U.S. East Coast a Hotspot of Sea-Level Rise

Harperdog writes "Nature just published this study of sea-level rise and how global warming does not force the it to happen everywhere at the same rate. Interesting stuff about what, exactly, contributes to this uneven rise, and how the East Coast of the U.S., which used to have a relatively low sea level, is now a hotspot in that the sea level there is rising faster than elsewhere."

Comments

It has nothing to do with global warming

[Overzeetop]

Global warming is myth. The sea levels are rising on the east coast of the US because all the fat Americans are causing a shift in mass distribution and locally higher gravitational forces.

The nurse is here with my medication...brb

Re:It has nothing to do with global warming

[pixelpusher220]

but in theory shouldn't the entire ocean level rise and fall together?

"In theory there's no difference between theory and reality...in reality it's the other way around" ;-)

One of the points made was that salinity levels, localized temperatures and other factors can play regional factors. If a current is flooding in warmer water to an ocean and it goes up by even a little bit there will be a coinciding increase in the volume of that ocean water. If salinity changes, I'm assuming (I don't know) there is likewise a change in volume.

Now, sure normal temperature and saturation processes will return that to equilibrium eventually, but how long does it take to do that on a scale of an ocean? Could be decades assuming the ongoing current input continues (even without change).

I also thought parts of the east coast, mid-atlantic I think, were sinking in response to the mid-west area rebounding back from ice age depression. Think about a table tilting with a pivot point somewhere in the middle, as one end goes up the other goes down.

Also consider that gravity isn't uniform. It does fluxuate minutely from place to place. You obviously don't notice this day to day since it's so small, but again with the scale of an ocean it might be significant enough to cause a lower amount of compression of the water column. And factor in that maybe a gravitational difference is related to how the molten core of the earth is orientated and being molten might change from time to time.

I don't know any of these things specifically but those are just off the cuff possible reasons that might explain why ocean levels would be different locally.

Re:It has nothing to do with global warming

[AdamHaun]

I understand sea levels fluctuate (tides, etc), but in theory shouldn't the entire ocean level rise and fall together?

I don't think so. Water doesn't move that quickly (think waves on a beach), and the sun, tides, and seasonal temperature changes are all adding energy. There are already ocean currents that flow continuously throughout the year. I don't see why there couldn't be a sustained force pushing up sea levels along the east coast.

But we don't have to guess -- the abstract of the article tell us:

Climate warming does not force sea-level rise (SLR) at the same rate everywhere. Rather, there are spatial variations of SLR superimposed on a global average rise. These variations are forced by dynamic processes, arising from circulation and variations in temperature and/or salinity, and by static equilibrium processes, arising from mass redistributions changing gravity and the Earth’s rotation and shape. These sea-level variations form unique spatial patterns, yet there are very few observations verifying predicted patterns or fingerprints. Here, we present evidence of recently accelerated SLR in a unique 1,000-km-long hotspot on the highly populated North American Atlantic coast north of Cape Hatteras and show that it is consistent with a modelled fingerprint of dynamic SLR. Between 1950–1979 and 1980–2009, SLR rate increases in this northeast hotspot were ~ 3–4 times higher than the global average. Modelled dynamic plus steric SLR by 2100 at New York City ranges with Intergovernmental Panel on Climate Change scenario from 36 to 51cm (ref. 3); lower emission scenarios project 24–36cm (ref. 7). Extrapolations from data herein range from 20 to 29cm. SLR superimposed on storm surge, wave run-up and set-up will increase the vulnerability of coastal cities to flooding, and beaches and wetlands to deterioration.

So no, even in theory the entire ocean does not rise and fall to exactly the same level.

Re:It has nothing to do with global warming

[Rei]

The concept you're having trouble with is known as hysteresis - that is, to oversimplify, a delay between a cause and its effect. In this case, "cause" can be something like "add water to ocean" and effect can be something like "water gets evenly distributed around the globe". Yes, of course gravity wants to equalize out the heights of all of the Earth's oceans (although it hates it when I anthropomorphize it ;) ). But that takes time; it's not instant, no more than is it instant that the water in a mountain river after a rain ends up in the ocean, even though that's where gravity is going to take it eventually. Meanwhile, a localized region can have all kinds of various inputs (such as rivers) and outputs (such as evaporation) which act on it fast enough to be more than noise against the rate at which gravity moves things toward equalization.

Re:It has nothing to do with global warming

[thrich81]

pixelpusher got most of it, but in a simplified nutshell -- the oceans are not static bowls of water - even neglecting tides, they have currents and winds pushing the water around. Steady currents and winds can push the water up against the continents and create semi-permanent "hills" and "valleys" of water which become part of the "normal" sea level for that area. If the currents change due to climate or any other reason then the local sea level there can have a change not reflected globally.

Re:It has nothing to do with global warming

[JTsyo]

Then why do they have locks on the Panama Canal, huh?
A search shows that the locks are actually for the mountain lakes that link the two oceans which are higher than sea level. The actual difference is only 20cm.

Sea level is about 20 cm higher on the Pacific side than the Atlantic due to the water being less dense on the Pacific side, on average, and due to the prevailing weather and ocean conditions. Such sea level differences are common across many short sections of land dividing ocean basins. The 20 cm difference is determined by geodetic levelling from one side to the other. This levelling follows a 'level' surface which will be parallel to the geoid (see FAQ #1). The 20 cm difference at Panama is not unique. There are similar 'jumps' elsewhere e.g. Skagerrak, Indonesian straits.

Re:It has nothing to do with global warming

[cayenne8]

New Orleans was built below sea level . . . I dont know of any other metropolotian cities built beloew sea level.

True..but then again...it was almost 300 years ago, before GPS and all the nifty tech tools we have now...and it was built where it is due to the important location, near the mouth of the MS river...hence, why the city is so important. It was just a bit disheartening to hear all the people, many from the NE saying "they shouldn't have built there, just leave, not worth saving...etc".

I guess many of the same people neglect the facts that NYC has pretty much the exact same disaster scenario, and are WAY overdue for a hurricane there...NYC can get hit by a medium level hurricane and if in the right place, kiss it goodbye.

Will people say it isn't worth saving, and they shouldn't have been built there too?

On a larger scale...do we say the same about the midwest in the country..when in recent years, flooding has knocked down cities there?

What about the panhandle area...prone to tornadoes annually? What about out west, where they seem to have annual problems with fires and mudslides....?

Seems like most of the country comes around for those areas...yet, NOLA, with its importance for energy and a great deal of commerce (not to mention the cultural influences on the whole US)....gets brushed off more easily.

Sorry...I still have some soft spots for the callous comments on this forum and other places when it hit.

PS. I believe Amsterdam is another city built far below sea level....and they had no problems doing what it took to built defenses against the sea for that little town....

Re:It has nothing to do with global warming

[GameboyRMH]

If I was a supervillain I'd destroy all the locks from the Pacific to the Atlantic just to see what happens. Muahahahaha! >:-)

Re:It has nothing to do with global warming

[CaptainLugnuts]

The other things that people don't understand is that the original 'New Orleans' city was build ABOVE sea level. The French Quarter is almost 20ft above sea level. It just all the newer development from the last century is in a shitty location. Below sea level shouldn't be rebuilt and the stuff above sea level wasn't flooded much.

Re:It has nothing to do with global warming

[colinrichardday]

Then why do they have locks on the Panama Canal, huh?

Because the Isthmus of Panama isn't flat.

Re:It has nothing to do with global warming

[Anonymous Coward]

The locks are all that's currently holding South America to North America. South America would spin off from the effect of ocean tides (Chile would get much chillier), and crash into Antarctica, killing millions of hapless penguins, but potentially providing a great relocation area for the dwindling polar bear population.

Re:It has nothing to do with global warming

[pixelpusher220]

Actually New Orleans itself wasn't built below sea level. The French Quarter survived Katrina just fine (obviously relatively 'fine') but it didn't flood. New Orleans was EXPANDED into below sea level areas, but it wasn't built there from scratch

Re:It has nothing to do with global warming

[pixelpusher220]

To your point, there are plenty of places on the East Coast that shouldn't be built on...like the barrier islands of North Carolina and the entire beachfront of South Carolina.

We tax payers subsidize those homes because they are given low cost insurance compared to what it would actually cost to insure homes that have a high likelihood of being destroyed every 10 years or so. There are calls to not allow new construction but they aren't terribly widespread, just like there wasn't terribly widespread complaints about New Orleans other than 'hey it might not be smart...'.

But none of those places need 'active' defenses like the low places in New Orleans. Everything is 'above' sea level.

Re:It has nothing to do with global warming

[steelfood]

Believe it or not, NYC is on fairly high ground. Staten Island, in particular, has hills that are as high as several hundred feet above sea level. Central Park itself is something like forty feet above sea level, and most of Manhattan is fairly high. This is the same with most parts of Brooklyn, Queens, and The Bronx.

Here's the thing about Manhattan and hurricanes. It's really, really well protected. Any storm surge would have to make its way past Staten Island and Brooklyn (through the Verizano Narrows) to get to Manhattan. New York Harbor is the only large body of water that's directly up against Manhattan, and it's just not that large.

There's another thing about Manhattan. It's sitting on some crazy hard bedrock. Manhattan Schist, I believe it's called, some of the oldest, hardest rock in the world (it doesn't seem to exist in most of the surrounding area and even in parts of Manhattan). Which means that the island isn't getting washed away anytime soon by a hurricane either. The smaller inhabited islands are mostly situated on the East and Harlem rivers, which are tidal, and thus wouldn't be in any danger of being washed away either.

Overall, the biggest areas of concern would be the outer boroughs and possibly some of the islands in the harbor, while the area of least concern would be Manhattan island itself. South Brooklyn, south Queens (Far Rockaways), and the eastern part of Staten Island are all at risk of major flooding. But the rest of New York City? Nah. It's about the safest place from a hurricane you can get, safer even than farther inland, where there's a greater chance of the local bodies of water (lakes, rivers, streams, etc.) overflowing and washing out roads, bridges, and even entire houses. Look at what happened during Irene.

Now, Long Island and New Jersey is a different story, especially the southern shore of Long Island, which has the highest chance of a storm surge. They usually fare much, much worse than the city proper, but that's largely due to the population density or lack thereof.

Re:It has nothing to do with global warming

[unitron]

"I don't understand how sea level can rise (or fall) in any real way in just a certain defined area...

I understand sea levels fluctuate (tides, etc), but in theory shouldn't the entire ocean level rise and fall together?"

You obviously fail to appreciate the full power and majesty of the Legislature of the Great State of North Carolina.

We've made sea level rise illegal here.

Obviously it has to increase more greatly elsewhere if the amount of water increases.

Question

[MyLongNickName]

I'm not an expert, I've tried to research this, but I find contradictory information which I assume is related to the political nature of the issue. In a nutshell, why can't we use GPS to determine the actual impact of rising sea levels? It would seem to me to be very elementary to place some sort of beacon in a few spots to determine what the actual sea level is. Granted, you might have to wait for calm waters, but nothing about this seems difficult.

Re:Question

[Baloroth]

GPS is nowhere near accurate enough. You are talking about yearly see-level variations of a handful of millimeters a year. GPS is only accurate to a few centimeters, at best, with maximum augmentation (practically the error is in the range of 10 cm or more). Nowhere near good enough.

Re:Question

[geekmux]

I'm not an expert, I've tried to research this, but I find contradictory information which I assume is related to the political nature of the issue. In a nutshell, why can't we use GPS to determine the actual impact of rising sea levels? It would seem to me to be very elementary to place some sort of beacon in a few spots to determine what the actual sea level is. Granted, you might have to wait for calm waters, but nothing about this seems difficult.

Yes, you're right, nothing about this does seem difficult. All we have to do is remove the political influence driven by greed.

Wow. I just realized I asked for the impossible. No wonder this has gone nowhere.

Re:Question

[ackthpt]

GPS is nowhere near accurate enough. You are talking about yearly see-level variations of a handful of millimeters a year. GPS is only accurate to a few centimeters, at best, with maximum augmentation (practically the error is in the range of 10 cm or more). Nowhere near good enough.

One of the fun things about chasing around with a GPSr, looking for Geodetic Survey markers is you learn a bit about them and the equipment used to place them. How did they get these elevations so darn exact? Well, pull your heads out of your digital-electronic-technology-saviour-for-everything sand pile and realise a very good quality spring with a reference weight and scale can tell you far more accurately what your elevation is, based upon readings taken at nearby sea level. 100 years ago they could tell you within 1 inch the elevation of a marker and to the best of satellite measure, these are still very accurate (using the sort of equipment they have at their disposal.

So not likely to be so much a case of local gravity fluctuation, try thinking what else could explain it? More fresh water introduced from Greenland Ice cap and Polar melting? Given time it will flow around the continents, but if the melt is happening fast enough that which has flowed to the Pacific and Southerly Atlantic is being replaced at a similar, if not accelating rate.

Re:Question

[Quiet_Desperation]

How about a test for sociopathy (or whatever they're calling it now) before being declared fit to run for public office?

Nah, the sociopaths would claim discrimination. And people would agree with them. Never mind.

Re:Question

[Antipater]

Humans are the only animal known to destroy their own habitat.

I laughed, but then I got a creeping suspicion you were actually serious. Why do people always say this? It's just flat-out wrong.

Re:Question

[ceoyoyo]

"Humans are the only animal known to destroy their own habitat."

The Matrix is not a reliable source for information about ecology and comparative zoology.

Re:Question

[Grishnakh]

You're right, it is wrong. Lots of animals will overfeed their habitat if their population grows too large; of course, then they have a famine, their population dwindles, and the problem is corrected. Humans, OTOH, invent new ways to grow crops to increase yields or find some other way of allowing an ever-increasing population.

However, what is true is that humans are the only animal known to destroy their own habitat, while being intelligent enough to understand what they're doing. A herd of overpopulated wild deer eating all the available food probably don't actually understand the long-term effects of what they're doing.

Re:Question

[dargaud]

How about a test for sociopathy (or whatever they're calling it now) before being declared fit to run for public office?

Very simple. If you want the job, you're a sociopath.

This was already known at the time of the Ancient Greeks. One famed philosopher stated that nobody who wants the job of public office should be allowed to have it.

Good thing I live in North Carolina

[GungaDan]

where that kind of shit is illegal!

http://blogs.scientificamerican.com/plugged-in/2012/05/30/nc-makes-sea-level-rise-illegal/

Re:Good thing I live in North Carolina

[cpu6502]

Wow way to twist a reasonable law into a MSNBC-style rant by Ed Schultz.

All the law says is that homes will not be eligible for government-paid flood insurance if they are not in the zones that previously recorded flooding (since 1900). Why? Because North Carolina can't afford to provide free insurance to nearly the whole state. MOST people comprehend that the money supply has limits..... others like George "duh" Bush drive-up 10 trillion dollar debts.

Story on the paper

[ananyo]

Nature also has a story on the research for those seeking an overview.

Slashdot. Still beating the dead horse...

[Mr. Firewall]

...of CAGW. It's been, what, 2 1/2 years now since it was exposed as a hoax?

Pay for your own mistakes!

[na1led]

If you put a house right on or near the beach and it gets washed away, don't make the rest of us pay for it!

Thought rising was caused by water dumping

[cpu6502]

I thought a report was just published that the ocean levels are rising because of humans sucking water out of underground reservoirs and dumping in into the ocean,

King Canute

[Roger W Moore]

Sorry but legislating against the sea rising was already tried 1,000 years ago. It didn't work then either.

It's OK

[srussia]

According to TFA, the sea-level is receding on various spots on the west coast (Seattle, San Francisco). Looks like the country tilting right!

Re:It's OK

[Comboman]

Looks like the country tilting right!

I blame Fox News.

Re:It's OK

[riverat1]

Sea level may appear to be receding in places on the west coast due to the land being pushed up by the subduction zone off the coast. When the big subduction zone earthquake hits they'll drop back down 4 or 5 feet in an instant.

How to differientiate sources.

[Anonymous Coward]

I've tried to research this, but I find contradictory information which I assume is related to the political nature of the issue. In a nutshell,...

Perhaps you should be a bit more discriminate in your sources when you do research.

Here's some help: ignore Talk Radio Hosts, Fox News , and industry backed Think Tanks with "advisers" who have scientific PhDs in everything BUT Climate Science. (ALL of whom tell half truths and lies ).

That should make things a bit more clear.

Glub!

[Ungrounded Lightning]

~Oh, disaster! The sea level rise on the east coast might be TRIPLE that of the world average in our previous prediction. It might rise 14 to 20 inches over the next century! That's as much as a whole 2 tenths of an inch per year! They're all going to drown.~

Somehow I'm not impressed. While it might be nice to see New York and Washington become awash, this is a number of orders of magnitude too low to be useful.

Compare this to Venice (which still seems to be doing very well, thank you.)

satallite altimeter better for GLOBAL sea level

[peter303]

The TOPEX satellite has been measuring the whole ocean surface for 18 years and found it has risen about two inches at a very even rate of increase. Various scientists attribute about 80% of this to thermal expansion of warmer oceans and the rest to melting ice. Although the ocean surface temperature appears to to have gone up a bit, that may bot be indicative of the total thickness of the ocean. The best proposed temperature experiment- measuring the speed of sound half around the world- has been tied in environmental litigation. The sound source might hurt marine animals hearing is the claim. The sound source is not an explosion, but a distinctive wide-frequency chirp that can be integrated at the receivers over a period of hours. This experiment would be repeated every few years to look for changes in sound travel time, which would show temperature changes of water velocity.

Local tidal guides or GPS would be affected by vagrancies of local land level changes, which are rather common. This ranges from ice age rebound, sediment deposition loading, sediment erosion unloading, and even a bit of tectonic rise in the Appalachians. And this Nature article says the pattern of water circulation in a region can change locally too, contribution to an apparent LOCAL sea level change.

Re:Or maybe

[ackthpt]

Perhaps the east coast is sinking, relative to the rest of the world?

I'm still here in California, waiting for the Big One .. when all the land East of the San Andreas Fault slides off into the Atlantic.

|o)

Continental Shft

[linuxrunner]

Last I check, we're on these floating masses called "plates" and they actually move around, shift and stuff. Some get pushed under others, etc. Wouldn't that simply explain why one section might be seeing a change in sea level and not another?

Lastly, why does everyone panic when the world changes a little? We have fish fossils on mountain tops, dinosaur bones, the land mass used to be one large hunk of land. Mountains were created through plate shifts and valleys and hills formed by ice ages. So, knowing all this... Where do we come off panicking when there is the slightest change from the prior year? Do folks expect the world to sit stagnant as we know if forever and ever, and all the history of the world be damned? It will never change again?

Seems like these things are more politically motivated and looking for someone to blame rather than someone rationally just standing up and saying "Well, what did you think was going to happen? The same thing year after year? Had to change sometime..."

Here's a nickel, kid . . .

[StefanJ]

. . . go get yourself some new talking points.

Seriously, the old "Oh, well, things have changed in the past, so what's the worry?" canard?

The processes you describe took place over millions of years.

We're talking relatively drastic changes, over the course of decades, on a highly developed area of an increasingly crowded and interdependent planet.

If a drunk driver speeding through a red light ran over your dog or your kid, would you accept the driver saying, "Look, people die in accidents all the time. In seventy years, a trivial fraction of the age of the Earth, your kid would likely be dead anyway. Calm down and accept change as a normal part of life. And anyway, can you really prove it was my car that killed your kid? Maybe you wiped his blood on my bumper so you could sue me, and infringe on my right to drink and drive!"

Re:Is water no longer a liquid?

[daq man]

Yes you are missing something. If the sea water was of exactly the same density, which varies with salinity and temperature, and was dead calm, and the rock under the sea was a uniform density so gravity was the same everywhere then what you say is true. Also the sea bed rises and falls too. Just off the East coast shore, we have the Gulf Stream which is a flow of warm, and therefore less dense water moving North. Not only is it moving North but the East coast juts out and it has to flow around the coast. So, the sea level at Cape Hatteras (where the East coast juts out the most) is a complicated combination of the mean sea level, the mean gravitational pull at that point, the flow of the Gulf Stream and probably 1001 other things.

What the article is saying is that MEASUREMENTS show that the sea level there has risen three times more than the world average. If you subtract from that the known motion of the sea bed and various other known contributions to the rise you are left with something unusual that needs explaining. The best explanation that fits the facts is that the difference is due to the Gulf Stream. That is particularly worrying because any change in the Gulf Stream is a big deal.

sea level change at New York from 1856 to 2006

[suppo]

Data point: Mean sea level at various harbors has been tracked since the mid 1800s. Sea level rise at New York since 1856 has been quite linear at +2.66 mm/yr (0.91 feet per hundred years).
Link:
http://co-ops.nos.noaa.gov/sltrends/sltrends_station.shtml?stnid=8518750%20The%20Battery,%20NY

Scientific Proof at Last

[n2hightech]

For the ocean to be rising higher only on the east coast there must be some attractive force acting to cause the water to flow from the rest of the world to accumulate on the east coast of the US. Gravitational surveys show no gravitational anomalies that could explain this. Prevailing winds are usually from the west in this area which would tend to push the water off shore. No evidence has been found to support the possibility that slower off shore wind speed could be allowing more water to flow back to shore. None of these reports show evidence of subduction due to plate movement. That leaves only one possible cause this is 100% scientific absolute proof with no other cause possible that Washington DC SUCKS!!.

Re:On Centimeters and Willful Ignorance

[linuxrunner]

Yep. I'm not a geologist but I don't think "floating masses" is a particularly great analogy. Gravity does have an effect on them at that point but once you hit turtles, I wouldn't bother digging any deeper.

Everest alone is growing ~ 2 inches every year. That's just there. So yeah... A geologist you are not.

Re:Slashdot. Still beating the dead horse...

[rrohbeck]

No, it was an evil plot by murderers and terrorists! Didn't you see the Heartland billboard?

Re:And The Proposed Solution Will Be...

[BlueStrat]

What does your hatred for sympathy and human collaboration have to do with the reality of rising oceans?

What does an emotional reaction like sympathy have to do with supposedly-rising local sea levels and increasing government power and taxation? I prefer logic and science myself, but I guess YMMV.

Strat

accidentally

[Kozz]

Quoth TFS:

Nature just published this study of sea-level rise and how global warming does not force the it to happen everywhere at the same rate.

Imagine what would happen if the editors accidentally the whole summary?

Re:And The Proposed Solution Will Be...

[BlueStrat]

Yeah, taking power away from the government (which by definition gives it to corporations

How is NOT taking power and wealth away from PEOPLE giving it to corporations?

Your logic fails.

Strat

GRACE

[TapeCutter]

The Earth's gravitational field is in constant flux, the exact shape of the field drives the ocean currents. This is where GRACE comes in. Since it's basic data about a basic force that controls so much of what happens on the surface lots of other interesting (and possibly useful) things can be messured, eg: changes in groundwater during a drought, the mass of winter snowfalls, seasonal vs non-seasonal changes in parmenant ice caps.