New Paper on Sea Level Rise – Purkey et al (2014) – Examines the Sea Level Rise by Basin

Guest Post by Bob Tisdale

Please see the Update at the end of the post to avoid confusion.

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The paper Purkey et al. (2014) Relative contributions of ocean mass and deep steric changes to sea level rise between 1993 and 2013 was recently accepted for publication at the Journal of Geophysical Research: Oceans.  The abstract reads (my boldface):

Regional and global trends of Sea Level Rise (SLR) owing to mass addition centered between 1996–2006 are assessed through a full-depth SLR budget using full-depth in-situ ocean data and satellite altimetry. These rates are compared to regional and global trends in ocean mass addition estimated directly using data from the Gravity Recovery and Climate Experiment (GRACE) from 2003–2013. Despite the two independent methods covering different time periods with differing spatial and temporal resolution, they both capture the same large-scale mass addition trend patterns including higher rates of mass addition in the North Pacific, South Atlantic, and the Indo-Atlantic Sector of the Southern Ocean, and lower mass addition trends in the Indian, North Atlantic, South Pacific, and the Pacific Sector of the Southern Ocean. The global mean trend of ocean mass addition is 1.5 (±0.4) mm yr-1 for 1996–2006 from the residual method and the same for 2003–2013 from the GRACE method. Furthermore, the residual method is used to evaluate the error introduced into the mass budget if the deep steric contributions below 700, 1000, 2000, 3000, and 4000 m are neglected, revealing errors of 65%, 38%, 13%, 8% and 4% respectively. The two methods no longer agree within error bars when only the steric contribution shallower than 1000 m is considered.

The full paper (preprint) is here.

I suspect the high rate of sea level rise east of Indonesia the Philippines (shown in the trend map below from the University of Colorado) is the reason the North Pacific trend discussed in the paper is so high with respect to the South Pacific.  That pocket of exceptional sea level rise in the western tropical North Pacific looks suspiciously like an ENSO residual (the residuals from a series of off-equatorial Rossby waves returning leftover warm water from El Niño events).  I’ve always wanted to remove that portion of the data to see its impact on global sea levels.

Sea Level Trends Univ of Colorado

Sea Level Map from University of Colorado.

I recently expressed my opinion about sea level in the post Maybe It’s Time We Stopped Wasting Money Studying a Problem And Spent That Money Adapting to It.  I’ll let you provide additional comment on this paper.

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UPDATE:  Please read the paper carefully.  The 1.5mm/year trend is the MASS component.  In other words, it’s the TOTAL rate of sea level rise MINUS the STERIC (thermal and saline) component.


106 thoughts on “New Paper on Sea Level Rise – Purkey et al (2014) – Examines the Sea Level Rise by Basin

  1. “The global mean trend of ocean mass addition is 1.5 (±0.4) mm yr-1 for 1996–2006 from the residual method and the same for 2003–2013 from the GRACE method”
    Hmmm, almost exactly the same as the ENVISO satellite showed before the data was up-justed to match US satellites:
    “Figure 7 below shows how easy it is to tamper with previously published satellite data from the European ENVISO satellite, which previously showed sea levels rising at 1.59 mm/yr [very similar to what global tide gauges show], but a convenient new processing algorithm magically increases or up-justs the rate of ENVISO sea level rise by 86% to match the US satellite data of 2.96 mm/yr.”

    • Had not known this. Many thanks for exposing it. You will be interested in several additional ‘wrinkles’ to the recent SLR story, exposed in the essay Pseudo Precision in my new ebook Blowing Smoke. Foreward by Prof. Judith Curry.

    • I’ve added an update at the end of the post to remind everyone that the 1.5 mm/year trend discussed in the paper is not the total sea level trend….it is the mass contribution.

      • And all the time the satellites see one thing, and the MSM records the satellites plus calculated GIA, the tidal guages see another.
        There should be a graph that shows sea-level rise from 1988 by satellite and by tidal guages, and another that shows the satellite rise ADJUSTMENTS over time, just as we have for the GISS temp adjustments.

  2. I am still waiting for clear evidence of an acceleration in the rate of global sea level rise.
    Sea level has been rising for thousands of years.

  3. Bob, very nice spot. Check out the GRACE gravitational anomaly map for Earths geoid. The map shows ‘extra gravity’ in the same general region, which is generally just east of the Marianas trench, the worlds most major tectonic subduction zone. It is possible (given all the massive recent earthquakes in the area) that recent geological changes in that region of the crust and mantle (which likely explain the observed GRACE anomaly in the region) are also partly responsible for the water pile up there. After all, sea water is free to flow until its relative density (also a function of thermosteric expansion as with ENSO) “smooths” any ‘felt’ gravitational differences. And those for sure exist, since basaltic iron rich mantle rock is denser than silicaceous/carbonate crustal rock. And givennthe Marianas Trench thrust (crust subducting to the west), there woild be more ‘gravity’ to the east, where the sea level is piling up. The mantle crust difference is also why the continents ‘float’, underpinning Wegoners brilliant 1912 ‘continental drift’ theory that in modern form is plate tectonics. My last book The Arts of Truth, recognition chapter, covers Alfred Wegoner. My new book’s essay Pseudo-Precision covers Grace gravitational anomalies in a sea level rise context.
    Regards to a true ocean expert.

  4. If a regional change is not CO2 related, is it legitimate to include that amount in the total sea level rise due to CO2? Or is the supposition that the rise in the Pacific causes an equivalent drop elsewhere in the system, so you have to add in the non-CO2 “up” to find out what the whole is doing?

  5. As regards basins, this is like telling me about the temperature of Australia and the temperature of East Antarctica. Basins’ sea levels rise and fall all the time.

  6. Lemme see: 1.5mm per decade equals 15mm per century. One inch equals 25.4 mm. So, in 100 years the sea level rises two-thirds of an inch. And this is what Hansen says will drown NYC?

    • As Mario says, you’re off by a factor of 10. Also Manhattan Island seems to be sinking at a rate of several inches a century, it’s not currently clear exactly how much but the long term rate of apparent sea level rise from all causes at the Battery tidal gauge is about 2.83mm/yr = 11 inches per century. Since NYC seems likely to be around for quite a few centuries, the sea level rise there is eventually likely to be a problem eventually and probably should be allowed for in infrastructure planning.
      OTOH, you are correct. I can’t think what if anything caused James Hansen to project massive short term sea level rise there. I can only guess that he simply wasn’t thinking straight when he gave that interview.
      There’s a chart accessible at (Scroll down and click Sea Level Trends). It certainly looks to be that if current trends continue, the tidal station and the adjacent parking lot are likely to be getting a bit wet at high tide sometime around 2500 AD — maybe sooner if the site photo wasn’t taken at high tide.

      • Theoretically, the post glacial rebound and associated sinking of offset areas should be slowing down. This means extrapolating current rates into the future yields excessive changes.

      • “Theoretically, the post glacial rebound and associated sinking of offset areas should be slowing down”
        Not only theoretically. Sea-level curves shows that it is slowing, at least in Northern Europe. On the other hand that slowing is not very fast, so it seems likely that it will continue for at least another 10,000 years. The next ice-age will probably start before equilibrum is reached.

  7. Seems like a large margin of error for a fairly small rise. Just curious but how do you measure an average rise per year of 0.059″ with an ocean surface of 139 million square miles. Probably milllions of sensors calibrated every week or so.

    • I would find it difficult to measure the water level on our fish pond to +- 0.4mm on a consistent basis let alone entire oceans. Climate ‘science’ is all about reducing incredibly complex systems over vast areas to a single figure, often with an unbelievable number of significant figures and accuracy.

      • I think you have to not try to measure the water level, you have to measure time, as Grace does.
        You measure the time it takes to receive your satellite signal, then you start calculating. I suppose the time measurement is actually a voltage measurement.
        I have some of the parts you might need for your satellite and will let you have them cheap as I lost faith in my attempts to measure our pond after the beavers took up residence.

      • That’s not the way GRACE works. Gravity is measured by the changes in distance between two co-orbital satellites which is influenced by the strength of the local gravity field. The distance is measured interferometrically, which is one of the most precise methods known. Actually GRACE is just about the most credible satellite dataset in existence. There are of course problems in interpreting it, since changes in gravity can have several causes, and the spatial resolution is fairly low, but these problems are relatively benign over oceans (much more complex for icecaps). It should also be noted that GRACE is getting old and the onboard electronics are known to be deteriorating. It’s time for a new set of satellites.

      • tty,
        I knew it was two satellites but I didn’t know it was a split beam.
        I’d like to persist with my claim of it being a measurement of time, since one beam arrives at the sensor later than its twin. 🙂

      • With no knowledge of metrology few people can even begin to challenge the ridiculousness of these and many other climastrology numbers. I have said it before and I will say it again. I defy anyone to measure even the temperature in their back yard with the accuracy claimed by theses voodoo artists. Every key number they use from pH, to temperature, to sea levels is irrelevant, insignificant and not even a notable fraction of the noise these massive natural systems contain. Averages are essentially meaningless without accounting for the variability of the data. Consider this. If I add a string of 10 measurements that result in 1, 2,3,4,5, etc. to ten, divide by ten I get an average of 5. If I add another string of ten measurements, all resulting in five, and divide by ten I get an average of 5. Now, what should I expect when I make additional measurements? Aside from concluding that the two sets of measurements are probably measuring two different systems with different controlling causes, both will average 5. A deviation from the average in the first set of data would not be a surprise, but something other than a five in the second set of date should attract attention because it means something is significantly different for that output measurement. Taking it a step further. If I combine both sets of original measurements, which would be silly because I really should consider them representative of two separate systems, I still get a falsely reassuring average of 5. Have I helped my expectations? No not at all. And that is the heart of the problem.

  8. For someone who’s not real sure what they’re looking at, does this mean that we have an ocean rise of about 1 inch every 10 years, but much of the distribution of that change is due to geophysical forces that we really don’t understand? Am I close enough to get a c- on my report card … thanks

  9. “Maybe It’s Time We Stopped Wasting Money Studying a Problem And Spent That Money Adapting to It.”
    Do you think that is three orders of magnitude difference in $$ or four? I mean, think about how money we could save on bridges if we didn’t spend money on designing them.

    • As dbstealey says, your analogy is goofy. There is nothing we can do about sea level rise. Nothing. We should adapt as all of civilization has done who have not perished.

      • so you don’t think knowing the rate of rise is important? and can it be stopped? doesn’t hurt to know, and it doesn’t cost anything compared to building just one sea wall. Just one. And we might need many…and unicorns aren’t real.

      • @trafamadore:
        1. The rate of SL rise is interesting. But important? Not really. If SL began accelerating like the alarmist crew has incessantly predicted, that would be important. But they were wrong, as always. In fact, SL rise appears to be moderating.
        2. Can SL rise be stopped? No. Not by people. But we can adapt.
        3. …unicorns aren’t real. Good to know. Neither is catastrophic AGW.
        The claim that “it doesn’t cost anything” is totally false, and the misallocated piles of money are the problem. More money is wasted on “climate studies” every year, but it has produced nothing except for a growing clique of self-serving rent seekers.
        The “climate studies” money would be as well spent studying unicorns.

      • trafamadore: Your response to my missive to you reads like you did not understand what I wrote. We have plenty of resources to adapt to what nature brings us. Your ilk spends money on creating fear of irrational political science, and your ilk squanders resources. Your chosen one wants energy prices to skyrocket which makes people less able to adapt to real world challenges.
        There is NO catastrophic climate change caused by mankind. None of the prophecies have come true as a result of CO2 increases. None of the policies make it better for the childrens’ futures who those policies portend to help. The truth is they will need to pay for your kinds’ policies. dbstealey answered for me. It’s clear isn’t it?
        And – I take note that you’re acting as if there is something wrong with the mods’ who let you write drivel, and yet you complain like a spoiled brat who refuses to learn or even take pause when you’re faced with reason.
        I submit that other sites do not allow your kind of ranting and twisting of words into the mantra of the non reasoned.

      • rafamadore October 30, 2014 at 5:31 pm:
        dbstealey answered for me.
        I’ll add that your rants about the mods is senseless –as you well know other sites will not tolerate your behavior. Your ilk does what it can to prevent us from adapting to natural climate change. Your chosen leader states that his policies that YOU voted for will skyrocket energy prices. How are the children, who your ilk portend to create these policies for, going to deal with the debt created as a result of people who can not think with a critical mind?
        People like you are incredibly harmful. Your hatred for reality and mankind’s right to thrive will get you if there is any sort of justice. You should give pause instead of reacting like you probably will. Maybe you’ll get some sense out of the free schooling. It’s up to you.

      • In case people are wondering why I don’t respond, it is because the clueless mod can’t make up it’s mind about [whether] I get people PO.
        [The clueless mods (note plural) always know whether or not you get people PO’ed. .mod]

      • “[The clueless mods (note plural) always know whether or not you get people PO’ed. .mod]”
        okay okay. haha.

  10. Re: “The 1.5mm/year trend is the MASS component. In other words, it’s the TOTAL rate of sea level rise MINUS the STERIC (thermal and saline) component.”
    The mass component also excludes the effect of the sinking of the ocean floor as a result of PGR (estimated by Peltier as 0.3 mm/yr), which reduces the rate of actual sea-level rise.

    • And The Sea Level Research Group at Colorado University adds it right back in along with the another 0.6 mm/yr worth of corrections they’ve made over the last ten years.
      If you believe the 0.3 mm/yr GIA correction, you have to believe that the Earth is growing.

    • How could it exclude that? It is a hypothesized measurement of the sea level, minus the hypothesized heat expansion.

  11. 1.59 mm/year would be only 20% or so of what we can observe geologically.
    And the technique to measure (accurately) such a small change is to observe it over a long period of time. Such as 10,000 years or so. Of course, that masks the short-term (100 year) oscillations.

  12. I wonder how the mass addition (ice-melt, land storage changes) and the thermal-steric (expansion due to warming) estimates would change if they used the tide gauge sea level calculations rather than satellite and Grace estimates.

    • Bill Willis: “tide gauge sea level calculations…” ####
      The NOAA mean sea level trends for about 50 or more tide gauges are posted. These show a flat trend except the northern Atlantic coast.
      The west coast guages show a flat trend for the past thirty years, the Gulf coast a steady trend for ten or fifteen years. Other stable coasts I suspect would show similar tidal gauge trends.

  13. Sea level has risen about 400 feet since the end of the Ice Age almost 20,000 years ago. We know that 395 and 1/2 of it had nothing to do with CO2, because CO2 never changed during that time frame. We are not really sure what caused that 395.5 ft rise, but we are super sure that the last 6 inches of the rise (since 1960) was caused by AGW, because what else could it be?. Got It!

    • .13%, that’s “point” 13%, was caused by fossil fuels, but 99.87% was caused by something else. And that something else is no longer a factor? Got It. Makes Sense.

      • “.13%, that’s “point” 13%, was caused by fossil fuels”
        Doesn’t that imply that ALL sea level rise since 1960 is caused by Man?

  14. I suspect the high rate of sea level rise east of Indonesia (shown in the trend map below from the University of Colorado) is the reason the North Pacific trend discussed in the paper is so high with respect to the South Pacific.
    On the map, the blob of hot pink looks north of Indonesia but east of the Philippines.

  15. 1.5mm a year seems almost irrelevant to me. I am sure back in 1914, there was absolutely no comprehension of the technologies we would have today, and I assume the same of us looking forward to 2114. I definitely don’t think 15cm would have worried them (at the time, especially), and I don’t think it should worry us.
    It’s about as meaningless as an annual increase of 0.007C, in terms of risk.

    • 1.5mm per year or even 3mm per year isn’t a lot.
      But bear in mind that we seem to be building infrastructure with too little allowance for storm surge and too little recognition that the infrastructure may be in use for many centuries. For example, some of the mostly century old rail tunnels in and out of New York were flooded by a NorthEaster in the 1990s and again by Sandy. Going forward, those tunnels are probably going to have less and less margin as time goes by. Presumably, they will eventually have to be hardened somehow or abandoned.

  16. Once again we are left interpreting color gradients that have no basis. The range ±3 should be white/neutral. Angry red planet graphics are getting tiresome.

  17. 1.5 mm = 0.0015 cm, correct? 1.5/25.4 = 0.059 inch, yes? per year times 100 years = 5.9 inches, check? Not quite “Water World” is it?
    [Look at the first decimals again. Meter or cm? 8<) .mod]

  18. “There is nothing that we as men can do that does not pale in comparison to the forces of nature.” So said James Van Allen for whom the Van Allen Belt is named after.

      • @ Simon
        October 30, 2014 at 9:15 pm : As far as I know, that idea was scotched by chemists e.g “Published online 26 September 2007 | Nature 449, 382-383 (2007) | doi:10.1038/449382a “. But as usual the facts are ignored by the believers. Brett

    • James Hansen’s dissertation chairman was Van Allen, who, like his student, knew very little meteorology or climatology.

  19. Can anyone name a single prominent warmist who has sold his/her oceanfront property because of rising sea levels?

  20. I understand sea level changes caused by tidal forces passing round the earth as it rotates. What I don’t understand is how you can have mean sea level changing at different rates in different places. I’m not talking about isostatic rebound, just the mean height of the water, say from the center of the earth. Aside from the tides, how can the height of water vary from one place to another? When the tidal forces pass on, the water flows back again. I would expect that same action to maintain mean sea level and its rate of change consistent world wide.
    Am I missing something?

    • Michael Wassail:
      Michael Wassail: No, you are not. I believe there is a lot of confusion on this sea level data. General sea level trends will perforce be reflected worldwide. A study of NOAA Mean
      Sea Level trends for US coasts indicate that sea levels have been steady since before this century began. These are tidal gauge data.
      Pacific coast data show flat trends for about thirty years.

    • Michael, the water column becomes slightly less dense as it warms up. This means sea level is a bit higher where the water is warmer. Sea level can also change if wind blows constantly in a given direction. The effects are very subtle, but they are also measurable.

  21. Something that I’ve wondered about when people use GRACE data. GRACE uses gravity to measure the mass between the satelite and the centre of the planet and that’s how they work out a mass change and therefore the change in the amount of water, or ice in Antarctica, or whatever.
    Underneath the 3 miles of water is about 3,000 miles of superhot, extremely dense, but above all FLUID magma. Due to Continental Drift, subsidance, volcanoes, isostatic changes and all the other large scale events going on, this fluid must move around in currents and eddies.
    So how do we know that the increase in gravity/mass is due to 1.3 mm of extra water and not a movement in the underlying 3,000 miles of magma?
    I don’t want anyone to think I’m dumping on the GRACE people, I’m not. The GRACE work is truly mind boggling. I’d just like to understand how this natural variation that must exist is compensated for in the readings.

    • They use models John.
      So its sure to be precise!
      Note GRACE calculation of Greenland and Antarctic ice mass loss depends upon modelling of crust/mantle rebound. Added to all the small imprecisions of satellite altitude and positioning …….

    • +10
      This is an excellent point! Changes in gravity may or may not be due to changes in sea level (or ice level). Trying to determine sea / ice level changes from gravity data is like trying to determine changes in the dandruff of an elephant by weighing the elephant and assuming he never changes at all. I too wonder if correct conclusions are drawn from the GRACE satellite data.

      • The fact that the mantle moves much more slowly than ice or water is undeniable. On the other hand, phase changes, (liquid to solid, solid to liquid, and solid to solid such as when basalt recrystallizes into peridotite) also affect gravity. JohnB and I are simply pointing out that we really don’t know squat about the workings of the Earth’s mantle and core. There are more components to GRACE gravity data than simple variations in water and ice. And at this point, their effects are unknown.

      • Fernando, it’s an extremely dense liquid, not a solid. I wouldn’t take bets on how fast it moves, especially when we look at how well it moves when it comes up. On the surface it can run like water. Look at the way it sprays in the Bardarbunga volcano clip from a few days ago.
        However it doesn’t have to move quickly. How much would 3,000 miles of very dense liquid rock have to move to give the same change in gravity as 2 mm of water would? Given that we are talking SLR, then the obs would be a year or so apart, plenty of time for things to move.
        Again, I’m not bagging GRACE, their sensors are just on the Sci Fi side of amazing. I’d just like to know how the variations due to currents in the liquid mantle are compensated for. It’s a liquid layer inside a spinning ball, the movement and currents must exist.

    • Viscosity of the Earth (which is mostly solid, not magma) is very high. Material moves very slowly down there, so gravity changes due changes in mantle flow (which undoubdetly occur) will be orders of magnitude slower than those due to surface changes,

  22. Went through the paper. My only non-expert comment is that the Figures were pretty p*ss-poor graphics.

  23. Coincidentally, this morning the California Water Plan eNews announced release of the Governor’s final update of the 2013 water plan. The link to the 12-volume opus is here:
    Page 23 of the 35-page executive summary (“Highlights”) summarizes sea level rise up to 66 inches by 2100. This is about ten times the number(s) reported in this WUWT post. Not to worry. The CA policy at:
    is to attribute the difference between measured sea level and computer-modeled sea level as “latent” sea level rise. See Page 124 of the guidance for this summary:
    “Ranges of sea-level rise projections that do not start at the year 2000
    “The NRC sea-level rise projections use the year 2000 as the base year. Since there has been little, if any, measureable (sic) rise in sea level since 2000 for most locations in California (Bromirski et al., 2011; NOAA Tides and Currents, 2013), there is little reason or justification for adjusting sea-level rise projections from 2000 to a more current start date. All of the latent sea-level rise might occur quickly, providing sea level conditions consistent with the future projections. Thus, when the needed sea level value is a projection of the future sea level that will be experienced by a proposed project for a proposed planning situation, there is no need to adjust the 2012 NRC projections for a different project starting year.”

    • Their statement makes sense because they treat sea level rise as a planning parameter to be applied regardless of the existing data or trends. This is sort of like the use of 60 degrees C to define standard conditions for gases. It’s an arbitrary decision.
      The use of sea level rise without an associated 100 (or 500) year storm surge is a bit dumb. Do they include the storm surge?

      • No. But FEMA does, without future sea level rise. FEMA uses a 50-year hindcast of tide gauge measurements over the last ~two tidal epochs to estimate the current 1% annual chance extreme high water including storm surge. The two methods are not compatible. There are other complexities and inconsistencies like ad hoc variable future sea level rise. The one I mentioned is only the latest. There are many more official sea level rises going back to the 2001 official state policy of about 36 inches by 2100.

    • This is the kind of thing that drives me crazy. Whenever some hired gun climatologist or politician quotes SLR , they always use the 90% confidence interval high point and portray it as the most probable value. Even then its not scary enough, so they invoke collapse of the West Antarctic Ice Sheet.

    • 66 inches of “latent” sea level rise? That is approximately equal to a third of all ice in West Antarctica. That ain’t gonna melt quickly.

  24. Simon I am quite confident we had nothing to do with the Ozone hole, It has not change since we started measuring it and we have only been measuring it with any accuracy for about 40 years. The Ozone crisis is another clear case of blame man first, learn later it is nature, not man. I expect that will take another fifty years though. God only knows what future generations will think about the collective stupidity of my generation.

    • “God only knows what future generations will think about the collective stupidity of my generation.”
      Probably they’ll wonder how we ever survived driving places, when all we had was ABS, 12 airbags, auto lane correction, adaptive cruise control, backup cameras, or cars that can only park themselves? Then they’ll ponder how we all survived with cell service that could only provide lethargic 4G coverage on a paltry 95% of the CONUS.
      I often wonder what imaginary crisis future generations will be force fed? Global Cooling maybe?

      • “I often wonder what imaginary crisis future generations will be force fed? Global Cooling maybe?”
        … and the terror threat presented by home schoolers, church-goers, raw milk providers, defenders of the Constitution and, of course, anyone who questions climate alarmism.

  25. “It’s Time We Stopped Wasting Money Studying a Problem And Spent That Money Adapting to It….”
    thank you!
    here in the Netherlands we spent billions of public money in keeping the rising sea out…
    again thank you for your advice

  26. The graphic is simply not creditable. Unless some cogent explanation can be given for these bizarre variations, it seems more likely that the data reflects something besides sea level, meaning that the signal has some unrefined noise in it.

  27. The map is interesting. Note the area east of Japan. It looks like a hot spot with ocean current carrying the water to the east. Another spot east of Madagascar. Even the area around the Philippines could have a similar cause as it is sitting north of the equator.

  28. The most recent data on the West Atlantic Ice Shelf is published in Geophysical Research Letters Vol 41,Issue 5,p1576, 2014. If read carefully, Figure 4 shows that the ice shelf as a whole has stabilized(no acceleration) since 2007, and is indeed not collapsing.

  29. Of that mass component of 1.5 mm/year about 0.4 mm/year to 0.9 mm/year can be attributed to groundwater extraction. See: Global depletion of groundwater resources by Yoshihide Wada et al in Geophysical Research Letters, Vol 37, Issue 20.
    Also: International Geophysics Volume 75, 2001, Pages 97–119 by Vivien Gornit: Chapter 5 Impoundment, groundwater mining, and other hydrologic transformations: Impacts on global sea level rise

    • I’m not entirely clear what you are asking, but the answer might be that GRACE coverage was basically global (i.e. the satellites flew (almost) over the poles, thus sweeping a swath of the entire planet from pole to pole and back again every 90-100 minutes. A quick Google search didn’t reveal how often samples were reported, but I’d guess several times a second — which would translate to sampling every few kilometers along the orbital path.
      Short answer: Looks to be lots of data covering the whole planet.

  30. Am I correct in thinking 1.5mm is good news if you look at the trend over the last 20,000 years with a 395 ft rise? Height in mm = 395 x 12 x 25 = a rise of 118,500mm in 20,000 years. = 5.925 mm per year. Food for thought?

    • Am I correct in thinking 1.5mm is good news

      Oh dear – I’m not sure why Bob T bothers. Please see the update to his post:

      UPDATE: Please read the paper carefully. The 1.5mm/year trend is the MASS component. In other words, it’s the TOTAL rate of sea level rise MINUS the STERIC (thermal and saline) component.

  31. Search this title “The Budget of Recent Global Sea Level Rise 2005-2012”
    Which is the official NOAA 2012 report written by Eric Leuliett.
    Steric (Argo) 0.2 ± 0.8
    Mass (GRACE, Paulson GIA) 1.0 ± 0.2
    Steric + mass (Paulson GIA) 1.2 ± 0.9
    Total sea level (Jason-1 and Jason-2) 1.6 ± 0.8
    Units are mm per year plus or minus the 95 percent confidence interval.
    I think Soon has criticized the altimeter calibrations (Jason)
    The paper includes full references, including the Paulson GIA. GIA is the so called “glacial isostatic adjustment” that claims that the ocean basin size is increasing.
    Thus the need to add another 0.3 millimeters per year to the real data.

  32. Would one of you geniuses please tell me what the REFERENCE POINT is for all these mm/yr measurements? There’s no place on Earth where the tectonic plates are so stable you could use it to measure such a tiny measurement against the scale of the Earth. The shape of the planet is also well known to wobble around on its axis, being pulled and pushed and squeezed by the VARIABLE nearby thermonuclear star and its various planets. How, in hell, do you say this rose 2.25mm/yr when your reference point is jumping up and down who knows how much up and down and sideways in every plane?
    What nonsense!

  33. What is of most interest is the total sea level rise, and the contribution of the steric and the mass components, and the heat expansion on different depths. That can tell us about how energies are stored.
    “Steric expansion is estimated globally to be adding 1.1 (±0.3)mm yr t SLR from 1993 -2010 [e.g., Cazenave et al., 2009; Church et al., 2011; 2013; Levitus et al., 2012; Rhein et al., 2013]. In the global mean, most of the steric contribution is from anthropogenic warming, with freshening having little net effect on the global mean [Lowe and Gregory, 2006].”
    “The upper ocean has expanded the fastest, with warming between the surface and 700 m contributing an estimated 0.7 mm yr from 1993– 2008 to global sea level rise, and the portion between 700 and 3000 m contributing an additional ~0.1 mm yr-1 [e.g., Church et al.,2011;2013]. Below 3000 m, the deep ocean is occupied by two water masses exhibiting different steric trends. ”
    “suggest an increase in global ocean mass at a rate of 1.8 (±0.5) mm yr-1 from 2003–2012, accounting for both internal variability and uncertainty in the Glacial Isostatic Adjustment (GIA) [Chambers, 2009; Chambers et al., 2010; Johnson and Chambers,2013]. This result is in good agreement with estimates in changes in land freshwater storage owning to glacier retreat, polar ice sheets loss and anthropogenic freshwater storage of 1.66 (±0.73) mm yr -1 between 1993–2008, despite the difference in time periods [Church et al., 2013].”
    “The deep ocean steric contribution is found to add 0.78, 0.40, 0.36, 0.07, 0.06, and 0.05 mm yr-1 from 300–700, 700–1000, 1000–2000, 2000–3000, 3000–4000, and 4000–6000 m, respectively.”
    “Finally, we have also estimated the relative importance of the deep ocean to the SLR budget, with the deep ocean steric expansion below 700m equivalent to 65% of the ocean mass contribution to sea level, and 13% below 2000m.”

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