Christopher Pearson foolishly relies on Ian Plimer for an article claiming that the link between global warming and sea level rises is "bad science":
Plimer notes that "the tidal measuring station at Port Adelaide is sinking, thereby recording a sea level rise". The same is true of many other areas of subsidence, a fact apparently lost on most contemporary oceanographers. "If there is a sea-level rise we would expect every atoll in every ocean to be inundated. But we don't see this. We would expect harbours around the world to record a sea level rise. This is not recorded. So something is seriously wrong with the catastrophist dogma."
Most contemporary oceanographers aren't aware that the land could be sinking? Apparently Pearson and Plimer think that oceanographers are idiots. I guess its possible but maybe Plimer (or Pearson) could have checked what the oceanographers actually say?
Here's TAR 11.1:
"Mean sea level" at the coast is defined as the height of the sea with respect to a local land benchmark, averaged over a period of time, such as a month or a year, long enough that fluctuations caused by waves and tides are largely removed. Changes in mean sea level as measured by coastal tide gauges are called "relative sea level changes", because they can come about either by movement of the land on which the tide gauge is situated or by changes in the height of the adjacent sea surface (both considered with respect to the centre of the Earth as a fixed reference). These two terms can have similar rates (several mm/yr) on time-scales greater than decades. To infer sea level changes arising from changes in the ocean, the movement of the land needs to be subtracted from the records of tide gauges and geological indicators of past sea level. ...
We estimate that global average eustatic sea level change over the last hundred years is within the range 0.10 to 0.20 m (Section 11.3.2). ("Eustatic" change is that which is caused by an alteration to the volume of water in the world ocean.)
In other words, the basis of Plimer's claim that there has been no sea level rise is
(1) ignoring the scientific evidence; and
(2) making up his own evidence.
Pearson quotes Plimer:
"Subsidence can play some cruel tricks ... This is what is happening in many Pacific Ocean atoll nations and this subsidence produces an apparent sea-level rise. We naughty fossil-fuel burners are not causing sea levels to rise. Some, but not all, of the Pacific Ocean atoll nations are sinking as part of a normal geological process," he says.
Samir Patel in Nature 440:734-736:
A mean sea-level rise in Tuvalu of just 20 to 40 cm in the next
hundred years would significantly increase the frequency and depth of
saltwater flooding and accelerate coastal erosion. It would threaten
the Tuvaluans' food and housing, poisoning the pits where they grow
giant swamp taro plants and undermining buildings. It could make the
country simply uninhabitable.
What's happening to sea levels in Tuvalu?
There are two tide gauges in Tuvalu. One, operated by the University
of Hawaii until 1999, sits on a small concrete wharf behind the
three storey Taiwanese-built government building. In 1993, the NTC
installed a more modern and accurate gauge a few kilometres north at
the country's only deepwater wharf. One of twelve in the South
Pacific, this gauge should in theory provide quantitative confirmation
that Tuvalu is being engulfed, as the king tides and the wet cuffs of
my trousers suggest.But in 2000 an NTC analysis reported a negligible increase of 0.07 mm
a year over the past two decades from the University of Hawaii gauge,
and a drop in sea level from the seven years of NTC data. It was clear
that the El Nino/Southern Oscillation (ENSO), which drives down sea
level in the western Pacific, affected both of these records. And the
international environmental group Greenpeace asked John Hunter, a
climatologist at the University of Tasmania, to have another look at
the data. When he adjusted for ENSO and the vertical movement of the
Hawaii gauge, which is thought to be sinking, Hunter found a sea level
rise of around 1.2 mm a year.Hunter's figure is consistent with the global estimate of the
Intergovernmental Panel on Climate Change (IPCC): 1 to 2mm a year for
the twentieth century. But the Tuvalu estimates are based on a couple
of gauges and a reasonably short record, points out John Church of the
Commonwealth Scientific and Industrial Research Organization (CSIRO)
in Hobart, Tasmania, who was one of the lead authors of the chapter on
sea level in the IPCC's most recent assessment.Recently, Church and his CSIRO colleague Neil White have moved to a
more regional approach. They have combined records from tide gauges
around the world, some of which date back as far as 1870, with
satellite altimeter data to assess regional variation in sea-level
rise. Their results for the South Pacific are in line with the Hunter
and IPCC estimates, and they are now looking specifically at Tuvalu
and other small island nations.
Plimer doesn't seem to have bothered looking at the scientific evidence, but Pearson fell for it, as did the always gullible Tim Blair.
(Via Ken Brook).
These people wholeheartedly believe that "skepticism" is ALL about "challenging the people who actually know something" ("mindlessly" challenging, much of the time).
They don't even seem to care that it makes them look foolish. In fact, in most cases, I doubt they even realize it.
I agree that the definition du jour of skepticism is disbelief of expert opinions or mainstream science, rather than critically examining all information and theory for evidence of weakness.
It would be amusing to see what would happen if they were to apply a small percentage of the same "skepticism" to each other's arguments!
Samir Patel found that in Tuvalu "... in 2000 an NTC analysis reported a negligible increase of 0.07 mm a year over the past two decades from the University of Hawaii gauge, and a drop in sea level from the seven years of NTC data. It was clear that the El Niño/Southern Oscillation (ENSO), which drives down sea level in the western Pacific, affected both of these records."
HOW TIRESOME OF THE ENSO, SO EXPUNGE IT. DONE!
"And the [WHOLLY OPEN MINDED NO AXE TO GRIND] international environmental group Greenpeace asked John Hunter, a climatologist at the University of Tasmania, to have another look at the data. [HOW MUCH DID THIS COST? HOW MANY CONSULTANTS DISAPPOINT THEIR SPONSORS' EXPECTATIONS?] When he adjusted for ENSO and the vertical movement of the Hawaii gauge, which is thought to be sinking, Hunter found a sea level rise of around 1.2 mm a year." PURE SCIENCE AGAIN - ABOLISH ENSO AND THE SINKING.
If some islands are in a sea level 'hollow' others must be in a 'mound'. The Maldives perhaps? Personally I'm watching where a nearby estuary backs up to a waterfall. Within a decade I expect the base of the falls to be salty.
Tim Curtin: [HOW MUCH DID THIS COST? HOW MANY CONSULTANTS DISAPPOINT THEIR SPONSORS' EXPECTATIONS?]
Well, obviously, only those hired by the petroleum industry can be relied on to fearlessly report the truth.
Plimer's another geologist who's forgotten to be modest about his ability in the hard sciences, but in his case there's also the collateral damage your brain must suffer if you spend too much time grappling with Creationists. That perhaps encourages him to underestimate the intelligence of others. Anyway it's dirty work that Plimer apparently relishes, so some blame probably attaches here.
Tim, leaving Pearson aside, what exactly in the above has Plimer said that you consider to be untrue?
"But in 2000 an NTC analysis reported a negligible increase of 0.07 mm a year over the past two decades from the University of Hawaii gauge, and a drop in sea level from the seven years of NTC data."
So either no change, or a fall.
""And the international environmental group Greenpeace asked John Hunter, a climatologist at the University of Tasmania, to have another look at the data. When he adjusted for ENSO and the vertical movement of the Hawaii gauge, which is thought to be sinking, Hunter found a sea level rise of around 1.2 mm a year."
Well that's hardly physical evidence is it, especially when it contradicts physical measurements like the NTC data. In fact, the data supports Pilmer, whatever Hunter's "corrections" might suggest.
And what precision! 1.2mm! You can make an adjustment accurate to one tenth of a millimetre, a scale beyond imperceptible?
Oh, and to make it more specific, you say:
"In other words, the basis of Plimer's claim that there has been no sea level rise is..."
Where does Plimer claim that there has been no sea level rise?
How does Greenpeace, which received millions of dollars from Enron, a fossil fuel company, keeps its hands so clean when just a few thousand paid by another fossil fuel company to another organization damns the entire scientific careers of anyone vaguely associated with it?
Or is it just the case that this nasty fossil fuel-based smear keeps the smoke in the eyes of true believers?
There have been three independent studies which have shown no significant sealevel rise at Tuvalu. Are they all idiots because they fail to get the "right" answer? Did they all magically join a conspiracy to hide the truth?
Sorry for the multiple posts, but to be fair to Hunter, he notes in his paper that the uncertainties are "undesirably large", however that doesn't undermine (and perhaps amplifies) my earlier remarks.
James posted above; "Well that's hardly physical evidence is it, especially when it contradicts physical measurements like the NTC data. In fact, the data supports Pilmer, whatever Hunter's "corrections" might suggest.'
Corrections are made to scientific measurements ALL the time -- to null out larger effects that would otherwise "swamp" the much smaller effects that are being measured.
Does this mean that the raw (uncorrected) data more acurately respresents the effect in question? Of course not.
An experiment to detect "gravity waves" is perhaps the best case in point. The effect (size change) that gravity waves are expected to have on material objects is miniscule compared to that caused by almost everything else: expansion and contraction due to temperature changes, earth quakes(!!), even vibrations due to traffic. So the system must be isolated and any interference subtracted out.
If one is looking at a trend in sea level rise over a relatively long period of time (years), one simply HAS to correct for short term effects like ENSO. If one has NOT taken such things into consideration and made appropriate corrections, one's conclusions are of dubious value.
Y'know, I don't see anyone disputing that. But if you're going to extrapolate from seven years of data in Tuvalu to a trend in mean global sea levels, you need to take into account factors such as ENSO and subsidence that would cause the two to differ. For all that Tim Curtin impunes Greenpeaces motives, he doesn't explain what is wrong with their methodology. In contrast Tim Lambert has succinctly summed up what is wrong with Ian Plimer's methodology.
"These people wholeheartedly believe that "skepticism" is ALL about "challenging the people who actually know something" ("mindlessly" challenging, much of the time)."
As I posted before, from the Colbert Report: "It is well known that reality has an antiBush agenda."
"It would be amusing to see what would happen if they were to apply a small percentage of the same "skepticism" to each other's arguments!"
Repeating old joke, at risk of injuring the tender of sensitivities: James Hansen doesn't come down to their jobs and show them how to put the dicks in their mouths.
"Where does Plimer claim that there has been no sea level rise?"
"If there is a sea-level rise we would expect every atoll in every ocean to be inundated. But we don't see this. We would expect harbours around the world to record a sea level rise. This is not recorded."
What else could that mean?
John A. claims that Enron donated MILLIONS to Greenpeace. Is there any sourcing for this or is it just another Maksimovich where we are going to have to go around the bush waiting for him to tell us that he doesn't have a clue where the source for that little bon mot was?
Laurence Jewett is talking about a slightly different case than I am (extrapolation to a long-term trend instead of extrapolation to a global trend), and the corrections necessary will likely be slightly different. But corrections are necessary.
... Er, make that two decades. Nonetheless, probably still not long enough that the effects of ENSO can simply be ignored.
I'm not particularly inclined to trust anything coming out of greenpeace; they do indeed have an axe to grind. But one doesn't have to trust greenpeace to see that Ian Plimer is spewing crap.
The problem is that the best data is from satellites http://sealevel.jpl.nasa.gov/ (http://sealevel.jpl.nasa.gov/science/time-series-data.html for some cool animation) and it does not go back nearly far enough to be a climatological record. What we have are tidal gauge records which have to be corrected for subsidence, el Nino, and more.
Lookit all the projection and mixing-up of tactics from the underinformed puppet/rube, John A:
How does Greenpeace, which received millions of dollars from Enron...[offset] just a few thousand paid by another fossil fuel company to another organization damns the entire scientific careers of anyone vaguely associated with it?
Aside from being a bullsh*tty big fat wish, tell us how the scientific careers of anyone vaguely associated with your totemic hockey stick are faring under the character assault on your site, John.
Or is it just the case that this nasty fossil fuel-based smear keeps the smoke in the eyes of true believers?
Usually when you rubes use the 'religion' or 'true believer' canard, you don't mix metaphors - it just stands alone (e.g. 'smoke' isn't needed). Could it be this particular canard is losing traction and you need to kick it up a notch?
There have been three independent studies which have shown no significant sealevel rise at Tuvalu. Did they all magically join a conspiracy to hide the truth? ?
Well, the contention at your little character assassination site is that there are all kinds of conspiracies out there wrt scientists and their findings. So why are you pooh-poohing a conspiracy in this case when you so eagerly trot out your colorful tinfoil hat on other convenient occasions?
Yer a hoot, son.
Best,
D
"A cautious estimate of present long-term relative sea level change at Funafuti, which uses all the data, is a rate of rise of 0.8 +/- 1.9 mm/year relative to the land. This
indicates that there is about a 68% probability of the rate of rise being between -1.1 and 2.7 mm/year.
A less cautious estimate, based on the rejection of data affected by El Nino / Southern Oscillation (ENSO) events, is a rate of rise of 1.2 +/- 0.8 mm/year relative to the land.
This indicates that there is about a 68% probability of the rate of rise being between 0.4 and 2.0 mm/year.
Although these estimates of relative sea level change at Funafuti are not directly comparable with the IPCC estimate of global average sea level rise during the 20th century (1 to 2 mm/year; Church et al., 2001), it is interesting to note that they are of similar magnitudes.
(...)
It is also shown that the uncertainty in sea level trend estimated from the data collected by NTF since 1993, using a modern acoustic tide gauge, is +/- 13.7 mm/year, indicating that this data set is presently of little value for the investigation of long-term sea level rise. The large uncertainty is caused mainly by the relative shortness of the record and the effect of ENSO-related events which occur every few years.
Even using the full 24 years of available data, the uncertainties in estimated trend are presently undesirably large."
Source: http://staff.acecrc.org.au/~johunter/tuvalu.pdf
Did you bother to look at the scientific evidence?
It would appear our geologist friends have not heard of satellites (or prehaps they don't trust them any more after the MSU stopped providing a crutch for their faith). The results from Topex/Jason are unambigous...
http://sealevel.colorado.edu/ .
david, that site is fantastic. They have an "interactive sea surface wizard" that charts the data for a given location:
http://sealevel.colorado.edu/cgi-sealevel/wizard.cgi
If you click around a few random locations, it gives a feel for the wide variation in patterns of sea level change.
Tuvalu is Long: 183 & Lat: -8. Using guassian smoothing with the default 60 day period, you can nicely see the annual (seasonal) cycle. Increasing the smoothing to 180 days gives perhaps an even better picture. The most striking feature is the fall in sea level associated with the 1998 El Nino. Apart from that, there doesn't appear to be any positive or negative trend at all.
I was about to direct a few people on here to my analysis of sea level at Tuvalu, but find Wolfgang Flamme had already done so -- thanks Wolfgang! It addresses issues such as "a drop in sea level from the seven years of NTC data" and shows why sea-level data from one site covering only a few years gives us no information about long-term sea-level rise. We also have a paper in Global and Planetary Change (in press) which describes sea level at tropical Pacific and Indian Ocean islands. For Tuvalu, using a more complete data set and the integration of satellite altimeter data, we find the same long-term rate of rise (within our estimated uncertainties). Overall, we find sea level is rising significantly in the Indian and Pacific Oceans.
John A notes the "there have been three independent studies which have shown no significant sealevel rise at Tuvalu". Perhaps he'd like to tell us which these are.
Finally, let's address issues like "HOW MUCH DID THIS COST? HOW MANY CONSULTANTS DISAPPOINT THEIR SPONSORS' EXPECTATIONS?" (i.e. was my research tainted by support from Greenpeace?). This is well covered at: http://people.aapt.net.au/~johunter/greenhou/greenhouse_industry.html which describes an earlier, very clumsy, attempt to make a similar imputation.
James: Statements like "there doesn't appear to be any positive or negative trend at all" aren't at all helpful (except to the contrarians!). If you can't provide a quantitative estimate (with uncertainty) of the trend, then you shouldn't say anything about it at all.
James: it also helps if you get the position correct. The location of the NTC tide gauge at Funafuti, Tuvalu, is at 8 deg 30' S, 179 deg 13'E (NOT 183 deg).
Hi John. Indeed i gave the wrong longtitude - it is 179 deg, which is what I was looking at when I made my comments. 183 deg is, as I'm sure you know, is Port Arthur, which I also had a look at (lat -35), for its topicality.
I disagree that it is unreasonable to eyball such a chart, and i stand by my statement that there doesn't appear to be a trend. (In contrast there is a clear upward trend at Port Arthur, for example).
I'll have a closer look at your paper.
Of course, this is the same James that eyeballed the paragraph from Plimer in my post and could see where Plimer was denying that the sea level was rising.
Why do deniers always go for a single factor explanation, and assume that the specialists in the field also have a (wrong) single factor explanation? Nice to see the work that is out there, and demonstrating that subsidence (the basis for atoll formulation), thermal expansion, ENSO, and icemelt can all be considered simultaneously. If they all go in the same direction, this will definitely be bad news for the land in that area. How stable is the English coast? Sea level rise is threatening some of the engineering marvels of the great railway boom, so plan your trips now.
http://www.guardian.co.uk/science/story/0,,1790048,00.html
I comment on:
I disagree that it is unreasonable to eyball such a chart, and i stand by my statement that there doesn't appear to be a trend.
and
Why do deniers always go for a single factor explanation, and assume that the specialists in the field also have a (wrong) single factor explanation?
I have commented on this many times. Denialists are Googlers with little or no education in the field they comment on (and often no education in the Natural Sciences).
It is, therefore, no problem for denialists to Google a chart that looks like it agrees with their narrow ideology, point to it, say "A-ha!!!!!!!!!!!!!!!!!", then start calling everyone who disagrees with them widdle namie-names.
[Caveat: I'm not saying all here have adopted every point of the above strategy, but the big picture is clear]
Best,
D
Sure. Problem is, in the context of this conversation people are going to assume you're talking about a 1.2 mm / year trend. And my eyeballs are not near good enough to distinguish a 1.2 mm / year trend from a stationary trend in that data. (Look at the scale.) And unless the noise in that graph can be better characterized than ENSO / not ENSO, even statistical analysis is not going be able to provide anything of use to this debate.
"there doesn't appear to be a trend"
which is not a useful statement without an indicator of the statistical power of the study.
OK, so if we look at John Hunter's "cautious" estimate of the trend, it's "a rate of rise of 0.8 +/- 1.9 mm/year relative to the land". That's not significantly different from zero.
Tim - Jennifer Morohasy has posted this:
http://www.jennifermarohasy.com/blog/archives/001424.html
Seems Vincent Grey is using it too.
James:
> OK, so if we look at John Hunter's "cautious" estimate of the trend,
> it's "a rate of rise of 0.8 +/- 1.9 mm/year relative to the land".
> That's not significantly different from zero.
I notice you only quote one estimate -- I actually gave two in my report -- the second one was a "less cautious estimate" of 1.2 ± 0.8 mm/year. You may want to argue about which is the better estimate, but of this latter one I commented "this indicates that there is about a 68% probability of the rate of rise being between 0.4
and 2.0 mm/year". In the paper that is presently in press in Global and Planetary Change, we use the most recent data (therby getting a longer record), more comprehensive information on vertical land movements and information from nearby sites and satellite altimeters, and come up with a best estimate of long-term trend in relative sea level at Tuvalu of 2 +/- 1 mm/year -- which is significantly positive at the 97% confidence level.
John, I'm aware of the second "less cautious" estimate. I don't really understand how you can frame confidence interals as being "cautious" and "less cautious". I would have thought that uncertainty would be expressed in any confidence interval.
But leaving that aside, even acepting the result of your new paper, the quoted sea level rise is imperceptible, especially in the context of the high variability of the tidal (or satellite) record. That is pretty much Plimers' point: there is no dramatic (or even perceptible) rise in sea levels
James: having said that you "don't really understand how you can frame confidence interals as being 'cautious' and 'less cautious'", you then feel that it is useful to describe the sea-level rise qualitatively as not "dramatic (or even perceptible)" -- what on earth does this mean?
The rise is certainly "perceptible" (otherwise we wouldn't be able to measure it), especially if we use longer and more records (as in our Global and Planetary Change paper). As for "dramatic" -- that is pure value judgement -- however, sea-level rise of that order is probably mainly responsible for the current predominance of shoreline recession along the world's coastlines, which is typically tens of meters per century -- if you live that close to the shore, then I guess you would call it "dramatic".
And that's not counting projections during this and coming centuries .....