Saturday, April 11, 2009

Rate of Sea Level Change

When I point out to global warming advocates that the sea level was 2 meters higher 5000 years ago than it is now, and that therefore the world has already experienced what the global warming advocates fear, I am often faced then, with another objection, that it isn't necessarily the height of the ocean but the rate of change that is so bad. I often think that these objections are psychological mechanisms used to avoid having to change one's mind. Most of the time they are, but occasionally, like with this objection, there is an interesting scientific issue involved.

Many hysteriacs say that the rate of rise is going to be cataclysmic. After pointing out that a new study says that sea levels are going to rise 1 to 2 meters this century, and citing a Science article, Dana Nuccitelli says,

"This is a rather dire predicition. A one meter sea level rise would flood 17% of Bangladesh, displacing tens of millions of people, and reducing its rice-farming land by 50 percent. Globally, it would create more than 100 million environmental refugees and inundate over 13,000 square miles of the United States. These studies provide further evidence that we must take action to address global warming as soon as possible to avoid such consequences."

The article that brought about Nuccitelli's comments is W. T. Pfeffer, J. T. Harper, S. O'Neel , " Kinematic Constraints on Glacier Contributions to 21st-Century Sea-Level Rise," Science 321(2008), p. 1340

I went looking for sea level data and found an interesting data set for Ireland at this website. There they have a database for Ireland's sea level record. I sorted the data according to the midpoint C14 date and then calculated the rate of change per century between the successive points. The chart below is what I arrived at.

I don't believe the rates of sea level change which are larger than about 3 meters per century, so I made the axes of the graph such that I cut off those values above 5 m/century to accentuate the fact that there are lots of periods in Irish history where the sea level was changing in relation to the land by as much as 1 to 3 m per century.

There is also the matter of tide gauges which don't show a currently rising sealevel, in spite of all the news stories.

{edited to add, this following paragraph has been fixed. Thanks to Dave, in the comments for pointing it out. It is explained in the April 16th 2009 post}

Looking at the above chart, one can see that between 1982 and 1984, there is a -.5 meter drop in monthly mean sea level!!!! That works out to be a rate of change of -25 meters per century!!!! Between 1985 and 1986 there is a .3 meter rise in sea level. That works out to be a rate of sea level change of +30 meters per century! Starting in 1993 the next two and a half years brings a rise in sea level of .43 m--that works out to be a 17.2 m/century. Yes, we should all worry about the rate of sea level rise. But not for the usual reasons. With every period of rising sealevel Tuvula gets lots of press as a victim of global warming, with no one looking back to see what has happened in the past, even the recent past.

There is no doubt that a 2m rise in sea level would be problematic. But, like everything else in the scary world of the climate hysterics, human history has seen rates of sea level change bigger than this within the past 10,000 years, long before there was a CO2 "problem". Because of this, one must ask why we must act to change that which the world has already seen before CO2 became the cause celeb?

There is an oft told story of King Canute setting his chair on the beach and commanding the tides not to rise. Of course, the tide refused to obey King Canute. Canute did this, according to the story, to teach his flatterers that even kings have limits to their powers. Unfortunately modern global warming hysteriacs seem to think that they can do what King Canute couldn't--stop the sea from rising.


  1. You know, someone who reads 5 m off a graph that clearly shows 0.5 m (500 mm = 0.5 m, by the way, just in case you were confused) maybe should consider toning down their arrogance just a tad.

    Also, did you actually read the paper that the dataset is based on (as the website asked you to)? If you look at the paper, they choose 4 representative locales to plot SLR for, showing temporal and spatial error estimates, and all 4 plots look like pretty consistent with 10 to 20 cm SLR/century for the past 2000 years. Did you notice that the errors in the estimates dates are such that you can't even reliably _order_ some of the data points in time? And the errors in SLR estimation range from 40 cm to 1 m? Didn't think that was worth mentioning on your graph somewhere?

    If you want some representative sea level rise data, from both tide gauges and from satellite data:
    Obviously, sea level rise is fairly complicated: in the past century both short term and decadal variability has been observed, the above plots show that there is significant spatial variability (the Pacific Ocean is especially sensitive to El Nino/La Nina), and for the tidal gauge data subsidence and uplift change local sea level rise. But it seems pretty obvious that globally, sea level is rising, and I believe the data indicates that we haven't seen a sustained rate of sea level rise like the past century in a couple thousand years.

    Now, yes, if you go back more than 5000 years or so, sea level rise was changing at much higher rates than we see today. Of course, back then we didn't have cities built on coastlines, nor did we care much if a few humans here and there were killed by storm surges or disappearing islands. Now is a different story.

    Once again, I suggest you go to the IPCC 4th Assessment Report and READ AND UNDERSTAND the appropriate section before going to your favorite skeptic paper published in J. Random Journal or on someone's blog. Once you've done that, then maybe you might be in a position to start critiquing it.

    btw, I did go back and look at that temperature data you posted about in early March, where you showed that nearby cities sometimes had widely divergent yearly mean temperatures: interestingly, just a little bit of digging into the _real_ raw data and not the stuff they feed you at co2science and you can find out that

    a) the spikes come from missing daily or monthly data
    b) the 20 year stretch at Walden that looks physically implausible is actually clearly flagged in the dataset as a change in observation time, which would pretty logically lead to a change in relative temperature.

    So, you claim that "but it is, of course, the raw data and when the climatologists 'fix' this, they are merely guessing at what the temperature of one or the other town is. Guesses are not data; and one can't possibly fix this data to the level of accuracy required to know how much the earth has warmed or cooled."

    Well, to me it seems like it is pretty easy to "fix" the data, actually. I mean, maybe _you_ couldn't fix the data, but fortunately climatologists, hysteriacs and sheeples that they are, actually have a few brain cells to rub together.

  2. Yes, Dave, I mis-wrote. It should be a 50 meter per year rate of drop in sea level PER CENTURY. The article is On rate.

    Per chance you can actually answer some of the data rather than, as you entitled your private email to me over this issue worry about "minor quibble"s. How about explaining why linear regressions are used on decidedly nonlinear data. How about explaining Why, 5000 years ago there were no or vastly reduced Alpine glaciers, Norwegian glaciers and the seas 2 meters higher, rather than focusing on things that are rather unimportant to the issue anyway--my minor mistake. How about explaining why we should worry about the glaciers and permafrost melting when they were melted 5-8000 years ago?

    I have read the IPCC 4th assessment. I wasn't impressed.

    They say this of the urban heat island effect

    "Urban heat island effects are real but local, and have a negligible infl uence (less than 0.006°C per decade over land and zero over the oceans) on these values." IPCC, 2007: Summary for Policymakers. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. , p. 5

    But they ignore the size of the heat island measured in independent studies

    April 26, 1999: As the heat builds during a blistering summer day in Atlanta, Georgia, you can almost hear the clouds overhead cry, "Let's get ready to rumble!"
    Urban growth has transformed Atlanta's environment, creating a uniquely altered arena of weather. Because urban areas both generate and trap heat, a bubble or "urban heat island" forms around the city. The temperature in Atlanta is 5 to 8 degrees Fahrenheit higher than outlying areas, and this excess heat produces increased rainfall and thunderstorms

    As to the raw temperatures, the issues you raise are exactly why that data is crap for measuring such small temperature rates of change as .06 deg/decade. Effectively you have proven my point.

    Gotta go to my ranch now, no more time to comment

  3. One additional comment, about the arrogance. I write to try to get some attention. But your side is more arrogant. I beleive it was your side that initially came up with the 'global warming denier' moniker, and treats anyone who disagrees with your side as a nutter who bays at the moon. So, arrogance isn't limited merely to me.

    As to your calling me on it, it seems that you like to dish it out (see your note above) but cant take it (see your note above).

  4. Well, I am back from the ranch. On my way up there, I realized that Dave is whacking me for a typo. The difference between 5 m and .5 m is a . just a dot before the 5. I actually have an appointment tomorrow to get new glasses. :-)

  5. While you're fixing that typo... don't forgot the dots you forgot in -153, 3, +150, 4.3, and 170.

    I do apologize for dishing it out - you are right that I should be better about not letting it get it to me, and this is your own personal blog so you have more right to be arrogant than a guest on it. Having said that... it is very frustrating to see people completely miss the point over and over again. And especially given that I hear rumors that you are quite a warrior on the evolution vs. intelligent design/creation front, which to me has always seemed like a very parallel sort of fight to the AGW consensus vs. denier battles (Lindzen may claim that AGW'ers are like the creationists, but I think there's more overlap between the Heartland signers and the ID signers than in any comparable AGWer list. Eg. Spencer).

    Finally: on urban heat island: the IPCC is making a statement about how local heat islands (which any IPCC scientist would agree exist - do you think they're stupid?) affect _global_ trends. You give Atlanta as an example: first, you have to look at the heat island effect in 1900 and compare it to 2000 - I'm guessing the difference will be smaller than 5-8 degrees fahrenheit. Then, you have to _average_ that change over all landmasses.

    Look at the recent paper on Chinese heat island effects, and note the two studies on London and... some other European city, I forget which right now, where they look at anomalies between temperature sensors in city centers and nearby rural areas and see no _change_, implying that at least in those cities the urban heat island effect has fairly mature at the point at which they started measuring.

  6. As to missing the point, once again, I see that you are in deep holocene denial. Would you care to comment on why the permafrost was more melted 5000 year ago than at the present time? Why will you not deal with the fact that the seas were higher? Even if I am totally wrong on the values in that blog(which I chose not to fix because I want people to see that you are more fixated on finding minor errors rather than actually dealing with substantive issues. I make errors, and have never beleived that I can't make errors. But it has been my experience with Holocene deniers, that they don't discuss anything except some perceived problem in those with whom they disagree. They ridicule spelling errors, typos, but never ever actually discuss the data, except as you do by citing unnamed studies on unnamed cities and claiming results for them. Sheesh. And you think I am full of it.

    Your guess as to the difference between 1900 and 2000 in Atlanta, is just that, a faith based statement, a guess. I cited NASA and you cite your guess. Sheesh. Hansen only corrects 0.3 deg C for urban heat island effect, even though every study I have ever seen gives a much higher value for it.


    Growth of the surface temperature urban heat island of Houston, Texas is determined
    by comparing two sets of heat island measurements taken twelve years
    apart. Individual heat island characteristics are calculated from radiative temperature
    maps obtained using the split-window infrared channels of the Advanced Very
    High Resolution Radiometer on board National Oceanic and Atmospheric Administration
    polar-orbiting satellites. Eighty-two nighttime scenes taken between 1985
    and 1987 are compared to 125 nighttime scenes taken between 1999 and 2001. Analysis
    of the urban heat island characteristics from these two intervals reveals a mean
    growth in magnitude of 0.8 K, or 35%.” David R. Streutker, “Satellite-measured growth of the urban heat island of Houston, Texas” p. 1

    and that study points out that over that same time period the rural area around Houston had a constant temperature. CO2, it seems doesn't work in the rural area around Houston.

    "The magnitude of the adjustment at the urban and periurban stations themselves, rather than the impact of these adjustments on the total data set, is shown in Plate 2l. The adjustment is about -0.3°C at the urban stations and
    -0.1°C at the periurban stations. In both cases these refer to the changes over 100 years that are determined by adjusting to neighboring “unlit” stations." J. Hansen et al, “A Closer Look at United States and Global Surface Temperatures,”
    J. Geophys. Res., 106, 23947-23963
    available at h tt p: // p 6