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How much is sea level rising?

What the science says...

Select a level... Basic Intermediate

A variety of different measurements find steadily rising sea levels over the past century.

Climate Myth...

Sea level rise is exaggerated
 

"We are told sea level is rising and will soon swamp all of our cities. Everybody knows that the Pacific island of Tuvalu is sinking. ...

 

Around 1990 it became obvious the local tide-gauge did not agree - there was no evidence of 'sinking.' So scientists at Flinders University, Adelaide, set up new, modern, tide-gauges in 12 Pacific islands.

 

Recently, the whole project was abandoned as there was no sign of a change in sea level at any of the 12 islands for the past 16 years." (Vincent Gray).

 

Gavin Schmidt investigated the claim that tide gauges on islands in the Pacific Ocean show no sea level rise and found that the data show a rising sea level trend at every single station.  But what about global sea level rise?

Sea level rises as ice on land melts and as warming ocean waters expand. As well as being a threat to coastal habitation and environments, sea level rise corroborates other evidence of global warming 

The blue line in the graph below clearly shows sea level as rising, while the upward curve suggests sea level is rising faster as time goes on. The upward curve agrees with global temperature trends and with the accelerating melting of ice in Greenland and other places.

Because sea level behavior is such an important signal for tracking climate change, skeptics seize on the sea level record in an effort to cast doubt on this evidence. Sea level bounces up and down slightly from year to year so it's possible to cherry-pick data falsely suggesting the overall trend is flat, falling or linear. You can try this yourself. Starting with two closely spaced data points on the graph below, lay a straight-edge between them and notice how for a short period of time you cancreate almost any slope you prefer, simply by being selective about what data points you use. Now choose data points farther apart. Notice that as your selected data points cover more time, the more your mini-graph reflects the big picture. The lesson? Always look at all the data, don't be fooled by selective presentations.

graph from Church 2008

Other skeptic arguments about sea level concern the validity of observations, obtained via tide gauges and more recently satellite altimeter observations.

Tide gauges must take into account changes in the height of land itself caused by local geologic processes, a favorite distraction for skeptics to highlight. Not surprisingly, scientists measuring sea level with tide gauges are aware of and compensate for these factors. Confounding influences are accounted for in measurements and while they leave some noise in the record they cannot account for the observed upward trend.

Various technical criticisms are mounted against satellite altimeter measurements by skeptics. Indeed, deriving millimeter-level accuracy from orbit is a stunning technical feat so it's not hard to understand why some people find such an accomplishment unbelievable. In reality, researchers demonstrate this height measurement technique's accuracy to be within 1mm/year. Most importantly there is no form of residual error that could falsely produce the upward trend in observations. 

As can be seen in an inset of the graph above, tide gauge and satellite altimeter measurements track each other with remarkable similarity. These two independent systems mutually support the observed trend in sea level. If an argument depends on skipping certain observations or emphasizes uncertainty while ignoring an obvious trend, that's a clue you're being steered as opposed to informed. Don't be mislead by only a carefully-selected portion of the available evidence being disclosed.

Current sea level rise is after all not exaggerated, in fact the opposite case is more plausible. Observational data and changing conditions in such places as Greenland suggest if there's a real problem here it's underestimation of future sea level rise. IPCC synthesis reports offer conservative projections of sea level increase based on assumptions about future behavior of ice sheets and glaciers, leading to estimates of sea level roughly following a linear upward trend mimicking that of recent decades. In point of fact, observed sea level rise is already above IPCC projections and strongly hints at acceleration while at the same time it appears the mass balance of continental ice envisioned by the IPCC is overly optimistic (Rahmstorf 2010 ).

Last updated on 3 June 2014 by doug_bostrom. View Archives

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Comments 101 to 109 out of 109:

  1. daniel at 00:36 AM on 14 July, 2010

    "The 1 sigma bounds are irrelevant Peter". This is not science, it is not recognisable statistics either. Irrelevant, or inconvenient? It fits the 1 sigma bounds where it is. It does not elsewhere.
  2. 20 Andrew Hobbs at 21:06 PM on 13 June, 2010

    Thank you for your post. Especially in light of no one else elaborating on the statement made in "The Skeptical Argument," and that I've been trying to find something on that charge for a little while:
    ~ ~ ~
    "Scientists from Flinders University, Adelaide, certainly DID NOT abandon the project. "

    "In 2003 the University decided to cease the operations of the National Tidal Facility Australia (NTFA).
    ... The operation was transferred to the Commonwealth Government effective from 1 January 2004."

    "It is possible to access their latest results on the Australian Bureau of Meteorology website at the web page for the South Pacific Sea Level and Climate Monitoring Project. "

    "These results support the general rate of global sea level rise noted elsewhere."
    ~ ~ ~
    Beyond that, earlier a comment was made: "... my comments have been deemed inappropriate by a rather draconian comments policy."
    Well, I for one, found this back and forth discussion another wonderful (and educational) example of how science should be discussed. Too bad such a sight can't be found in the AGW Hoax blogosphere.
    My point is that I'm sure it is the "draconian comments policy" that makes such discussion possible so thank you John for sticking to your guns.
  3. What is the maximum possible sea level rise if all of the glaciers and ice sheets melted, and how much sea level rise can we get from thermal expansion? I read in "Global Warming FOR DUMMIES" that the maximum possible sea level rise from global warming is 650ft(200m) is this correct?
  4. Re: Karamanski (103)

    Not accounting for an additional rise due to an unknown level of thermal expansion, if it all goes at some unknown point in the future, Greenland contains enough water to raise sea levels by 7.2 meters while Antarctica (WAIS + EAIS) has enough to raise sea levels by 61.1 meters for a total of 68.3 meters (224 feet).

    Dunno where you got those figures (not cited in my powerpoint of the same name), but that total amount is approximately the vertical interval between the lowest of the sea levels during glacial max and that if all the ice melted. Perhaps that is what they meant.

    As far as thermal expansion, my understanding is that per each 1 degree C of ocean temperature rise will be accompanied by 1 meter sea level rise just from thermal expansion. Unless memory is deserting me.

    The Yooper
  5. Originally posted in the front-page article about Greenland ice loss. The moderator determined it was off-topic and that this would be the better place for the discussion.

    How is the short-term (last decade) accelerating land-ice loss (in Greenland and elsewhere) reconciled with sea level rise not accelerating? Does thermal expansion/contraction dominate over this time scale, is there too much error in the measurements, or is this truly something not clearly understood because of insufficient data like the energy budget?

    I guess the question is more broad in the sense that I wonder if the temperature, land-ice, and sea-level rates of change are fully reconcilable with available data.
    Response: [Daniel Bailey] Thank you for setting a positive example!
  6. PDT:

    I have no idea why sea level rise does not show an acceleration as a consecuence of accelerating melt in Greenland and Antartica.

    However, the University of Colorado data seems odd to me, because (to the delight of the folks at WUWT) shows instead a deceleration of sea level rise.

    I suggest to follow the CSIRO and AVISO data and graphs:

    http://www.cmar.csiro.au/sealevel/sl_hist_last_15.html

    http://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/products-images/index.html

    That show a nearly constant trend of aproximately 3.2 mm/yr unlike the University of Colorado (U. of C.) that show a deceleration and a lower mean (linear) trend: 3 mm/yr, that seems to coincide with the AVISO trend when Glacial Isostatic Adjustement (GIA) is not applied, so I suspect that the U. of C. do not apply GIA in their product.

    Note to the moderator: how can I post IMAGES and ACTIVE LINKS here at skepticalscience?
    Response: [Daniel Bailey] Try here. Remember to use the image width tag if the image width is more than 450. Use the Preview function to make sure everything looks right before posting. Thanks!
  7. So, is there simply no answer to my question (post 105), or is the question so undeserving as to not warrant a response? I didn't really find anything on a Google search. It seems like sea level should be predictable from temperature change and land-ice loss. Has someone looked at that? Perhaps it's the other way around, one could measure the average sea temperature by a combination of land-ice loss and sea level rise.

    Anyone?
  8. I believe the accepted term for the topic of my question is "sea level budget" and the first link given by Google for this is this one, from a website that claims higher atmospheric CO2 is a good thing for us. Seriously, the climate science community needs to figure out how to make sure the first links for searches on climate science are to actual science.
  9. Chemist1 - Glacial isostatic adjustment is a known issue, and sea level rise estimates are corrected for it. Your claims that sea level rise cannot be measured are unjustified; if you disagree, please provide references.
  10. #30 under One of the best climate change ads I've seen les at 07:47 AM on 21 March, 2011
    I wasn't sure because the first data points on both are not the same as yours...

    That's because folks at University of Colorado at Boulders for some obscure reason have omitted the first three data points at the end of 1992 from the graphs, although it's included in the text files.

    If you give the comparative fit qualities, we can all judge whether a linear fit is not appropriate compared to your function...

    You miss the point. A linear fit is insufficient to raise alarm, it only implies a 27 cm rise by 2100 which is entirely manageable. For a disastrous multi-meter sea level rise you'd need acceleration but you simply don't have it.
  11. For a disastrous multi-meter sea level rise you'd need acceleration but you simply don't have it.

    What we would EXPECT is surely what models predict. Looking at say Vermeer 2009 I dont think we do expect to much acceleration yet. 2050 will be different.
  12. 110 - no I don't miss the point.
    You presented some new and significantly different numbers without details (the fitted functions, confidence etc.). You can't expect that to go unchallenged, surely.

    A challenge to which you are failing to rise.
  13. Well, no defence of your numbers. I think we can take them as false and without credibility.
  14. Jay - Googling "average ocean depth", as I noted earlier, provides the average depth of 3790 meters in the summary of the first link.
    Response:

    [DB] Fixed link.

  15. Jay,

    NSIDC says at least ">70 meters. As others have pointed out, it was very easy to find.

    If you don't trust authority to do the calculation properly...a simplistic way to calculate it is to multiply the average depth of the ocean (3790m) by the ratio of the fraction of earths water crrently in land ice (0.02) vs seawater (0.97). You get about 70-80 m.

    It's a rounded estimate and doesn't account for thermal expansion, salinity effects on density, changes to shorelines etc, but it gets you in the ball park. It also says nothing about time scales of melting.
  16. Okay so that would be a 2% rise in average sea level, that is reasonable.

    I think Robert Laughlin's take on sea level is the most accurate, however.

    "the amount of water on the earth hasn’t changed significantly over geologic time, and that the rise and fall of the oceans is adequately accounted for by the waxing and waning of the polar ice sheets and slow changes in ocean basin volumes. The sea level has had a complex and interesting history, but it has never deviated more than 200 meters from its present value."

    Also

    "The last glacial melting, cross-dated at 15,000 years ago by the radiocarbon age of wood debris left by the glaciers as they retreated, occurred rapidly. The sea rose more than one centimeter per year for 10,000 years, then stopped. The extra heat required for this melting was 10 times the present energy consumption of civilization. The total melt­­water flow was the equivalent of two Amazons, or half the discharge of all the rivers in all the world."

    So we can conclude that our energy consumption is far too low to significantly impact sea levels.
  17. Dr. Jay >So we can conclude that our energy consumption is far too low to significantly impact sea levels.

    Your conclusion is invalid. The heat energy that drives global warming comes from the sun, not from human energy consumption. Humans emit CO2 which increases the amount of solar energy retained by the earth. The "waste heat" produced by humanity is indeed too small to have a significant effect on global temperatures, a topic that is covered in the waste heat post.
  18. @e

    Did you mean the waste heat is too small to have an impact on "global sea level"?
  19. Jay - That's what 'e' said.

    Note, however, that human energy use is 1% of the energy trapped by anthropogenic greenhouse gases - it's 2 orders of magnitude smaller. See the interminable waste heat thread for details.

    Hence the greenhouse forcing is 10x what you describe in your post, more than sufficient to be an issue.

    Nobody is predicting complete melt of the Antarctic ice caps, mind you. More appropriate comparisons are with peak Holocene or Eemian conditions: global temperatures ~2°C warmer, 4-6 meter higher sea levels, which would take quite some time to occur.

    And it looks like we're committing to an even higher temperature with AGW.
  20. @Dr. Jay,

    Sea level rise is caused by increasing global temperatures and ice melt (which itself is caused by increasing global temperatures), so my comment is transitively relevant to global sea levels.
  21. KR>Hence the greenhouse forcing is 10x what you describe in your post, more than sufficient to be an issue.

    Actually it's 100x more, sufficient indeed.
  22. e - I was discussing that in the light of Jay's claim that industrial energy was 1/10 that involved in the last peak interglacial sea levels, and that AGW provides energy 10x greater than that - 100x overall.

    Jay - Robert Laughlin's take on climate appears to be a mix of Climate's changed before and It's not bad. Both arguments are discussed here, and shown to be wrong, and Laughlin himself has been roundly criticized for his illogical stand on these matters. Personally, I would not rely on him as a climate expert.
    Response:

    [DB] Fixed text.

  23. The Chapter 5 Executive summary of the IPCCs AR4
    Says:
    The oceans are warming. Over the period 1961 to 2003, global ocean temperature has risen by 0.1°C from the surface to a depth of 700 m.

    globmaritime.com
    Says:
    At temperature 15°C, and atmospheric pressure, the coefficient of thermal expansion is... 0.000214 per degree Celsius for average seawater.

    The National Climatic Data Center
    Says:
    Average annual sea surface temperature is 16.1°C

    engineeringtoolbox.com
    Has a nice Online Thermal Cubic Expansion Calculator:

    700 meter column V0 - initial volume (m3, ft3, gallons ..)

    0.000214 β - volumetric expansion coefficient (1/oC, 1/oF)

    16.0°C t0 - initial temperature (oC, oF)

    16.1°C t1 - final temperature (oC, oF)

    Which yields:

    Change in Volume - dv = 0.015m (column)

    From above 2003 minus 1961 equals 42 years and it follows that 0.015 m divided by 42 years equals 0.36 mm/yr

    Table 10.7 from the IPCC's AR4
    Says:
    By 2100 we can expect thermal expansion to account for as much as 6.8 mm/yr.

    That is nearly 20 times the rate (calculated above) over the last 40 years or so.

    Colorado University Sea Level Research Group
    Says:
    The rate of sea level rise over recent years has been less than the long-term average believed to be due to the recent La Nina's.

    In other words, the rate of sea level rise has decreased in recent years due to lower temperatures.

    So, how likely is it that the current decreasing rate in sea level rise will do a turn around resulting in values represented in Table 10.7 from the IPCC's AR4?
  24. Steve, are you sure you're taking everything into account with this back-of-the-napkin calculation? Applying a simple thermal expansion formula to a global average affected by regional ENSO, large-scale circulation, and isostatic rebound issues is a sketchy proposition. Why not take a look at what the professionals are saying.
  25. Steve Case -"So, how likely is it that the current decreasing rate in sea level rise will do a turn around resulting in values represented in Table 10.7 from the IPCC's AR4?'





    What decreasing rate?. Do you mean short-term as in the last La Nina?
    • Do you mean short-term as in the last La Nina?

    That's what the Colorado University Sea Level Research Group said. How short term that is remains to be seen.
      Are you sure you're taking everything into account with this back-of-the-napkin calculation?

    I think the "Back-of-the-Napkin" assessment is accurate I also think that with respect to the information given in the Executive Summary of the AR4's Chapter 5 it's not likely to be that far off the mark.

    The Chapter 5 Executive Summary quote is in regard to the empirical record and Table 10.7 is a projection, and the 6.8 mm/yr is worst case. Worst case is often what is reported in the popular press. So it ought to be realistic. So how realistic is it that in the next 89 years that the thermal expansion component of sea level rise will go from 0.36 mm/yr to 6.8 mm/yr?
  26. Steve Case - 'So how realistic is it that in the next 89 years that the thermal expansion component of sea level rise will go from 0.36 mm/yr to 6.8 mm/yr?"

    Well, observations show the thermal (steric) component of sea level is rising at 0.69mm per year over the last 6 years, so your calculations appear to be missing important details- I see a glaringly obvious one in your calculations. Unless you're going to develop back-of-the-napkin climate models, that's going to continue to be the case.
    • Well, observations show the thermal (steric) component of sea level is rising at 0.69mm per year over the last 6 years,

    Is rising 0.69 mm/yr or is 0.69 mm/yr? It does make a difference. In any case, do you have a link for that observation? Even at 0.69 mm/yr is it reasonable to expect a possible 6.8 mm/yr due to thermal expansion by 2100?

      so your calculations appear to be missing important details - I see a glaringly obvious one in your calculations.

    And that glaringly obvious one is?

  27. Steve:
    I think you are overestimating sea level rise. Envisat data, which at this time is the most advanced, iindicates a sea level rise of approx 1.78mm/yr if memory serves me.
  28. Re #129,

    You memory fails you. GSL is increasing at about 3.22 mm/yr, almost double what your memory thinks:


    [Source]
    • Camburn ... I think you are overestimating sea level rise. Envisat data, which at this time is the most advanced, iindicates a sea level rise of approx 1.78mm/yr if memory serves me

    The IPCC tells us that Over the period 1961 to 2003, global ocean temperature has risen by 0.1°C from the surface to a depth of 700 m. The IPCC also tells us, in table 10.7, that by 2100 we can expect thermal expansion to account for as much as 6.8 mm/yr.

    I'm questioning if those two facts are compatible. The graph that Albatross put up is nearly a straight line. In order to achieve the 6.8 mm/yr it's going have to change. So, how likely is it that it will begin a sharp upward trend resulting in that 6.8 mm/yr contribution from thermal expansion the IPCC tells us could happen by 2100?

    As I pointed out earlier, 6.8 mm/yr is worst case, but that's what the popular press will report, so it ought to be reasonable. Is it?

  29. Steve:
    The transition from XBT data to ARGO data showed a huge step rise in OHC. We know because of instrument splicing, changes in models etc that XBT data had huge error bars.
    The results to date of ARGO data would indicate that the XBT data had a strong negative bias in measurement.
    With that in mind, and the fact that co2, because of its emissions spectra does not penetrate beyond the skin of the ocean. the idea of a 6.8 mm/yr thermosteric rise in sea level to 2100 is virtually impossible.
  30. Albatross:
    Note I said Envisat.
    Multiple sat observations of sea level
    Response:

    [DB] You continue to be disingenuous with your graph.  Envisat data is actually shown here:

    Envisat

    [Source]

  31. Camburn,

    I am well aware of what you said.

    You continue to be incredibly disingenuous. You are cherry picking a satellite dataset that only starts in 2004.

    There are multiple satellite datasets going back to circa 1993, yet you choose one dataset that presents the answer that you want, and then present a trend that is probably not statistically significant give the limited time window.
  32. Albatross:
    My memory was wrong in that it is 1.02MM/yr. as DB shows.

    Take a look at the coverage of Envisat does, verses the other satillites. Envisat is suppose to be the widest coverage.

    This is all the data from this satillite as this is the age of this satillite.

    The thing to watch in the long run being it has better coverage of the globe is to see if a divergence develops.

    I presented what it shows.

    I wanted to show them all. You will see that early it showed an increased rate of rise, and now it shows more of a decreased rate in rise. Are those slight divergences because of the coverage above 70 degrees?

    This thread is about sea level rise...right? And one has to look at all the data available....right?
    Response:

    [DB] "This thread is about sea level rise...right?  And one has to look at all the data available....right?"

    Excellent point.  One in which the entire thrust of your point is lacking in.  So, let's look at ALL of the data, shall we?  You mean like this, right?

    SLR

    Or this, right?

    SLR

    Or this, right?

    SLR

    Or this, right?

    SLR

    Multiple sources, using the all of the data available, rightly show the long term trend is far worse than your dissembling, cherry-picked case.

  33. Steve Case- And that glaringly obvious one is?

    The global ocean is a lot deeper than 700 mtrs. The executive summary in the IPCC document you cited says:

    "The oceans are warming. Over the period 1961 to 2003, global ocean temperature has risen by 0.10°C from the surface to a depth of 700 m. Consistent with the Third Assessment Report (TAR), global ocean heat content (0–3,000 m) has increased during the same period, equivalent to absorbing energy at a rate of 0.21 ± 0.04 W m–2 globally averaged over the Earth’s surface. Two-thirds of this energy is absorbed between the surface and a depth of 700 m"

    What do you think happens to that leftover third? And regardless it doesn't explain the discrepancy between your calculations and actual observations.
  34. Camburn

    Your data and examples are so very clearly cherry-picked that I find it increasing difficult to consider this an error. I rather hate to say it, but I've come to the conclusion that you are deliberately distorting the data to make your point - that you are trolling. Unless you significantly improve the quality of your posts, I see no reason to take them seriously.
  35. KR @137,

    I concur.

    DB @135,
    Thank you.
  36. Rob Painting - The Question I have asks if it's reasonable to project a 6.8 mm/yr thermal component to sea level rise by 2100.

    Adding in that leftover third and something less than a half for the salinity portion of steric rise won't change the overall gap between the current assessment in the Executive summary and the projection in table 10.7 by very much.

    Your actual observations link was a link to method, not data.

    So, is it reasonable or is it an exaggeration to project that the thermal component of sea level rise by 2100 might be over ten to nearly 20 times what it is today?
  37. Steve Case - "Your actual observations link was a link to method, not data"

    Now Steve that's being a little bit silly. Data is useless without analysis. I'm sure you know this. The point was that your simplistic calculations bore no to relationship to reality.

    "So, is it reasonable or is it an exaggeration to project that the thermal component of sea level rise by 2100 might be over ten to nearly 20 times what it is today?"

    Well climate modelling sure suggests an increase in the thermal component. It's to do with the greater temperature rise expected this century. Much more than the 20th century. Like this study for instance:



    Note the inset portion, where the thermal component reaches 6mm per year by 2100.
  38. So I present data from a new satillite and that is suppose to be bad?

    And from that data we can see that MSL rise has slowed.

    Do we know why it has slowed?

    All satillite data shows that it has slowed. That is why I posted the link to all of the current measureing satillites.

    Ya know, to make an observation supported by all metrics, and then be told that I am cherry picking?

    A valid question is, the major temp metrics all show wraming, yet MSL is not responding....why?
  39. "Your actual observations link was a link to method, not data"

      That's being a little bit silly. Data is useless without analysis.

    Analysis without any data is even more useless.

      The point was that your simplistic calculations bore [no] relationship to reality.

    What doesn't bear any relationship to reality is the mismatch of claims within the IPCC's AR4.

    So, is it reasonable or is it an exaggeration to project that the thermal component of sea level rise by 2100 might be over ten to nearly 20 times what it is today?

      Well climate modeling sure suggests an increase in the thermal component.

    Climate modelers can most likely make sure their models do whatever they want.

      It's to do with the greater temperature rise expected this century.

    We are over ten years into the century and certainly sea level is not demonstrating any positive change in trend. this graph

    certainly doesn't and if you plot out the tide gage data from PSMSL you will find that the timeline over the last 120 is nearly as straight.

      Much more than the 20th century. Like this study for instance:
      Note the inset portion, where the thermal component reaches 6mm per year by 2100.

    The IPCC no doubt got their value for table 10.7 from such a study. I assume they got the value for the observed 0.1°C over 42 years in that 700-meter layer of ocean from a legitimate source.

    I'm questioning whether or not it's reasonable that the empirical record described in the Chapter 5 Executive Summary of the AR4 could lead to the worst case projected outcome in table 10.7.

    If it's reasonable, then the annual rate of sea level rise, and it's claimed that it's mostly thermal expansion, has to change very dramatically in the next few years. The only place I see that happening is in the models. World temperatures have been on an upward trend for 120 years but the sea level trend during that time has remained relatively constant. It's on course for about 275 mm or less than a foot.

  40. Steve Case -"Analysis without any data is even more useless."

    So ARGO is now useless because the data do not match your preconceived notions? You're not making any sense whatsoever.

    "Climate modelers can most likely make sure their models do whatever they want"

    This comment is skirting dangerously close to a violation of the comments policy. No comments of scientific malfeasance please. As well as breaking this forum's rules, it just demonstrates you have no rational argument to make.

    " I assume they got the value for the observed 0.1°C over 42 years in that 700-meter layer of ocean from a legitimate source."

    Ditto, my comment above.

    "The only place I see that happening is in the models."

    Note that the actual sea level rise is at the upper end of IPCC projections:



    "World temperatures have been on an upward trend for 120 years but the sea level trend during that time has remained relatively constant. It's on course for about 275 mm or less than a foot.'

    So you didn't even bother to read the post you are commenting on? Did you not notice the graph in the post above?. Just to refresh:



    That steadily rising curve, that's an acceleration in the long-term rate of sea level rise. It doesn't mean sea level won't slow-down or speed-up on short timescales however.
  41. "Climate modelers can most likely make sure their models do whatever they want."

    Another baseless assertion. Please explain then why skeptics cant use the models to make anthropogenic warming go away?

    Camburn, so you would bet on that being a long term trend?
  42. scaddenp:
    I would not bet on that being a long term trend at all. What I would like to know, being Envistat covers more of the globe and has demonstrated a slowing of MSL rise, why?

    Physically, it does not make sense.
  43. Fair enough, good questions and I would like to know some answers as well. I found some other interesting puzzles with spatial distribution of sea level rise that dont have easy answers either. However, I would guess at short term variability, which is what Trenberth is also interested in.
  44. scaddenp:
    Being no one that reads this seems interested, I will make a stab at it.
    According to ARGO data, the OHC of the top 700 meters has a cooling bias at present. The sea level rise has slowed, which would confirm that data.
    I think the ocean is stabalized and that evaporation is enough to keep the temperature flat.
  45. scaddenp:
    Nice that your brought up short term variability.
    The amount of thermal energy in the top 700 meters of the oceans dwarfs all the thermal energy of the atomosphere.
    At this time, the atmosphere has shrunk br approx 150 miles, which is a huge amount.
    My point is tho, that for the ocean to have even a minor change overall in temperature requires either recieving a lot of energy or expending a lot of energy.
    It is almost ocmical to see the step change in OHC graphs. The amount of energy required to either heat or cool the oceans that fast in that short of a time frame has not been observed. And it most certainly would have been observed.
  46. Given the Von Schuckmann and La Traon paper on 0-2000m, I will wait till there has been a full analysis of Argo before leaping to conclusions on that. I had been discussing the question of sealevel with local professor of surveying. He had been studying 100 year records for Australia and NZ, together with continuous GPS stations at some guages over last 15 years or so. Interesting questions. In short, there are many contributors to short term sea level change. He lacks confidence in the satellite reference frame being accurate enough for short term conclusions, preferring 50 year trends for tide gauge data and maybe 15 for satellite. I havent had time to look at the papers he has sent me yet.
  47. scaddenp:
    Looking at tidal guages and satillites, both at this time show a reduction in sea level rise. That puts the Von Schuckmann paper in question because for them to be correct, we should be seeing a steady if not increasing rate of rise.
    We are not observing that. The amount of energy required for thermal expansion is huge to say the least. There has been no spike in energy, and it appears there has been a decrease in energy which is not being measured.
    There is something here that is being totally missed and I have no idea what it is.

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