RealClimate

Comments

RSS feed for comments on this post.

  1. Eh, language nit:

    “What makes sea level rise” vs. “What causes sea-level rise”

    ;-)

    [Response:What makes you think this? Is the same grammar, I use rise as a verb here just like think. Anyway, here's a Dutch guy living in Finland discussing the English language with a German guy ... We need natives. -stefan]

    Comment by Martin Vermeer — 1 Jun 2012 @ 12:05 PM

  2. If we assume again that Pokhrel’s numbers are roughly twice as high as this, also for the future,

    Yes, but how sensible is this assumption? Isn’t the shape of their curve very different?

    Article here. According to their Figure 1, the depletion of groundwater (GWD) is an almost linear function of time, meaning that the extraction rate would be constant… if this continues into the future, the “calibration” and “projection” effects for the semi-empirical approach would precisely cancel :-)

    (Such precise cancellation doesn’t happen in our paper with either Wada et al. or Konikow.)

    [Response:Indeed - I noticed as well that there is very little increase in the rate of groundwater extraction in Pokhrel et al, in contrast to other studies. In my view that is another feature that does not sound all that credible. -stefan]

    Comment by Martin Vermeer — 1 Jun 2012 @ 12:32 PM

  3. A little light relief http://denialdepot.blogspot.co.uk/2012/05/summer-shattered-no-warming-since.html#comment-form

    Comment by Louise — 1 Jun 2012 @ 12:35 PM

  4. The statistical minutia notwithstanding, the Saudi experiment in pumping their aquifers for irrigation proves the theory is right. Their aquifers are depleted and most of the water has presumably ended up in the ocean.

    Had they, or anyone else, irrigated instead with desalinated water or water that was captured before it ended up in the oceans then their aquifers would remain, sea levels would be less and the irrigated desert would be a Natural carbon sink.

    The area of the Earth’s surface covered by the oceans is 361 million square kilometres. A few years ago the mean estimate for sea level rise was 480 mm, which is the amount used in this example.

    To maintain current levels it would be necessary to sequester 173,280 km3 (361,000,000 km2 X .00048km) of desalinated water in the world’s hot desert – if this was the only approach to the problem.

    Warm deserts cover an area of 15,559,000 km2, therefore .0111km (173,280 km3/15,559,000 km2) of water will have to be taken up in the deserts over the next hundred years or 1.11 m every year.

    According to the U.S. Geological Survey, for the year 2000, the rate of application of water for irrigation purposes in the U.S. was 2.48 acre-feet, which is near enough the desert take-up required to prevent sea level rise.

    The lowest hanging fruit for the Middle East and North Africa, it seems to me, are their oil tankers deadheading with salt water as ballast rather than fresh water in segregated collapsible bladders that would keep the water clear of oil residue.

    According to the 2006 Review of Maritime Transport by the United Nations Conference of Trade and Development, Geneva, in 2005 total world shipments of tanker cargoes reached 2.42 billion tons of which 76.7 per cent was in crude oil for a total of 1.85 billion tons.

    The specific gravity of Texas crude oil at 15.5°C is 873 kg/m3 whereas purewater at 4°C = 1000kg/m3, thus the world tankers transported roughly the equivalent of 1.62 billion tons of pure water which is 1.62 BCM.

    Saudi Arabia is the largest producer of desalinated water in the world. In 2004 the volume of water supplied by Saudi Arabia’s government-operated desalination plants reached 1.1 BCM and by 2009, new plants were expected to add an additional 0.58 BCM of water per year.

    Deadheading tankers could therefore match the output of Saudi desalination plants and could presumably double the 32,000 km² the country has currently under irrigation.

    If all of the world’s hot deserts were irrigated, they would sequester 6.8 gigatons of carbon a year whereas according to the Kansas State Soil Carbon Center, the atmospheric carbon pool is currently expanding by about 6.1 gigatons.

    Converting ocean heat to energy with OTEC is another viable means of addressing the sea level problem but it seems the easiest approaches should be tried first.

    Comment by Jim Baird — 1 Jun 2012 @ 2:29 PM

  5. Jim Baird, that looks worthy of thought. I looked at your website:
    http://www3.telus.net/gwmitigationmethod/Summary.htm

    I don’t know enough to identify whether it could work, and it appears you are involved in the idea as business – money with mouth, one might say.

    A little aesthetic vs. readability quibble: You might make the type a color that contrasts in value with the glittering sea – I had to “select” to create contrast and make it readable.

    Comment by Susan Anderson — 1 Jun 2012 @ 3:46 PM

  6. > readability
    This tools removes all the aesthetic, leaving readable text.
    Bookmarklets for Zapping Annoyances – Jesse Ruderman

    Comment by Hank Roberts — 1 Jun 2012 @ 4:38 PM

  7. Thanks Susan Anderson, I’ve received that complaint before – the aesthetic as opposed to money with mouth.

    Will have a look at revision.

    Comment by Jim Baird — 1 Jun 2012 @ 5:27 PM

  8. Susan:

    I see what you mean; the white text blends into the sunlit water on the right-hand side of the column.

    A quick-and-easy fix is to simply highlight all the text. In this case it stays white, but the background turns blue. You can scroll it up and down without losing this effect.

    Comment by Chris Winter — 1 Jun 2012 @ 7:01 PM

  9. Chris Winter, thanks for the great tip and easy fix.

    Comment by Jim Baird — 1 Jun 2012 @ 8:23 PM

  10. Jim Baird #4:

    The statistical minutia notwithstanding, the Saudi experiment in pumping their aquifers for irrigation proves the theory is right. Their aquifers are depleted and most of the water has presumably ended up in the ocean.

    If you’re right, the other implication is that this is a short-term effect because there;s a limit to the amount of fossil water that can usefully be used. While there are some huge aquifers out there, it’s hard to imagine they are on the same scale for example as ice sheets that are up to kilometres thick on a continental scale.

    In any case I don’t think you can dismiss the data as “statistical minutiae”. Either it’s reasonable to add up the numbers in a certain way or it’s not.

    This article is another good example of how science is done. A paper is published with cause to doubt the result. The follow up is discussion of whether the result is reasonable followed up I would hope by a paper correcting any errors found in the paper. Even the Nature family can sometimes let through bad science, and this can and should be corrected. Those wanting to make a political case will of course focus on the results that please them so this paper will get wide circulation whether shown to be flawed or not.

    [Response: Good point: before we published our projections last year, I asked a groundwater hydrologist whether this was reasonable or whether we'd run out of fossil water before. He said there was plenty enough for those projections (i.e. up to raising sea level by 10 cm). Would be great if some knowledgeable hydrologists would join the discussion here! -stefan]

    Comment by Philip Machanick — 2 Jun 2012 @ 12:50 AM

  11. Do they give region by region, or aquifer by aquifer estimates? If so, couldn’t the models be compared with the observations here? If they agree then maybe the models are right. If they don’t, then the observations are more likely to be right.

    Comment by MarkR — 2 Jun 2012 @ 3:44 AM

  12. #1 They’re both sound OK.

    for similar reasons
    “what makes hair colour change” and
    “what causes hair colour change” are both OK.
    (verb applied to a compound noun)

    It doesn’t work with adverbs though
    e.g.
    “What causes global warming?” is OK
    “What makes global warming?” isn’t.

    similarly
    “What makes dogs bark” OK
    “What causes dog-barking?” OK if strange.
    “What makes dog-barking?” Borat

    Comment by prianikoff — 2 Jun 2012 @ 5:37 AM

  13. #12 oops!
    editing typo line 1
    “They both sound OK” or
    “They’re both OK”

    Comment by prianikoff — 2 Jun 2012 @ 5:58 AM

  14. Hi Guys
    Here in NZ we use a lot of groundwater – however most or nearly all is very young with the aquifers being re-charged annually

    I know there are some large fossil aquifers – but I would have expected most countries to be more like NZ

    Comment by duncan cairncross — 2 Jun 2012 @ 6:56 AM

  15. Jim Baird, Even it all tankers traded with Saudi Arabia, that amount of fresh water is 1 cu km – of no consequence. However, if we ratchet bask the vision to simply warehousing water in any form (forget the greening of the deserts), there are plenty of areas where seawater could be pumped into geologic basins that have no role in irrigation or use as potable water. A good place to start would be uninhabited depressions that are below sea level – e.g. the Qattara Depression (http://en.wikipedia.org/wiki/Qattara_Depression#cite_note-19) were 1,213 cubic kilometers could be poured to bring 19,605 square-kilometers up to sea level, producing a transformative inland sea.

    Comment by Clifford Goudey — 2 Jun 2012 @ 9:03 AM

  16. Last week the science community was shocked by the claim that 42% of the sea-level rise of the past decades is due to groundwater pumping for irrigation purposes.

    I think the 42% figure relates to total net terrestrial storage contribution, inclusive of negative reservoir storage changes. Their groundwater depletion figure on its own is ~1.1mm/yr, over 60% of observed sea level change.

    Comment by Paul S — 2 Jun 2012 @ 9:15 AM

  17. Philip Machanick (10), my interest is in resolving the problem regardless of its source. I agree with you the threat from ice sheets would seem exponentially greater than our ability to pump aquifers dry. The Saudi experiment however demonstrates that if you try hard enough you can impact sea levels through this mechanism.

    How then would you address the ice sheet problem?

    A recent study by researchers from the Canadian Centre for Climate Modelling and Analysis at the University of Victoria and the University of Calgary concluded that even if we stopped putting CO2 into the atmosphere today the impact from the greenhouse gases already in the atmosphere will cause unstoppable effects, including sea level rise of at least four metres, over the next 1,000 years.

    The reason is the ocean’s thermal inertia.

    The science would indicate then, it seems to me, we should convert as much of the accumulating ocean heat – 330 TW a year over the period 1993 to 2008 according to the NOAA study published in Nature 05/20/2010 – to energy in accordance with the First Law of Thermodynamics.

    OTEC is the technique to accomplish this and it would be a triple threat against sea level rise. You would cool the ocean limiting thermal expansion, limit the erosion of icecaps for the same reason and cooler oceans dissolve more CO2.

    Irrigating deserts is another tool which addresses both the cause and effect.

    It seems to me totally irrational we are doing neither.

    I am accused above of having an economic interest. To date the capital flow has been all outward over a period of 25 years. I make no apology for wishing this circumstance would reverse and as quickly as possible.

    It seems to me there is far too little Constructive Capitalism being practiced at the moment. And perhaps far too much study as well, when what is required is action.

    Comment by Jim Baird — 2 Jun 2012 @ 9:27 AM

  18. Could salinity tests or other be used to estimate fresh water flows into the oceans near land?

    Comment by CPV — 2 Jun 2012 @ 9:42 AM

  19. Clifford Goudey (15), no objection to anything that works.

    By my calculation above, 173,280 cubic kilometers of water would have to be taken up. The Qattara Depression would only make a dent and seems to be one of the larger areas where this approach is possible.

    It is also likely going to be a problem convincing people of these regions their land should be a sacrifice zone.

    Those whose land would be turned into productive fields are likely to be more responsive.

    Didn’t the Romans salt Carthage so that nothing would grow there?

    One square kilometer is a pittance but it is a start and it seems like an opportunity being squandered.

    Comment by Jim Baird — 2 Jun 2012 @ 9:51 AM

  20. Do any of the studies/models/projections take into account changes in the water holding capacity of soils? Just curious as i know a few percentage points increase in soil organic matter translates into substantially higher water holding capacity. Obviously current global trend in agricultural land is very much in the other direction – ie decreasing organic matter therefore decreasing water retention

    Comment by Tim — 2 Jun 2012 @ 10:23 AM

  21. to Jim Baird: I’m afraid, You can’t get the heat out of the ocean as it is heat of quite a low temperature level and You end up shoveling the lion’s share of it to somewhere else with even a lower temperature level which makes in sum no difference concerning thermal expansion.

    Comment by Dominik Lenné — 2 Jun 2012 @ 10:38 AM

  22. Tim, Deserts can reach temperatures as high as 45 degrees C and will radiate this heat back to the atmosphere, exacerbating the warming problem.

    Vegetation influences how hot the surface of the land can become. In areas where vegetation is dense, the land surface temperature very rarely exceed 35 degrees C. As you rightfully point out it also retains moisture.

    Comment by Jim Baird — 2 Jun 2012 @ 10:57 AM

  23. > changes in the water holding capacity of soils

    Good question, that. It could change reversibly or irreversibly — and the same question is worth asking about aquifers. Some collapse physically when the water’s drained out, and can’t refill (Kettleman in California is a famous example); in other materials the empty space can hold the void spaces open for a while so there’s a place water can fill again later.

    http://www.scribd.com/mschoenberg/d/39335365-Groundwater

    ‘The term “base-level” is usually related to surface water drainage systems and erosion processes. Several definitions exist to this term in the literature, one of which is “The lowest level to which a land surface can be reduced by the action of running water”. In general, the groundwater base-level was described as “a drainage level for the aquifer that represents the lowest groundwater level that will occur from groundwater flow only” (Olin 1995). It is herein, in analogy, defined as the ultimate discharge zone down-gradient of groundwater basin….’

    Comment by Hank Roberts — 2 Jun 2012 @ 11:03 AM

  24. just had a very rough bash at some numbers for soil water retention.
    1% increase in soil carbon results in additional 60000gallons of water held per acre
    Approx 16.6billion acres farmland globally (7.6 arable, 9 grazing)
    So 1% increase in soil carbon across the board would mean something like 4500cubic km of additional water stored on land.
    Pre agriculture soil organic matter levels of 10-15% were not uncommon. Post agriculture levels of below 2% are the norm. Also read of a rancher who has increased his soil organic matter content by 8% in less than a decade.

    Comment by Tim — 2 Jun 2012 @ 11:15 AM

  25. In February I brought up this topic on Skeptical Science. It is interesting to see the same topic brought up here. Wonder if the Skeptical Science crew will go after if as much as they did when I brought it up.

    http://www.skepticalscience.com/news.php?p=2&t=67&&n=1278

    Comment by Norman — 2 Jun 2012 @ 12:59 PM

  26. Dominik Lenné, if you are not converting heat to work by OTEC then you are producing the electricity mystically.

    Granted conventional methods pump over 20 times more heat to the depths than energy produced.

    Richard Smalley suggested 10 billion people would need 60TW by 2050 with a good deal of being required to produce water.

    If you created this 60TW with conventional OTEC you would pump 1.2 peta watts to the depths, which is the same amount as heat driving the Thermohaline. Obviously not a good situation.

    I suggest therefore a counter-current heat transfer system that captures the latent heat of condensation in a condensed working fluid and brings it back to the surface. Ideally you would produce Smalley’s 60 TW by extracting 120TW of the 330 currently being accumulated and dumping 60TW to the depths.

    Major hurricanes can release between 50 and 200 Terawatts of heat energy and there are as many as 21 major storms a year and many smaller storms. Clearly therefore the oceans are capable of producing all of the renewable energy the world needs provided the bulk of the heat used vaporize the working fluid is recycled back to the oceans surface in the same matter as a hurricane returns heat to the earth’s surface as falling rain.

    Produce 60 TW with fusion or fission on the other hand and you generate an additional 120 TW of entropy, which invariably ends up in the ocean to melt Antarctica all the quicker.

    Comment by Jim Baird — 2 Jun 2012 @ 1:31 PM

  27. Subglacial erosion (Pine Island glacier):
    http://www.agu.org/pubs/crossref/pip/2012GL051651.shtml

    I remember only a few years ago, ‘moulins’ were unexplained but thought to be produced very slowly — then someone imaged one being produced rapidly under one of the Antarctic glaciers. This stuff all used to be thought to happen slowly.

    Surprise …

    Comment by Hank Roberts — 2 Jun 2012 @ 1:45 PM

  28. @24 >Also read of a rancher who has increased his soil organic matter content by 8% in less than a decade.

    Tim, do you have link for this one?

    Thanks–

    Comment by Gordon Cutler — 2 Jun 2012 @ 1:49 PM

  29. http://www.unl.edu/nac/atlas/Map_Html/Stable_and_Productive_Soils/National/Soil_Organic_Matter_Content/Soil_Organic_Matter_Content.htm

    “This is the map of soil organic matter derived from the national STATSGO database which was developed by the Natural Resources Conservation Service. The color scale ranges from gray sandy soils to dark brown loamy organic peats. Again the midwest stands out, and so does the Okefenokee swamp in south Georgia and the Everglades of Florida.

    Taken from the report:
    A New High-Resolution National Map of Vegetation Ecoregions Produced Empirically Using Multivariate Spatial Clustering by William W. Hargrove and Robert J. Luxmoore “

    Comment by Hank Roberts — 2 Jun 2012 @ 2:54 PM

  30. There are certainly some fascinating ideas in the geo-engineering department, including desert greening. Other than the question of scale, and ‘likely’ rates of deployment and long-term C sequestration, a question that might need some firm answers is what side-effects (particularly regional) may arise from albedo changes and all that extra moisture being evaporated/transpired from those land masses. I suspect there are some interesting factors to study there.

    Comment by A.J. — 2 Jun 2012 @ 3:19 PM

  31. When I saw the post title, I immediately assumed this was about land subsidence due to pumping aquifers (could be oil fields as well). But I guess subsidence would be too restricted or localized to have a global impact.

    But I also wonder about the identification of the source of pumped water that is being considered, and its fate. Do the pumpage figures reflect ground water that is not circulating (in which case it will eventually discharge)? How do irrigation waters divide into wet biomass, runoff, and evapotranspiration? And what about pumpage that derives at least a component from induced recharge from streams?

    Comment by Mark Duigon — 2 Jun 2012 @ 4:34 PM

  32. Many thanks for this Stefan, really helps in understanding the issues

    Comment by john byatt — 2 Jun 2012 @ 4:38 PM

  33. A.J. and any other interested parties.

    Dr. James Lau and I have formed a loose organization we call the Ocean Energy Group to try and advance OTEC as an energy/environmental solution and a major solution to sea level rise. Our association evolved from a mutual commitment to a deep water condenser, which circulates a small volume of working fluid to the depths and pumps the condensed fluid back rather than circulating massive amounts of hot and cold water. This we believe overcomes most of the cost and environmental concerns inherent in the conventional OTEC approach.

    Our technology is evolving and we still are strongly debating the merits of CO2 as a working fluid and the necessity for counter-current heat flow.

    Dr. Lau has made a brilliant suggestion of scaling the approach from a lab scale consisting of two tanks representing the ocean’s hot and cold reservoirs. Conditions in any ocean could be replicated in these tanks and the effect of OTEC on the reservoir tested. It would also be the cheapest way of optimizing the approach before scaling.

    Our efforts would benefit from expansion and the kind of debate exemplified on these pages.

    Anyone interested can contact us at oceanenergy at telus dot net.

    Comment by Jim Baird — 2 Jun 2012 @ 5:17 PM

  34. Re- Comment by Jim Baird — 2 Jun 2012 @ 10:57 AM currently at #22:

    I am no expert, so please explain for me how higher ground temperature in the desert versus, for example, below a forest canopy is an important factor for increasing global warming. It is my understanding that desert soil has an albedo around 2.5 times that of forest foliage.

    Steve

    Comment by Steve Fish — 2 Jun 2012 @ 6:32 PM

  35. I agree with Steve Fish, the tradeoff greening and humidifying a high-albedo dry-air desert is going to lose as well as gain. The total volume of water can’t change sea level by much, the water will come back via the atmosphere.

    The other tradeoffs involved with trying to change the Sahara or the Sonora or Australia’s deserts into irrigated sites have been assessed over and over for a long time. Nobody’s solved the problem of salinization of irrigated soils, nor of contaminating the groundwater with nitrates — anywhere, yet, have they?

    Heck, you could just desalinate Mediterranean water and let it flow downhill to restore the diminishing Dead Sea, make hydropower, and — hmmm, what would you do with all the salt?

    “Method” patents are pretty weird. Either the processes described are already in existence and proven (in which case you can do the business case numbers) or they’re not.

    If OTEC becomes viable, the energy needed to pump all that water could be used to replace fossil fuel and the net gain would I think be greater, faster, with no downsides.

    But this is already way off topic.

    Comment by Hank Roberts — 2 Jun 2012 @ 7:12 PM

  36. Steve Fish, by definition deserts lack water the evaporation of which has a significant cooling effect due to the absorption of the latent heat of evaporation.

    Irrigated deserts would further cool the deserts through the process of evapotranspiration.

    DESERTS ARE COLD AT NIGHT:Because of the lack of water in the ground, and little water vapor – a significant greenhouse gas.

    Comment by Jim Baird — 2 Jun 2012 @ 8:09 PM

  37. If agricultural groundwater release figures significantly in sea level rise, the Coasean economic remedy would be to reduce evaporation in agriculture.

    Comment by Russell — 2 Jun 2012 @ 9:15 PM

  38. Hank hit the nail on the head.

    I‘ve been silently following this side-thread with growing concerns. One of the biggest current environmental problems produced when extracting freshwater from seawater is what to do with all of the salt, which is usually collected in the form of brine. At the scale at which Jim Baird appears to be proposing this, there would be an awful lot of it (starting with 32 grams of various salts per liter of seawater). Since no desalination process is completely efficient, this can amount to up to a gallon of brine for each gallon of freshwater produced.

    Desalinating ocean water also poses another environmental problem: it is virtually impossible to do efficiently without killing a whole lot of the plankton that exists in ocean water to begin with. In a warming world, who knows how this will affect the eggs and/or larvae of many ocean creatures already at risk.

    I’m also wondering how ever-increasing amounts of degraded plastics in ocean water will affect this already problematic pollution stream…

    I know this sounds a little obvious, but to address the problem of rising sea levels as the result of anthropogenic global climate change, why not focus on finding more and/or better ways to reduce the emission of CO2 gas into the atmosphere, which got us into this situation in the first place?

    Dwindling freshwater supplies on a warming planet with a growing human population is a huge problem; so is climate change, and its associated rising sea levels. Even if one could solve the energy issues, I don’t think that water desalination is the best answer for any of these problems.

    Comment by Craig Nazor — 3 Jun 2012 @ 12:31 AM

  39. I know this sounds a little obvious, but to address the problem of rising sea levels as the result of anthropogenic global climate change, why not focus on finding more and/or better ways to reduce the emission of CO2 gas into the atmosphere, which got us into this situation in the first place?

    Smartypants

    Comment by Martin Vermeer — 3 Jun 2012 @ 7:28 AM

  40. Craig, the objective is to keep sea levels in equilibrium. They are rising due to thermal expansion, icecap melting and aquifer pumping. OTEC is a tool for addressing thermal expansion. Melting and aquifer pumping add fresh water and thus decrease salinity. Desalination would simply maintain the status quo. Another objective is to capture runoff before it enters the water or mixes with the water at the ocean/river interface. This would be the low hanging fruit as are tankers deadheading to the MENA to carry it the desert.

    Martin, OTEC done properly can provide all of the energy we need carbon free. As an energy carrier it can produce hydrogen, ammonia or methanol to replace transportation fuels. Most believe there is already significant sea level rise built in due to the thermal inertia of the ocean. The only way you can eliminate that is by backing the heat out, converting it to work.

    We are also well over the 350 ppm considered sustainable. Natural sinks, like irrigated deserts are the best and quickest way to get back down to that.

    Comment by Jim Baird — 3 Jun 2012 @ 9:06 AM

  41. Craig, I missed your phytoplankton point and it is extremely important because they are the base of the ocean food chain and the lungs of the planet.

    The study Global phytoplankton decline over the past century by Daniel Boyce postulates the volume of phytoplankton in the world’s oceans, which produce half of the oxygen in the atmosphere by consuming the equivalent amount of carbon dioxide, has been declining steadily for the past half century-down about 40 percent since 1950.

    “What we think is happening is that the oceans are becoming more stratified as the water warms,” said Boyce. “The plants need sunlight from above and nutrients from below; and as it becomes more stratified, that limits the availability of nutrients.”

    OTEC would cool the surface to alleviate this problem.

    Some propose upwelling of cold water with conventional OTEC would promote phytoplankton growth and thus marine aquiculture. I think it more likely it would overstimulate this growth, as does agricultural runoff from the Mississippi and as in that case dead zones would result.

    Entrainment and impingement is also a problem moving massive amounts of water with conventional OTEC. The proposal of Dr. Lau and I is to instead move the working fluid in a closed cycle to the depths for condensing and then pumping it back. The heat dumped to the depths in that case first reduces thermal stratification then induces gentle convection that would bring with it nutrients vital to phytoplankton and those on which they feed.

    Comment by Jim Baird — 3 Jun 2012 @ 9:25 AM

  42. Craig re salt. Open cycle OTEC produces water by flash evaporation so the residue is slightly more salty but there is no solid to deal with. The problem is the best OTEC sites aren’t that close to where the water is needed so transportation is a big problem and the infrastructure is massive and costly. Tankers would be an economical solution to a small part of the transportation problem.

    My preference however is to produce hydrogen by electrolysis. It is both an energy as well as a water carrier and is a fraction the weight of water. There are transportation issue if overcome I think this would be the way to go.

    Comment by Jim Baird — 3 Jun 2012 @ 9:43 AM

  43. This is a great graphic: http://ga.water.usgs.gov/edu/earthhowmuch.html

    All Earth’s water in a bubble

    This drawing shows various blue spheres representing relative amounts of Earth’s water in comparison to the size of the Earth. Are you surprised that these water spheres look so small? They are only small in relation to the size of the Earth. This image attempts to show three dimensions, so each sphere represents “volume.” The volume of the largest sphere, representing all water on, in, and above the Earth, would be about 332,500,000 cubic miles (mi3) (1,386,000,000 cubic kilometers (km3)), and be about 860 miles (about 1,385 kilometers) in diameter.

    The smaller sphere over Kentucky represents Earth’s liquid fresh water in groundwater, swamp water, rivers, and lakes. The volume of this sphere would be about 2,551,000 mi3 (10,633,450 km3) and form a sphere about 169.5 miles (272.8 kilometers) in diameter. Yes, all of this water is fresh water, which we all need every day, but much of it is deep in the ground, unavailable to humans.

    Do you notice that “tiny” bubble over Atlanta, Georgia? That one represents fresh water in all the lakes and rivers on the planet, and most of the water people and life of earth need every day comes from these surface-water sources. The volume of this sphere is about 22,339 mi3 (93,113 km3). The diameter of this sphere is about 34.9 miles (56.2 kilometers).

    Comment by Fred Magyar — 3 Jun 2012 @ 12:07 PM

  44. One source of groundwater storage not apparently considered is the change caused by changing climate itself. There is evidence of long-term natural decline in some areas, simply due to natural discharge exceeding natural recharge. That difference would now end up in the ocean and contribute to sea level change. There are obvious changes in some basins in the Great Basin, but I’m less clear on whether this could be a global phenomenon or whether the magnitude could be sufficient to account for the “missing” source of water.

    Comment by Tom Myers — 3 Jun 2012 @ 12:37 PM

  45. >> What we think is happening is that the oceans are becoming more stratifie
    >
    > OTEC would cool the surface to alleviate this problem.

    Oh please. OTEC would do how much to change stratification of the world’s oceans? Some fraction of one percent, but how small a fraction? And reducing stratification reduces thermodynamic efficiency of OTEC.

    Sorry, I won’t follow this OTEC digression further. It ought to be on a blog somewhere it can be commented on, but it’s way off topic.

    The news from Antarctica is relevant though; posted some in the open thread hoping the scientists will revive this topic.

    Comment by Hank Roberts — 3 Jun 2012 @ 12:38 PM

  46. Jim Baird #40

    The only way you can eliminate that is by backing the heat out, converting it to work.

    Sorry Jim, you’re mistaken about that.

    The only potential way that OTEC can help is by replacing current greenhouse gas emitting ways of power generation, bringing down the existing — and growing — imbalance in the Earth’s heat budget due to those greenhouse gasses. Compared to that, anything the OTEC installations themselves do to the heat content of ocean water at various depths is very nearly negligible.

    What OTEC does, as a minimum, is move heat from the surface to the deep; this could have a climatic effect, e.g., on the formation of hurricanes, but that would be local and unrelated to the big picture. You cannot take heat out of the ocean unless you have a place to put it; the only way to put it back into space is by radiating it out. You cannot “convert it to work”; that only works for temperature differences.

    Comment by Martin Vermeer — 3 Jun 2012 @ 12:51 PM

  47. What Martin, and others, have said. This looks like an attempt to get a “method patent” on a bunch of different technologies combined, to do something that wouldn’t work.

    A few of the many ideas that are wrong, and would be obviously wrong if the numbers were worked out:

    – Add humidity to dry desert air — and the desert no longer radiates as much heat away to space during the night.
    – Evaporative cooling is a local surface effect, it’s rearranging the heat by transporting it within the planet’s atmosphere, not getting heat off the planet.
    – Shuffling heat around with OTEC is not cooling the planet, it’s rearranging heat within the ocean.

    Yes, OTEC is a promising technology and a good idea to improve. Use it to replace fossil fuel and that will help reduce human-caused warming.

    Comment by Hank Roberts — 3 Jun 2012 @ 1:08 PM

  48. #10 Stefan asked for a hydrologist to comment.

    What seems to be lacking from this discussion is the fact the little of the water abstracted for irrigation finds its way back to the sea; the basic aim of irrigation is to provide plants with water for transpiration not available from rainfall. In a well designed irrigation system in a region which does not have a wet season (i.e. a part of the year in which rainfall exceeds potential evaporation) some extra water is pumped to prevent a build up of salts in the soil but often this excess returns to an aquifer rather than a river (which big users of fossil water like Libya and Saudi Arabia do not have).

    Comment by Ron Manley — 3 Jun 2012 @ 1:14 PM

  49. Martin, if I’m not mistaken OTEC operates like any other Rankine Cycle, heat vaporizes a fluid to drive a turbine and the vapor is then condensed and the cycle is repeated. It seems to me your argument is like saying a nuclear plant doesn’t consume uranium when it produces power.

    Paul Curto states in his article, American Energy Policy V — Ocean Thermal Energy Conversion, with respect to producing 2.5 TW of power with OTEC “The amount of heat dumped by that much OTEC into the ocean’s heat sink at depth is therefore just over 50 TWth, and that is also equal to the heat removed from the surface plus the power output, about 53 TW.

    My take from this is you have converted 2.5 TWh to 2.5TWe.

    In another part of the article he comments on early OTEC investigation, “Oddly enough, the concern was that we might cause an Ice Age!”

    It turns out we have the opposite problem which I believe OTEC can resolve.

    The massive heat dump to produce 2.5 TW (which I admit is not much cooling) would limit the amount of power you could get from the ocean and thus the amount of heat you could covert to energy because you are sapping the hot reservoir and warming the cold thus reducing the delta T.

    That is why I think you need a counter-current heat flow to limit the amount of heat you take out of the surface as well as the amount you dump. If you could convert 60TWh to 60TWe then I think you would be making a difference. Especially if you are replacing carbon sources and thus are chipping away at a problem already created rather than one that is accelerating away from you.

    I stand to be corrected.

    Comment by Jim Baird — 3 Jun 2012 @ 1:44 PM

  50. Jim Baird opines in #40:

    Craig, the objective is to keep sea levels in equilibrium. They are rising due to thermal expansion, icecap melting and aquifer pumping. OTEC is a tool for addressing thermal expansion.

    I’ve seen you say this several times now Jim, But I’m far from convinced.

    As I understand it, the extra heat being absorbed because of increased GHG’s, which ends up mostly in the oceans, greatly exceeds that used by mankind. Taking out what we need isn’t going to make a dent in the oceans heat budget. Mixing the heat into the cold depths doesn’t make it go away, it just warms the depths. The depths will expand when they warm.

    So, please, show me where I’m wrong.

    The other thing that concerns me is the effect of the mixing. Would cold waters would make their way toward the surface due to convective currents? Nutrients being brought up? CO2 being brought back from millenia ago?

    Cooling the sea surface *sounds* like a good thing given our rising temperatures, but can we, for example, reasonably model how localized changes will affect regional weather?

    Comment by David Miller — 3 Jun 2012 @ 3:06 PM

  51. Jim,

    Even if OTEC could produce electricity be harvesting heat from warm(ed) surface waters at, say 5-10% efficiency, why would you go through the trouble and expense of “hiding” the heat rejected (>90%)in deep ocean layer, when it could be rejected instead, (much more easily) directly to the upper troposphere (above CO2 layers)-a location where heat could more efficiently be radiated to outer space.

    The technology to accomplish this isn’t “rocket science”–it’s the Atmospheric Vortex Engine, proposed by your compatriot, Louis M. Michaud. This “enhances upward convection, far above and beyond that accomplished by natural (non-rotating) processes.

    Nature accomplishes this easily from locally warm water via waterspouts, videos of which one can easily find on the internet.

    Further, the amount of heat transported upward by a single hurricane would far exceed anything that could be accomplished by going through the expense (including pumping and heat-transfer equipment) of building OTEC machines.

    One technology for “greening the desert” that has already been proven is Charlie Paton’s Seawater Greenhouse. I might add that one doesn’t necessarily have to “desalinate” seawater to effectively use it’s “humidification potential”. The chemical potential of (pure) water (vapor pressure) over seawater is about 98-99% of fresh water. One just has to figure out ways of controlling (containing) evaporation and rejecting the (enriched) brine back into the sea after some of the fresh water has been removed from it.

    Comment by Jerry Toman — 3 Jun 2012 @ 3:55 PM

  52. Ron Manley:
    Doesn’t the water that evapotranspirates in the desert fall as rain somewhere else and end up in the ocean? The amount of water vapor in the air is roughly the same all the time (increasing slowly due to increasing temperature). Fossil water brought to the surface ends up in the ocean, even if it does not enter a river to flow there.

    Jim Baird’s proposal to irrigate the desert to get rid of water does not appear to account for the evaporation loss either. If you put 2 meters of water on the land to irrigate it you do not sequester 2 meters of water forever. Most of the water evaporates and is not sequestered.

    Comment by michael sweet — 3 Jun 2012 @ 4:21 PM

  53. Re- Various statements by Jim Baird about desert hot soil exacerbating global warming and OTEC:

    I am beginning to get the same feeling I get when I listen to the guy who thinks that all our energy and CO2 problems can be solved with a Tesla turbine/pump.

    As for OTEC, it is theoretically only 5% to 7% efficient and I believe that demonstrations have been much less. So, the process harnesses energy flow between warm surface and deep cool water, thus effectively mixing them, while converting a small percent of the flow into electricity. When the electricity is used it is ultimately converted back to heat and this is a net wash. By itself, deriving all of our energy needs from OTEC would have very little effect on the thermal expansion of the oceans, only stopping CO2 pollution will. CO2 is the gift of chaos that keeps on giving.

    What I would like to know is what is the cost per watt for OTEC relative to, for example, PV (photovoltaics- please explain acronyms). Steve

    Comment by Steve Fish — 3 Jun 2012 @ 5:27 PM

  54. Ron, I do account for evaporation http://www3.telus.net/gwmitigationmethod/evaporation.htm .

    A true desert is described as a landscape receiving less than 250 millimetres (10 in) of average annual precipitation, which is not enough to sustain plant life.

    The U.S. Geological Survey says the rate of application of water for irrigation purposes is 2.48 acre-feet. There is clearly therefore a lot of room for sequestering water in the desert that otherwise would be adding to sea level rise.

    Comment by Jim Baird — 3 Jun 2012 @ 6:01 PM

  55. Jerry, my proposal http://www3.telus.net/gwmitigationmethod/Images.htm uses a heat pipe which is essentially a hurricane turned on its head. A hurricane has been described in some instances as an atmospheric heat pipe.

    And I do not try to hide the heat rejection in the deep. I try and return it to the surface like a hurricane does with ran by using a counter-current heat transfer system a schematic of which is shown at http://www3.telus.net/gwmitigationmethod/drawbacks.htm

    I don’t see much distinction between the Seawater Greenhouse and Open Cycle OTEC other than the fact OTEC generates power and water.

    Comment by Jim Baird — 3 Jun 2012 @ 6:07 PM

  56. David Miller, a statistical analysis of 55 years of cloud cover and temperature observations for the north-eastern Pacific Ocean by Amy Clement and Robert Burgman of the University of Miami and Joel Norris of the University of California-San Diego found that low-level cloud cover decreases as temperature increases — and that a feedback mechanism arose. As the water warms the atmosphere warms – the water warms more.

    I guess the question is, is the greater danger in action or inaction?

    Personally, on behalf of my grand kids, I would prefer to try to solve the problem.

    In response to some other posts it is the surface temperature that is producing this effect and also the thermal stratification that is threatening phytoplankton, the source of half the oxygen we breath and the base of the ocean food chain.

    Tohihiko Sakurai makes the case in US application Publication No. US 201000018567, Solar Power Generating System Employing a Solar Battery and Publication 20100300095, the problem is significant enough he would use OTEC simply to pump deep water to the the surface for no other reason than to cool it.

    And of course it is surface temperature which drives hurricanes so mixing that heat to the depths can’t be all bad.

    Comment by Jim Baird — 3 Jun 2012 @ 6:28 PM

  57. Jim,
    You apply 2.5 acre feet of water to irrigate the plants. Most of the water evaporates and returns to the ocean. It is not sequestered in the soil. Farmers only add as much water as they need to to grow the plants, not enough to saturate the soil kilometers deep. Why should anyone listen to you when your basic facts are so completely wrong? Your claims about ocean energy also do not withstand minimal scrutiny.

    Comment by michael sweet — 3 Jun 2012 @ 7:06 PM

  58. Martin Vermeer @1
    “Anyway, here’s a Dutch guy living in Finland discussing the English language with a German guy …”

    That made me laugh out loud!

    Make: from the German, machen (to construct)
    Cause: from Latin, causa “a cause; a reason,

    Though correlation is not necessarily causation, (pardon the pun), I would argue that sea level rise probably tends to have more of a ’cause’ than a ‘maker’…

    BTW, for the record, “What makes sea level rise” is perfectly acceptable usage! In the sense of what makes it work. This is probably closer to a mechanistic and scientific explanation. Cause or reason can also imply more of a legalistic argument that might be better suited for a debate among lawyers. Ain’t language and etymology fun?

    This from a Brazilian born, native speaker of American English, (yes, that is possible) and of mixed Hungarian and Danish ancestry.

    You might of course prefer to discuss the nuances of Latin influence on the Anglo Saxon vernacular with a Frenchman… but do stay away from the Finno-Ugric perspective >;^)

    Cheers!

    Comment by Fred Magyar — 3 Jun 2012 @ 7:10 PM

  59. How much of sea level rise is caused by soil being discharged into the oceans from rivers or by erosions of coasts by waves?

    How much of apparent the sea level rise is due subsidence of the continents?

    Comment by Harold Pierce Jr — 3 Jun 2012 @ 7:20 PM

  60. > upper troposphere (above CO2 layers)
    What CO2 layers?

    > mixing that heat to the depths can’t be all bad

    Nobody’s put a number on it yet, that’s what people are asking you to do.

    Mixing warm surface water into deep water warms and expands the deep water.

    What volume would your patented method change and in which direction?
    You must have done some of the arithmetic on this.

    Oh, wait, I’m following the digression. Never mind.

    I suggest you offer a link to your site and blog software there, to carry on the discussion, so people can try to help clarify some of the unanswered questions.

    Comment by Hank Roberts — 3 Jun 2012 @ 8:10 PM

  61. Jim Baird:

    > My take from this is you have converted 2.5 TWh to 2.5TWe.

    Yep. And once you consume this, it becomes heat again.

    And note it’s no more than 5% of the heat that’s moved between ocean layers.

    Comment by Martin Vermeer — 3 Jun 2012 @ 9:42 PM

  62. Jim Baird, the guys here are really good at science. If they have questions, your best bet is to answer them and pursue answers if you haven’t got ‘em.

    If you really have a viable solution, it can only benefit from some true skepticism.

    I know you’re invested in your work, and more power to you, but that investment will be wasted if you don’t do your best without fear or favor.

    Comment by Susan Anderson — 3 Jun 2012 @ 10:12 PM

  63. @59–Hank Roberts

    “upper troposphere (above CO2 layers)”

    …poorly phrased, to be sure. I didn’t mean to imply that there exist “CO2-rich” layers (except perhaps in “canopies” above cities) in the atmosphere.

    Would have been better if I had said instead “above layers where most of the CO2 is contained”, which absorb a large fraction of the long-wave radiation emanating from the surface.

    Comment by Jerry Toman — 3 Jun 2012 @ 11:59 PM

  64. Hank Roberts, the upper troposphere (above CO2 layers) statement is not mine.

    I believe I put a number on the heat to depth in 48. The thermodynamic efficiency with conventional OTEC is just less than 5% in best cases. You dump therefore about 21 watts of surface heat to the depths for every 1 watt of power you produce. The thermal expansion you would reduce would be the amount that would arise from the 1 watt of heat that was instead turned to 1 watt of electricity.

    I also tried to explain that because of this massive dumping from the surface to the depths you degrade the capacity of the ocean to produce OTEC power and accordingly the amount of heat you can covert to power and by extension the thermal expansion you reduce.

    Gerard Nihous wrote a paper a few years back that estimated the max you could get out the ocean would be 5TW a year. Martin Hoffert said he was a fan of OTEC but it couldn’t produce as much energy as he was looking for which was 30TW.

    To try and overcome this limit I propose a counter-current heat flow mechanism that would bring most of the 20 watts back to the surface again like hurricanes do. I would like to see Smalley’s 60 TW or Hoffert’s 30 TW, which ever you prefer, produce by converting 60TWh or 30 TWh of ocean energy and the amount of thermal expansion deep or shallow would be that 30 or 60 TW worth.

    Martin says the the 2.5 TWe would be consumed and become heat again. Of course it would put that would apply to the 2.5 TWe you produced with nuclear power also plus except in that case you produced 5TWh in entropy as well. In other words 2.5TWe of OTEC is 3 times better in terms of thermal expansion of the ocean as 2.5 TWe of nuclear power.

    Susan, I welcome the skepticism and do learn from it.

    I have also seen it lead to paralysis. Over 20 years ago I invented the Subductive Waste Disposal Method for the elimination of nuclear waste. There were all kinds of skeptics then as well. e.g. local scientists believed they found water movement near where the repository would be located. Funny thing is a couple of years ago the Russian developed a whole new idea of depositing nuclear waste in deep boreholes with active hydrology because that is how most of the most valuable ore bodies are formed.

    Funny thing is the same Natural phenomena that would have eliminated both spent fuel and excess weapons material instead precipitated the Fukushima disaster and the same province of Canada that could have provided the solution was instead the first down winder to receive the fallout. With potentially a lot more to come if Reactor 4 keels over.

    Comment by Jim Baird — 4 Jun 2012 @ 12:19 AM

  65. Over 20 years ago I invented the Subductive Waste Disposal Method for the elimination of nuclear waste.

    Nope.

    Comment by dbostrom — 4 Jun 2012 @ 12:45 AM

  66. Jim Baird #63:

    In other words 2.5TWe of OTEC is 3 times better in terms of thermal expansion of the ocean as 2.5 TWe of nuclear power.

    This is interesting only if you ignore the elephant in the room: the heating caused by released greenhouse gases. In this respect, both are completely negligible (if done right) compared to fossil fuels.

    BTW another detail that’s easily overlooked: the thermal expansion coefficient of water is a very nonlinear function of temperature. This makes moving 50 TW of heat down from the warm surface layers to cold depth a seriously non-neutral proposition, expansion wise!

    Comment by Martin Vermeer — 4 Jun 2012 @ 1:16 AM

  67. #51 – Michael Sweet
    “Doesn’t the water that evapotranspirates in the desert fall as rain somewhere else and end up in the ocean?” Not necessarily. After all, if all the extra evaporation, whether from irrigation or CO2 induced global warming, ended up as rain in the oceans, not as increased water vapour or clouds, there would be no positive feedback and climate change would be manageable.

    #53 Jim Baird
    “Ron, I do account for evaporation.”
    Jim, when I made my statement about little attention to evaporation from irrigation I was referring to the suggestion in the nature paper that 42% of the sea level increase was due to groundwater pumping. With regard to your proposal, fossil aquifers are typically 300 to 500m deep. Can I suggest you also calculate how much CO2 would be relased by the energy needed for pumping ?

    Comment by Ron Manley — 4 Jun 2012 @ 1:30 AM

  68. Trolls don’t have this much success at hijacking a thread.

    Comment by owl905 — 4 Jun 2012 @ 3:16 AM

  69. Speaking of sea level rise, I live in North Carolina. When I recently told my girlfriend about our legislature’s response to sea level rise, her response was “what a complete waste of stupidity!” – an elegant counterpart to “not even wrong.”

    Comment by Brian Dodge — 4 Jun 2012 @ 5:53 AM

  70. > 20 years ago I invented the Subductive Waste Disposal

    It’s amazing what the Patent Office thinks is new, sometimes.

    That idea was talked about by radiation biologists in the 1950s, to my personal recollection.

    By the 1970s if not sooner, the idea was well known, for example, http://www.nature.com/nature/journal/v239/n5371/abs/239330a0.html
    Nature 239, 330 – 331 (06 October 1972); doi:10.1038/239330a0
    Subduction Zones: Not Relevant to Present-day Problems of Waste Disposal
    or http://www.tandfonline.com/doi/abs/10.1080/10641197609388169

    and by 1981, “The internationally agreed criteria for the selection of sites for any proposed seabed disposal of radioactive waste exclude the use of trenches for this purpose.” http://www.springerlink.com/content/r63l444500676285/

    But we digress.

    What makes sea level rise?

    Comment by Hank Roberts — 4 Jun 2012 @ 7:57 AM

  71. dbostrom, US, New Zealand and Canadian patents say otherwise. It was the only solution that accessed a subduction zone from land and thus was never banned by the London Dumping Convention despite all claims to the contrary.

    Ron Manley, all pumping I proposed is powered by renewable sources. Further hydrogen produced by OTEC power and electrolysis can rise by its own buoyancy to an elevation where it could produce both power and water that would flow to where it is required without the need of pumping.

    Martin, I was not aware of the non linear expansion. Perhaps we could discuss privately so as not to offend owl905

    Comment by Jim Baird — 4 Jun 2012 @ 8:08 AM

  72. Thermal expansion of water is covered, e.g., here:

    http://earth.geology.yale.edu/~avf5/teaching/ResourcesGG535/Lecture4.TS.Ice.LinEqState.pdf

    and here in the last IPCC Report:

    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-5-1.html

    “The reasonable agreement in recent years between the observed rate of sea level rise and the sum of thermal expansion and loss of land ice suggests an upper limit for the magnitude of change in land-based water storage, which is relatively poorly known.”

    and here:

    http://www.skepticalscience.com/print.php?n=587

    Deep ocean warming solves the sea level puzzle
    “… Model result for sea level rise from thermal expansion of the deep ocean. Simple addition of the numbers above (1.2 + 0.85 mm/year = 2.05 mm/year) shows that the result from the upper ocean thermal expansion and addition of water mass is still about 1 mm/year short of the observed 3.1 mm/year …”

    Comment by Hank Roberts — 4 Jun 2012 @ 9:21 AM

  73. Aside — floating ice displaces almost exactly its own weight in sea water– not quite, because “the ice is fresh water and the sea is denser salt water. However, the effect is tiny. Melting 1 kg of floating ice increases the sea level as much as melting around 30g of ice on land”
    csiro.au/helix/sciencemail/activities/icemelt.html

    When water freshly melted from sea ice warms up, how much does its warming cause it to expand, and does that change its contribution to sea level?

    (As Martin notes it’s nonlinear, and I don’t find the numbers handy for either the temperature change or the expansion — I’m wondering how much the temperature of the meltwater changes as it mixes into the local cold polar ocean, first, then into the average global water temperature over time).

    I assume it’s a trivial amount, considering the rest of what’s happening.

    Comment by Hank Roberts — 4 Jun 2012 @ 9:27 AM

  74. US, New Zealand and Canadian patents say otherwise.

    Ok, whatever; don’t let a little thing like chronology get in your way! :-)

    Comment by dbostrom — 4 Jun 2012 @ 9:53 AM

  75. Hank Roberts, thanks for the references. The skeptical science piece references the study of Purkey and Johnson, which is persuasive. It is logical deep water would be warming, apparently faster than predicated by the circulation models, thus it would contribute to sea level rise through expansion.

    My proposal is to convert some of this heat to energy to alleviate the problem. Full stop.

    I am amazed by the ad hominems.

    Comment by Jim Baird — 4 Jun 2012 @ 10:39 AM

  76. OK, Jim Baird described his patented idea to dig a tunnel to what may or may not be a subduction zone “… off the west coast of Vancouver Island…. at a distance 50-70 kilometers from the western terminus of the line. Accessing the Explorer Crust at the depth show, from the Brooks Peninsula, could be accomplished with conventional tunneling techniques.”
    http://www.nwmo.ca/uploads_managed/MediaFiles/1287_baird-submissiononthetopic_cho.pdf

    Geological map: http://ars.sciencedirect.com/content/image/1-s2.0-S0264817211002340-gr1.jpg “… The Winona Basin extends south from the Tuzo Wilson Seamounts (TWS) ending just offshore Brooks Peninsula. This peninsula is thought to define the northernmost extent of a subducted plate under Vancouver Island and of present day subduction tectonics.”
    From: http://www.sciencedirect.com/science/article/pii/S0264817211002340
    See also: http://ars.sciencedirect.com/content/image/1-s2.0-S0264817211002340-gr2.jpg

    It’s a fascinating area geologically speaking, with many surprises, and much sea level research has also been going on throughout the Cascadia subduction zone. There are terraces from changes around the ice age and from large vertical movements during subduction quakes, so even establishing “sea level” for any given location over geological time isn’t all that assured.

    Comment by Hank Roberts — 4 Jun 2012 @ 10:55 AM

  77. aside: a 1997 Japanese plan:
    http://www.aist.go.jp/GSJ/PSV/Pub/gsj_pube/bull/vol48e/vol48_3-4.htm

    “Japanese Ultra-deep Drilling and Geoscientific Experiments (JUDGE project) is a proposal …to conduct land-based drilling at southern Kanto region to intersect the subduction zone that exist at a depth of 10 km … to penetrate through the earthquake source fault of giant inter-plate earthquake which did and will continue to attack Kanto area…. to widen the option on geological disposal of high level radioactive waste for a country like Japan that locates in the subduction zone.”

    I’m sorry. I’ll stop chasing this digression now.

    Comment by Hank Roberts — 4 Jun 2012 @ 11:02 AM

  78. There’s much that could be discussed (again, decades after the first go ’round) about disposal of effluvia in deep ocean trenches but perhaps the unforced variations thread would be a better place? Or somewhere else entirely? The connection w/climate is not clear other than as a indicator of lack of confinement by practical considerations.

    Comment by dbostrom — 4 Jun 2012 @ 11:29 AM

  79. A study published today in Nature Climate Change projects further disruption to supply (electricity), with a likely decrease in thermoelectric power generating capacity of between 6-19% in Europe and 4-16% in the United States for the period 2031-2060, due to lack of cooling-water. The likelihood of extreme (>90%) reductions in thermoelectric power generation will, on average, increase by a factor of three.

    What then is the rationale thing to do? Contribute even more entropy to the system or convert the heat already doing damage to productive use?

    Hank the Explorer Plate is a complicated region and there are arguments on both sides whether it is still subducting. The fact the triple point between the three plates is continuously moving northward suggests to me it is. If it is not on the other hand, placing waste in it beneath the sedimentary layer of about 2K gives you 2K more buffer than any other proposal to deposit nuclear waste in the seabed. A solution that is still considered technically sound. The push against it was lead by Maurice Strong, who at the time was a director of Molten Metal Technologies that was pushing a now debunked alternative. The political shenanigans in that episode make for interesting reading. Unless of course you were affected.

    Comment by Jim Baird — 4 Jun 2012 @ 11:34 AM

  80. Per Martin Vermeer’s grammar nit: As a native US English speaker, I agree with him. To me, “sea level” is a phrase that is not normally hyphenated when used as a noun phrase, but becomes hyphenated when it is used as a modifier.

    So it’s “What makes sea level rise?” but “What causes sea-level rise?” since in the latter case “sea level” has become a modifier for “rise”.

    The typical usage may be different in other dialects of English.

    Comment by Matt McIrvin — 4 Jun 2012 @ 12:41 PM

  81. Hank re 75, me too last digression. The JUDGE project grew out of a proposal by Masao Kasuya, “Sub-Seabed Disposal Using a Submarine Tunnel – A solution to High-Level Radioactive Waste Disposal in Japan.” in which he stated, “I would like to thank Mr. J. R. Baird of British Columbia Canada for providing useful information and sharing out his insight.”

    In personal correspondence he stated, “You have presented a brilliant idea of drilling a tunnel from land, instead of drilling holes from the sea floor. This method is definitely irrelevant to the London Dumping Convention because waste would never go through seawater during the disposal. . . It is regrettable anyway that the LDC is being politically used for impeding sincere efforts to find technically sound solutions.”

    I brought it up because it is a cautionary tale of how legitimate solution are snuffed out with consequences.

    1. Fukushima reactor 3 waste went ballistic according to Gundersen. http://enenews.com/nrc-chunks-radioactive-materials-found-around-fukushima-reactor-cores-spent-fuel-pools-worse-sfps-nuclear-engineer-video

    2. Reactor 4 waste is vulnerable.

    3. DOE spent how many billions on Yucca Mountain after 1996 when water problems were discovered, which the science suggested and the law provided should have disqualified the site. DOE’s and Congresses’ response was to change the law instead. – Say Amen to the nuclear industry thanks to this kind of oversight.

    4. Canadian taxpayers say Amen to their $20 billion investment in CANDU reactors thanks in no small part to the waste and proliferation issues this solution would have provide.

    Sorry last comment on subduction of Explorer Plate. I put my cursor on the current site of the Explorer Plate in an old Microsoft Video on plate tectonics. In about 50 million years the cursor is sits in the Midwestern United States.

    How this happens without the Explorer Plate being subducted is beyond me.

    Comment by Jim Baird — 4 Jun 2012 @ 2:03 PM

  82. How much of sea level rise is due to soil and silt being deposited into the oceans from rivers?

    How much of sea level rise is due to erosion of coasts by the action of wind and waves?

    How much of the apparent sea level rise is due to subsidence of the continents?

    How much of sea level rise is due dust being blown out deserts and falling into the oceans?

    WRT to the latter. I have seen a documentary on the TV that so much dust was blown out of west Africa and deposited in various Caribbean islands the natives were able to use for making pottery and clay tiles.

    Comment by Harold Pierce Jr — 4 Jun 2012 @ 2:11 PM

  83. Jim Baird’s rationalization for his radical proposal is that it would turn deserts into “natural carbon sinks”. (Post 4 and 40).

    There is nothing “natural” about the large-scale anthropocentric transportation of any kind of water to a desert.

    Given such a blunder, I do not trust the ecological wisdom of OTEC’s advocates one iota.

    Mark E

    Comment by Mark E — 4 Jun 2012 @ 2:29 PM

  84. PS Another US English native speaker, I agree with Matt (80)

    Comment by Mark E — 4 Jun 2012 @ 2:31 PM

  85. Drawing down of existing fossil aquifers can cause saltwater intrusion from the ocean, presumably contributing a negative term to sea-level rise. Has this fact been taken into account at all?

    Comment by Guy Schiavone — 4 Jun 2012 @ 7:09 PM

  86. Harold Pierce Jr says: 4 Jun 2012 at 2:11 PM

    (How much)^n

    Were those rhetorical questions?

    I’m wondering because it takes such a short time to produce answers using Google Scholar:

    Causes of world-wide changes in sea level
    D. T. Donovan and E. J. W. Jones

    Possible factors responsible for world-wide sea level changes are reviewed. The major causes are variations in the volume of land ice and changes in oceanic ridge systems, with sediment accumulation in the oceans and desiccation of isolated basins producing second-order effects. Alterations in effective water volume (by ice sheet growth or desiccation) are much faster than changes in ocean basin capacity, but the latter are considered likely to be the cause of long-term trends, which are ultimately related to the history of mantle convection.

    Sedimentation apparently requires millions of years to effect significant changes.

    Get the whole combination plate including a side of context w/this chapter

    Comment by dbostrom — 4 Jun 2012 @ 10:04 PM

  87. Guy, isn’t it more likely to be a wash in terms of sea-levels?

    Comment by Jim Baird — 4 Jun 2012 @ 10:11 PM

  88. Yet another diversion:
    #54
    “A true desert is described as a landscape receiving less than 250 millimetres (10 in) of average annual precipitation, which is not enough to sustain plant life.”

    Many people here in the Southwest would take issue with your statement that 250 mm/yr is not enough to sustain plant life. Our deserts have their own specially-adapted species of plant life that are just fine with a 250 mm/yr or less.

    Comment by AIC — 5 Jun 2012 @ 1:57 AM

  89. There seems to be two distinct camps regarding the input of groundwater depletion. The CSIRO, Chu, and Moore(Annals of Glaciology, 2011), view it as a minor effect; while the new paper is a high-end revision of Marc Bierkens’,Utrecht University, study in 2010 which pegged the contribution at.57mm annual in 2000:

    http://www.agu.org/pubs/crossref/2012/2012GL051230.shtml

    Background to the Bierkens work is here:

    http://www.agu.org/news/press/pr_archives/2012/2012-25.shtml

    National Geographic has picked up on it,

    http://news.nationalgeographic.com/news/2012/05/120531-groundwater-depletion-may-accelerate-sea-level-rise/

    Comment by owl905 — 5 Jun 2012 @ 2:45 AM

  90. Jim – If we assume that all of the water taken from particular fossil aquifers where sea level intrusion is taking place is returned to the sea, then the positive term might roughly cancel the negative term. But if a significant fraction of the “upstream” fresh fossil water is being used to support lush new moisture-laden vegetation, filling reservoirs, bottled for use elsewhere, and filling suburban swimming pools and toilet tanks…then not so much balance.
    Harold – No, Chu 2001 does not mention seawater intrusion. That does not mean it is insignificant.

    Comment by Guy Schiavone — 5 Jun 2012 @ 6:05 AM

  91. Fixation of carbon to calcium and magnesium carbonates by shell-forming creatures could contribute to sea-level rise. When these creatures die, their shells fall to the ocean floor which would increase sea level as these depsits build up. However this probably a slow process.

    Limestone deposits are formed from shells of sea animals

    Comment by Harold Pierce Jr — 5 Jun 2012 @ 6:48 AM

  92. Mark E, this thread is entitled, What makes sea-level rise?

    The more interesting question, it seems to me, is what prevents this rise?

    To summarize, I propose:

    1 Converting ocean heat to energy to prevent thermal expansion.

    2 Capturing water that otherwise would enter the ocean or desalinating and moving ocean water to productive terrestrial use. (the deserts are the only location on the planet capable of accepting the volumes required and would benefit most from the enterprise.)
    3 Converting ocean volume to its gaseous components and using the hydrogen in turn either as a transportation fuel (or as a component of another fuel) or as a water carrier.

    These approaches would in turn draw down CO2 levels in both a cooler ocean and a fertile desert.

    And your alternative is _______________?

    Comment by Jim Baird — 5 Jun 2012 @ 7:30 AM

  93. “Many people here in the Southwest would take issue with your statement that 250 mm/yr is not enough to sustain plant life. Our deserts have their own specially-adapted species of plant life that are just fine with a 250 mm/yr or less.”

    Same thing here in South Australia. Generally speaking, saltbush country, though a lot of it supported extensive sandalwood scrubland before it was cleared for agriculture.

    However, we do have Goyder’s line. http://en.wikipedia.org/wiki/Goyder's_Line. This turns out to be a pretty accurate 10 inch rainfall demarcation, though Goyder’s focus was more on unreliability of rainfall on the inland / desert side than on the amount.

    Comment by adelady — 5 Jun 2012 @ 10:20 AM

  94. Jim: Converting ocean heat to energy to prevent thermal expansion.

    Going down a slight diversion…

    I’m quite certain Jim intended to imply “convert energy of ocean heat to a form capable of doing work” but what jumped out at me is that we actually need is get the energy off the planet entirely (not within our means), hide it, or preferably reduce the amount being stored here (stunning insight, eh?).

    Whatever energy is extracted from the ocean isn’t going to vanish from dynamics unless it’s applied to some sort of endothermic reaction building a stable compound. Failing locking it up, presumably energy extracted from the ocean will once again end up as heat in the atmosphere once it’s done doing work. Where does that leave us?

    Jim’s thrust of course is that of geoengineering sea(-)level but– leaving aside practical considerations of harnessing OHC for work– if such a course were to be seriously investigated it seems worth doing rigorous evaluation as to whether work done to move water from A to B might better be applied elsewhere in a way that improves the energy budget of the planet.

    Comment by dbostrom — 5 Jun 2012 @ 11:24 AM

  95. > Converting ocean heat to energy to prevent thermal expansion.;

    Going from not knowing it happens to claiming it’s a benefit was rather quick.
    You need to calculate the amounts involved here; I’d be surprised if you could claim any detectable benefit would happen after doing the math.

    Seriously, if you put a discussion forum on your website you could be getting significant help (that is, serious criticism from knowledgeable people) that would, if incorporated in your plans, improve the credibility of the idea.

    But with no numbers, you haven’t got an answer to contribute to the topic here.

    Comment by Hank Roberts — 5 Jun 2012 @ 11:37 AM

  96. Jim Baird @ 92 wrote: “3 Converting ocean volume to its gaseous components and using the hydrogen in turn either as a transportation fuel

    As soon as you burn that fuel the H will be incorporated right back into H2O, which will then precipitate back onto the surface, land, ocean, doesn’t matter. In other words, you’re only borrowing that H for a very short time. The net ocean volume flux would only equal the current global inventory of unburned H.

    Comment by Jim Eager — 5 Jun 2012 @ 11:42 AM

  97. @adelady#93

    While Jim Baird’s suggested transportation of water inland to increase desert productivity hasn’t received much support here, I do believe it’s possible to “geoengineer” desert spaces “at the margins”, by “pushing the envelope” (dry line) farther inland, if you will.

    Warm sea water would be transported a short distance inland through large pipes, or, in some cases, by building canals. There, Atmospheric Vortex Engines would be employed to evaporate the water, while at the same time, generating the necessary electrical energy required for its movement as well as to create sufficient “mass and heat transfer” surface to enable the evaporation. In “shoulder season” at least, this should fall nearby as rain.
    The localized cooling would create a positive feedback, encouraging yet more rain to fall, if enough of the devices were built in a local area.

    I think it’s also a concept worth consideration in the northeast Mediterranean, where there is a very warm bay from which water could be efficiently extracted. The objective would be to send enough water aloft which would fall as rain at the headwaters of the Euphrates River, to replenish this supply of freshwater, located in the mountains of Turkey. This would work best in the August-November period when the water is still warm (high vapor pressure) and the highland areas have cooled somewhat, promoting condensation.

    In Australia, the person who knows most about the potential uses of the AVE there would be Don Cooper.

    Comment by Jerry Toman — 5 Jun 2012 @ 12:19 PM

  98. Owl905,

    …the new paper is a high-end revision of Marc Bierkens’,Utrecht University, study in 2010 which pegged the contribution at.57mm annual in 2000:

    The paper you link is actually the 2012 paper by the same team. Their 2010 paper found 0.8mm/yr contribution in 2000.

    In the 2012 paper note that they indicate 2015 as the point at which total net terrestrial water storage will have a cumulative positive effect on sea level change. In other words, at this point in time they suggest human terrestrial storage activities have overall acted to lower sea level. This is very different to what Pokhrel et al. 2012 suggests.

    Comment by Paul S — 5 Jun 2012 @ 12:33 PM

  99. dbostrom, my premise starts from Richard Smalley’s Terrawatt challenge. He estimated the world could need as much as 60 terrawatts and I am of a similar mind to his – the aspirations of the rest of the world for the living standard we on this continent take for granted are going to be hard to deny. (He has a wonderful lecture on YouTube http://www.youtube.com/watch?v=CpYTVMhPUzc in seven parts on the subject and spent his remaining days, while seriously ill, giving this lecture.)

    By the way he ranked the most serious challenges we face as first energy and then water.

    Starting from there I have tried to figure out how you could provide this kind of energy and water without ruining the planet.

    My proposal stems from that premise and I believe would provide some environmental benefit in the production of OTEC energy that nevertheless will provide more heat in its use which might be inevitable in any case.

    Hank Roberts, my email address is on the contact page of the website and I would welcome the serious critic of knowledgeable people to say nothing of their collaboration in an effort to solve the planets two greatest problems. Dr. Lau and I are trying to find the best way do reduce the parasitic losses inherent in using CO2 as a working fluid in OTEC and are seeking input on this problem and others. I hope that we could work together on these.

    Not really sure how to up a forum on my page and my allotment of user space is pretty much maxed out.

    Jim Eagers, that is why I propose Hydrogen as an energy carrier. It is light but hard to transport but in a desert environment would recombine to make the water I am looking for.

    Jerry Toman, thanks for the contribution. The transportation problem is a huge one. That is why I think oil tankers deadheading to the MENA are a wasted opportunity that would be a good first step in this endeavor.

    adelady, the definition isn’t mine it is Wikepedia’s, nevertheless in the states ,according to the U.S. Geological Survey, for the year 2000, the rate of application of water for irrigation purposes was 2.48 acre-feet (730 mm). At that rate the desert would take up just about all of the annual projected rise over the next century.

    No offense intended.

    Comment by Jim Baird — 5 Jun 2012 @ 2:03 PM

  100. Have they taken in to account irrigation, which diverts much water which would have reached the sea over parched land instead? It’s not all the result of big dams, much of it being small scale. This must be a big offset.

    Comment by DP — 5 Jun 2012 @ 3:01 PM

  101. Re- Comment by Jim Baird — 5 Jun 2012 @ 7:30 AM, currently at #92:

    Addressing your points 1 and 3, I want to see the numbers. So, please tell us how much power would have to be generated in order to prevent 1 mm of ocean rise. I believe that this is so impractical as to be not worth talking about, but I am willing to be proved wrong.

    Steve

    Comment by Steve Fish — 5 Jun 2012 @ 3:39 PM

  102. @Paul S 98 – thx for the correction.

    Additionally Bierkens et al.

    http://tenaya.ucsd.edu/~tdas/data/review_iitkgp/2010GL044571.pdf
    (600k pdf download)

    “We estimate the contribution of groundwater depletion to sea
    level rise to be 0.8 (±0.1) mm a−1, which is 25 (±3) % of the
    current rate of sea level rise of 3.1 mm a−1 reported in the last
    IPPC report [Bindoff et al., 2007] and of the same order of
    magnitude as the contribution from glaciers and ice caps
    (without Greenland andAntarctica).”

    It suggests the Pokhrel study has taken the larger groundwater+aquafir, treated it all as zero-sum aquafir, and concluded that all the output added to sea-level rise. It doesn’t seem to allow for recharging, or measure the obviously increased wet surface regions, or factor the huge growth of urban storage. Indeed, if the study has made correct assumptions, then AGW takes one on the chin.

    Comment by owl905 — 5 Jun 2012 @ 6:32 PM

  103. Side questions–did the last couple of bigger-than-imagined earthquakes make any detectable difference in sea level for any period? Not the tsunami waves, but any persistent change? I realize a year of tide data may well not suffice for testing for such a tiny effect, but wonder if anything would be detectable.

    Same for undersea volcanos, actually — do sea level and sea temperature over the next months or year or two show a blip, when one of those events happens?

    Haven’t found data sets, haven’t tried to do the math, just … wondering.
    How big an effect does it take, to make a detecta

    Comment by Hank Roberts — 5 Jun 2012 @ 7:50 PM

  104. Steve re 101, let me come at it on the basis of the NOAA study in 2010, http://www.noaanews.noaa.gov/stories2010/20100519_ocean.html

    “The upper layer of the world’s ocean has warmed since 1993, indicating a strong climate change signal, according to a new study. The energy stored is enough to power nearly 500 100-watt light bulbs per each of the roughly 6.7 billion people on the planet continuously over the 16-year study period.”

    This is about 330 TW a year and this is the accumulation of heat that is driving thermal expansion. According to this article, a bit less than half of 7 cms from 1972-2008.

    According to Richard Smalley, “To give all 10 billion people on the planet the level of energy prosperity we in the developed world are used to, a couple of kilowatt-hours per person, we would need to generate 60 terawatts around the planet—the equivalent of 900 million barrels of oil per day.” cohesion.rice.edu/NaturalSciences/Smalley/emplibrary/120204%20MRS%20Boston.pdf

    If you had created this 60 TW with OTEC over the period 1972-2008, I would assume you would have reduced about 3Cm * 60/330 worth of sea level rise.

    If you had done this however you wouldn’t have accumulate this much heat in the ocean or thermal expansion because there would be substantially less carbon dioxide in the atmosphere.

    If you had converted this 60TW to hydrogen to get it to market you would have further reduced sea level rise by some amount. I could do a calculation but then so could you.

    Ultimately if you replace all carbon emitting energy with renewables the atmospheric carbon concentrations will decrease. – you could reverse the build up each year by greening the deserts see post number 4 even with current additions.

    Once heat is no longer building up in the ocean then you would start to shrink them by extracting heat.

    These are all ideals. None of the 3 techniques is going to be the single answer, much less an overnight fix. It is attempt though to look at the energy/water/environment problem holistically.

    Comment by Jim Baird — 5 Jun 2012 @ 9:09 PM

  105. > If you had created this 60 TW with OTEC

    What efficiency are you assuming?

    This may help:
    http://www.triplepundit.com/2006/10/askpablo-otec-and-engine-efficiency/

    Comment by Hank Roberts — 6 Jun 2012 @ 12:12 AM

  106. All those off topic comments are too hard to not answer:
    Ocean Thermal Energy Conversion OTEC: another renewable source of energy or power that doesn’t work that well in practice.

    “geological disposal of high level radioactive waste” is a bad idea because spent fuel is fuel for the next generation of reactor.

    Why don’t we leave those subjects for the engineers who work for the electric companies and reactor companies? They aren’t going to miss a dollar to be made by OTEC or whatever.

    Fukushima: 573 certified deaths were due to evacuation-related stress at Fukushima. Zero due to radiation. February 4, 2012
http://www.beyondnuclear.org/home/2012/2/4/japanese-authorities-recognize-573-deaths-related-to-fukushi.html
    In other words, people they evacuated from intensive care units, died. Fukushima’s natural background radiation plus the radiation from the reactor leak is still less than the natural background radiation here in Illinois. It would almost be humorous if…..

    Let’s stick to sea level rise, please. I would like to know what happens if the ice on Greenland weakens and collapses. Does it make a tsunami or only raise sea level 23 feet? Does anybody know for sure the ice won’t all slide into the ocean next year? Joe Romm said Greenland is having record hot weather.

    When we desalinate sea water to irrigate the whole US, will that make sea level drop a little?

    Will the sea level get high enough to flood the Jordan river valley in Israel or Death Valley? When the Mediterranean basin and the Black Sea basin flooded, sea level must have dropped.

    Can sea level rise cause earthquakes if the Jordan river valley in Israel floods? Aren’t below sea level dry places part of rift valleys and won’t the extra weight make more rifting happen?

    Are there any more places below sea level that could flood soon? Are any as big as the Black Sea? It seems that a little sea level rise in the past made some big changes in geography.

    Comment by Edward Greisch — 6 Jun 2012 @ 1:09 AM

  107. Hank Roberts, 105

    “With a slightly different design, using an ammonia heat pipe instead of a cold water pipe, proposed by Jim Baird and Dominic Michaelis (British Patent No. GB 2395754). . . The parasitic losses are cut in half. The costs for the cold water pipe are eliminated, along with the cold water return pipe and condenser pumps, the cleaning system for the condenser, and the overall plant efficiency approaches 85% of Carnot vs. about 70% with a cold water pipe.

    The parasitic losses could be reduced as much as 50% and the complexity, mass (and cost) of the system reduced by at least 30%. The vast reduction in operating costs and environmental impacts would be worth investigation alone.”

    http://www.opednews.com/articles/2/American-Energy-Policy-V–by-Paul-from-Potomac-101214-315.html

    Comment by Jim Baird — 6 Jun 2012 @ 8:44 AM

  108. Edward Greisch, 106 “I would like to know what happens if”

    Which begs the question, what would you do if you knew?

    Comment by Jim Baird — 6 Jun 2012 @ 9:21 AM

  109. I give up on this one.

    Comment by Hank Roberts — 6 Jun 2012 @ 9:49 AM

  110. Re- Comment by Jim Baird — 6 Jun 2012 @ 8:44 AM:

    Your unsupported sales pitch figures on OTEC efficiency are off topic for a thread on sea-level rise. Further, your response to me regarding justification for your claims that OTEC can have a realistic effect on sea-level rise are off topic because they support my assertion of insignificance. Do your homework.

    Steve

    Comment by Steve Fish — 6 Jun 2012 @ 10:32 AM

  111. Here are three additional reasons why wide-spread use of OTEC for power generation (e.g., “grazers”) will not be practical any time soon (except possibly for niche applications where cold bottom layers come close the surface (Hawaii?):

    1) “Fouling” of the vast heat transfer surfaces required.

    2) No allowance for error or upsets.

    3) There exists a vast amount of low-grade heat available at temperatures much greater than even local sea water “hot spots” which can be converted to power using ORCs (or ammonia) as working fluid–e.g., industrial heat, including effluent water from power plant condensers (including CSP), low-grade geothermal sources, buildings or Urban Heat (A/C condensers), etc.,–I’m sure there are many others.

    Warm surface water is simply not yet the “lowest hanging fruit” available as a source of heat for a power cycle. In a few cases, it could be used as a base feedstock that would be further heated in solar collectors, for example.

    When it comes to efficiency, “temperature matters” for your heat source (a lot!)

    Comment by Jerry Toman — 6 Jun 2012 @ 1:52 PM

  112. Jerry, at the risk of offending Steve Fish, one last post on the issue.

    With a deep water condenser, biological fouling is a minimal issue because the working fluid circulates internally and condensation takes place beneath a depth of 500 meters were biological activity is greatly reduced.

    With the Lau design warm water heat exchanger would not severely affect performance. He is working on a paper on his proposal which hopefully will emerge shortly.

    With respect to error or upset, a massive release of ammonia would have consequences. The Lau design however uses CO2 as the working fluid so a release would have minimal impact. The design is also for a subsurface unit that would be removed from the wave and wind action that has lead to the demise of a lot of prior efforts.

    With efficiency temperatures matters, hurricanes however are one of the most powerful forces on the planet and operate off of the same delta T as OTEC.

    Comment by Jim Baird — 6 Jun 2012 @ 2:28 PM

  113. How about a short list with magnitudes?

    The answer is — the increase being measured is about half due to warming of the deep water, and half due to meltwater.

    Hoping (oh, please) to avoid further digression, is it safe to say that warming a given amount of cold deep water causes more sea level rise than warming the same amount of warm surface water? Remember this isn’t linear.

    Comment by Hank Roberts — 6 Jun 2012 @ 2:48 PM

  114. Jerry: 1) “Fouling” of the vast heat transfer surfaces required.

    IIRC fouling was a fly in the ointment w/the Hawaii pipe. Some of the gear is still used to retrieve deep water for aquaculture.

    One possible additional use for this water could be improved efficiency for AC heat dump? But again, fouling…

    At the risk of feeding still further off-topic discussion (who can resist the siren call??) there an interesting update on the Hawaii facility here.

    Comment by dbostrom — 6 Jun 2012 @ 3:04 PM

  115. Hank Roberts 113, wouldn’t the cold water expand less.

    A small calorie is the energy needed to increase the temperature of 1 gram of water by 1 °C

    At 4C it is 4.204 Joules

    At 20C it is 4.182 Joules (both from wikepedia http://en.wikipedia.org/wiki/Calorie

    If you transfer one calorie from the surface to the deep you wouldn’t raise the temperature 1C and therefore the gram of water at depth wouldn’t expand as much?

    Comment by Jim Baird — 6 Jun 2012 @ 4:47 PM

  116. Re De-salination

    If the desalinated water is used in areas with few or no river systems, then at any one time it will either be in the soil, the vegetation, an aquifer or the atmosphere. If it is in the atmosphere, it will act as a potent greenhouse gas. If it goes into an aquifer, that will come to a natural end when the aquifer fills up.

    If it is in an area with a normal number of river systems, a large portion of it will end up in the oceans, thus further reducing their salinity, which is already being reduced by the run-off of melt-water from glaciers and icesheets.

    So, could we simply pump the brine back into the oceans in order to combat this reduction in their salinity? If this is correct, would it not make sense to have the desalination plants near the Arctic where most desalination is currently occuring and pump/transport the desalinated water to arid regions instead of them producing it locally? This, of course, neglects geo-political considerations.

    Comment by Mel Tisdale — 6 Jun 2012 @ 6:04 PM

  117. I think it might be possible to verify the hypothesis by comparing the data of “Satellite Grace” every year. Aquifers are concentrated and thick, removal of water can be determined gravimetrically.

    Comment by Rogerio Maestri — 6 Jun 2012 @ 7:27 PM

  118. > desalination plants near the Arctic

    That would be after the icecaps melt;
    until all that fresh water ice is gone,
    it’s free.

    Well, it’ll probably get expensive
    when there’s very little left.

    Comment by Hank Roberts — 6 Jun 2012 @ 8:52 PM

  119. 65 dbostrom said, “Over 20 years ago I invented the Subductive Waste Disposal Method for the elimination of nuclear waste.

    Nope.”

    Gee. An abstract dated “Copyright 2012″. Im not clear how that invalidates a claim from 20 years ago. perhaps a tad better documentation?

    Comment by Jim Larsen — 6 Jun 2012 @ 10:17 PM

  120. 82 Harold P says, “How much of sea level rise is due to soil and silt being deposited into the oceans from rivers?

    How much of sea level rise is due to erosion of coasts by the action of wind and waves?

    How much of the apparent sea level rise is due to subsidence of the continents?

    How much of sea level rise is due dust being blown out deserts and falling into the oceans?”

    Well, these things have been going on for billions of years. Obviously, the average result is: “NONE”

    So, yep, there could be some deviation due to current circumstances, but basically, all of these issues are non-issues unless you provide some rationale as to why their effect is larger today than average.

    Comment by Jim Larsen — 6 Jun 2012 @ 10:33 PM

  121. Gee. An abstract dated “Copyright 2012″. Im not clear how that invalidates a claim from 20 years ago.

    Hard to know how to reply other than “care to try again?” How about a free clue? Proc. R. Soc. Lond. A 8 September 1971 vol. 324 no. 1558 353-367

    Personally I like the borehole disposal idea; the irony of using technology developed principally for petroleum extraction to get rid of nuclear waste is pleasingly twisted.

    Comment by dbostrom — 7 Jun 2012 @ 12:55 AM

  122. Mel Tisdale, I like the way you think. OTEC only works within 30 degrees of the equator so the power isn’t available for desalination. Seems to me it would be easier to capture Greenland runoff without the need for desalination. Quebec and British Columbia have also looked into bulk water sales. Quebec found shipping costs too great and there is a lot of public resistant (irrational to my mind) in this province. No thought has been given to sea level rise, which will impact BC coastlines significantly, in this regard.

    There are a number of new designs for pumping using wave action that could move this water economically.

    Steve Fish, I can’t let your comment that an 18% conversion of accumulating ocean heat to power is insignificant go unchallenged.

    Comment by Jim Baird — 7 Jun 2012 @ 2:30 AM

  123. Jim Baird @122
    18%? This is getting entirely silly as well as off topic.
    Go back to your numbers @104. Do you not see the error?

    The NOAA present the annual rise in OHC in terms of 500 100-watt light bulbs burning continually for each of the 6.7 billion folk on the planet. (Perhaps a tad high as it calculates out to 11zJ pa.)
    So that is every man jack burning 50kWh every hour of every day. That would worry me. My house might melt with that sort of energy use.

    You then take a a figure touted by this Richard Smalley who talks of “a couple of kilowatt-hours per person” (over an undisclosed period) with the world population marginally higher and, hey presto, by using exclusively OTEC sea-level rise is reduced by 18%.
    Now tell me – does this reduction in sea-level rise account for all the melted houses & household products that will be flowing seawards?

    Get a grip. Your numbers are nonsensical.

    Comment by MARodger — 7 Jun 2012 @ 6:21 AM

  124. dbostrom, you didn’t actually expect him to read for comprhension, did you? ;^)

    Comment by Jim Eager — 7 Jun 2012 @ 8:26 AM

  125. Hank Roberts #113:

    is it safe to say that warming a given amount of cold deep water causes more sea level rise than warming the same amount of warm surface water?

    Hank, just the other way around. Though the difference is not so big if you also take the pressure increase with depth into account.

    Note to all: physics is one domain in which idle speculation can be fruitfully replaced by looking it up… but you knew that :-)

    Comment by Martin Vermeer — 7 Jun 2012 @ 8:54 AM

  126. Dr. Rodgers 123, In all honesty, I’m not sure with whom you are taking issue? I read the NOAA article again and that is what it says.

    Dr. Smalley is a Noble Laureate and if you don’t like his numbers the Intergovernmental Panel on Climate Change report on emissions scenarios foresees a wide range of primary power demand of anywhere from 20 to 50 TW by 2050.

    How producing this much power from the conversion of ocean heat is not a benefit with respect to sea level rise truly does escape me. Particularly when nuclear or fusion, which are the only other constant base load sources of power that do not emit carbon would add an additional 40 to 100 TWh to the oceans in the IPCC scenario?

    Comment by Jim Baird — 7 Jun 2012 @ 9:49 AM

  127. dbostrom, 65, sorry I missed the link to the paper. My proposal was a little different because it would have incorporated similar technology to that being used on the Chunnel at the time. Still it was a good idea in 1971 and to this day. I remain disgusted with the way the spent fuel problem has been handled. I contacted Lord Oxburgh at one point and he said he too had considered subduction as a solution.

    Comment by Jim Baird — 7 Jun 2012 @ 10:10 AM

  128. For a guy who said he was making a last post on the subject Jim has a lot to say. If I understand right, Jim has a financial interest in OTEC. You do have a related patent, right?

    Then comes the buzzword-laden sales pitch (where Jim has a personal financial stake), where Jim talks of turning deserts into “natural” carbon sinks with massive man-made water inputs, and a “holistic” removal of vast quantities of ocean heat in a context where we have no clue how mixing surface heat into the cold depths will impact overall ocean currents, and therefore trivial little things like distribution and timing of precipitation over the agricultural regions of the entire globe. Such personal profiteering while glossing over science is what continues to put all the extra heat into the ocean in the first place.

    Jim, I can appreciate your desire to to attract venture capital to your OTEC efforts. I have created two businesses myself. In my opinion, you’ll fare better without the buzzwords of “natural” and “holistic”.

    Comment by Mark E — 7 Jun 2012 @ 10:25 AM

  129. Jim Baird wrote: “nuclear or fusion, which are the only other constant base load sources of power that do not emit carbon”

    That is incorrect on two counts.

    First, fusion is not a “base load source of power” because the technology to generate base load electricity from nuclear fusion does not exist, and now knows whether or when it ever will.

    Second, concentrating solar thermal electricity generation with thermal storage (using molten salts) does exist, is already used in commercial power generation and has already demonstrated the ability to generate 24-hour base load power.

    And then there is a cutting-edge technology for generating zero-carbon base load electricity that you may have heard of … it’s called “hydro-electric dams”.

    Comment by SecularAnimist — 7 Jun 2012 @ 10:26 AM

  130. Good luck with getting 10TW with your hydro-electric dams. Agree fusion is nowhere but that doesn’t arrest the bundles of money being funneled into it. Fail to see how solar thermal benefits sea levels.

    Mark E., promise this is it. It is obviously an exercise in futility. My mistake anyone might be interested in discussing solutions to the problem highlighted in the original article.

    Comment by Jim Baird — 7 Jun 2012 @ 11:28 AM

  131. Well, the tangent can be bent back around to some relevance for sea level rise, at least for how people have to plan for future scenarios. Planning for earthquake and/or tsunami will overlap planning for sea level change.

    > similar technology to that being used on the Chunnel

    Subduction zones produce repeated earthquakes larger than anyone a few years ago thought possible.

    “… describe a possible megathrust quake in the Pacific Northwest in this way: “Rather than 17 seconds or 30 seconds we’re going to be dealing with ground motion running perhaps six minutes total for the rupture to occur, that starts on one end and goes to the other, and strong ground motion in our area of maybe three minutes.”
    Based on historical averages, researchers from Oregon State estimate in the next fifty years, the odds of a megathrust quake occurring off the coast of the Pacific Northwest is roughly thirty percent….”
    http://anniesearle.com/web-services/Documents/ResearchNotes/ASA_ResearchNote_PacificNorthwestEarthquakeRisk_Feb2012.pdf

    “… scenarios (M8.8-9.2 or a series of M8′s), given a 550 year average recurrence time and the time since the 1700 earthquake ….” http://wgcep.org/sites/wgcep.org/files/CSZucerf3.docx
    _____________

    I think most people worry about what may happen during short term emergencies during their lifetime.

    Anticipating climate change in planning for short term emergencies ought to be possible.
    A 10-meter tsunami barrier is one thing; a higher storm surge for centuries to come changes things in very different ways. For a tsunami, you want a backflow preventer in the sewage outfall. For higher high tides, you want a different way of managing sewage entirely.

    Comment by Hank Roberts — 7 Jun 2012 @ 1:20 PM

  132. One point needs to be perfectly clear in this discussion–

    The ONLY thing that really matters with regard to renewable energy technology is the extent to which it can produce electricity (work) while reducing (displacing) the emission rate of carbon dioxide to the atmosphere, now occurring via the burning of carbon-based fuels–the total “emergy” impact of construction, operation and maintenance must be considered.

    Everything else is merely a second or third order effect. This includes the miniscule reduction (if any) in the specific volume when warm sea water near the surface is mixed with cooler layers below, where the specific volume of water is near its minimum.

    This is true whether or not the layers are actually mixed, or heat is just transferred between the layers (increasing global entropy in either case, of course).

    Comment by Jerry Toman — 7 Jun 2012 @ 1:49 PM

  133. Jim Baird wrote: “My mistake anyone might be interested in discussing solutions to the problem highlighted in the original article.”

    With all due respect, I think your mistake is in mistaking skepticism of your particular ideas for disinterest in solutions to the problem of sea level rise.

    Judging by the number of comments on this thread devoted to discussing your ideas, there has clearly been no lack of “interest” in them. It’s just that a lot of people don’t find them to be very credible, and have stated in some detail why that is so.

    Comment by SecularAnimist — 7 Jun 2012 @ 2:55 PM

  134. The comments in this thread have gone way off topic. Seve3ral of the comments also contain incorrect content but to avoid further derailing this thread I’ll let those pass here.

    Comment by David B. Benson — 7 Jun 2012 @ 9:52 PM

  135. http://www.nasa.gov/home/hqnews/2012/jun/HQ_12-184_NASA_Discovers_Ocean_Plant_Life.html

    NASA Discovers Unprecedented Blooms Of Ocean Plant Life

    A super-bloom of phytoplankton was found under thin Arctic ocean ice that has meltwater on top of it. I hope this makes up for some of the 40% phytoplankton loss we heard about earlier. Not that it solves GW or sea level rise. But more phytoplankton helps eat up some of the CO2 that is causing the GW. The water is really green where the bloom is. But is the ice required? Or is this just one more thing to make your math too complicated?

    “Ocean current data revealed that these blooms developed under the ice and had not drifted there from open water, where phytoplankton concentrations can be high.” So the Arctic ocean at least saves the phytoplankton. Tropical water is clear. I recall that somebody proposed adding iron to the ocean to stimulate phytoplankton growth, then gave that up. Getting sea level to fall still requires getting CO2 to fall. Phytoplankton can’t keep up with coal burning.

    I Agree with 134 David B. Benson on off topic [and impractical] energy ideas getting too thick. Try those ideas with your own money some place other than where I live.

    What would I do if I knew collapsing Greenland ice could cause a tsunami? Stay away from the East coast. The more consequences of GW we know more about, the better the argument we have to stop GW.

    Comment by Edward Greisch — 8 Jun 2012 @ 12:46 AM

  136. Jim Baird @126

    You say of me “In all honesty, I’m not sure with whom you are taking issue?
    You are the one lobbing the numbers in here. Try and be responsible for them. Try and make some sense of them. The NOAA talk of OHC circa 2000 rising 440,000kWh pa per head of human population. You compared that figure to one taken from an incoherent quote (by I don’t care who) relating to 2050 which equates to 83,000kWh pa ph.. Thus, you contend @122, here is a scheme that is significant (18%) to reducing the rate of sea-level rise.
    If this analysis were on-topic I would likely give it a more detailed critique & shepherd you down to a more realistic level of significance (probably below 1%). As it is not, I will suggest the following as a useful consideration in this matter.
    Today’s mix of fossil fuels release energy equal to one year’s worth of the energy trapped by the CO2 added to the atmosphere by its burning. That ‘trapping’ will be multiplied some fifty times the initial annual value before equilibrium is reached. That ‘trapping’ will essentially be heating the oceans. Coicidentally, today’s emissions are some 2% of total emissions to date. Sourcing today’s primary energy from today’s oceans would thus reduce the rise in OHC by (50/100) 2%. As half of today’s sea-level rise is not due to dOHC, the significance of your scheme would today be a whopping 1%.

    The OTEC you propose may have merit but you are wrong about its significance to sea-level rise.

    Comment by MARodger — 8 Jun 2012 @ 4:12 AM

  137. Dr. Rodger, thank you for the clarification.

    A hurricane is Nature’s response to an over heating ocean. It seems to me we would be wise to follow the analogy to get the power we need.

    Subduction is also Nature’s recycling mechanism, ergo how spent fuel should be eliminated.

    Comment by Jim Baird — 8 Jun 2012 @ 9:02 AM

  138. A couple of sandbox101 questions: 1) is a changing sea level floor considered? 2) I assume that sea temperature rise is kept within a band of surface water. What is the accepted/reasonable depth of such a band? Is the expansion assumed to be all seen at the surface or is some pushed into the seawater below the band?

    Comment by Rod B — 8 Jun 2012 @ 10:47 AM

  139. 3) has anyone considered holes, maybe bore, spontaneously emanating from the sea floor compensating for sea leve rise

    Marcus

    Comment by Marcus — 8 Jun 2012 @ 11:33 AM

  140. Handy for checking assumptions:

    https://www.sciencemag.org/content/336/6081/550.summary
    http://www.nature.com/scitable/knowledge/library/modeling-sea-level-rise-25857988

    Comment by Hank Roberts — 8 Jun 2012 @ 11:42 AM

  141. Rod B says: 8 Jun 2012 at 10:47 AM

    Helpful starting points on deep ocean heating:

    Warming of Global Abyssal and Deep Southern Ocean Waters between the1990s and 2000s: Contributions to Global Heat and Sea Level Rise Budgets

    Recent Bottom Water Warming in the Pacific Ocean

    Warming and Freshening in the Abyssal Southeastern Indian Ocean

    Recent western South Atlantic bottom water warming

    Comment by dbostrom — 8 Jun 2012 @ 11:49 AM

  142. Rod B, long time no see.

    > 1) is a changing sea level floor considered?

    Actually it is. It is part of the GIA (glacial isostatic adjustment) after-effect of the last termination. The ocean floor is still subsiding at a rate of 0.3 mm/year as a plastic response to the increased ocean water load after deglaciation. This effect has been studied extensively by Richard Peltier of Toronto.

    What it means is that, if the total ocean volume were not to change at all, we would still see the ocean surface subside. Conversely, if we want to obtain a measure for the change in total ocean water volume (the climatologically interesting quantity, also in the context of this post!), we have to add 0.3 mm/year to the “raw” observed change in mean position of the sea surface obtained by, e.g., satellite altimetry. This reduction is nowadays routinely made.

    It has no relevance for any change in rate of sea-level rise however, as the effect has been constant for the last 4000 years at least.

    Comment by Martin Vermeer — 8 Jun 2012 @ 1:48 PM

  143. Martin Vermeer 142 — Thank you. That is certainly of interest.

    Comment by David B. Benson — 8 Jun 2012 @ 2:54 PM

  144. > Subsiding
    Does that go all the way down through the plates, is the underlying plate being pushed down at all, or is it the softer sediment that’s subsiding?

    Are the sediments squeezed, closing pores, so becoming more compressed?

    I noticed this: GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L11310, 7 PP., 2012
    doi:10.1029/2012GL051854 on the earthquakes in that material:

    A self-consistent mechanism for slow dynamic deformation and large tsunami generation for earthquakes in the shallow subduction zone

    “… Dynamic pore pressure changes in the overriding wedge above a shallow-dipping plate interface significantly affect the rupture dynamics of shallow subduction zone earthquakes and their tsunamigenesis….”

    Comment by Hank Roberts — 8 Jun 2012 @ 7:51 PM

  145. I’m not sure of the effect of OTEC on the carbon cycle, but the effect on sea level would be to increase sea levels. Pumping heat from the surface, where most of it is lost to evaporation in a matter of weeks, to the deep ocean, where it may reside for millenia, will serve to increase sea level rise due to thermal expansion. It’ll also make the Earth’s energy budget (energy received from the sun – energy lost to space) even more positive, by reducing heat losses from the upper ocean. Any reduction in temperature will be local or limited in duration.

    Comment by Yartrebo — 8 Jun 2012 @ 10:24 PM

  146. Stefan: I’d like to use that haunting photo in a class that I teach…would that be OK? Can you say more about the picture? Location, elevation of the photographer? ( I don’t see a different way to contact you, so trying here in comments).

    Comment by Michael Spencer — 9 Jun 2012 @ 8:03 AM

  147. Before signing off on this thread, since nobody responded to my assertion in my first comment (#51) with regard to where it is best to reject heat removed from the sea surface (after energy in the form of work is extracted), while rightfully insisting that those commenting be more quantitative, I’m including in this comment a link to paper where not only is the process described, but the “math” is also done.

    While the “theoretical” work in such an ideal process is calculated to exceed 30% even in a “marine air” environment from sea water with temperature at 26 C, the need to consume energy to accelerating air into the vortex, as well as to create surface area for mass transfer (spray +elevation required for “trickling” over packing) would reduce this by an estimated 50%.

    After considering other mechanical losses as well, I think it’s reasonable to assume that about a third of the “theoretical work” , or ~10% of the heat removed from the sea could be extracted from the device—more than double that obtainable from OTEC at a fraction of the investment cost..

    Only by building an experimental device can we know for sure what to expect.

    At the same time, the heat rejected from such a device would go to a location above the clouds where it could be more readily dissipated to outer space.

    No need to take 20 steps backward for every 21 steps taken forward on this journey, which is what is done by mixing it back into (any) ocean layer.

    http://vortexengine.ca/Publications.shtml

    Comment by Jerry Toman — 9 Jun 2012 @ 12:20 PM

  148. Answering my own question, there is a map of where higher sea level goes at:
    http://palaeo.gly.bris.ac.uk/Palaeofiles/Marsupials/Origin%20-%20Australia.htm

    WOW! The Black sea and Caspean sea become one and grow. Etc.

    Comment by Edward Greisch — 9 Jun 2012 @ 4:28 PM

  149. Edward Greisch @148
    That map of yours is a bit worrying. It appears to show that global warming in the tropics will be severe enough to melt entire islands. Look! Your map shows Papua New Guinea completely disappeared!

    A more up-to-date world map is used at this site to show the inundations from varying levels of sea-level rise. The maximum rise it provides for is 60m so it doesn’t show the full results for both Antarctica & Greenland melting to zero and raising sea level 70m+
    Its main failing however is how it deals with land below sea level (eg the Dead Sea, Caspian, etc.). The map fills them to the increased sea level even when they would remain unconnected to open sea.
    This one here does show the 70m contour & when basins like the Dead Sea or Caspian would flood but is less easy on the eye for accurately assessing the impact of any rise lower than 70m.

    Comment by MARodger — 10 Jun 2012 @ 3:12 AM

  150. For Jerry Tolman, you posted a link to a “Pre-publication manuscript submitted for peer reviewed publication IEEE Power Energy System Magazine / sustainability Transaction in September 2011″ — it’d be good to post the reviewers’ comments and whether a final version emerges that’s publishable.

    Comment by Hank Roberts — 10 Jun 2012 @ 10:17 AM

  151. Lovely photograph! A click on its properties shows ‘Outer banks’, which a Google indicates is in North Carolina. At first, I would have thought ‘Middle East’, as one of the people in the foreground look as if they are in Arabic dress. But perhaps just wrapped in a large shawl.

    Comment by oakwood — 11 Jun 2012 @ 11:46 AM

  152. Oakwood, that person you see wrapped in Arabic dress?

    That’s a surfboard.

    Comment by Hank Roberts — 11 Jun 2012 @ 12:11 PM

  153. Here are three more: http://imgc.allpostersimages.com/images/P-473-488-90/61/6166/TTNG100Z/posters/three-surfboards-standing-on-beach-in-a-row.jpg

    Comment by Hank Roberts — 11 Jun 2012 @ 12:15 PM

  154. Stefan:
    A hopefully trivial question- how much of the buoyancy of floating ice is due to occluded air bubbles?

    How does this number vary from new ‘black ice’ , to calved bergs that started as porous snowfall?

    Comment by Russell — 11 Jun 2012 @ 4:12 PM

  155. Glacier simulator: http://intern.forskning.no/arnfinn/polaraaret/glacier.html

    Comment by Hank Roberts — 11 Jun 2012 @ 5:21 PM

  156. Russell, looks like there would be answers out there; here’s a zero:

    Characterization and flexural strength of iceberg and glacier ice
    http://www.igsoc.org/journal/igs_journal_vol41_issue137_pg103-111.pdf
    RE GAGNO – Cited by 11
    Icebergs, large floating pieces of glacier ice, pose a serious hazard to ships and …. This zero-porosity limit for the density of ice is 916.9 kg m-3 at O°C. Using this …. Fabric demonstrated a fairly strong degree of preferred c-axis orientation.

    Comment by Hank Roberts — 11 Jun 2012 @ 9:45 PM

  157. Re HR 52. Of course its a surf board. The resolution on my screen was limited. Zooming in, I see you’re right. Show’s how easily the eye and brain can be tricked into ‘seeing’ the wrong thing.

    Comment by Oakwood — 12 Jun 2012 @ 12:24 AM

  158. > That’s a surfboard

    Fooled me too for a moment

    Comment by Martin Vermeer — 12 Jun 2012 @ 2:56 AM

  159. Gnarly right body break, but the board is better off in the sand.

    Hank: as glacial erratics testify, bergs can contain a lot more than air, so I think I’ll discount the zero limit.

    Comment by Russell — 12 Jun 2012 @ 1:50 PM

  160. You’ve got to love Hank and his whole ‘it’s out there’ thing!

    Yes, my dimming memory of the density of glacial ice, as opposed to firn, is that a cubic meter of it is so close to being solid water that you wouldn’t want to hit it at speed with any sort of sea-going vessel.

    Comment by Hasis — 12 Jun 2012 @ 1:53 PM

  161. > bergs can contain a lot more than air

    Sure, they carry rocks, gotta account for the ballast. I recall studies of the erratics found on the seabed carried out during episodes of icebergs.

    Yup, just sayin’, there’s at least that one journal full of detailed investigation of what was found in floating ice, ample reading for those who like that kind of thing.

    I suppose those navies that operate under the ice would also have info on both sea ice and bergs broken off ice shelves and glacers, since they’d be looking upward at the stuff and interested in what it was. Doubt they’d publish.

    I wonder how much sea ice has added plastic frozen in nowadays.

    Comment by Hank Roberts — 12 Jun 2012 @ 4:17 PM

  162. Martin, Hank, dbostrom, et al, thanks for the info. I would guess that spreading and subduction would have an effect, though maybe (another guess) cancel each other. I need to pursue some of the references given.

    Comment by Rod B — 13 Jun 2012 @ 10:07 PM

  163. “whole ‘it’s out there’ thing!” — I am the merest of acolytes.

    [Response:"With a flip of the wrist they can hide your dissertation behind piles of old Field and Stream magazines" Exactly as it should be :) --Jim]

    Comment by Hank Roberts — 13 Jun 2012 @ 10:31 PM

  164. Hank 144:

    > Subsiding
    Does that go all the way down through the plates, is the underlying plate being pushed down at all, or is it the softer sediment that’s subsiding?

    This particular subsidence mechanism is the same (but in reverse) as the GIA (glacial isostatic adjustment) land uplift mechanism, i.e., the whole oceanic lithosphere is going down squeezing out asthenospheric mantle material that moves to below the continents, causing those to move up. The role of compression is very small and may be neglected.

    Part of this is the on-going post-glacial uplift in the large ex-glaciation areas of Hudson Bay (Laurentide ice sheet) and Fennoscandia; a large remote zone or “forebulge” around these areas is subsiding, including most U.S. coastlines. But otherwise the phenomenon is global.

    Comment by Martin Vermeer — 14 Jun 2012 @ 3:32 AM

  165. Rod B 162:

    I would guess that spreading and subduction would have an effect, though maybe (another guess) cancel each other.

    The second guess would be mine too. Yes, the ocean floor spreading from the mid-oceanic ridges slowly subsides due to cooling of the rock (that’s why those are ridges!), but this is a stationary situation where new, warm ocean-floor rock is manufactured at the same rate as old, cold ocean floor disappears down the subduction zones.

    Also the role of sediment porosity is stationary: new sediment is created by erosion and laid down at the same rate as subduction takes it down into the mantle and squeezes out the pores and volatiles, which bubble up through conduits creating island-arc volcanism (like Japan).

    Comment by Martin Vermeer — 14 Jun 2012 @ 3:44 AM

  166. Thank you Martin.

    Comment by Hank Roberts — 14 Jun 2012 @ 10:33 AM

  167. I posted this link on the NC thread, but maybe it’s more appropriate here:

    http://thinkprogress.org/climate/2012/07/01/508782/greenland-ice-sheet-melt-nearing-critical-tipping-point/

    Should this radically change our view on how fast the rate of global sea-level rise will be? Would this put it into the multi-meter range by the end of the century?

    Comment by wili — 1 Jul 2012 @ 2:46 PM

  168. Wili, that article quotes scientists on
    > “… a state of inevitable decline” …
    > “It appears that we’re about to cross a threshold in summer . . .
    > you might even call it a tipping point
    > as we go into a net energy absorption”

    So my take on your questions is:

    No, this does not radically change … sea level rise, and
    No, this does not put it into multi-meter … end of the century

    It doesn’t say that, it doesnt’ suggest that, and I don’t see how you get to it except that you seem to keep posting the conclusion, offering a variety of possible reasons to reach it.

    Be wary of starting with the answer and looking for citations or even blog reports of press reports of interviews to support the answer.

    “Reverse citation” is not a good approach to science.

    Comment by Hank Roberts — 1 Jul 2012 @ 3:05 PM

Sorry, the comment form is closed at this time.

Close this window.

0.509 Powered by WordPress