Open Mind

Water World

March 14, 2008 · 109 Comments

That’s the title of a film about a world in which the one thing humanity can’t seem to find is: dry land. I saw it on TV recently, and it lived up to its reputation as one of the worst movies ever. Thank goodness that’s not the topic of this post!

This post is about sea level rise. Climate change has a profound impact on sea level, primarily in two ways. First, water expands when it heats up, so a warmer climate and warmer seas will make the oceans expand and sea level rise. Second, during colder times there’s more water locked up as ice on land, both in glaciers and ice sheets.


A few words are in order about the meaning of “sea level.” The definition we’re most interested in is the global mean sea level, or GMSL. This is the global average height of the ocean. There are regional variations which don’t correspond to changes in the global average, for many reasons including changing patterns of winds and currents. The global mean sea level depends mainly on the volume of water in the oceans and the volume of the ocean basins. That can change because of tectonic movements of earth’s crustal plates, erosion of landforms, and other non-climate factors, but the dominant factors influencing GMSL are the exchange of water between land-based ice and liquid oceans, and the thermal expansion of water in times of rising temperature.

During glacial periods, there’s enough water stored in ice sheets to affect sea level dramatically; at the peak of the last glaciation it was some 120 m (nearly 400 ft.) lower than it is today. But around 18,000 years ago earth began to deglaciate, bringing us to the present interglacial. As a result, sea level rose about 120 m over a span of about 10,000 years, albeit irregularly. In fact there was a significant event between 15,000 and 14,000 years ago of much faster sea level rise known as “meltwater pulse 1A,” during which sea level rose by about 20m over a period of less than 500 years. The source of the meltwater is often believed to be a collapsing ice shelf, probably in Antarctica. But overall the total deglaciation rise of 120m over 10,000 years corresponds to an average rate of increase of 12 mm/yr.

postglacialsealevel.jpg

The situation began to stabilize around 8,000 years ago, with a much slower rate of change, and about 2,000 years ago even greater stability became the order of the day. Sea level is believed to have been remarkably constant from the 1st century until the 19th; studies from a number of geographically diverse regions provide convincing evidence that the rate of change was no greater than 0.2 mm/yr. This situation remained in effect until the middle of the 19th century, when sea level began to rise; since then it’s risen at an average rate of around 1.5 mm/yr, although the rate has been variable. Hence a plot of sea level over the last 2,000 years would definitely resemble — dare I say it — a “hockey stick.”

For the last few centuries we have measurements based on tide gauges, which measure sea level relative to a reference height on land. The longest tide gauge record is from Amsterdam, dating from 1700, and shows the pattern of reasonable constancy (with fluctuations of course) until sea level began to rise in the mid-19th century:

amsterdam.jpg

There is of course a complication involved in measuring sea level relative to a land reference, that the height of the land is itself not constant. Tectonic movements can alter it, as well as glacial isostatic rebound (also called post-glacial rebound), whereby land which was formerly depressed by the weight of massive ice sheets, rebounds now that the ice sheets are gone and their downward force is relieved. The situation is also complicated by regional variations in sea level, so no single location (even if not subject to other factors) can indicate global sea level.

Nonetheless it’s possible to collect tide gauge records from locations not near plate boundaries, subject to little isostatic rebound, and to compensate for isostatic rebound, in order to average results from many geographic locations and thereby estimate GMSL. This has been done by numerous researchers; one of the most up-to-date and reliable results is that of Church & White (2006, Geophysical Research Letters, 33, L01602, doi:10.1029/2005GL024826). They compute a time series of monthly average GMSL from 1870 to the end of 2001:

churchwhite.jpg

Since 1992, sea level measurements have been taken by satellites, first Topex/Poseidon, then Jason. These have two distinct advantages: first, they measure the actual height of the sea, not its height relative to some possibly moving land reference; second, the coverage is nearly global. We can add the satellite data to the end of the tide gauge estimates so as to make a continuous estimate of GMSL from 1870 to the present. The two data sets are defined relative to different zero points, so I’ve offset the satellite data so that it has the same average value as the tide gauge data during their period of overlap:

sealevel.jpg

The data from Church & White are monthly, that from the satellites are every 10 days. To make things a little simpler and more consistent, here are annual averages of the above data:

sealev1y.jpg

Two things are clear. First, sea level has been rising. Second, the rate of rise has not been constant. As the graph shows, the average rate of increase over the entire interval is about 1.5 mm/yr. However, it was less in the earlier part of the data, more later. This is clear from computing the residuals from the linear fit (the difference between the actual value, and the value it would have if it followed the line exactly):

resid1.jpg

Clearly, until the early 1920s the rate of change was less than the 1870-2008 average (so the residuals are declining), but after that the rate has been greater. We can also investigate the later time period by fitting a trend line to only the data from, say, 1930 onwards, and computing residuals:

resid2.jpg

The very steep rise from about 1990 onward indicates that the rate of sea level rise has been higher still during that time period. I’ll identify four time spans during which there are different rates of increase:

Time span Rate (mm/yr) Error Range (2-sigma)
1870-1935 0.7 0.2
1935-1957 2.4 0.5
1957-1990 1.5 0.4
1990-2008 3.3 0.2

This is not to say that the rates were constant during the individual time spans, just that the rates during different time spans are different. Sea level was reasonably constant for about 2,000 years, then started rising in the mid-19th century, and the rate of increase at present is notably higher than previously. Thermal expansion and melting of land ice each account for about half of the observed sea level rise, although there is some uncertainty in the estimates.

The seas are expected to rise higher still in the upcoming century. The IPCC projection is for continued rise at a rate comparable to (possibly higher than, but not by much) the present rate:

ipcc1.jpg

However, the IPCC has been criticized for being too conservative in its projections of future sea level rise. This is because very recent observations point to faster ice loss from Greenland, one of the large repositories of land-based ice on earth. Also, over the last decade we’ve learned that the disintegration of ice sheets need not be a slow process; in particular, meltwater can penetrate to the base of ice sheets, lubricating the land-ice interface and accelerating ice flow. The disintegration of ice masses can be a mechanical rather than purely thermodynamic process, as the breakup of the Larsen B ice shelf in Antarctica demonstrated vividly. Some scientists (perhaps most notably James Hansen) are expecting greater sea level rise over the next century. Hansen expects at least a meter, and opines that greater levels are a distinct possibility. A meter or more of sea level rise will have a tremendous effect on humanity, because so many millions of people live near the sea. Large ares which are now populated will be under water, ecosystems near the land-ocean interface will disappear, and costly infrastructure may be inundated as well.

In any case, sea level rise is likely to be with us for a long time, even if we manage to stabilize greenhouse-gas levels, because it takes so long for heat to penetrate deep into the ocean that thermal expansion of seawater will persist for centuries. And if we continue on the path of increasing greenhouse-gas emissions and warming proceeds unchecked, we can ultimately expect the disintegration of the Greenland ice sheet and/or the West Antarctic ice sheet. Each of those holds enough water to raise sea level around 7 m (over 20 ft). The world of the future is likely to look very different from the world of today.

Categories: Global Warming · climate change

109 responses so far ↓

  • chriscolose // March 14, 2008 at 3:12 am

    I’d just like to say that after thermal expansion, glaciers should contribute to most sea level rise in the coming decades, and then the ice sheets. There was a paper that came out in Science after the AR4 claiming that accelerated glacier melt may knock up the IPCC number by some tenths of a meter by the end of the century
    http://www.sciencemag.org/cgi/content/full/317/5841/1064

    I have a feeling the sea level rise will be larger than we’re showing. The last time it was some 3 C warmer, it was many, many meters higher. There is at least one publication that Greenland contributed to 0.5 meters in the mid-Holocene when the Northern Latitudes were warmer from orbital variation. However, given changes occurring in Antarctica and the last remnants of the Laurentide, one can’t really look at the global sea-level record and see that amount with high confidence. But I’ve not seen much from the paleoclimate literature to make me comfortable about sea level rise with several C of warming. Accelerated glacier flow is a problem worth being considered, because we cannot now model it very good, and it turns out to be one of those areas where we are just underestimating what is going on.

    If you follow the link on my name, I had a guest speaker come to my school and speak on global warming (the skeptic side), and although I did not address it in my blog response, one of the points he made was that daily fluctuations (from tides) are considerably larger than the projected global rise. Needless to say, this is scientific hogwash in the context of global climate change. I just found that a funny mention given this topic.

  • dhogaza // March 14, 2008 at 4:42 am

    one of the points he made was that daily fluctuations (from tides) are considerably larger than the projected global rise.

    So he feels that it doesn’t matter if your feet are wet at high tide, as long as they’re dry at low tide.

    Interesting!

  • jacob l // March 14, 2008 at 5:47 am

    H.B. has anyone tried using sea level to put a constraint on how warm the M.W.P was??
    The other use I could see with this data is if you could separate the melting from thermal expansion ,the increase in ocean heat content could be measured ..

    [Response: I wonder the same thing myself. Despite finding numerous studies, of diverse regions, establishing little or no sea level rise for the two thousand or so years from AD 0 to about 1850, I wasn't able to track down atual time series estimates.]

  • Gavin's Pussycat // March 14, 2008 at 6:34 am

    A possibly interesting reference is also the study of the Stockholm tide gauge / sea level record by Martin Ekman:

    “Climate changes detected through the world’s longest sea level series”, Ekman 1999.

    There are all kinds of problems in such analyses, related mostly to the stability of the tide gauge and its immediate surroundings over centuries. In Stockholm the additional problem of postglacial rebound. But it appears to confirm the gist of the other evidence.

  • fred // March 14, 2008 at 7:42 am

    Very interesting. You would expect there to be a statistically significant relationship with global temps - presumably with a lag of some years. Is there? Or are the 20C fluctuations too short term to have much effect?

    [Response: I haven't run the numbers, but the 20th-century pattern of slower rise until 1935, faster 935-1957, slower until 1990, faster post-1990, seems to mimic the temperature pattern of slight cooling until 1915, warming to 1945, stasis until 1975, warming after, if one applies a 15-year lag. I don't know whether that's a physically plausible lag time, or even whether it's just a coincidence.]

  • Andy // March 14, 2008 at 8:24 am

    Has there been any estimate how much of sea level rise is due the usage of non-renewable ground water reserves, and burning the carbonhydrates? I suppose they have just a minor effect, but any numerical estimate?

    [Response: I've seen claims that groundwater use may have been an important factor initiating sea level rise in the mid-19th century, but that today it isn't as great as thermal expansion or meltwater. Unfortunately I don't think the effect is very well quantified.]

  • John Lederer // March 14, 2008 at 12:54 pm

    It occurs to me that there might be five other factors that would affect sea level:

    1. Siltation
    2. Land form changes from continental movements and vulcanism.
    3. Glacial rebound
    4. Changes in evaporation rates, or the overall water transport cycle.
    5. Changes in the earth’s shape and in the net gravitational effect from the earth’s orbit and sidereal motion.

    I suspect these would likely be immaterially small, but I have no idea.

    The evaporation rates would be large enough to be significant — on the order of 100+ cm/yr if my memory serves but they are part of a cycle balanced by rain.

    I do recall from a long ago oceanography course that evaporation rates are very sensitive to wind, so the rate is not a simple matter of heat. Evaporation rates from the trade wind zones for instance are much higher than those from the warmer equatorial zones.

    I had a friend who worked for NASA who for one of the exploratory space missions had the task of determining precisely the earth’s motions. He left me agog after explaining all of the motions and changes in them. The earth is downright wobbly.

    In any event, I suppose all these various possible confounding factors in sea level have been examined and discarded as trivial?

  • P. Lewis // March 14, 2008 at 2:19 pm

    Glacial (or isostatic) rebound is factored in by people who look at sea-level changes: the UK is a case in point, with the southeast sinking (~2 mm/year IIRC) and the opposite occurring in northwest Britain.

  • Winnebago // March 14, 2008 at 2:43 pm

    New research shows the negative impact of even modest future seal level rise.

    http://www.nytimes.com/2008/03/12/science/12coast.html?_r=1&em&ex=1205467200&en=f4fd1d869d29e1ee&ei=5087%0A&oref=slogin

  • John Lederer // March 14, 2008 at 2:53 pm

    There is an excellent Wikipedia article on sea level rise that mentions and attempts to quantify the factors I mentioned, and other that did not occur to me. I should have read it first.
    http://en.wikipedia.org/wiki/Sea_level_rise

  • John Cross // March 14, 2008 at 3:47 pm

    I recall seeing an interesting analysis that attempted to look at sea level rise through changes in the earth’s rotation. If we are seeing significant mass lost from the polar regions which then act to raise general sea levels it will result in a change of mass from near the axis of rotation of the earth to further from the axis of rotation. This should show up as an increase in the moment of inertia which should reduce the rotation rate of the earth.

    John

  • J // March 14, 2008 at 3:56 pm

    Re: Meltwater Pulse 1A, Tamino writes: “The source of the meltwater is often believed to be a collapsing ice shelf, probably in Antarctica. ”

    This may count as nit-picking, but ice shelves per se don’t have much impact on sea level, since they are floating. All the speculation I’ve seen about an Antarctic source for MW Pulse 1A refers to grounded ice, AKA the ice sheet, not the shelves.

    In Science, Weaver et al say “In any event, this warming may have triggered a partial collapse of the Antarctic Ice Sheet, perhaps by destabilizing ice shelves” but the idea is that the loss of an ice shelf facilitates the collapse of grounded ice, not that the shelf itself contributes to sea level rise.

    Excellent post, though.

  • Hugh // March 14, 2008 at 4:57 pm

    #P. Lewis

    Re the UK there is a nice map of the isostatic contribution and projected relative SLR around the coast here:
    http://www.ukcip.org.uk/resources/publications/documents/124.pdf

  • Joel McDade // March 14, 2008 at 4:57 pm

    Andy: Globally the impact of ground water withdrawal is probably trivial. Locally the impact can be huge. Below is a famous USGS photo from San Joaquin valley. In many cases this is misreported as sea level rise due to AGW. Examples include Bangkok, and, yes, islands such as Tuvalu.

    http://wellfunction.com/images/subsidence.gif

    Technically, confined aquifers are not dewatered when pumped (the pores remain saturated). Instead the aquifer releases water by aquifer compression.

  • Ellis // March 14, 2008 at 6:55 pm

    Better get started on building that boat, HB. And I know, I know two of every kind, except skeptics and Republicans. ;)
    Of related intrest,this paper seems to be claiming there was a 6m jump in sea level in about a hundred years. This happened about 7-8 thousand years ago, and was found in reef relics in the caribbean sea. It looks like it was slightly warmer then, judging by the proxies only. So, I guess if temperatures begin to rise again we should watch out for rapid changes in the ice sheets, although with CO2 up, and aerosal loading down global temperatures should really be going through the roof any time now.

  • Ian // March 14, 2008 at 8:20 pm

    Another consideration for meltwater, on land or not, is that fresh water is less dense than salt water (general ratio to seawater of 1 : 1.025). This means that a floating iceberg will raise water levels a bit if it melts. One estimate is that melting all floating and shelf ice (of course, not likely for a long time) would raise global sea level by 4 cm. (For anyone near a library, it’s: Noerdlinger PD, The melting of floating ice raises the ocean level, Geophysical Journal International, 170(1): 145-150, July 2007.)

    Freshwater also freezes faster than saltwater – speculatively, this may account for some of the rapid re-freezing of arctic ice this past winter. (That is, melted ice water, which is fresh, tends to lie on top of the salt water, and can freeze more quickly in arctic winter.)

  • John Lederer // March 14, 2008 at 8:46 pm

    In looking for information on sedimentation, continental shelves, and sea level, I happened upon on thing I had not know. Apparently, sedimentation is not a gradual even process, but one that proceeds in intense bursts overlying relatively quiescent periods.

    No sign of the ark in any of the bursts…

  • Aaron Lewis // March 14, 2008 at 11:12 pm

    Dear HB,

    You have posted on my favorite topic.

    However, the situation is more urgent and dire than you hint.

    First, there is a good deal of permafrost in the Arctic. As the Arctic Ocean loses ice cover, and the Arctic warms, this permafrost could melt in a hurry. With an open Arctic Ocean collecting heat, and that heat transferred to permafrost as rain, permafrost melt could be quite rapid by mechanisms not contemplated in current GCM. At the outside, there is a potential for 0.5 m rise from permafrost within a couple of decades (my calculation based on a loss of summer sea ice within 3 years.)

    Then we have ice sheet stability. Ice gets weaker as the temperature rises. (See http://skua.gps.caltech.edu/hermann/ice.htm ) However, the conventional ice strength equations go to nonsense as ice approaches its melting point, and ice under high pressure has a lowered melting point. Moreover, the ice at the bottom of the ice sheets is at extreme pressures. This makes modeling ice sheet behavior near ice’s melting point very difficult.

    We now know that there is substantial liquid water under GIS, WAIS, and EAIS. We know that during the melt season there areas of liquid water on the surface of GIS, WAIS and EAIS. We now know that water can advect heat into ice faster than other mechanisms can remove such heat. Certainly, most of the ice is still fairly cold. On the other hand we know that big blocks of cold ice can slide down hill if something lets go. Consider for example, (http://query.nytimes.com/gst/abstract.html?res=980CE1D81F39E233A25757C1A9619C94639ED7CF )

    When Hansen wrote Scientific reticence and sea level rise (http://pubs.giss.nasa.gov/docs/2007/2007_Hansen.pdf) , even he understated the problem I would consider 5 meters per/century, a sea level rise rate that we can be 95% certain will occur.

    However, policy makers and engineers planning public safety infrastructure must consider events at lower levels of certainty, if such events will affect large numbers of people. Give the large volumes of ice that have liquid water above for some melt season and below them, and the extreme nonlinear behavior of ice near its melting point, we need to have contingency plans for sea level changes much greater than 5 m/ century.

  • TCO // March 15, 2008 at 12:35 am

    I like it warm.

  • terence // March 15, 2008 at 3:56 am

    “New research shows the negative impact of even modest future seal level rise.”

    Dear god! Not more seals!
    (sorry, someone had to… ;)

  • James Brown // March 15, 2008 at 7:08 am

    Climate changes detected through the world’s longest sea level series

  • Steve Bloom // March 15, 2008 at 7:13 am

    Ellis, this much more recent paper also discusses the final meltwater pulse in the mid-Holocene. The upshot seems to be that the 5 meters/century found in the 2002 paper you cited is an extreme maximum, with something consistent with the recent results for the last interglacial (about 1.5-2.5 meters/century) sounding more likely. While there doesn’t seem to be much direct evidence for it, a destabilization of the WAIS by NH meltwater-induced SLR seems to be the probable mechanism.

  • fred // March 15, 2008 at 7:25 am

    AL, are you really saying that we can be just about certain of a 5 meter rise by 2100, and should be actively preparing for the possibility of a greater one?

    How much of a rise do you think is just about certain by some earlier date, like, say, 30 years from now?

  • mmghosh // March 15, 2008 at 8:54 am

    Looking at the NCDC sea ice figures for Feb from 1979 to current

    http://www.ncdc.noaa.gov/oa/climate/research/2008/feb/global.html

    This shows

    a decrease in N hemisphere sea ice by 2.8%

    an increase in S hemisphere sea ice by 3.4%

    I read the RC article on Antarctic cooling

    http://www.realclimate.org/index.php/archives/2008/02/antarctica-is-cold/

    which explains this in terms of thermal inertia.

    In the context of sea level rise, though, it seems to be intuitive that the melt water of the NH is somehow compensated by the increasing ice in the SH. In that case should the sea level rise be a function of rising thermal expansion rather than melt water?

  • mmghosh // March 15, 2008 at 9:09 am

    http://www.aber.ac.uk/aberonline/en/archive/2008/02/au308/

    http://www.igsoc.org/journal/54/184/j07J086.pdf

    The above two references describe some of the causation behind the the collapse of the Larsen B ice shelf. From the contribution of global warming to the breakup POV, they now appear to lay greater stress on oceanic temperature rise, rather than atmospheric temperature rise,.

    “Ice shelf collapse is not as simple as we first thought,” said Professor Glasser, lead author of the paper. “Because large amounts of meltwater appeared on the ice shelf just before it collapsed, we had always assumed that air temperature increases were to blame. But our new study shows that ice-shelf break up is not controlled simply by climate. A number of other atmospheric, oceanic and glaciological factors are involved. For example, the location and spacing of fractures on the ice shelf such as crevasses and rifts are very important too because they determine how strong or weak the ice shelf is”.

    The study is important because ice shelf collapse contributes to global sea level rise, albeit indirectly. “Ice shelves themselves do not contribute directly to sea level rise because they are floating on the ocean and they already displace the same volume of water. But when the ice shelves collapse the glaciers that feed them speed up and get thinner, so they supply more ice to the oceans,” Prof. Glasser explained.

    Professor Glasser acknowledges that global warming had a major part to play in the collapse, but emphasises that it is only one in a number of contributory factors, and despite the dramatic nature of the break-up in 2002, both observations by glaciologists and numerical modeling by other scientists at NASA and CPOM (Centre of Polar Observation and Modeling) had pointed to an ice shelf in distress for decades previously. “It’s likely that melting from higher ocean temperatures, or even a gradual decline in the ice mass of the Peninsula over the centuries, was pushing the Larsen to the brink”, said co-author Ted Scambos of University of Colorado’s National Snow and Ice Data Centre.

  • mmghosh // March 15, 2008 at 10:10 am

    This should be interesting:

    http://nsidc.org/news/press/20080314_Telecon.html

  • John Lederer // March 15, 2008 at 11:12 am

    There will be a paper published soon that is an attempt to examine better sea level rise using all the neat new whiz bang instrumentation being orbited or deployed.

    The authors gave a presentation with these slides earlier
    http://www.dgfi.badw.de/typo3_mt/fileadmin/20071015-17-Potsdam/mo_1410_03_chambers.pdf

    They have a conclusion that the observed sea level rise is because of an increase in the mass of the oceans and not through steric (expansion from temperature) factors.

    That is a mixed bag for AGW .

    Assuming their results are accurate one possible explanation might be constant temperature with reduced input of precipitation to polar areas.

  • John Finn // March 15, 2008 at 12:29 pm

    Tamino says

    “Sea level is believed to have been remarkably constant from the 1st century until the 19th; studies from a number of geographically diverse regions provide convincing evidence that the rate of change was no greater than 0.2 mm/yr. This situation remained in effect until the middle of the 19th century, when sea level began to rise;”

    Interesting. What on earth could have initiated a sea level rise after 1800 years. Whatever it clearly can’t have been CO2. I suppose ice melt following the end of the LIA might have had something to do with it, but the flat 1800 year trend is a puzzler.

    How reliable is the early data?

    [Response: Just my opinion: the data are reliable, cover Europe (densely), parts of N. America, and Australia, and all seem to be telling us the same thing. The researchers seem to have established a very firm concensus.]

  • John Willit // March 15, 2008 at 1:56 pm

    Here is an expert with his views on the issue.

    http://www.mitosyfraudes.org/Calen7/MornerEng.html

    [Response: I notice two things immediately about the statements by Dr. Mörner. First, he expends an embarrassing amount of effort claiming his superiority to the rest of the world, and pointing out the complications involved in tide gauge measurements as though the rest of the world was ignorant of the issues; this, in my opinion, undermines his credibility. Second, he makes this statement:

    And you measure it by satellite. From 1992 to 2002, [the graph of the sea level] was a straight line, variability along a straight line, but absolutely no trend whatsoever. We could see those spikes: a very rapid rise, but then in half a year, they fall back again. But absolutely no trend, and to have a sea-level rise, you need a trend.

    I’m looking at the satellite data at this very moment. He is just plain wrong. Whether this is because he’s grossly incompetent as a data analyst, or he’s applying the strategy of the telling the “biggest lie possible,” I don’t know.]

  • Arch Stanton // March 15, 2008 at 2:51 pm

    I like Hippocrates. Those that don’t heed his oath practice “bad medicine”.

    [Response: ???]

  • dhogaza // March 15, 2008 at 4:29 pm

    mmghosh

    This should be interesting…

    Is it usual for them to hold their press conferences at night (10 PM) or is this a typo, with the real time being 10 AM? Anyone have a clue?

  • David B. Benson // March 15, 2008 at 4:45 pm

    Tamino — Once again, nicely stated.

    To fill in more details on some of the comments:

    (1) During the Eem (Eemian interglacial, termination II), not only was the temperature a few K warmer than now and the sea high stand about 4–6 meters higher than now, but also the orbital forcing on Greenland was substantially greater than now. Some climatologists (James Hansen, Gavin Schmidt) attribute the sea high stand to this intense orbital forcing.

    So the situation, for sea stand rise, was different then than now. The measured rate for the Eem, around maybe 2 cm/y, may well not be applicable to near future. Instead of orbital forcing with CO2 at about 288 ppm, now the ordibtial forcing is weaker (and growing even weaker) while CO2 concentrations are already at 385 ppm and growing around 1–2 ppm/y. Until shown otherwise, I will assume that data from the Eem underestimates the anticipated sea stand rise rate.

    (2) The longish interval of quite stable sea stand during the Holocene can be attributed, I suggest, to two factors: the slowly declining orbital forcing since the so-called Holocene Climatic Optimum, which should have lead to modest ice acumulation and so modest sea stand decline; anthropogenic influences as suggested by W.F. Ruddiman, popularized in his book “Plows, Plagues and Petroleum” (highly recommended), and defended recently by him against quite a variety of criticism, in any case supposedly stabilizing the Holocene climate against the declining influences.

    But we have now left the Holocene for the Anthropocene. The data is a bit arbitrary, pick any time from 1850 CE onwards. (The last time CO2 was at 288 ppm was 1850 CE.) I would welcome you to the Anthropocene, but I actually think you’ll not enjoy it…

  • matt // March 15, 2008 at 5:32 pm

    So, if we look at 1.8mm/year SLR as being “natural”, and pick something like 8mm/year as being one of the worst-case predictions for the next 100 years….

    Parts of Florida and the rest of the world are going to be under water sooner or later no matter what–even if Man never set foot on Earth. If the worst case has parts of Florida flooding in 100 years, then the “natural” case (no mankind) has Florida flooding in 400 years.

    Both are a problem, and yet neither is a problem for me, my kids, their kids or their kid’s kids. Presumably the price of this real-estate will trend towards zero over the next 100 to 400 years.

    Seems a non-issue that the free market will readily handle.

    [Response: I don't see how you got 1.8mm/yr as being "natural." I also get the impression you're perfectly willing to do nothing as long as it's somebody else's problem, not yours.

    Maybe that's one of the reasons I find the "let the market handle it" approach so offensive.]

  • Petro // March 15, 2008 at 5:58 pm

    HB answered to matt:

    “I also get the impression you’re perfectly willing to do nothing as long as it’s somebody else’s problem, not yours.”

    Yeah, for matts of this world there are no problems until the shit hits own face. And then, it is always the fault of somebody else. With this kind of mindset it is impossible to converse intelligently.

  • Ian // March 15, 2008 at 7:05 pm

    Matt,
    Part of the reason that sea level rise is worrisome in the short term is that a small rise can cause big increases in shore erosion and in the height of storm surges. We don’t have to wait for 100 years of rise to experience costly problems. See, for example: N.B. Bernier, (2007), Mapping the return periods of extreme sea levels: Allowing for short sea level records, seasonality, and climate change, Global and Planetary Change, v 57(1-2): 139-150, doi:10.1016/j.gloplacha.2006.11.027 .

  • P. Lewis // March 15, 2008 at 7:33 pm

    I wonder whether Arch was referring to

    To avoid attempting to do things that other specialists can do better.

  • matt // March 15, 2008 at 9:31 pm

    HB:Response: I don’t see how you got 1.8mm/yr as being “natural.” I also get the impression you’re perfectly willing to do nothing as long as it’s somebody else’s problem, not yours.

    What recent historic rises do you see before CO2 began warming things? Wouldn’t those have happened whether or not humans were here? I look at your data above and it seems between 1.5 and 2 mm/year happened before CO2 levels started rising. Disagree?

    [Response: Look again. The average rate over the entire interval from 1870 to the present is 1.47 mm/yr, and the rate before 1930 was considerably smaller than that. So how do you get 1.5 to 2 mm/yr "before CO2 levels started rising"? Take a look at the table: the rate from 1870 to 1935 is only 0.7 mm/yr.

    And as the data show, CO2 increase starts just about the time that sea level starts to rise.]

    If someone smokes, I consider that their problem. If someone opts to live next to the ocean, I consider that their problem. If someone knows that their land will be under water in 100-400 years, I consider that their problem. Note I don’t mind if they live there, please just don’t ask me to pay for it. If they want to pay for the risk, and there is an insurer that likes the odds, then great.

    [Response: If someone chooses to smoke, that's their problem. If you choose to smoke and it exposes my kids to carcinogens, that's my problem -- and your fault.]

    We have enough problems to worry about right now. Incredibly, there are folks without clean water in this world. There are folks wihtout enough to eat.

    [Response: I'll take a wild guess -- you're perfectly content to do nothing about that, either. Just leave it to "market forces." As long as it's not your problem.]

    Why don’t we tell the rich people living on the beach in Miami to make plans to find a new place to live in the next 100 years, and make sure that those that are barely getting by have a path to keep themselves alive over the next month and a plan to ensure they are creating 3 kids for every two adults.

  • David B. Benson // March 15, 2008 at 9:55 pm

    matt — Read my previous post on this thread dated March 15, 2008 at 4:45 pm.

  • dhogaza // March 15, 2008 at 10:17 pm

    We have enough problems to worry about right now. Incredibly, there are folks without clean water in this world. There are folks wihtout enough to eat.

    The old false dichotomy - if we address global warming, we won’t be able to provide clean water, food, etc - rises its tired, discredited head once again, though in somewhat disguised form.

    The disguise doesn’t make it any less false, though. Sorry, Matt …

  • luminous beauty // March 15, 2008 at 10:18 pm

    matt,

    I’m sure if the shipping and commerce infrastructure, that provides you with the comfortable and secure lifestyle you enjoy, collapses, it won’t bother you any more than when the millions of subsistence or near subsistence delta and coastal plain farmers’ land gets inundated and salted and they either starve or emigrate as penniless refugees to your neighborhood.

  • Brian Klappstein // March 15, 2008 at 10:35 pm

    “…I’m looking at the satellite data at this very moment. He is just plain wrong. Whether this is because he’s grossly incompetent as a data analyst, or he’s applying the strategy of the telling the “biggest lie possible,” I don’t know.]….”

    Morner is talking about the “pre-adjusted” satellite sea level dataset is he not? Rightly or wrongly he’s making a claim that prior to some alleged “corrections” made to the satellite dataset there was no trend. In other words his statements wouldn’t apply to the alleged “post-corrected” dataset you are looking at. It certainly is true that the rate of sea level rise appears to have fallen in the last 5 years or so.

    In any case Morner is right about Tuvali. There appears to be no trend in the tide gauge sea level data since the big El Nino of ‘98. That’s pretty much true of all of the South Pacific Islands in the Australian BOM climate monitoring network.

    [Response: Those "alleged" corrections are based on demonstrable factors involving changing instrument properties, orbital drift, and a broad network of calibration data, including both relative (tide gauge) and absolute (GPS), and detailed orbit updates. Calibration is absolutely necessary and quantifiable.

    But those who don't like global warming will try to discredit the data by discrediting the calibration. To believe Morner, you have to believe that orbits don't decay, that instrument response doesn't change over time, and that all the calibration analysis is wrong. It's a sure sign of a fundamentally flawed approach when one side insists on calibration and correction when it favors their case (urban heat island, anyone?) but disdains it otherwise.

    Morner seems to believe that everybody doing calibration of satellite data, and analyzing tide gauge data, is wrong -- except of course himself. It seems to me that his opinions on sea level have no more credibility than his many publications supporting the validity of dowsing.]

  • Brian D // March 15, 2008 at 11:30 pm

    Matt:

    Would you actively get in the way of someone else trying to solve what you see as their problem?

    That seems somewhat counterintuitive to claiming ‘it’s their problem, therefore they should deal with it and it’s none of my business’ (paraphrasing). It’s also downright immoral.

    Make no mistake: Spreading misinformation on climate change — especially information that seems compelling until you realize what it actually means — is definitely interfering with other people trying to solve what, to them, is their problem.

    Where’s the logic in that? If you’re convinced it won’t happen to you, then get out of the way so that those who care about it can try to save their standard of living. Oddly, the people trying to do that are also convinced they’re trying to save *your* standard of living, too. Can you make the same claim while standing behind laissez-faire?

  • Surly // March 16, 2008 at 2:09 am

    “Incredibly, there are folks without clean water in this world. There are folks wihtout enough to eat.”

    Incredibly, most of us already knew this. And even more incredibly, these “folks” also will be hit hardest by the effects of global warming. It is up to us in the developed world to ensure that they don’t bear the brunt of our irresponsible development of the past 100 years and as well, that our attempts to prevent dangerous climate change do not hurt them further.

    For years, policy makers have been discussing how to ensure the developing world is able to use the fruits of technological innovations so that they are able to develop without further threatening the planet.

    This “But what about the poor of the world” is one of those claims made by “skeptics” as a means of deflecting attention from the main issue. Certainly climate mitigation policies should not prevent development in those parts of the world where it will lift people out of absolute poverty, but there is no reason that the development can’t be carbon neutral. The West and North developed in an extremely irresponsible manner with little or no regard for the effects on the environment and climate. As a consequence, all the globe now faces the threat arising from this irresponsible — some might say criminal — economic development. As the East and South develops, it is necessary that they don’t make the same mistake. Transfer of clean technology from the developed to developing world is an absolute necessity — for all our benefit.

  • mmghosh // March 16, 2008 at 4:12 am

    dhogaza

    I’m not sure why it gives that time. It is a curious time for a teleconference, perhaps they are trying to bring together from different time zones?

    In any case it sounds like a good expert panel. I’m not going to be able to watch it, but it would be nice if a report could be linked here by someone.

  • Julian Flood // March 16, 2008 at 6:59 am

    quote And as the data show, CO2 increase starts just about the time that sea level starts to rise.]

    1850? Humanity was pushing out a negligible quantity of CO2 in 1850 — there’s a nice graph at
    http://www.mongabay.com/images/2006/graphs/co2_global_1750-2000.jpg

    [Response: Hmmm... CO2 began to rise about 1850, when the industrial revolution was well under way, after having been reasonably stable for about 10,000 years. It has continued rising ever since. That's just the data talking -- but you just wave your hand and dismiss that by claiming it's "negligible."

    It sure is a lot less than today. But since it was enough to start the modern upward trend, I wouldn't say negligible.]

    So, if sea rise was happening then it wasn’t our fault. How could it have been? We were not producing enough CO2 to be causing the greenhouse effect which is the reputed wellspring of this result, so why was the level rising?

    Using the same graph you might wonder why temperatures began to rise at the same time: again, not us. or, if us, then something other than anthropogenic CO2.

    I begin to wonder about the corrections applied to stilling wells during stormy weather. Do wells under-read at high seastates?

    JF

  • No dog in hunt // March 16, 2008 at 7:06 am

    Geez, if this is the best argument you can make–that GMSL is going to rise about 2 mm a year for the next century, if nothing changes (Club o Rome made the same mistake in 1972 when it predicted that half the planet would be starving to death and the rest at global war over resources by 2001) Then there is nothing to worry about, is there?

    Most of the world’s beach front property is owned by the rich even in developing countries. They live and die by market economies, albeit as imperfect and manipulated as they are.

    Nevertheless, rising sea levels predicted here are well within the scope of the free market of capital and ideas to manage without UN intervention. The same free markets you diss have plenty of time to react far more efficiently than a centrally commanded economy can even imagine.

    In fact, the ultimate free markets– ecosystems such as coral reefs and mangrove swamps, will also have plenty of time to react as well, because, lo and behold, such rising of the seas isn’t a one off event as Hansen’s Bulldog has outlined. Meltwater Pulses are a regular clockwork-like feature of the global biosphere. And we still have coral reefs and mangrove estuaries.

    As a scare tactic to incite politic and social agitation for collectivist economic mandates to limit carbon emission, the rising oceans fright is among the most feeble.

    [Response: I've noticed a new habit from the denialist side.

    If they want to suggest that modern sea level rise is natural, they'll attribute 1.8 mm/yr to "before CO2 levels started to rise," even though the average *since* CO2 levels started to rise is only 1.5, and the average before that is less than 0.2. But if they want to suggest that future sea level rise isn't a problem, they'll suggest that I myself am claiming "2 mm/yr for the next century, if nothing changes," even though the *present* rate is 3.3. And of course, they'll ignore everything about how it might be faster than that -- maybe a lot faster.

    Are you people unable to read?

    And the single most ridiculous statement you've submitted is: "Most of the world's beach front property is owned by the rich even in developing countries." I wonder whether you're using the lawyer-like trick of talking about *ownership* when the real issue is, who's *living* there? There are hundreds of millions of people living at low enough elevation, that they'll be inundated by a single meter of sea level rise. Do you believe there are hundreds of millions of "the rich," even in developing countries? That dog won't hunt -- most of them are in abject poverty. But the "free-market" advocates will do anything to avoid having to spend a dime to help them, in spite of the fact that it's the "free market" which is to BLAME for their predicament.

    Absolutely despicable.]

  • fred // March 16, 2008 at 7:48 am

    Aaron Lewis seems to be forecasting something higher than 50 cm rise within 20 years, and 5 meters within 100. How much higher isn’t quite clear.

    This prospect deeply troubles someone living in a landscape that will probably be totally submerged by a 50 cm rise, and one who also hopes to live for longer than 20 years.

    And, if its going to happen in the next twenty years, there is nothing one can do about except move. In that time frame, CO2 lowering is not going to make any difference one way or the other.

    Is that really what is being argued? Should I sell now and move to the Alps or the Massif Central? What a prospect!

    [Response: It seems to me that there isn't yet a concensus on the issue of how likely it is that sea level rise will be dramatically more than the IPCC projection. Claims that it might be are coming from the folks who study glaciers and ice sheets, so it's well to take it seriously. But claims of 5m this century seem to me excessive; that's on the high side even for meltwater pulse 1A. It also seems extreme to be talking about big rises in just the next 20 years, but again I wouldn't want to "bet the farm" against it. Bottom line: if it were me, I'd move inland.]

  • impulsoverde // March 16, 2008 at 12:24 pm

    Congratulations, You are making a very good work.

  • Ellis // March 16, 2008 at 3:43 pm

    Tamino, your notion that free market “advocates” will do nothing to help those beset by natural disasters rings hollow in the overwhelming evidence of the past few years.
    If you go here you will see a detailed response from all countries in regards to the 2004 tsunami. I note that the last bastion of free market “advocates”, the U.S., gave as much as Australia, Canada, and the U.K combined. It is because of that evil free market that countries have enough disposible income to be able to help those less fortunate than themselves in their time of need. You need more proof, look at Korea: S. Korea total aid around 2.2 million USD, N. Korea total aid 150,000 USD. More? China citizens alone 18 Million USD, Hong Kong citizens 72 Million-population China 1.3 billion vs. 7 million Hong Kong.
    Granted, this is but one example, but I am fairly confident that if I look through the history of humaitarian aid in the world for the past 150 years, I would find that it is the countries that espouse the free market philosophy are consistantly the ones that give the most, and its not because they are “better” people, but only because they actually have more to give.
    And, one last point, these people that live in abject poverty in the coastal areas that you are talking about, have lived the same way for thousands of years, the market did not change their lifestyles one bit, except for maybe giving the best and brightest of these people a way out of the slums and shanty towns.

    [Response: Interesting that you mention that the U.S. contribution to disaster relief for the tsunami was roughly the same as Canada, Australia, and the U.K. combined. You don't mention that the GNP of the U.S. is about 3 times as great as that of those other three countries combined, and about the same ratio holds for population. So whether we measure it by fraction of GNP, or per capita, this particular incident makes the U.S. look pretty stingy.

    Do you know the story told in the Bible where Jesus compares the big contribution from the wealthy man (who *of course* makes a big show out of his generosity) to the poor woman who donates a measly few copper coins to the temple? Jesus seems to think that her generosity, which is a much bigger fraction of her "wealth," is far more noble than the sham effort of the wealthy man. I'll agree with Jesus on this one.

    I believe in free markets for *most* economic situations; the profit motive is a strong incentive to innovation and efficiency. But when people are threatened with death and disease, leaving it to "free market" solutions is pure greed in action. Giving free rein to the profit motive is immoral when the goal is humanitarian relief of suffering. ESPECIALLY when it's the free market, through exploitation of the planet's atmosphere, that is the CAUSE of the problem.

    It sure seems that the one thing "free market" advocate never want to do, is take *responsibility* for their actions.]

  • Aaron Lewis // March 16, 2008 at 4:23 pm

    Fred,
    How much do I think sea level will rise in the next 30 years?

    I expect .5 meter from permafrost, .5 meter from glaciers (see for example : http://news.yahoo.com/s/ap/20080316/ap_on_sc/un_melting_glaciers_1), and 1 meter from both the GIS and WAIS. So that would make a total of 2 meters of SLR in the next 30 years. However, I would not be the least surprised to see another meter in the following decade for a total of 3 meters in 40 years.

    I see GIS ice loss facilitated by polar cyclone type storms driven by both the temperature differential between the North Atlantic and the GIS; and, the temperature differential between the soon to be open open Arctic Ocean and the GIS. The cumulative effect of having a high, ice covered island with strong prevailing winds and open water on 3 sides of it is — lots of rain. Greenland is big. It is a huge rain collection basin. We could see sights to rival the great Lake Missoula Floods, sooner rather than later.

    Much of WAIS stands in fairly deep sea water that is below 0C in temperature. If (and here I assume things for which there are hints, but not firm evidence) a bottom current with a temperature greater than 0C contacted the base of the ice, a low salinity melt plume would form. That rising fresher water would tend to drive the bottom current. The first evidence that we would have for such a situation would be additional sea ice around Antarctica as the fresher surface water froze at higher temperatures.

    I am not certain that these things will come to pass. However, I feel that they are plausible at probabilities of greater than 1 in a hundred-thousand, would affect many people – and therefore should be subject extensive review and consideration. I do not see such review and consideration. Whether this lack of review is due to the fact that people do not want to talk about unpleasant issues, or whether I have simply become a crackpot and can no longer do reasonable physics, I cannot tell. After all, I always had to walk most people through a lot of physics that seemed obvious to me.

    But, if someone tells you that it will take thousands of years for GIS to melt or collapse, ask them for their reasoning. Do not accept, “the computer says so.” Make them tell you how the computer got that answer. Make them tell you what physics the computer program included, and did physics it did not include. Ask what scale of phenomena were considered and what were ignored. Ask what conditions and assumptions were used to initialize the computer run. Ask yourself, “Are those conditions consistent with the reality of the last couple of years? Do those conditions include current levels of sea ice? Do those conditions include current production of greenhouse gases?” Do they look at the structural strength of ice in contact with liquid water as a foundation material? (For most climate models, this is all on the Internet, and you have only to look, to think, and to ask a few intelligent questions.)

    I guess I am an old crackpot. I think everyone should spend an hour a day with a good science textbook (or Global Circulation Model Manual ; D )

  • matt // March 16, 2008 at 5:47 pm

    TB: Response: Look again. The average rate over the entire interval from 1870 to the present is 1.47 mm/yr, and the rate before 1930 was considerably smaller than that. So how do you get 1.5 to 2 mm/yr “before CO2 levels started rising”? Take a look at the table: the rate from 1870 to 1935 is only 0.7 mm/yr.

    And as the data show, CO2 increase starts just about the time that sea level starts to rise.

    Are you asserting that CO2 rise directly causes sea level rise? Of course not. CO2 increases, some time later temperature increases, and some time later sea level rises.

    [Response: This is what you said:

    I look at your data above and it seems between 1.5 and 2 mm/year happened before CO2 levels started rising. Disagree?

    I disagreed. Because you're wrong. You seem to be ignorant of both how much sea level rose, and when CO2 levels started rising. But I can certainly understand why you'd *want* people to believe that I'm claiming something else, or change the subject in any way possible: your own words are very embarrassing for you.]

    Globally, the air temp from 1910 to 1940 showed a rise that rivals the warming we saw starting around 1980 until about 2000.

    [Response: Where do you get this crap? The early-20th-century rise is about 0.3 (GISS) or 0.4 (HadCRU) deg.C, that from 1975 to the present is about 0.6 deg.C.]

    Two questions for you: First, do you believe the warming from 1910 to 1940 was due to industrialization? Second, do you believe the higher sea level rise in your table for the years 1935 to ‘57 was due to this warming?

    TB:Response: I’ll take a wild guess — you’re perfectly content to do nothing about that, either. Just leave it to “market forces.” As long as it’s not your problem.

    You’d be wrong about that.

    [Response: Guess what? I don't believe you.]

    I’d note, though, that the religious right in this country gives far more to charity than the secular left, in spite of the secular left having a much higher income.

    [Response: Well since you claim it with no supporting evidence whatsoever, it *must* be true.

    As for the religious right in this country, I'll have some respect for them when they start following the teachings of Jesus Christ.]

  • John Lederer // March 16, 2008 at 5:50 pm

    “And as the data show, CO2 increase starts just about the time that sea level starts to rise.”

    In terms of sea level, CO2 has no known direct effect, does it? It only matters for sea level in terms of whether it changes the heat retained by earth.

    My impression is that most evidence suggests that temperature was fairly stable or slightly declining from about ~1850 to ~1920.

    So, whatever caused the sea level to start rising in the latter half of the 1800’s it would not be greenhouse effect would it? Have to be something else, I would think.

    I realize that the climate records are a bit poor back then.

  • Aaron Lewis // March 16, 2008 at 6:01 pm

    In line, HB wrote: “It seems to me that there isn’t yet a concensus on the issue of how likely it is that sea level rise will be dramatically more than the IPCC projection. Claims that it might be are coming from the folks who study glaciers and ice sheets, so it’s well to take it seriously. But claims of 5m this century seem to me excessive; that’s on the high side even for meltwater pulse 1A. It also seems extreme to be talking about big rises in just the next 20 years, but again I wouldn’t want to “bet the farm” against it. Bottom line: if it were me, I’d move inland.]”

    This appears to science by vote, or science by feelings! Why does 5m/ century “seem” extensive? Because we did not see such SLR before CO2 concentrations approached and surpassed 400 ppmv? Because 5m/ century SLR would not be pleasant? I want ONE good paper on WHY sea level rise will not be dramatically more than IPCC forecasts. I want a paper that says, “Here is why it is going to STOP raining on Greenland.”

    Melt Water Pulse 1A was driven by Orbital Change forcing? Orbital Change is a very gentile and slow forcing. If such a gentile and slow forcing could produce, such rapid changes in sea level, what kind of huge changes in sea level could our current, rapid, and vigorous greenhouse gas forcing produce? 5+ m/ century?!

    Think the system through. Even moderate rises in sea level will affect industrial infrastructure that is near sea level. That includes oil refineries AND the factories that produce the steel pipe that is needed to build new refineries.

    Most of the factories that produce farm fertilizer are near sea level. A SLR hurts those factories, the farmers that use the fertilizers, the millers and bakers that make bread, and everyone that eats bread. Of course, the transportation systems that move food products around would already have been damaged as refinery production was impacted and less fuel produced to run our truck based transportation systems.

    Most organic chemicals are made near sea level. Most microprocessors depend on components that are produced near sea level. Most fiber is manufactured near sea level (except for cotton that depends on large amounts of fertilizer) . . . . . A modest rise in sea level would knock out much of what we THINK we need to live in a city – or to build new cities.

    Consider New York City. A modest rise in sea level would damage its underground utilities making it much less livable. That would impact the millions of inhabitants of NYC, and also everyone that depends on the financial services that NYC provides to the world. I think economic studies on the costs of sea level rise have been as incomplete as the IPCC studies that did not include ice sheet dynamics with respect to sea level rise.

    So, as you move inland, you should think about what is required to produce food without a petroleum subsidy. Can you farm without industrial herbicides and pesticides? Can you produce clothing without the fiber factories?. Yes! We had several very nice civilizations without petroleum products. On the other hand, these civilizations had very specific skills, many of which have been lost. These skills were difficult, which is why people abandoned them.

    Let us consider a very basic skill – knitting. For hundreds of years, sailors kept warm in hand knit, hand spun, wool garments. Most modern hand knitters do not know how to knit such warm garments, and when they try, they ruin their wrists. Yet, in the past, professional hand knitters, knit such garments, day in and day out for years on end. We still have hand knitting, but we have lost the skill of knitting clothing that is truly functional without central (petroleum intensive) heat. You would not last very long wearing modern hand knit garments in a traditional stone cottage heated with wood or peat. You would die of hypothermia. (Researching the physics of how the fishermen of old stayed warm has been my hobby for the last decade. It turns out to have other lessons.)

  • Barton Paul Levenson // March 16, 2008 at 8:34 pm

    TCO writes:

    [[I like it warm.]]

    Would you like a pillow? How about a nice cup of juice?

  • David B. Benson // March 16, 2008 at 8:39 pm

    Julian Flood // March 16, 2008 at 6:59 am — The graph you linked (thank you) proports to show the annual rate, right?

  • matt // March 16, 2008 at 9:26 pm

    HB:Where do you get this crap? The early-20th-century rise is about 0.3 (GISS) or 0.4 (HadCRU) deg.C, that from 1975 to the present is about 0.6 deg.C.]

    Note I stated: Globally, the air temp from 1910 to 1940 showed a rise that rivals the warming we saw starting around 1980 until about 2000

    Looking here: http://www.cru.uea.ac.uk/cru/info/warming/ my statement looks 100% truthful. Disagree? I’m not talking absolute. I’m talking rate of rise. I’m trying to understand why sea level rise was so high in ‘35 to 57 while temps were so low but rising quickly. Is this not a worthy question? We experienced very high sea level rates of rise although temps were well below normal????

    HB: Guess what? I don’t believe you.

    Again, two anonymous people arguing over who is more virtuous will never be solved. I’m not convinced you care enough to help those that need the most help, and you aren’t convinced I care enough. Alas, we move on.

    HB: Well since you claim it with no supporting evidence whatsoever, it *must* be true.

    As for the religious right in this country, I’ll have some respect for them when they start following the teachings of Jesus Christ.

    If you are lookign for studies that back my statement, please look at Social Capital Community Benchmark Survey, spearheaded by several universities, Roper and Harvard’s Kennedy School of Government from 2000 to 2001.

    From a sample of nearly 30,000 interviewees, they found those that attended a house of worship at least weekly gave annually $2210, of which $532 was to secular charities. Those that went to church a few times per year or less gave $642 anually, of which $467 was to secular causes.

    So it seems churchgoers give a LOT MORE to non-church causes than non-church goers.

    And the fact that liberals are better off than convervatives is already well known. But holler if you want that data too.

    [Response: If you equate churchgoers with the "religious right," then you're a bigger fool than I thought.

    The religious right in this country are the pharisees and the sadducees, who make long-winded loud prayers not for the glory of God, but to glorify themselves. Those who cry "let market forces handle it" when it comes to global warming, are the money-changers in the temple. Jesus threw them out.]

  • David B. Benson // March 16, 2008 at 9:53 pm

    John Lederer // March 16, 2008 at 5:50 pm asks “In terms of sea level, CO2 has no known direct effect, does it?” That is correct. It is only its global warming effect.

    With regard to the period 1850–1920 CE, one might find records of ice loss in the Alps and in Norway. This might be due to a regional temperature increase but might also be due to the increase in black carbon, “soot”.

    The black carbon might also have effects further afield, say Greenland. In addition, there are the temperature proxies in the ice core records for Greenland. Nothing requires these to closely match estimates of global temperature (unless the ice core proxies are themselves the estimates of global temperature.)

  • Barton Paul Levenson // March 16, 2008 at 10:07 pm

    Aaron Lewis — You’ve hit the nail on the head. Sea level rise can destroy a coastal city long before it is underwater. All that has to happen is for sea level to rise enough to back up sewers and seep into the aquifers. Without fresh water and sanitation, New York, Miami, New Orleans, Jacksonville, and many other coastal cities will be uninhabitable quite soon. As will most of Bangladesh. Sea level rise is going to hurt rice production badly; a lot of rice is produced close to sea level, but it won’t grow in seawater.

  • Ellis // March 16, 2008 at 10:19 pm

    Three billion. Stingy? I guess that is just a matter of perspective. To add on to your parable, if the poor had only to choose between the $100 of the proud, in the biblical bad sense, man or the $10 from the saintly lady, who’s money do they take? Note I say your parable, it’s alot like science, you can’t be quoting Jesus without citing chapter and verse. But, enough about politics and religion, those subjects are way to contentious. Let’s just talk about something everyone can agree on. How about the weather. :D

    [Response: That's a good idea.]

  • John Lederer // March 16, 2008 at 10:25 pm

    “With regard to the period 1850–1920 CE, one might find records of ice loss in the Alps and in Norway. This might be due to a regional temperature increase but might also be due to the increase in black carbon, “soot”.”

    I had not thought of the soot effect or localized temperatures. The soot effect seems apparent as my yard “de-glaciates” from winter– the area where I blowed snow and dirt melted first.

    I seem to recall that glaciers do not immediately respond to temperature changes, with a very substantial delay of at least decades.

    Wouldn’t the input side, in the form of precipitation , also be a very pertinent factor on glacier/ice field growth or decrease, and thus on sea level?

  • JCH // March 16, 2008 at 10:26 pm

    Lol. Do those studies include the charitable contributions wingers make to their TV preacher’s bank accounts?

    [Response: I agree with Ellis, let's change the topic back to the weather.]

  • P. Lewis // March 16, 2008 at 10:49 pm

    matt said

    Note I stated: Globally, the air temp from 1910 to 1940 showed a rise that rivals the warming we saw starting around 1980 until about 2000

    Now I haven’t followed this particular thread closely yet, but if you care to dig a bit deeper you will see that the major component of that global average rise (and subsequent fall) was due to data from north of latitude 64°N; the rises south of this latitude were modest.

    The possible/probable importance? Think magnitudes instead of/as well as anomalies.

  • mmghosh // March 16, 2008 at 10:57 pm

    About the effect of sea level rise (80% of the effect will be on the population of the Indian subcontinent and SE Asia):

    http://www.grida.no/climate/vital/33.htm

    http://www.fao.org/sd/EIdirect/EIre0046.htm

    As Mr McDade pointed out in this thread the effects are compounded by subsidence due to groundwater extraction, as these coastal areas do not have seawater desalination plants or river water purifiers to provide drinking water.

  • David B. Benson // March 16, 2008 at 11:01 pm

    Here is an oddly written (and possibly not that relaible) account of the so-called little ice age. The relevance here is that conditions in Iceland to restart agriculture did not occur until about 1880 CE and that glaciers in the Alps only began to retreat around 1860 CE. (Nothing, really, about Norway during this period.)

    http://williamcalvin.com/readings/Fagan%201999%20chapter%20on%20LIA.htm

  • mmghosh // March 16, 2008 at 11:56 pm

    I also feel that for the purposes of discussion we should not exceed the IPCC predictions.

    The KNMI for example predicts a rise of upto 80 cm by 2100. The Netherlands is planning for this level of rise.

    http://www.knmi.nl/

  • TCO // March 17, 2008 at 12:37 am

    BPL: Yes, but the destruction will still be gradual. It could be a bad thing (do some calcs to find out). But it is not going to be South Park running up and down in the street, pack yourself in the community center quick. There will be time for migration. (Now I’m open to discussion and analysis as to the costs of that. But let’s not get all Randy Marsh, please.)

  • Hansen's Bulldog // March 17, 2008 at 12:41 am

    (Posted by chriscolose, moved by request to this thread)

    Here’s a neat site where you can view what land will be lost to sea level rise. You can choose a range from 0 to 14 meters anywhere in the world and can zoom in for detail.

    http://flood.firetree.net/?ll=54.0000,-2.4000

  • P. Lewis // March 17, 2008 at 12:56 am

    Places like Bangladesh and into India along the Brahmaputra/Ganges Delta (and parts of China) will be hit by a double whammy. As well as rising sea levels having a dramatic effect in terms of loss of fertile agricultural land and population displacement in the many millions, they will also have an increasing tendency to floods and droughts because of change/loss of freshwater input to the river systems due to shrinking Himalayan glaciers. Whether the two events coincide or overlap to a significant degree or whether they happen in separate periods, the potential cost in human suffering terms will likely be on a scale unheard of.

    Whither the free market solutions in this instance?

  • TCO // March 17, 2008 at 1:50 am

    Note: I’m not saying there won’t be bad effects, or that bad effects won’t outweigh good ones, but there must be some places where there are good effects? Where do you think? US/CA midwest warming? Sahara greening? Just curious.

  • Andrew // March 17, 2008 at 3:53 am

    I’ve seen no mention of the possibility of a Holocene high sea level stand in your post or the comments. Though dismissed by most coastal geologists, some folks have found evidence that at some point in the Holocene, global sea level could have been 1 meter above recent levels. There are some interesting mud-filled tidal channels near Houston that now stand a couple feet above high tide (following a foot of subsidence plus recent eustatic sea level rise) that would support + 1m some time from 8K ybp to 2K ybp. At any rate, such a here today, gone tomorrow rise would argue for a greater sensitivity of the world’s ice to warming than most scientists in the field currently assume (my opinion, I really don’t know what they think, but that is the impression I get from reading the literature).

    Also, reading through the comments I’m struck with the seeming ignorance folks have regarding the implications of a rapidly rising sea. Enjoy the beaches and barrier islands today and bring the kids often as they or their grandchildren will only talk about them in the past tense. The same with the world’s great river delta coastal marshes and our beautiful beyond words tidal cypress swamps.

    The people who will shed the most tears won’t be wealthy condo owners, but rather will be those like me who seek peace fishing, boating, and camping on the beaches and bays. The cheapest out of country vacation I’ve taken was a two week trip living out of a hammock on a beach in Mexico. I shared the place with many working Mexicans from Guadalajara. Not a wealthy person in view.

    Where I live, Texas, all beaches are public; and so they are where working class and poor families can find some bit of grace and show their children why life is worth living. Not to mention the millions of Bangladeshi’s who live within a meter of sea level. So, hey y’all, most of the rest of the world in no way resembles California or New York or where ever in the hell in England those who think the coast is only the rich’s retreat are writing from.

  • John Mashey // March 17, 2008 at 4:00 am

    Good effects:
    1) Scotland will have wineries.
    http://www.winelandsofbritain.co.uk/lecture.htm
    The author is a geologist and oenophile, and thinks Loch Ness is well-placed for a great winery and probably Nessie will be seen more often.

    [of course, Italy and Spain will lose more].

    2) The wines of the Okanagan Valley in British Columbia (where I’m sitting right now) will continue to improve. They’re already quite drinkable. By amusing coincidence, Lake Okanagan has a Nessie-equivalent, called Ogopogo, and presumably, with more wine around, it too will be seen more often.

    [Downside: Napa & Sonoma lose. This is not amusing to California.]

    3) Upper Midwest and nearby Canada get warmer, and (maybe) get more rain. This helps some, although recall that growing crops requires:
    - sun
    - water
    - soil/nutrients
    - temperature
    - other climate patterns
    - CO2
    - and it’s nice to have flat country

    Whichever is in *least* supply puts a limit on the growth. (Liebig’s Law) No amount of extra CO2 will grow corn in the Sahara.

    Likewise, more heat isn’t always good: sugar maples need some cold, hence that business is moving North out of Vermont and new Hampshire. Oh, I guess that’s a plus for Quebec.

    Likewise, while warmth helps the B.C. wine business, its timber is getting decimated by mountain pine beetles:
    http://www.for.gov.bc.ca/hfp/mountain_pine_beetle/faq.htm
    [I heard all about this from a B.C. lumber guy today .] Really cold weather (-40C) is needed to suppress these things, as they make natural antifreeze.

    Warmer temperature doesn’t provide more sun, and it doesn’t turn barren ground into topsoil. A lot of great topsoil is where it is because the glaciers scraped it off the North and moved it South.

    Downside: southern US gets hotter and (probably) loses water.

  • Petro // March 17, 2008 at 6:31 am

    matt declared to HB:

    “Again, two anonymous people arguing over who is more virtuous will never be solved. I’m not convinced you care enough to help those that need the most help, and you aren’t convinced I care enough.”

    Wrong. matt is a selfish jerk with strong beliefs which do not correspond with reality, while HB is trying to explain scientifically what happens with climate. There is no way to change matt’s beliefs, while HB:s views change with scientific evidence.

    Since truthfulness is a virtue, thiscomparision is easily solved: HB is virtous while matt is not.

  • Brian Klappstein // March 17, 2008 at 9:14 am

    “…Morner seems to believe that everybody doing calibration of satellite data, and analyzing tide gauge data, is wrong — except of course himself. It seems to me that his opinions on sea level have no more credibility than his many publications supporting the validity of dowsing.]…”

    To my mind you’re wasting time commenting on Morner the man, as opposed to Morner’s arguments. That’s a problem for both sides in this argument. We assume since we know what a person stands for we also know why. But even if that is true, is it relevent? In your case, you’ve decided (I think anyway) that Morner is against global warming (whatever that means). However, it’s possible he’s just hostile to the lack of objectivity on subjects like sea level change and is neutral on global warming, or at least he started off being neutral on global warming, but after being attacked for criticizing….etc.

    Back to Morner. Is he right about sea level trends in the South Pacific or not?

  • Nils Simon // March 17, 2008 at 3:56 pm

    Tamino, I haven’t read through all the comments, so I might have missed it if anyone else already mentioned it. But regarding the apparently lower 1957-1990 figures, there was a recent (5 March 200 8) study published in Science by Chao et al. claiming that the riddle may be due to humanity building large water reservoirs (dams) that kept a LOT of water from flowing into the oceans. Accounting for that effect, they claim, would flatten out the lower rate of sea level rise in the second part of the 20th century. Here:
    http://www.sciencemag.org/cgi/content/abstract/1154580v1

    Impact of Artificial Reservoir Water Impoundment on Global Sea Level

    Abstract: “By reconstructing the history of the water impoundment in world’s artificial reservoirs, we show that a total of ~10,800 km3 of water has been impounded on land to date, reducing the magnitude of global sea level (GSL) rise by –30.0 mm, by an average rate of –0.55 mm/yr during the past half century. This demands a significantly larger contribution to GSL rise from other (natural and anthropogenic) causes than otherwise required. The reconstructed GSL history accounting for the impact of reservoirs (by adding back the impounded water volume) shows an essentially constant rate of rise at +2.46 mm/yr over at least the last 80 years, contrary to the conventional view of apparently variable GSL rise based on face values of observation.”

  • David B. Benson // March 17, 2008 at 5:29 pm

    Nils Simon — That paper has been criticized for not taking into account ground water depletion. I don’t have any idea how important that is world-wide, but in the U.S. it is quite serious.

  • Lee // March 17, 2008 at 11:13 pm

    Masher says:
    “[Downside: Napa & Sonoma lose. This is not amusing to California.]”

    There is a much more serious impact on California, a direct effect of sea level rise.

    Most of California’s water falls in the north part of the state. Most of the water usage is in the south part of the state. California’s economy is dependent on a water system that wheels N Cal water to the south.
    The hub of that water distribution system is the Delta - a sea-level network of chanellized ‘rivers’. Water enters from the north and east, and flows through various rivers to pumping stations in the south. Enough water escapes from the network into San Francisco bay to keep the transition zone from fresh to salt water way downstream, out of the rivers, and protect the fresh water supply.
    The entire system of levees that maintains this network of rivers is just barely above high water - which is a function of spring flood flows, sea level, and tides. The levees are necessary at ALL water stages - most of the agricultural islands lying between those rivers are below the normal water level, and many of them are below the level of the BOTTOM of the river. Levee failure means loss of the island, means the levees to other rivers are endangered - and means the tidal flow increases, and salt water intrudes further up river and threatens the fresh water system. Lose more than a handful of islands, and salt intrudes to the pumping stations, and the system fails.

    A seal level rise of jut a couple feet will be sufficient to overtop the levee system during spring floods at high tides - its barely adequate as it, and we lose one or another island every few years and have to repair the system and reclaim the island - and will knock out this key to California’s economy.

    Not to mention the thousands of square miles of the most productive farmland on the planet that will be lost, the electric, natural gas, petroleum, et al distribution network that also lives in the delta, and will become inundated.

  • JCH // March 17, 2008 at 11:41 pm

    Andrew,

    I found your Texas comments very interesting. At what amount of SLR would the continued existence of the barrier islands be in serious doubt? Would they reestablish as the “beach” moves inland?

  • John Mashey // March 18, 2008 at 12:49 am

    Lee: yes, for sure. I didn’t mean to ignore that, it was that the original article wanted advantages of higher temperatures, and I just paired them with the most obvious corresponding disadvantages, not necessarily the biggest.

    If you’re around the SF Bay Area, Stanford has a great lecture series called “Troubled Waters” running, and the last one I attended included a detailed talk about the Delta. FO those who don’t care about CA:
    a) About half the fruit & vegetables sold in the US come from CA.
    b) CA is the biggest net contributor to the US Federal Government, i.e., if you figure (returned - paid) we have the largest negative number, although not quite the largest negative percentage. Around 2000, this was -$60B. Some of that money goes to the Fed, some of it subsidizes other states…

  • Bill Illis // March 18, 2008 at 3:19 am

    I’m afraid that if we don’t stop global warming in its tracks now, sea level rise might exceed even the most conservative estimates and be as much as 27 metres like Hansen estimates.

    3 billion people could drown (or at least they will be displaced which could lead to wars never seen before.)

    We could all end up like the Dutch having to build sea walls to keep the rising sea out or like Venice where we have to use boats to navigate the cities.

  • Julian Flood // March 18, 2008 at 5:04 am

    Do stilling wells under-read in stormy weather?

    JF

  • Gavin's Pussycat // March 18, 2008 at 6:42 am

    Julian Flood: http://www.eoearth.org/article/Carbon_dioxide (see the graph)

    There is more to CO2 emissions than burning fossil fuels… can you say “deforestation”? Atmospheric concentrations were already well on the way up by 1850.

    The full picture is even more complicated: methane, aerosols… and we cannot even trust the “global” temperature record to be really global before, eh, 1880 or so.

    Global mean sea level is a nice, sensitive integrator though.

  • Gavin's Pussycat // March 18, 2008 at 11:00 am

    > And the fact that liberals are better off than convervatives is already well known.

    Yes, earning power comes with intelligence and education.

    [Response: It was a mistake on my part to get caught up in politics and religion. I did so because I'm so offended when people try to associate Christianity with conservatism; anybody who does so, doesn't understand what Jesus' life was all about.

    So let's "let it go" and talk about the weather.]

  • Gavin's Pussycat // March 18, 2008 at 5:14 pm

    Yes, I agree. Okay, the weather…

    Here in Scandinavia we’re experiencing the fifth November in a row… last January for a week, Spitsbergen was the
    warmest place in Norway :-)

    Weather, not climate. Still, the Finnish winter has been the warmest in the instrumental record. Forest
    owners are having problems getting their logs out of the wood, as the ground is soft. Dirt roads suffer massive
    damage. As I argued elsewhere, when the Bell Curve shifts a little, absurdly improbable events suddenly become
    imaginable.

    Is that what is happening here? Is this a legitimate, or even wise, argument?

  • The Tuatara // March 18, 2008 at 9:24 pm

    (Since animal handles are “in” ;)

    GP: Is that what is happening here? Is this a legitimate, or even wise, argument?

    You go where the observations lead. And in this case, it leads to rapid climate change linked to Arctic warming.

  • S2 // March 18, 2008 at 10:07 pm

    John Mashey wrote:

    Good effects:
    1) Scotland will have wineries.

    We don’t need wineries, we’ve got distilleries.

    Living on the 5m contour, I guess I really should think about a move - but I don’t want to, I really like it here.
    I don’t think that there’s any chance of me drowning in my bed, but I guess that it’s just a matter of time before coastal property values start to plummet while inland ones start to soar.
    If I don’t move before then, I won’t be able to afford to afterwards.

    [Response: If global warming interferes with the distilleries in Scotland, that would be a *real* emergency!]

  • David B. Benson // March 18, 2008 at 10:14 pm

    Lee stated “A seal level rise …” You bet. In Puget Sound there are serious plans to shoot all those pesky Californian and Oregonian seals.

    Sorry. Couldn’t resist.

  • Julian Flood // March 18, 2008 at 10:15 pm

    Re Gavin’s Pussycat // March 18, 2008 at 6:42 am

    Well, thank you. But all I see is the CO2 graph. Did you answer my question about stilling wells in error?

    JF

  • Ian Forrester // March 18, 2008 at 10:29 pm

    HB said: “If global warming interferes with the distilleries in Scotland, that would be a *real* emergency!”

    People are already concerned about this. It is being referred to as “Dram-ageddon”. See this article in the Scotsman:

    http://preview.tinyurl.com/3yuq2f

  • Bella Green // March 19, 2008 at 3:19 am

    Whoa. Would you believe I’ve got a glass of Bowmore in my hand right this minute? Cheers, HB — (lifts glass, which tastes like history) and thank you for all the good work you do for us. It is *not* in vain.

  • JCH // March 19, 2008 at 3:32 am

    “We could all end up like the Dutch having to build sea walls to keep the rising sea out or like Venice where we have to use boats to navigate the cities. …” - Bill Illis

    I don’t think anybody is going to be building seawalls capable of holding back 27 additional meters of sea level.

  • Gavin's Pussycat // March 19, 2008 at 10:50 am

    Julian Flood:

    > Did you answer my question about stilling > wells in error?

    No, I didn’t.

  • Julian Flood // March 19, 2008 at 11:21 pm

    Re a rather ungracious quote No, I didn’t. unquote

    Ah, I see, an earlier post. Thank you for being so helpful. I thought it was established that CO2 warming became important only around 1945, but perhaps I’m mis-remembering –things change so fast in this science that I have trouble keeping up. One wonders, however, why a system which seems to be capable of dealing with 4 Gt carbon out of the current 8 (plus, no doubt, other outputs not accounted for in the normal figures) failed to cope with about .5 equivalent. You know the saw-tooth signal in the Mauna Loa figures? How much C variation does that mean? Does Tamino believe it is non-negligible, or is the coping system tied to seasonal variation?

    Anyway, does anyone know anything about stilling wells? I’ve wondered about their behaviour under different wind states. Do they under-read in storms? Perhaps no-one knows.

    I’m only asking questions.

    JF

  • JCH // March 20, 2008 at 1:12 am

    JF - google it. I didn’t see a direct answer, but they’ve been around for a long time - improvements of many sorts are mentioned. It sounds like they came into existence as a means to gather more accurate data so they must be better in wind and storms than what came before them,which was probably a stick or a rock with lines on it.

    You might get an answer by emailing an engineer who works at a company that makes liquid level measuring devices. He’s probably bored to death and would be astounded to get such a question.

  • KuhnKat // March 20, 2008 at 3:29 am

    Julian,

    I didn’t know the answer either. I googled it.

    So, you like to bait the host??

    HAHAHAHAHAHAHAHAHAHA

  • EliRabett // March 20, 2008 at 4:29 am

    JF, first of all the initial response of the system was due to land clearing in North America and Australia principally (also Africa) for farming. This is known as the pioneer effect. Second the variation in the ML signal is seen in the Northern Hemisphere, but not in the Southern one. Your answer lies there

  • Julian Flood // March 21, 2008 at 1:49 am

    quote EliRabett // March 20, 2008 at 4:29 am

    JF, first of all, the initial response of the system was due to land clearing unquote

    Presumably that’s albedo change? That’s a topic I’ve been puzzling over. You know Palle’s work? He’s got albedo forcings varying by over 7 watts/m^2. Is that reasonable? Compared with a CO2 forcing of 4 W/m^2 for doubled CO2 it seems a bit excessive, or it suggests that CO2 is far from being the only cause of the current warming.

    Have you ever looked at low level stratus figures for west-coast, west-facing land stations? I’ve been wondering what the response of the ocean flora is to warming — warmer seas might well be less productive of DMS and give a promising feedback which may not have been incorporated into the models. The blue deserts are spreading — I’d bet a swift half that starved oceans are altering the isotopic C balance, but I’ve seen no research on the matter.

    Oh, yes, while you’re here… You know the wind velocity figures which show a cyclical variation? Have you got any explanation for the notch of 2 m/s shown in.. . damnation, I’ve lost the reference. No doubt you know the paper which argues, IIRC, that the wind variation (emissivity of ruffled surfaces) accounts for SST variation. The notch is 39 - 45. Most peculiar, it is sharp in the NH (more so in the Atlantic) and smears out in the SH.

    Anyway, has there been a paper published explaining the rise in temps before CO2 kicked in? I’d be grateful for a reference. NB: I can’t afford to go to the pay to read sites. TIA.

    Does anyone know anything about stilling wells in stormy weather? Thanks for the suggestions so far, but Google has not helped.

    Re KuhnKat // March 20, 2008 at 3:29 am

    I don’t know what you’re on, but I hope you didn’t pay too much. It doesn’t make you as funny as you think. Try Laphroaig*.

    JF
    * Google it, sonny, Google it.

  • Andrew // March 21, 2008 at 4:40 am

    JCH:
    Ship Shoal, Healds Bank, and Sabine Bank are all former barrier islands now submerged off the Texas coast that were unable to retreat quickly enough during past sea level rise episodes no greater than those predicted to occur under many AGW scenarios These barrier islands were submerged by the final deglaciation following the end of the Pleistocene where sea level rise = about 10mm/year. For every foot of sea level rise, the upper Texas coast retreats about 1,500′. For every foot of sea level rise, the Louisiana coast retreats about 10-15,000 feet (three miles). Barrier islands and beaches and salt marshes can’t exist under the Gulf Coast’s microtidal regime unless sea level is fairly stable. The massive sand pumping that occurs to keep beaches from the west coast of Florida to Mexico is evidence of that. Billions have been spent and yet sea level rise has been moderate to date. Yes, other problems contribute to beach loss, but in the near future sea level rise will become an stoppable, unsolvable problem for coastal communities and natural areas such as Padre Island, 60 miles of pristine or nearly so barrier island (good-bye - I’ve loved you dearly). I only hope that this is stopped before it’s too late to save some semblance of a natural coastline (versus rock walls). Meanwhile I’ve resolved to take the kids to the shore as often as possible.

  • JCH // March 21, 2008 at 6:18 am

    JF,

    I see no direct answer to your question. Just in case you missed this one:

    http://aip.org/pt/vol-55/iss-3/p35.html

    Or this one:

    http://www.io-warnemuende.de/homepages/schernewski/Littoral2000/docs/vol2/Littoral2002_13.pdf

    Email these guys and ask them:

    Southampton Oceanography Centre, Empress Dock, Southampton SO14 3ZH, UK

    ixa@soc.soton.ac.uk

  • Julian Flood // March 21, 2008 at 1:54 pm

    Re: JCH // March 21, 2008 at 6:18 am

    Thanks, that’s very interesting. I’m reluctant to email busy scientists with questions which, to them, must seem trivial — besides, the last thing they need is to pestered by one of us swivelly-eyed loonies. I was hoping someone here might know, as, after all, we’re putting in a lot of worry-time on something which might be adjusted out of all recognition. Roll on the next generation of satellites. I’m pretty sure we can cope if it really is going up by just 1 or 2 mm per year.

    The graph with the wind notch, BTW, is in a presentation by Hartwig Volz — Seawater Emissivity, a Neglected Climate Forcing. Page 19.

    JF

  • Barton Paul Levenson // March 21, 2008 at 2:58 pm

    Julian Flood writes:

    [[You know Palle’s work? He’s got albedo forcings varying by over 7 watts/m^2. Is that reasonable? Compared with a CO2 forcing of 4 W/m^2 for doubled CO2 it seems a bit excessive, or it suggests that CO2 is far from being the only cause of the current warming.]]

    I think Palle has recently graciously admitted that his albedo reconstructions are probably not correct. They mentioned this on RealClimate a while back.

  • Julian Flood // March 21, 2008 at 8:35 pm

    Re: quote I think Palle has recently graciously admitted that his albedo reconstructions are probably not correct unquote

    Thanks, I’d not seen that. So the albedo case is just left with
    http://visibleearth.nasa.gov/view_rec.php?id=17177

    .9w/m^2 in four years, now that’s what I call a forcing.

    JF
    I’m surprised I’ve not seen you on rec.arts.sf.comp.

  • Aaron Lewis // March 21, 2008 at 11:57 pm

    It is spring. It is raining in Greenland! Well, good drizzle anyway. Still there are big swathes that are above freezing. That will leave melt that changes the albedo.

    How much ice could rain melt? And, it has been what? - 5 months since the last good rain in Greenland? After all this rain is just weather, it is not like CLIMATE, right?

  • littlerobbergirl // March 22, 2008 at 7:51 pm

    has anyone mentioned large dams? might that be a part cause for the slowing of the rate of change 1959-1990?

    http://www.scar.org/researchgroups/physicalscience/Sea_levelStatement_2006.pdf

  • KuhnKat // March 28, 2008 at 11:39 pm

    littlerobbergirl,

    out west we are DESTROYING DAMS to return the watersheds to natural flow. Other areas of the US are also taking down old dams. This is probably balanced by the Chinese Dam of the Yangtze and others world wide.

    Basically, with a new dam, there is a temporary loss of water to the oceans, but, an increase of evaporative loss from the huge surface areas behind the dams. Should have little net effect.

    Any experts who have studied this with hard data??

    I believe that the fellows actually studying the loss of Arctic ice have come to the conclusion that it is primarily from prevailing WINDS blowing warm water into the Arctic at a higher than normal rate.

    Which brings up the recent published data on the OCEAN temperature staying flat over the last five years. It takes a lot of energy to melt ice. Could cause a lot of water to lose extra temp before being recirculated!!

    Anyone step on Mr. Spencer and his Argo paper yet??

    Julian,

    Stilling Wells are basically what is used to measure sea level. See:

    http://www.usbr.gov/pmts/hydraulics_lab/pubs/wmm/chap06_07.html

    http://sealevel.colorado.edu/tidegauges.php

    If you don’t have time to read the first reference, think about what happens when you blow across the top of a straw with the other end immersed in your drink.

    This will affect sea level measurements. I have no idea whether the tide gauge measurements are adjusted for this, but, would seem to be what our friend is agitating about.

    Of course, it would be interesting to see data on sea level in areas with lower air pressure to see if there are actually bulges. Could the pressure signal move that fast through the ocean??

  • Lost and Confused // April 14, 2008 at 8:57 pm

    After reading several papers on sea levels, I am given the impression they lag behind temperature by ten to twenty years (the papers I read noted the possibilities of this lag, but none really looked into it). This makes me wonder, how well would sea levels correlate with temperature, and would it be possible to use sea levels as a temperature proxie?

    Also, I note it seems around 1990 the rate of sea level change increases greatly. I noticed the use of satellite measurement of sea levels started around the same time. How much of a bias could using satellite measurements have introduced, and is it meaningful? The timing could be coincidental, but what effort has been made to check?

    I apologize if the answers to these questions are already well known.

  • climatewonk // April 14, 2008 at 10:09 pm

    L&C, this musing about sea level rise and bias of the satellites sounds (suspiciously) like a post that one would find at CA. Have you tried posting it there? I’m sure there are many people there who would eat this stuff up.

  • Lost and Confused // April 15, 2008 at 4:45 am

    I do not care to post it at CA, as my question is on the methods used to account for possible bias. I have not seen anything at CA which would suggest the posters there would have this information, so I suspect the responses would only be to criticize the science, which would not help me understand anything.

    It is troubling to see an honest, and even necessary question raises suspicion. I asked here because I could not find any analysis of this issue, and hoped someone here might know of one. The closest I have seen is papers which seem to only use tide gauges, and still get the high numbers. This would suggest the problem, if there is one, would not be severe.

    However, I was hoping for something more conclusive.

  • Hank Roberts // April 15, 2008 at 2:36 pm

    > could not find any analysis

    Remember I can’t tell if you’re a bright gradeschooler, a retired PhD, or what, so I can’t phrase this answer without risk of sounding rude. But I’ll try:

    Here is a guide that will help.
    http://catb.org/~esr/faqs/smart-questions.html

    Basic principle (generally applicable): tell us what you did — what you used for search terms, where you tried them, who you asked, what you found.

    If you haven’t asked a local library reference desk, you really should. They can help far better than amateur readers like me.

    “Could not find any” isn’t enough information to give us an idea what you’re doing that is unproductive of any information. A good reference librarian hears this many times a day, and will smile when you say it.

    Once we know, we can help improve your search method.

    Eric Raymond’s last point is how to be helpful when answering. I try….

    I did one quick broad search:
    http://www.google.com/search?q=%22sea+level%22+%2Bsatellite+%2Bstation

    That’s basically a way to find articles like this one, to pick up better search terms:
    http://news.bbc.co.uk/1/hi/sci/tech/7195752.stm

    Search Scholar with the satellite names from the BBC article and you’ll find much on the whole long process of calibrating the new instruments and the old ones. Note the discovery that the planet is not a sphere, not even a smooth geometric oblate spheroid, has affected this whole area!

  • Lost and Confused // April 16, 2008 at 10:13 pm

    While the attitude of offering help is kind Hank Roberts, I am not particularly interested in that form of help. I am quite capable of using Google and the other normal methods. In this case Google does not do a good job. The example search you provided finds only one source addressing the issue (in the first fifty when I ran it), and that is only an abstract.

    I have managed to find a few papers which are relevant to this issue. These papers, while interesting, have barely touched upon it. I asked here not in the hopes of someone being able to find such papers for me, but rather on the chance someone already knew of them.

    I am quite willing to do my own work in finding sources of information when necessary. I just prefer to ask and see if other people know first, so as not to just retread their path.

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