NASA satellites detect pothole on road to higher seas

Aug 24, 2011 By Alan Buis
The red line in this image shows the long-term increase in global sea level since satellite altimeters began measuring it in the early 1990s. Since then, sea level has risen by a little more than an inch each decade, or about 3 millimeters per year. While most years have recorded a rise in global sea level, the recent drop of nearly a quarter of an inch, or half a centimeter, is attributable to the switch from El Niño to La Niña conditions in the Pacific. The insets show sea level changes in the Pacific Ocean caused by the recent El Niño and La Niña (see http://sealevel.jpl.nasa.gov/science/elninopdo for more information on these images). Credit: S. Nerem, University of Colorado

Like mercury in a thermometer, ocean waters expand as they warm. This, along with melting glaciers and ice sheets in Greenland and Antarctica, drives sea levels higher over the long term. For the past 18 years, the U.S./French Jason-1, Jason-2 and Topex/Poseidon spacecraft have been monitoring the gradual rise of the world's ocean in response to global warming.

While the rise of the global ocean has been remarkably steady for most of this time, every once in a while, sea level rise hits a speed bump. This past year, it's been more like a pothole: between last summer and this one, global sea level actually fell by about a quarter of an inch, or half a centimeter.

So what's up with the down seas, and what does it mean? Climate scientist Josh Willis of NASA's Jet Propulsion Laboratory, Pasadena, Calif., says you can blame it on the cycle of El Niño and La Niña in the Pacific.

Willis said that while 2010 began with a sizable El Niño, by year's end, it was replaced by one of the strongest La Niñas in recent memory. This sudden shift in the Pacific changed rainfall patterns all across the globe, bringing massive floods to places like Australia and the Amazon basin, and drought to the southern United States.

Gravity Recovery and Climate Experiment (Grace) map shows how much water was lost or gained over the continents between the spring of 2010 and the spring of 2011. The red colors show dry regions where water was lost. The blue colors show places that gained water, usually because of heavier-than-normal rainfall or snow. Credit: NASA/JPL-Caltech

Data from the /German Aerospace Center's twin Gravity Recovery and Climate Experiment (Grace) provide a clear picture of how this extra rain piled onto the continents in the early parts of 2011. "By detecting where water is on the continents, Grace shows us how water moves around the planet," says Steve Nerem, a sea level scientist at the University of Colorado in Boulder.

So where does all that extra water in Brazil and Australia come from? You guessed it--the ocean. Each year, huge amounts of water are evaporated from the ocean. While most of it falls right back into the ocean as rain, some of it falls over land. "This year, the continents got an extra dose of rain, so much so that global sea levels actually fell over most of the last year," says Carmen Boening, a JPL oceanographer and climate scientist. Boening and colleagues presented these results recently at the annual Grace Science Team Meeting in Austin, Texas.

But for those who might argue that these data show us entering a long-term period of decline in global sea level, Willis cautions that sea level drops such as this one cannot last, and over the long-run, the trend remains solidly up. Water flows downhill, and the extra rain will eventually find its way back to the sea. When it does, will rise again.

"We're heating up the planet, and in the end that means more ," says Willis. "But El Niño and La Niña always take us on a rainfall rollercoaster, and in years like this they give us whiplash."

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SteveL
3.4 / 5 (10) Aug 24, 2011
Per their graph such dips, though not quite as large, happen periodically, followed by a sharp upward trend. When it comes to climate, 18 years of readings really isn't enough data to conclude anything.
GSwift7
3.3 / 5 (12) Aug 24, 2011
To SteveL:

If you want to see something really interesting, take a look at the original data from Colorado University Boulder (where they claim above to have gotten their data). They must be using some kind of whacky smoothing and/or seasonal modification above, but it does a good job of hiding the fact that the upward trend of 3.2 actually slowed down prior to the recent el nino, and is slowing down even more now that we're in a neutral state. That's another whacky thing they say above. They say La Nina, but we've been neutral, La Nada, for a while now. They also say "2010" but it's clearly still dropping based on the most recent from CU. There's some 2011 data on the one I linked to.

Here's the source data from CU:

http://sealevel.c...obal.jpg

GSwift7
2.8 / 5 (10) Aug 24, 2011
One more comment in regard to sea level:

It's really not usefull to talk about sea level on a global scale. You really need to look at each ocean basin on its own. The Indian Ocean has maintained a steep increase in sea level, despite the opposite happening elsewhere. It's really hard to say much about long term trends based on such a short period of reliable record. It's becoming clear, now that we have good satellite records, that historical tide guages aren't a good measure of sea level in the deep oceans. The tide guages haven't agreed with satellite measurements very well at all since we started doing the satellite thing. By the way, in addition to showing that the current slowdown started around 96, it also shows that the recent rapid dip isn't unusual. It's likely to spring back up next year.
GSwift7
2.9 / 5 (10) Aug 24, 2011
The next 10-20 years will be very informing. As you said, Steve, 18 years is nothing. The official definition of climate is 30 years. Anything smaller than that could just be noise, and the oceans might even act on a longer time scale than 30 years. Maybe ocean climate is on a slower clock than the air. I'd be willing to bet that it is.
SteveL
4.4 / 5 (9) Aug 24, 2011
One of the things about statistics is that you can take bits of data out of context to "prove" whatever you want to. For instance, if you took the last 2 - 3 years you could say "The oceans have stopped rising and the levels are holding", or if you just took the last year or so you could state that "The ocean levels are falling. No worries!" - with data to back up your agenda. The vast majority of people wouldn't realize that you hand picked bits of data out of context with the greater picture. For all we know, ocean levels actually have peaked and will start to decline, or the levels will only decline a few years and continue to rise. We simply don't know enough.

As the earth's atmosphere warms it should hold more moisture, but there has to be a saturation point. I've sometimes wondered if the increase of moisture in the atmophere has been included in the calculations for sea level. For now though, the trend still seems to be an increase in sea levels.
thermodynamics
5 / 5 (9) Aug 24, 2011
SteveL: Good question when you asked: "I've sometimes wondered if the increase of moisture in the atmophere has been included in the calculations for sea level." The answer is yes. When the models couple oceans and air they take into account the changes in enthalpy and mass as water changes state in evaporation and condensation. That is the way they account for mass motion as well as energy motion. The Earth is a giant heat engine that runs on water vapor. Each model looks at evaporation (or sublimation) as a removal of mass and energy and then condensation as a deposit of energy and mass in a different location. That is the way energy is removed from the equator and moved toward the poles. So, any coupled model looks at heat and mass transfer and the motion of energy and mass.
gmurphy
4.9 / 5 (7) Aug 24, 2011
@SteveL, no long term conclusion was drawn from the graph, it merely noted the dip in sea level followed by the (really cool) corresponding observations of gravity changes across the globe caused by the redistribution of the water.
MikPetter
5 / 5 (5) Aug 24, 2011
Extract from CU Sea Level Research Group
University of Colorado "Tide Gauge Sea Level"..." Major conclusions from tide gauge data have been that global sea level has risen approximately 10-25 cm during the past century."
http://sealevel.c...ea-level
Pete1983
4.7 / 5 (7) Aug 24, 2011
So what's up with the down seas


I love it when they sneak lines like this into the article.
ubavontuba
2.6 / 5 (10) Aug 24, 2011
So like are they suggesting we've never switched from an El Nino to a La Nina before?

Even the previously "measured" sea level rise is questionable. They adjust the sea level up to compensate for a sinking sea floor.

"Gatekeepers of our sea level data are manufacturing a fictitious sea level rise that is not occurring,"

http://www.foxnew...el-data/

Of course statistical blips are to be expected. We'll just have to give data collection more time to determine if this is a blip, or a real "sea change" (pun intended).
rwinners
3 / 5 (9) Aug 25, 2011
Ah, FAUX news! Much better than any scientific digest.

Oh, and if anything, the sea floors are rising, as they slowly fill with the detritus of humanity.. and other natural processes.
Guy_Underbridge
5 / 5 (6) Aug 25, 2011
... as they slowly fill with the detritus of humanity.. and other natural processes.
So that's where my detritus went. I've been looking for it and couldn't remember where I'd left it.
SteveL
5 / 5 (6) Aug 25, 2011
@ubavontuba: While scientific sources can be politically skewed, at least they are subject to peer review. FOX, ABC, CBS, CNN, MSNBC and the rest will nearly always skew their reporting based on their political agendas. For a "news" outlet the truth is what they say it is (rather than reality). If we really want the truth, we have to question everything, look into the sources of their news and at least consider what any opposition has to say and look into its data.
GSwift7
3.1 / 5 (8) Aug 25, 2011
The CU sea level is adjusted for GIA (Glacial Isostatic Adjustment) and for barometric pressure. The graph I linked to in my first post, the source data from CU, is annotated as such. The following page talks about that Fox story and includes useful links for accurate information about it.

http://sealevel.c...rrection

The following FAQ section explains why tide guage measurements are not the same thing as global sea level measurements:

http://sealevel.c...all-link

It also explains that the GIA adjustment is because the ocean basins are getting larger (deeper and wider), therefore they do adjust sea level upwards from acutal measurements over time. It's a valid methodology, and not some conspiracy thing. They openly discuss how and why it is done, in detail. It's only about -0.3 mm/year adjustment to the rate of sea level rise. Nothing to get excited about.

GSwift7
3.3 / 5 (7) Aug 25, 2011
By the way, would anyone care to explain why they are downrating my comments? I see no comments expressing any reason why you disagree with me. My posts have been non-agenda driven concensus view scientific theory, with links to the same official source as the article above to back me up. I'd really like to hear you explain which part of my comments you disagree with or think is inaccurate. I'm prepared to link to official sources to further back my comments if you like. I don't use Fox as a source for my info. Heck, I don't even have cable TV at home.
GSwift7
3.7 / 5 (6) Aug 25, 2011
Oh, and if anything, the sea floors are rising, as they slowly fill with the detritus of humanity.. and other natural processes


According to the experts at CU, you are completely incorrect. (see the links in my previous post for reference.)

If we really want the truth, we have to question everything, look into the sources of their news and at least consider what any opposition has to say and look into its data.


That's for sure. It sometimes takes me a whole day to really dig into a story like the one above to fact-check and cross reference the things I'm curious about. I've found that I usually learn something new every time I do that. I'm a huge geek I guess.
SteveL
3.7 / 5 (6) Aug 25, 2011
@GSwift7: I've noticed that some people will downrate if they simply don't like the poster, don't understand the post or don't like what is being posted because it doesn't match their agenda or perhaps what their favorite news personality said on TV.

Failure to include a post to back up the downrating can be from a variety of issues from being just too lazy because some kind of research and source linking may be required and an actual discussion may be expected, to simply not really understanding the issue being discussed.

I don't rate folks very often unless something really stands out. I saw the downratings and popped in a few 5's because they were good posts that were on topic and added to the content of the discussion.
GSwift7
3.4 / 5 (5) Aug 25, 2011
Yeah, I saw that you uprated me. I suspect that some or all of the downrating in this case came from one or maybe two people with multiple accounts. That's nothing new here, and it's clearly a sign of a personality disorder.
ubavontuba
2.5 / 5 (4) Aug 25, 2011
Ah, FAUX news! Much better than any scientific digest.
LOL. I knew this would get a reaction like this. This serves to prove folks will ridicule the source over the content.

The story is essentially correct and includes multiple links to the University of Colorado's sea level data. Try doing a little reading and research yourself before you dismiss something out of hand. You might actually learn something.

And, anyone who downranked GSwift7 for any of his posts here should be ashamed. The guy brings it, almost every time.

rwinners
4.5 / 5 (2) Aug 26, 2011
After reading some of the references and then looking at the chart again, I think it is an anomoly, similar to the extreme rise that occurred in 96/97.
Time will tell.
GSwift7
2.3 / 5 (3) Aug 26, 2011
After reading some of the references and then looking at the chart again, I think it is an anomoly, similar to the extreme rise that occurred in 96/97


Yes, like I said above, it isn't unusual for sea level to fall and then rise again. This could simply be natural variation in the trend, and it could bounce back upwards next year. However, all the forcasters I can find are now predicting a return to La Nina conditions by Winter. If the coming La Nina is significant in durration and magnitude, it could really knock sea level down a lot, and make it difficult to discerne what the real long term trend looks like. I really think another 20 or 30 years of good observations is needed before we can draw very certain conclusions. With the current change in trend, it brings into question how much natural variability there is, and the length of those natural variations. If we get a third wave of La Nina after the next one, it'll make it even worse as far as predictions go.
Shootist
3 / 5 (4) Aug 27, 2011
Ah, FAUX news! Much better than any scientific digest.

Oh, and if anything, the sea floors are rising, as they slowly fill with the detritus of humanity.. and other natural processes.


You would think that until you discover that the sedimentary column of the eastern Rocky Mountains is 6000 meters deep, while the Amazon Basin sports a debris depth of 10000 meters. The land sinks (subsides) as fast as the sedimentary column is created. Compaction of material occurs as well.

What the article doesn't mention is whether the continental shelves are subsiding under the mass of the additional water, and, what percentage of this additional water is being injected into subduction zones (as the mass of the water column increase more water will be subducted into the mantle).

It seems to me both of these numbers are significant.
GSwift7
1 / 5 (1) Aug 29, 2011
to Shootist:

That's actually an interesting question. There's a problem when it comes to answering it though, and that's the problem of human limitations in our ability to perceive large scales. I've heard an analogy which describes the surface of the Earth as being proportionatly smoother than the surface of a bowling ball. The atmosphere, oceans, mountains and valleys are so insignificantly thin relative to the size of the planet, that you woudn't be able to feel them on a scale model of the planet the size of a bowling ball. Even if you include the crust, you're still talking about a very thin skin on the surface of the bowling ball. It's difficult for people to grasp the insignifigance of the troposphere compared to the planet as a whole. We know relatively little about the mantle and core, which make up the bulk of the planet. How much carbon is there in the mantle? How much exchange is there? What is the chemistry there? High pressure chemistry is still little understood.
Howhot
not rated yet Aug 30, 2011
I can answer your question G7. Everything below the earths crust in more or less the same as it is on the surface; averaging everything. The denser elements migrated over billions of year toward the center. Planetary core pressures for sure.

So if the question is how much carbon is in the mantle, my guess is that it would float relative to other minerals. Its a discussion for a vulcanologist.

That said, CO2 levels in the atmosphere at an ALL TIME MAXIMUM could be a cause. Just saying.

GSwift7
1 / 5 (1) Aug 30, 2011
to howhow:

can you please provide a source for your claim that the mantle is generally composed of the same things as the crust? I don't believe that's in line with current theory.

From wiki:

http://en.wikiped...geology)

If you have a reference that says co2 is at an all time max, please link to your source.

Once again, you don't even bother to google stuff before you start posting a bunch of incorrect BS. Typical alarmist nonsense.
GSwift7
1 / 5 (1) Aug 30, 2011
Strange, it cut out my quotes from wiki and one of my links.

in re. crust versus mantle, from wiki:

The distinction between crust and mantle is based on chemistry, rock types, rheology and seismic characteristics


and

Typical mantle rocks have a higher magnesium to iron ratio, and a smaller proportion of silicon and aluminium than the crust


And in regard to the max co2 content, here's a reference for that. The following chart shows the most recent times on the left, clearly showing that we are FAR from the historical max for co2.

http://en.wikiped...xide.png
bluehigh
1 / 5 (1) Aug 30, 2011
With narrow minded dismissive comments such as ...

Once again, you don't even bother to google stuff before you start posting a bunch of incorrect BS. Typical alarmist nonsense.


... and quoting Wikipedia as an authoritative source and you wonder why you get down rated.

Have a 1 from me too, you overbearing opinionated git.

Howhot
3 / 5 (2) Aug 30, 2011
G7, never-mind what I said in that other thread. I thought you might have some sanity in your arguments. Now I know where your feet are planted. So you say to me that I'm just "Typical alarmist nonsense."

Yeah, well you just exposed your true colors. Good luck with your credibility.
Howhot
not rated yet Aug 31, 2011
Here is what I want you to look at; look at the map in this Article and look at Texas, and then read the scale below. That is in need of a straight focus. We don't need BS. We need an applied forceful response to global warming right now.
GSwift7
1 / 5 (1) Aug 31, 2011
Bluehigh:

and quoting Wikipedia as an authoritative source and you wonder why you get down rated


I can post links to official sources such as the sources used to back up the wiki page for this. Can you find any source that says the wiki is wrong and howhot is right? I'll be you can't.

Howhot:

Here is what I want you to look at; look at the map in this Article and look at Texas, and then read the scale below. That is in need of a straight focus. We don't need BS. We need an applied forceful response to global warming right now.


It's not global warming, it's ENSO. From the article above:

Willis said that while 2010 began with a sizable El Niño, by year's end, it was replaced by one of the strongest La Niñas in recent memory. This sudden shift in the Pacific changed rainfall patterns all across the globe, bringing massive floods to places like Australia and the Amazon basin, and drought to the southern United States


It's a cycle.
GSwift7
1 / 5 (1) Aug 31, 2011
to bluehigh:

here is the source of the portion of wiki page which I quoted.

http://books.goog...q=mantle chemical composition&source=web&ots=szv6r4wlPA&sig=zRN1iHTek4r4pXxeTYLS2JOGazs#v=onepage&q=mantle%20chemical%20composition&f=false

And here's a reference from the USGS. They both agree with my statement and disagree with howhot:

http://pubs.usgs....nterior/

As for his claim that co2 is at an all time high, the following site contains the same graph that is available at 1000 other sites. It's a composite of paleo records which estimate atmospheric co2. All sources agree that we are near all time low co2 concentration right now.

http://www.geocra...ate.html

from the chart description:

Late Carboniferous to Early Permian time (315 mya -- 270 mya) is the only time period in the last 600 million years when both atmospheric CO2 and temperatures were as low as they are today
MikPetter
5 / 5 (1) Aug 31, 2011
Co2 concentrations are at a twenty million year high in atmosphere see https://wesfiles....ence.pdf
See also for a discussion on what happen at higher Co2 concentrations -
http://973.geobio...2101.pdf
Higher Co2 concentrations in Earths history were during times of no life, simple life or very different lifeforms to now. This makes comparisons difficult.
While greenhouse growers can use higher concentrations not all plants thrive and to achieve high growth rates nutrients and water need to be readily available. In recent field trials using outdoor conditions the results were different see - http://www.physor...cts.html
Howhot
1 / 5 (1) Aug 31, 2011
G7
Willis said that while 2010 began with a sizable El Niño, by year's end, it was replaced by one of the strongest La Niñas in recent memory.

and
Each year, huge amounts of water are evaporated from the ocean. While most of it falls right back into the ocean as rain, some of it falls over land. "This year, the continents got an extra dose of rain, so much so that global sea levels actually fell over most of the last year,"


So global warming is evaporating the oceans putting water into the air, and an a pacific equatorial ocean weather pattern suddenly shifts. Man if those aren't signs of Global Warming, I don't know what is.
Howhot
1 / 5 (1) Aug 31, 2011
Look at the very first graph. In other words G7, if you see the transition from El Niño to La its just water evaporation (from an very hot El), and the evaporation (which cools the water) leads to a very cool La Niña.

Evaporation is what the of the water column under the El Niño (the hot weather pattern) evaporated six mm off the ocean cooling the ocean at the same time. Leaving the La La Niña in it's wake.

It's an effect of Global Warming my friend.
Howhot
1 / 5 (1) Aug 31, 2011
It's an effect of Global Warming my friend.

Just to clarify, not El Niño and La are weather patterns (climate features). The severity of the El Niño and La Niña is very much related to global warming.
bluehigh
1 / 5 (1) Sep 01, 2011
GSwift7:

Others are doing fine refuting your view, without my help. In fact I did NOT take a view in these comments. My gripe is that you were initially dismissive of others without verification of your view. "..incorrect BS" and "alarmist nonsense" do not contribute anything worthwhile.

It so happens that I tend to view Global Warming with a pinch of salt (I am a fan of Ian Plimer).

GSwift7
1 / 5 (1) Sep 01, 2011
To MikPetter:

Thanks for those good references which support my points. Howhot claimed that we are at an all time high co2 level. We are near an all time low actually, as your references show.

To Howhot:

Preset concensus view is that global warming will either make ENSO weaker or not have much effect at all. That's based on paleoclimate records, which is the best measure we have, though it's debatable, as the following journal paper says:

http://www.nature...224.html

Whether ENSO magnitude is related to global temperature is uncertain according to every reliable source I can find.

To Bluehigh:

Howhot is still making stuff up, and I provided reputable links to show it. That is nonsense.

I don't care what your opinion is. I read the journals and official government agency reports. IF you care to prove that anything howhot said is correct, then I eagerly await your supporting links to reputable sorces.
GSwift7
1 / 5 (1) Sep 01, 2011
Personal attacks, straw man arguments, and emotional appeal. Typical.

HOwhow, your view of the relationship between ENSO and sea level is really interesting. Can you show me where you got that from? I'd really love to learn about your very unique theory about ENSO and sea level. I've read a TON of stuff about that but I Must have missed that paper.

Try looking it up on NOAA. They have oodles of info about how ENSO affects sea levels and precipitation. Think in terms of pressure and temperature rather than precipitation.

The current drop in sea level isn't unusual anyway, and as I said way back in this thread, sea level is likely to jump back up after the next la nina is done. It tends to rise with el nino and fall with la nina. That's not climate change, or global sea level change, it's just ENSO, which is a short term thing. It's just noise in the data.
Howhot
not rated yet Sep 01, 2011
BS G7. I'm not making anything up. The graphs in this article show clearly what I'm saying. You deniers jumped on because it looks like sea level rise has dropped dramatically, when what is really happening is sea-level evaporation (under the El weather pattern).

I don't need to sight any paper; it all reference in the story.

ENSO (or the global circulatory flow of the atmosphere) that causes the EL and the LA patters is certainly influence by global temperature rise. How can you deny that G7?

Howhot
1 / 5 (1) Sep 02, 2011
it tends to rise with el nino and fall with la nina. That's not climate change, or global sea level change, it's just ENSO, which is a short term thing. It's just noise in the data.

Then you would agree with the sea level rise graph. All of the bumps along the way are noise but the trend is sea level rise.
Then the graph takes a huge swing when the EL heat bubble is super hot evaporating a huge swath of the pacific ocean. When the heat bubble (the El) is finally pushed off, a large chunk of the ocean is left in the atmosphere to be dumped in other locations; South america, and Australia.

Global warming; the El has never been as hot as it is today. The texas droughts have never been as bad as they are today.
etc.. etc.. etc.

SteveL
5 / 5 (1) Sep 02, 2011
The texas droughts have never been as bad as they are today.
etc.. etc.. etc.


Never? Really? The Texas State Historical Association may have a different story to tell.

http://www.tshaon...es/ybd01
GSwift7
1 / 5 (1) Sep 02, 2011
ENSO (or the global circulatory flow of the atmosphere) that causes the EL and the LA patters is certainly influence by global temperature rise. How can you deny that G7?


I'm not denying it, the experts seem to be saying that they aren't sure. I'm just providing links to what those experts had to say about it. There's a difference between denial and simply saying that nobody knows yet. If you're so sure about it then you need to write a letter to NOAA and inform them that you've figured it out and they can stop spending money trying to solve a problem you've already solved. I'm sure they will thank you.