Pielke on ground water extraction causing sea level rise

Where does the groundwater eventually end up? In the sea of course! Image: Department of Earth and Ocean Sciences, University of British Columbia.

Report On Sea Level Rise And Ground Water Extraction

There is a news article from the University of Utrecht [thanks to Erik for alerting us to this!] titled

Rising sea levels attributed to global groundwater extraction

The article starts with the text

“Large-scale groundwater extraction for irrigation, drinking water or industry results in an annual rise in sea levels of approximately 0.8 mm, accounting for about one-quarter of total annual sea-level rise (3.1 mm). According to hydrologists from Utrecht University and the research institute Deltares, the rise in sea levels can be attributed to the fact that most of the groundwater extracted ultimately winds up in the sea. The hydrologists explain their findings in an article to be published in the near future in the journal Geophysical Research Letters.”

The article is based on the paper

Y. Wada, L.P.H. van Beek, C.M. van Kempen, J.W.T.M. Reckman, S. Vasak, and M.F.P. Bierkens (2010), Global depletion of groundwater resources, Geophysical Research Letters, doi:10.1029/2010GL044571, in press.

This is yet another paper that shows the interconnection among the components of the climate system. The attribution of a climate effect (in this case sea level rise) to just one cause (e.g. ocean warming and glacial melt due to positive radiative forcing from anthropogenic greenhouse gases) is too narrow of a perspective.

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What else causes this?

http://sealevel.colorado.edu/current/sl_noib_global_sm.jpg

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79 thoughts on “Pielke on ground water extraction causing sea level rise

  1. OMG…..It is indeed worse than we thought. Add in the contributions from WWTPs and stormwater retention basins along with AGW and the sea will really be going up fast.
    Cluelessness examplified.

  2. As water is part of the Earth’s emission field they are just moving its charge from one place to another, spending, of course, energy to do it, then nothing changes…however if that water is to be used for drinking. be it by vegetables, by animals or men, i.e.by life on earth, and being “life” nature’s trick for overcoming entropy (a.k.a. death), it is a highly valuable activity. For more on general laws:
    http://www.scribd.com/doc/38418051/Unified-Field

  3. Right on. Yours truly commented on the relationship between groundwater and sea level in a recent letter to Earth Magazine.

  4. WaaaHaahaaa! .8mm? That’s .03inch for us old timers. Sorry, but I just can’t get worked up over that. That’s about the thickness of a shaving from my handplane. Somebody should give these guys a useful job – maybe flipping .8mm burgers.

  5. So all the argument about the steric vs eustatic components of SLR, compounded by the uncertainty in the glacial isostatic adjustment (eg Wu et al. 2010) has ignored a potential 0.8mm element from ground water extraction??
    ONE QUATER of annual SLR might NOT be steric and attributable to abyssal heating?
    Or eustatic and attributable to continental ice-sheet melt?
    And errors in the GIA calculation too?
    What do we really know about:
    a. Seal level rise
    b. Ocean heat content as estimated by steric SLR
    c. Ice melt as estimated by eustatic SLR
    I mean, really KNOW?
    Dominic
    This is genuinely block-rocking stuff.
    Dominic

  6. What about the amount of rain that falls on the oceans every year? Right now we’re seeing many inches of unprecidented rain falling on the coastal waters of Florida from the global warming storm Nicole. That’s all going to wash up on the beach somewhere. A lot more rain falls on the ocean than on the land and ALL of the rainwater falling on land runs off into the sea so that’s got to have some effect.
    How long do you have to run your garden hose to raise the level of the Gulf of Mexico an inch? Wouldn’t rain add to the water level faster than irrigation?
    Is it just me or is all this stuff getting a whole lot stoopid-er.

  7. Forgive my saying this, but is it not true that, save for artesian basins closed off from easy water escape, that this water will escape on its own to the sea eventually? It would seem likely that, when the rate of water escape exceeds the rate of water intake in such wells, that the water level would become self-regulating from lack of supply.
    Aquifers are very rarely closed systems, they always have a source, and usually have an outlet. On the Snake River Aquifer, the refill rate, for instance, is about 300 years, to fully cycle the water. Land use changes have altered the flow rate over the refill rate, forcing water levels to drop, and many of the natural springs along the canyon to change.
    In the case of the aquifers under limestone, in most cases, they’re a flowing aquifer, limited by outlet and uptake, and changing over time. The water comes from rainfall in the local area or other areas.
    You may, however, see substantial changes in humidity due to the aerosol effect from sprinklers. A proportion of the water evaporates before it hits the ground.
    Crop changes and land use changes contribute to this effect with changes in albedo. The real question is… is the effect this paper talks about sustainable, and is it something that is not self-correcting due to lack of refill?

  8. An interesting concept; I have not read the article yet but my 1st thought is I wonder what the error bars on this estimate are – you have to know how much water is being pumped world-wide, know how much is re-absorbed into the soil, how much evaporates (and of that, how much is re-precipitated & flows into the ocean), how much of the absorbed water is taken up by plants & re-released by transpiration (and of course how much of that is re-precipitated) , how much is caught in other storage prior to getting to the ocean, etc, etc. This seems like a terribly complicated calculation which should have very large error bars given all the uncertainties of each of these components of the article. None the less, an interesting concept

  9. Addendum to my recent comment: here in Ventura County CA, where the groundwater meets the sea, it’s especially obvious. The hydrologic cycle, which straddles the hydrosphere, atmosphere, biosphere and lithosphere, demands an inter-disciplinary approach, which is often sadly lacking among over-specialized “experts”.

  10. Gil Dewart says:
    September 29, 2010 at 11:30 am
    I would suggest better a “reeducation” of all “post normal and stoned new age scientists” 🙂

  11. All these comments miss the basic, most important point. Humans are bad and destroy the planet. We use so much water and flood the earth.

  12. The Fens in England are an example of thousands of sq miles of peat bogs drained to make the land better for agriculture. The water ends up in the ocean and the Fens have been sinking and are now well below sea level protected by dikes.
    Pumps lift the water up to the rivers as much as 16feet.
    http://en.wikipedia.org/wiki/Burnt_Fen

  13. Here may be another factor (Note- not a peer reviewed study):
    In the spring of 1986, I published my explanation of the black spots in a scientific journal: The Earth’s atmosphere was being bombarded by house-sized, water-bearing objects traveling at 25,000 mph, one every three seconds or so. That’s 20 a minute, 1,200 an hour, 28,800 a day, 864,000 a month and more than 10 million a year.
    http://smallcomets.physics.uiowa.edu/wp.html

  14. From the Press Release:
    ‘Researcher Marc Bierkens says, “We calculated it at eight-tenths of a millimetre per year. This is surprisingly large when compared to the current annual rise in sea levels, which the IPCC estimates at 3.1 mm.” About half of the current rise in sea levels can be attributed to thermal expansion, a little over one quarter to run off from glaciers and ice caps, and the remaining quarter to groundwater depletion. “Although the role of groundwater depletion in rising sea levels had already been acknowledged, it was not addressed in the most recent IPCC report due to a lack of reliable data to illustrate the severity of the situation. Our study confirms that groundwater depletion is, in fact, a significant factor.”’
    So presumably AR4 estimates of the steric/eustatic components of recent SLR were both too high?
    Given the hideously complex task of calculating ‘global average’ sea level rise, I have always wondered how much reliance can be placed on the estimates. The more I learn about satellite altimetry and GIA, the less confident I am in the widely accepted value for SLR.
    The error bars alway seem so tiny: 3.2mm +/- 0.4mm/yr.
    0.4mm either way… Really?

  15. So does this negate the argument that the construction of dams and irrigation systems resulted in less water reaching the oceans (due to increased evaporation and storage), thereby reducing the rate of sea level rise. This was put forward around the time of IPCC AR4 to suggest that sea level rise should be much worse than measured.

  16. As a hydrologist I have heard comments along this line before, though I have no idea whether or not it is right. I know that in some regions of the world they have ancient ground watersources, some a million years old which being depleted, and these are not being recharged. These would contribute to sea level, though you would have to know how many aquifers are like this and how much is extracted each year. Much of what would be extracted would be used for irrigation and evaporate. I also suspect much would evaporate back to the atmosphere and return as rain, as any rise in sea level should also result in an increase in sea extent, thus an increase in evaporation and rainfall. It would however, be ironic if this contribution of groundwater to the sea was the cause of the observed warming (somehow?), as man would still be responsible!

  17. In addition to adding water from aquifers, has anyone considered the effect of sediments transported to the sea via rivers or dust?

  18. Moderator: Clue me in on your decision please. Based on my screen shot I have included my name and email. What am I missing.
    [Patience. It’s only been 2 minutes between posts. ~dbs, mod.]

  19. What about all the water displaced by Ships & Boats including wrecks, pipe lines, Docks, Bridges, Harbours, Off shore wind farms! and land reclamation? It must add something to the sea level?

  20. Willem:
    A couple of years ago in Science, a couple of scientists published the results of their very detailed study into the effects of the impoundment of water behind newly built dams on sea level over the last hundred years. I don’t have access to it now, but the basic result was that the plot of reduction in sea level rise looked like an upside-down “V” over the past century, peaking in mid-century at about 1.0mm/year.
    The reduction now is about 0.5 mm/year less than the mid 20th century, which means that, relatively speaking, 0.5 mm/year of present sea-level rise can be ascribed to the reduction in recent dam building.

  21. I have been wondering (aloud) about this very thing for years, and a few times here in the comments at this site even. I am glad someone with the proper credentials and required information resources has looked into this.

  22. “I also suspect much would evaporate back to the atmosphere and return as rain”
    While this is true, it may not fall where it was evaporated. Take for example the Great Basin of the US where huge amounts of water are extracted from deep aquifers for irrigation. Some of this certainly will percolate into the soil and charge shallow aquifers and much will evaporate but the rain doesn’t fall there, it is still a desert.
    In fact, I doubt much of what percs will reach an aquifer as once the irrigation is done, the plants will continue to absorb the moisture from the soil and put it into the air through transpiration. Pretty much all of it will go into the air to fall at some distant place as rain.

  23. The Total Idiot says:
    September 29, 2010 at 11:28 am
    Forgive my saying this, but is it not true that, save for artesian basins closed off from easy water escape, that this water will escape on its own to the sea eventually?
    The same thoughts came to my stupid head as soon as I read the title then, while scrolling down to the comment box. You got there beore me.. good one.

  24. We would need to know the total amount of groundwater that don’t get replenished fast enough to comment on any of this. If the amount is small compared to the ocean, well nothing there. However, if the amount is significant, more dangerous than sea level increasing, is the dilution of the ocean. A reduction of salinity could be more disastrous than a little rise.

  25. The opposite is true here. Pump out too much fresh water from a well or borehole & you get brine. The groundwater floats on salt water (halocline) and as you consume it the sea water flows in to equal the different head pressure. So I am doing my bit to prevent global inundation, how about you?

  26. Good grief. First of all, not ALL rainwater falling on land ends up in the ocean. There are many basins that have no outlet to an ocean or sea. Examples abound: The Great Salt Lake in Utah, Salton Sea in California, to name just two.

  27. I think Hansen should figure out a way to protest this & then get arrested.
    Maybe he could picket a wellhead at the Ogallala Aquifer? He could wear that cool “Indiana Jones” hat & everything!!
    Folks, it’s called the Hydrologic Cycle. Don’t forget, when we burn any hydrocarbon (coal, oil etc), we generate water in addition to carbon dioxide. Here:
    http://www.elmhurst.edu/~chm/vchembook/511natgascombust.html
    I have a good friend (chemical engineer) who posits that the combustion of coal, oil etc. since the Industrial Revolution has raised sea level, and I’ve never run the numbers to verify, but I’m certain there is some impact.

  28. That’s 20 a minute, 1,200 an hour, 28,800 a day, 864,000 a month and more than 10 million a year.
    That’s about a cubic mile of water per year, assuming each house is 2000 square feet and 10 feet tall. The ocean is 329 million cubic miles, and is about 12,400 feet deep on average. The effect of the small comets would be about 13 microns of sea level rise per year (about a half-thousandth of an inch)
    So to put that into perspective, if 0.8mm is being withdrawn from the ground AND finds its way to the ocean, that is 61x the amount described by the 20 houses per minute.

  29. Surely the volcanoes must be injecting a not too insignificant amount of H2O into the atmosphere from deep within the Earth’s crust? For example, it is estimated that Mount Etna releases roughly 200,000 metric tons of water vapor into the atmosphere each day. It’s also interesting to note that in 1991, Mount Pinatubo ejected 491 million tons of water directly into the atmosphere during a single eruption. I’m guessing all that water vapor eventually rains down on Earth and goes somewhere like, you know… the oceans.
    Then of course there are the small comets and icy meteorites that are constantly bombarding the Earth. No one has any idea how much water those are contributing to the oceans — but we know it’s happening.

  30. Which Pielke? The first link goes to Pielke Sr.’s site, but perhaps you should have a more visible identification.
    😉

  31. “All the rivers run into the sea, yet the sea is not full: unto the place from which the rivers come; thither to return again.” Ecclesiastes 1:7
    Hey, they figured this one out around 300 BCE. How long does the AGW crowd take to catch on to things?

  32. Are we now simply accepting the sea level rise based on altimetry data from Topex and Jason without any conjecture at all? Surely, there is some doubt about this rate (3.2 mm/yr), given that many, many other, largely, tide-guage based measurements give around half this rise. For example, Church and White, 2006 give 1.7 mm/yr; Holgate, 2007 around 1.7 mm/yr; Domingues et al, 2007 ~ 1.5-1.6 mm/yr; Woppelmann et al, 2009 – 1.58 mm/yr; Leuliette and Miller, 2009 – 1.5 mm/yr.
    I always thought that altimetry data were supposed to be corrected with data from properly sited tide guages that allowed for vertical geology movements to be taken into account. How has this almost double measurement by altimetry not come under further question? While tide guages have become less frequently used in modern years, surely there is enough of an overlap period with altimetry to resolve this issue. It is a really big deal.

  33. All the glacier melt from CAGW is providing, at most, a theoretical 0.6mm increase per year in sea levels. Extraction around 0.8 according to this article.
    The amount of water contained in the atmosphere- if it all fell at once- is equivalent in a year to 25 mm of increase over the whole surface of the planet, so around 40mm when directed into the ultimate repository-the oceans.
    Accepting that some water is always going to be locked up in transit in rivers or impounded in reservoirs, the annual rainfall and its affect on sea levels would seem to be potentially a much more acute problem than sea level rise from melting glaciers.
    As the earth gets naturally warmer it holds more moisture (and Co2) For this to have no impact on sea levels (and overall Co2 levels) it must remain in broad equilbrium, that is to say the amount of precipitation equals the rate of evaporation.
    However, more warmth tends to lead to cloudier skies and more rain, so therefore leading to a net increase in precipitation and a reduction in evaporation. It wouldn’t take too many years of high rainfall and low evaporation to make a considerable difference to ocean levels and one considerably greater than glacier melt or groundwater extraction.
    Can I have some funding to explore this please?
    tonyb

  34. I think a lot of people on this blog are losing sight of the significance of this announcement.
    If the amount of Eustatic water from borehole depletion is increased from 0.1mm/yr (IPCC AR4) to 0.8 mm/yr (Pielke), there is now a lot less heat that has entered Earths system. Where before the IPCC used (or should have used) the oceans rise as a gage of heat content.
    The article above mentions a total rise of 3.2 mm/yr, but the short term present rate is closer to 1.6 mm/yr. Taking all the eustatic inputs into the oceans rise would now indicate that the Steric rise is negative. This would fit with the findings of the Argos bouy system; a cooling ocean.

  35. BBD says:
    September 29, 2010 at 11:54 am
    “Given the hideously complex task of calculating ‘global average’ sea level rise, I have always wondered how much reliance can be placed on the estimates. The more I learn about satellite altimetry and GIA, the less confident I am in the widely accepted value for SLR.
    The error bars alway seem so tiny: 3.2mm +/- 0.4mm/yr.
    0.4mm either way… Really?”
    The notion that we “know” what MSL is to a millimeter or tenth of a millimeter accuracy is such utter hogwash that I am continually amazed at the number of threads here and elsewhere, even where the vast majority of commenters are self proclaimed skeptics, in which that dubious notion is implicitly accepted as fact in many arguments.
    To save time I will reproduce a part of a comment I posted on one of the Trenberth “missing heat” threads a few days ago
    “I would recommend once again that people study this document
    http://www.osdpd.noaa.gov/ml/ocean/J2_handbook_v1-3_no_rev.pdf
    It is the data products handbook for the Jason 2 satellite system, which is the latest and greatest of the number of satellites that have been the source of data used to calculate MSL as the basis of that oft displayed graph of rising sea level, The pertinent section for this discussion is 2.3.1 where they describe how they hope to achieve globally averaged RMS accuracy of 3.4 CENTIMETERS, which would seem to be a fantastically optimistic hope since in the following table they indicate that there ability to measure significant wave height is limited to accuracies of o.4 to o.9 METERS
    In other words we have another example of data quoted to phenomenal levels of precision, where the underlying accuracy is numerous orders of magnitude worse. If you lay a +/- 3.4 cm error band on that rising MSL graph it nicely covers the entire difference from the beginning to the end and as I said this is the latest and greatest sat. which is probably several orders of magnitude better than the sats that provided the earliest data”
    Personally I think if they are getting +/- 1 meter accuracy for MSL with satellite altimetry it is probably a minor miracle, given the multitude of mostly modeled corrections and the physical limitations of the ranging method itself.

  36. It’s an interesting topic. I find it hard to believe that you can accurately measure this. You are talking about 10’s of thousands of communities with dozens of variables that would change from year to year.

  37. Our problem here on the coast is salt water infiltration as a result of groundwater extraction. As noted above, this is where several fields of study come together: geology, oceanography, meteorology, biology, agronomy, soil science. As to the latter, it’s about time we heard more about that essential resource, soil, in these discussions.

  38. This is a little too simplified. In my area 98% of all the water we use goes into septic systems and dry wells and percolates back into the water table. Virtually none makes it to the rivers much less the oceans.

  39. The water taken from an aquifer is only relevant for aquifers which refill more slowly than water is being taken out, and more is being taken out than would have otherwise leaked out. A shallow well from uncapped sandstone in Florida is irrelevant, as that aquifer will be quickly refilled from rainfall. An aquifer with 10,000-year-old-water which is being emptied ten times faster than it is refilling is relevant, unless the water being taken out has reduced the outflow by the same amount. The simplest example is an aquifer which is completely sealed from the outside, as any water taken out of there will end up in the ocean and the space won’t trap replacement water.

  40. How does that effect the ocean heat content? You’re taking water that has heat that is from the earth’s interior and adding it to the oceans, or is it the other way around? Are you diluting the heat content of the oceans by adding ground water?

  41. Extraction of groundwater, over a long period of time, leads to local drops in ground level. Witness for example, Venice in Italy, Jakarta in Indonesia, or the famous New Orleans ie any city that allows extraction of ground water. I read a paper a number of years ago, where sea levels relative to the Australian landmass appear to be falling, but the cities with the extraction of ground water are sinking. Most of the old sea level measures are based in cities, which means by most measures, sea levels are indeed rising, in that location, but one to two hundred kilometers away sea levels are falling, with respect to the local land mass. I suspect the paper is a gross over simplification.

  42. This is getting out of hand! Most aquifers are recharged by rivers. Where this is the case, the river itself reduces its flow to the sea if the head above the aquifer is positive. If the aquifer is not used it feeds the river. Other commenters have also pointed out that the water tied up in vegetables, livestock and drinking water use was going to get used anyway, and evapotrans and rain on land would be returned, etc. These guy’s must be Post Normal hydrologists. Old time bluesman Robert Johnson sold his soul to the devil at “The Crossroads” but at least he got to master the guitar in exchange. What do these people get out of it?

  43. About a year ago there was an article (in Science?) which totaled up all the water held behind dams and showed that it significantly decreased sea level rise. If it ain’t one thing it’s another.
    REPLY: Well without a citation, it’s just rabbett pellets – Anthony

  44. Dave Wendt – I have to agree with you.
    I did a personal test on sea level rise recently when I returned to a beach I knew very accurately as a child. ( 10) I knew all the rocks that projected out from the beach and how they related to the sea level. When I returned at low tide I found the relationship with the sea level to be exactly the same after 50 years. There was no discernible sea level rise.

  45. The late Prof Lance Endersbee from ANU believed that the water in the aquifers has come up from the mantle below, they are not filled with rainwater seeping down.
    He believed the draining of our great aquifers, especially the Great Artesian Basin in Australia was more of a threat than AGW which he had little time for.

  46. Eli Rabett says:
    September 29, 2010 at 7:36 pm
    “About a year ago there was an article (in Science?) which totaled up all the water held behind dams and showed that it significantly decreased sea level rise. If it ain’t one thing it’s another.”
    Eli is referring to the same article I referred to earlier today ( Curt says:
    September 29, 2010 at 12:38 pm ). I now can find the report. It is:
    B. F. Chao, Y. H. Wu, Y. S. Li, “Impact of Artificial Reservoir Water Impoundment on Global Sea Level”, Science, 11 April 2008, Vol 320, pp. 212-214. (behind paywall)
    But Eli misses the most important aspect of the report, that the amount of impoundment has decreased significantly since the 1960s and 1970s because we are building fewer dams now. They show a very steady decline in the amount of “global sea level drop” (their term) due to impoundment from a peak of about 0.7mm/year in the 1960s, to about 0.2mm/year in the 2000s. So even if there were a recent increase in net sea level rise of 0.5mm/year since the 1960s (which the best tidal gauges do not show), it could be entirely due to this change.

  47. Terry Miller says:
    September 29, 2010 at 12:21 pm
    In addition to adding water from aquifers, has anyone considered the effect of sediments transported to the sea via rivers or dust?

    Yeah. I did a back of the envelope calculation of sealevel rise due to sediment transport, and it comes out to a couple hundredths of a mm, about .03mm. This doesn’t include land reclamation projects though.

  48. The stupidity and shortsightedness on display here is absolutely astonishing…
    “A quarter of sea level rise is due to humans pumping out groundwater and it eventually ending up in the sea. So sea level rise due to climate change is overblown, and since this aquifer water is used for drinking and irrigation, it’s an useful activity”.
    And nobody ever stops for a second to think what people will drink and irrigate their crops with after the aquifers have been depleted? Which is not that far, in fact quite close, into the future in many regions
    How is that possible??

    AnonyMoose says:
    September 29, 2010 at 4:53 pm
    The water taken from an aquifer is only relevant for aquifers which refill more slowly than water is being taken out, and more is being taken out than would have otherwise leaked out

    Of course, it had never occurred to you that the places where aquifers aren’t depleted fast enough are also the ones where rainfall is insufficient and where people are most dependent on them. Which, BTW, includes a very large number of people and an even larger proportion of world’s agricultural production.

  49. And if you are extracting water (and oil) from the ground, the ground often subsides a little**. So while sea levels are increasing due man’s activities, the land is also sinking.
    ** They used to say in UK coal mining that for every 4ft of coal taken out below, the surface sank by 1 ft.

  50. Well, since sea level rise has dropped to around 1.3mm year since 2005, this would account for most of it. However, I wonder if they have considered how much more natural flow there would be in the river estuaries if the water wasn’t being extracted from the water table higher up the valleys.

  51. I would have thought that irrigation water would, through evapotranspiration, end up back in the atmosphere to fall as rain and become ground water again. A little tenuous I would have thought especially when you think how much water would go to raise sea levels by 0.8mm. Probably more than falls as rain per day.

  52. And this will be spun thus.
    Not only are massive sea level rises due to Fossil Fuel combustion but we’re making the problem worse by our exploitation of Fossil Water.
    Conclusion. We’re worse than we thought!

  53. RoyFOMR says:
    September 30, 2010 at 2:51 am
    And this will be spun thus.
    Not only are massive sea level rises due to Fossil Fuel combustion but we’re making the problem worse by our exploitation of Fossil Water.
    Conclusion. We’re worse than we thought!

    There is no need for spinning it, that’s exactly how it is. Climate change and Peak Fossil Water are simply different aspects of our global ecological overshoot. The latter rarely gets paid much attention so we are indeed much worse than most people think

  54. garymount says:
    September 30, 2010 at 3:21 am
    You can extract water from air for drinking purposes. The 2010 Vancouver PNE Prize home had such a system built in.

    You can also desalinate it. If you had the energy to do that. Unfortunately, the coming shortage of concentrated sources of energy is yet another aspect of our global overshoot

  55. I wondered and posted about irrigation here a couple of years ago. The numbers from the UN for irrigation are enough for about 2mm/year, but that was all irrigation, not just groundwater. Regardless of where it comes from, center-pivot systems that spray the water add some to the atmosphere.

  56. I suspect what anyone says re: a 3.1mm/yr. sea level rise, when the satellite only has an accuracy of some 25-35mm per pass over the ocean. Apparently, it is assumed that multiple passes will somehow reduce the error to some 10X less, but do we really know this to be the case or is it just intuitive? After all, doesn’t tidal gauge info dispute the 3.1 number, which should make the satellite data suspect, at the very least? To me, as a lay reader, SLR is more like 1.7 to 2.0, which would make extraction influence more like 40% or so. Can someone out there show me that the satellite measurement of 3.1mm is real?

  57. From GM on September 30, 2010 at 12:44 am:

    The stupidity and shortsightedness on display here is absolutely astonishing…

    We know, yet you still keep coming back with your zero-sum, everything-is-getting-used-up-too-fast, we-are-running-out-of-everything-right-now-and-we-will-all-die-quicker-because-of-it, the-species-would-be-better-off-if-most-of-the-people-were-dead, doomy-gloomy nonsense and adding to the total.
    Genus Malthusian, why can’t you just accept this is a very large planet with individual resources from sources we can tap for hundreds and thousands of years, then switch to other sources of individual resources for as long or longer, and we can also substitute one resource for another? We’re a very creative species, we will survive and prosper, with or despite you.
    Since you are again failing to frighten we adults with your Peak Whatever of the day, just go past Peak Pessimism, and try something other than sounding like a little kid with a bag of candy screaming “I can’t share, it’ll be all gone and I’ll never get anymore!” We are far more at risk from an imagined resource scarcity than any real one. Is that your game, to bring about the collapse of civilization and the death of billions by panicking people into hoarding anything possible by convincing them it’ll soon be gone?

  58. Just a thought… As sea-levels have been reportedly rising, has there been any measurable drop in salinity commensurate with the assumed influx of fresh water? I realize that any such change, even over many years, might be too small to measure.

  59. Of course, extracting ground water in say, the area around San Francisco or the area around LA, lowers the level of the land, and makes it appear in those locales that sea level has risen. Witness the case of Alviso.

  60. I agree in rough outline with TheTotalIdiot’s objections. It seems RP is being a bit too glib in his figuring. Perhaps there is an effect of the sort he’s claiming, but it would only be valid insofar as aquifers are actually being depleted, and there is evidently an upper bound on this. The amount of ocean volume increase by this cause (neglecting temperature and pressure considerations) could not exceed the amount of volume decrease in the worldwide groundwater reserve.
    If he is correct and we are steadily increasing ocean volume by 8mm/yr this translates into a rather large depletion of aquifers! I hate to rally to the alarmist side, but I would suggest that this should be a matter of serious concern, if true. But I think not — or not to the degree RP’s figures suggest. Surely much of the groundwater is simply refreshed from rainfall, and some was being depleted (and refreshed) anyway, by underground runoff. In terms of the freshwater reserve, a lot of groundwater is distinguished from surface water only by being underground — there is a continuum between them. Drawing from a well near a lake is hardly different from drawing surface water from the lake. There IS some aquifer depletion in dry areas, but I expect the effect is small compared to RP’s figures.
    I think protection of aquifers, in dry regions, is a serious concern and, in developing countries, alternatives to groundwater must be sought for irrigation if agriculture is to be improved (this is also true even when no aquifer is available). I thought this was a practically unsolvable problem until I looked at solar tower generation of power, which has the happy side effect of extracting H2O from the air on a large scale. So you get a steady, relatively cheap source of electricity PLUS a steady, clean source of fresh water. Imagine one of these towers outside each of thousands of small villages of Mauritania (for example). If you watch the video I link to you see that it gives a modest nightly collection of water; but this is a “small” tower. As the scale increases, the square footage of the collection area increases quadratically and so does the volume of water collected. It is naturally situated for “greenhouse” agriculture with no extra infrastructure, but with a large enough tower, H2O could be harvested for potable domestic use as well. One thing not mentioned in the video is that there is probably an extra amount of condensation on the inside of the tower itself due to adiabatic expansion…

  61. RE: “but one to two hundred kilometers away sea levels are falling”
    A bit WSW of Bangkok, along the Gulf of Siam, there used to be myriad salt evaporators set up in what used to be saline intertidal wetlands and swamps with indigenous mangrove, pickleweed, etc.
    Today, the few that survive are finding it necessary to replace the old style windmill type pumps with modern ones iorder to pump the increasingly distant saline water but most simply fold or sell out to shopping mall builders. Where mangrove and pickleweed once grew now there is acacia scrub. Yeah, sea level rise … right.

  62. “…Yeah, sea level rise … right.”
    The area you speak of is tectonically active and you present no evidence that the salt ponds have not been closing due to the changing sea level rather than economics (not to mention local techtonics). Nor do you present any evidence that the sea level has actually fallen there.
    http://thailand-business-news.com/news/top-stories/19335-thailands-capital-is-under-threat-of-being-underwater-within-a-century/

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