by the emissions of one cross-country plane flight  , so if you're concerned about optimizing the inner loop, that's what you, as a typical reader of this site, probably need to look at.)
A small number of concerned and informed individuals trying to reduce their own carbon footprint is pointless. There's no way it pencils out to anything even vaguely worthwhile, even if they went to extremes. Even if they committed suicide and left their entire inheritance to carbon reductions it simply doesn't add up.
On the other hand, a carbon tax that introduces virtually imperceptible changes across the entire economy of the world, would actually fix the problem.
So yes we can do both, but one makes effectively no difference, even if it feels like a big deal to the person doing it.
I fear this is the thing that'll prevent any real progress toward managing climate change. While everyone will accept using canvas bags instead of plastic, they also want to keep the luxuries they've become accustomed to.
If you're wondering "why not use targeted legislative mandates instead of carbon taxes?", I'd say that taxes have an advantage in that they're harder to game and need fewer adjustments over time. For example, if you introduce a mandate to make cars more fuel efficient, manufacturers will tweak the vehicles they sell so they are no longer "cars" but some legislatively distinct class of vehicle, and people who like gas guzzlers will just drive those tweaked vehicles. But if instead there's just a carbon tax on fuel it's a lot harder to game your way around the legislative intent.
 Assuming that the balance between just paying the tax and evading the tax still favors paying it. You don't want to impose a $20/pack tax and find that you've just given organized crime a major boost.
There's a whole lot of businesses where that's relatively easy, but since carbon is effectively free, they'll happily squander it for no real gain.
Obviously, subsidies to cattle ranchers are bad. But whether they are funded from increased debt or a carbon tax does not affect their badness.
Rising sea level is the _result_ of Mr.Trump swearing in 3 months back?, I understand this forum is echo chamber for anti trump discussions, but you are reaching so far here.
Most peoples behavior is mainly due to capitalism, all of them, multiple generations, were raised watching ads which gets them to buy new "stuff" all the time, so "stuff" gets made/sold to keep the cycle going.
Internet and TV ads are storefront's of this "stuff". Instead of using your personal dislike of few people and spreading the message to blame them for climate change, you could get politics/personal feelings out of it, and tell people not to buy so much "stuff".
In comparing abstinence-only programs with comprehensive sex education, comprehensive sex education was associated with a 50% lower risk of teen pregnancy.
And it's a finger in Putin's eye too!
It is not as if we just lose a bit of beach, if sea levels rise then everything at the new level that can be sought by water through rivers or otherwise will be under water. Not Atlantis style, but no longer habitable by cities as we currently build them.
What's more, the coastline going missing is but one symptom. Weather patterns are set to get more erratic and extreme which will cause significant damage and loss of life continuously for the forseeable future.
As we are being reactive rather than proactive in this matter, it will likely take significant disasters before anyone begins to make the changes even once weather begins to worsen and cities begin to sink.
The argument about eratic weather is not very good. I have heard multible storm experts say that they can really not model the overall changes. There might be more and bigger storms in one area but less in another. I really think that if anybody is pretending he can predict storm frequence in 50 years is just confirming their bias.
It really doesn't, when you have 7 billion people working hard to make the climate change as quickly as they can, and unfortunately we've already spent half a century knowing about the problem and doing nothing. The whole point is that we've changed major climatic change from a geological time frame to a human-scale time frame.
You'll see major upheaval as a result of climate change in your lifetime, and your children will see much worse.
The storm predictions, incidentally, are quite safe - no chance of them being wrong. Higher sea surface temperatures will absolutely lead to more frequent and violent storms; there's no chance at all of that not happening.
One to two generations is a long time.
I have listen to interviews with storm experts and it seems that they are not quite so sure about is then you. That said, it seems that compared to the world economy and what some people suggest, the damage from storms seems quite low.
Are there any more concrete numbers about how much destruction is expected from global warming? It's not infinite and it must be less than some amount of money.