Dave Burton wants to level the seas at WUWT

Over at WUWT, deniers are clutching at straws to continue to reject science in the face of all the "hottest evers". They really, really liked the last big El Nino in 1997-98, but they really, really dislike this current El Nino of 2015-16. It means they'll have to wait a while before they can start pointing to a drop in the surface temperature although Anthony Watts keeps jumping the gun and is excitedly telling his readers that a La Nina is just about here.

Here is some of what they got up to today, with a moan and lots of misdirection from a WUWT regular commenter called Dave Burton about another bane of deniers' existence - rising seas (archived here). But first, what's been happening...

It's not a trick - sea level rise is accelerating

Dave Burton is complaining about a NASA web page on sea level. The chart at the top on the right hand side is from satellite readings. Remember, deniers love satellites in areas where the readings are difficult and have wide error margins, like lower tropospheric temperature. They don't like satellite readings when the error margins are smaller and the results don't suit their purpose, like sea level change. Here is the chart Dave didn't like:

Figure 1 | Global sea level change 1993 to 2016. Source: NASA

NASA also showed a chart of sea level derived from tide gauge analysis from John Church and Neil White of the CSIRO, and didn't put up a big sign saying what the trend was. What Dave Burton didn't point out and maybe didn't even see, was that the chart only showed data to 2000. (I don't know why there isn't a plot using the most recent data.) Anyway, Dave probably missed seeing that because he didn't read the label in big letters, and didn't look at the x axis which was from 1870 to 2000:

Figure 2 | Global sea level change 1870 to 2000. Source: NASA with data from Church and White

So there's an entire article at WUWT all complaining that there wasn't a little sign up the top of the tide gauge data (to 2000) when there was a little sign about the satellite record (to 2016). Dave Burton's whiny WUWT article starts off with this piece of conspiracy theorising:

NASA’s tricky sea level newsletter
Anthony Watts / 6 hours ago April 7, 2016
Dave Burton writes:

Those NASA guys are tricky.

Click the “Update: Sea level change / Ocean rising at 3.42 mm per year” link in their latest Newsletter and you’ll see the big, bold “3.42 mm/yr” near the top of the web page, and two very similar-looking graphs of sea-level: one from satellites, and one from tide stations.

Since only one rate of sea-level rise is shown, the casual observer is likely to think that the same 3.42 mm/yr rate applies to both graphs. Here’s a screenshot:

Under the chart, Dave Burton says to "Look closer at the scales, and do the arithmetic". Pity he didn't take his own advice. The rate of change of the top chart is the rate of change for the period from 1993 to 2016. The rate of change of the bottom chart, or what Dave said he estimated, was for the period from "the late 1920s" to 2000. Those are different periods. Dave wrote:

Since the late 1920s it shows a slope of about 1.8 mm/yr, with no evidence of acceleration. But those tricky NASA guys scaled it to look like the slope is about the same as the first graph. It’s pretty obvious why they didn’t show a rate of sea-level rise for that graph.

Dave Burton's tricks

Dave Burton ranks highly on the conspiracy theory meter thinking NASA is out to trick deniers who don't know how to read a chart. What about the data? What tricks is Dave Burton trying to pull? :D

From the late 1920s to 2000 or so, the slope is 1.8 mm/year. From 1993 to 2016 the rise has been 3.42 mm/year. That means Dave is wrong. There is evidence of acceleration.

While deniers like to claim that the rate of sea level rise hasn't increased, if you go by what Dave Burton is saying, he's accepting there has been an acceleration of sea level rise. It used to be less than 2 mm a year and now it's up to 3.42 mm a year.

The paper by Church and White (2006) used tide gauge data through to 2001, with the data downloadable from the CSIRO website. In that paper the authors look at the data in different ways. For example, because there is a slope change, they wrote that you could: "do linear regressions on the two halves (1870– 1935 and 1936 –2001) of the record. The slopes are 0.71 ± 0.40 and 1.84 ± 0.19 mm yr 1 respectively". That 1.84 mm / year is close enough to Dave's estimate though the periods are slightly different.

The other thing is that Dave complains about adjustments to the tide gauge data. He wrote:

What’s more, the second graph is not really just from tide gauge data; it’s from tide gauge data inflated by a +0.3 mm/yr GIA “adjustment,” to subtract off the rate by which the sinking ocean floor is hypothesized to reduce sea-level rise. 

He reckons that this is wrong and that "The real rate of coastal sea-level rise from averaged tide gauge measurements is only about 1.4-1.5 mm/yr (under six inches per century), and that rate hasn’t increased since the late 1920s." He quoted from the website of some denier who referred to a NOAA tide gauge website, which reported "the absolute global sea level rise is believed to be 1.7-1.8 millimeters/year". That looks to be in need of an update. But more importantly, Dave saw fit to subtract the GIA adjustment from the NOAA data when it wasn't applied in the first place. He's a double adjuster.

There's sea level rise and there's sea level rise

There are at least two main reasons for people wanting to know about sea level rise:

• Coastal planning and management
• Monitoring global climate change

The thing is that for coastal planning, what people want to know is how much and how fast the sea will encroach on the coastline. They need to know the sea level relative to the local land. That will vary depending on where you are. The NASA website Dave was moaning about is for global climate change. (In case you missed it there's a big clue on the top left of the web page.) In that case the information needed is how fast are the oceans filling up? How quickly is ice melting. How quickly is the warmer water expanding? That's a different purpose and scientists need to have an indication of the change in the total volume of water in the world's oceans. That's why they allow for glacial isostatic adjustment.

Dave doesn't want to adjust the global tide or other sea level data to allow for glacial isostatic changes? What about barometric adjustments - does he approve of that? What about slippage where the tide gauge sinks or rises relative to the land surface? Does he want that adjusted for? Why doesn't he just pull a number out of the air and claim that the seas are falling? I think that probably what is happening, apart from Dave wanting to reject any and all climate science, is that he is mixing up the data and the purpose for which the data are used.

If he's concerned about the coast where he lives, then he'll need local information more than global. Different coastlines have markedly different rates of rising and sinking relative to the sea level. There's been a lot of research into what happens around the world.

On the other hand, John Church and Neil White were researching global change in their more recent 2011 paper (as in previous papers). In the introduction they explain:

Correctly estimating historical sea-level rise and representing global ocean heat uptake in climate models are both critical to projecting future climate change and its consequences. The largest uncertainty in projections of sea-level rise up to 2100 is the uncertainty in global mean sea level (GMSL) and thus improving estimates of GMSL rise (as well as regional variations in sea level) remains a high priority.

The fact that they were looking at global change, not local change, is why they allowed for glacial isostatic adjustment, and wrote:

Here, the ongoing response of the Earth to changes in surface loading following the last glacial maximum were removed from the tide-gauge records using the same estimate of glacial isostatic adjustment (GIA; Davis and Mitrovica 1996; Milne et al. 2001) as in our earlier study (Church et al. 2004). 

John Church and Neil White know what they are doing. They tested for all sorts of things and added that they even tested for the impact of the changes in dam storage, writing:

We tested the impact of correcting the tide-gauge measurements for terrestrial loading and gravitational changes resulting from dam storage (Fiedler and Conrad 2010). For the large number of tide gauges used in the period of major dam building after 1950 (mostly over 200), the impact on global mean sea level is only about 0.05 mm year−1 (smaller than the 0.2 mm year−1 quoted by Fiedler and Conrad, which is for a different less globally-distributed set of gauges). Tests of similar corrections for changes in the mass stored in glaciers and ice caps, and the Greenland and Antarctic Ice Sheets show that these effects have an even smaller impact on GMSL.

Glacial isostatic adjustment

If you're wondering about glacial isostatic adjustments, there's some information on the U Colorado sea level page. What it is is the mantle is still responding to the reduction in ice cover from around 20,000 years ago. Ice is heavy. When it melts, it means that some land surfaces pop up higher and the bottom of some oceans are falling relative to the Earth's centre. In other words, the oceans are getting bigger. If it wasn't for global warming, the sea level would be falling if there were no change in the actual volume of sea water. The CU Sea Level Research Group said in 2011 that "Including the GIA correction has the effect of increasing previous estimates of the global mean sea level rate by 0.3 mm/yr."

Meg Rosenburg submitted a video to the 2013 AGU student contest on the subject of glacial isostatic adjustment, which will give you some idea of the cause and effects:

If you have the time, there are 17 videos from the Permanent Service for Mean Sea Level 80th Anniversary Workshop on Sea-Level Science, including one specifically on glacial isostatic adjustment, by Giorgio Spada.

How much has the volume of ocean water changed?

You can see the chart in Figure 1 up top to see how much the volume of water in the ocean has changed in recent years. On the CSIRO website there's a data update of Church and White (2011), which goes up to 2013 for tide gauges and 2014 for satellite (altimeter), and is plotted below. The data are available at different levels of detail. I've just plotted the annual data. The faint grey lines are the upper and lower error margins for the tide gauge data. I've added linear trend lines for different periods as shown in the legend and on the chart. (Hover over the chart to see more detail):

Figure 3 | Global mean sea level from tide gauge and altimeter from Church and White (2011) update. Source: CSIRO.

It's obvious from the above that the rate of sea level rise has been increasing. However the CSIRO website has a caution and a reference to a workshop. I'm not sure what it means, but I'll copy it below:

We are currently attempting to more thoroughly evaluate the methodology and to improve the reconstruction so that it better represents the variability (Legresy et al., Workshop on Global and Regional Sea Level variability and change, Mallorca, Spain, June 2015).

Here is a video of an interview with John Church, at that workshop in Spain. (Added by Sou at 9:38 pm 8 April 2016)

More about sea level changes

As well as the videos I talked about earlier, there's the 2011 video with Jerry X. Mitrovica of Harvard, in which he addresses some of the false claims by fake sceptics. (He also says what many of us have found, that by investigating denier's claims, you can learn much.)

From the WUWT comments

Deniers are loopy. I don't think their brain works - or most of them don't permit their brains do any work. The deniers at WUWT are so intent on rejecting science that they stop thinking rationally. They don't check the claims other people make and they make up stuff without providing any evidence.

ferdberple

April 7, 2016 at 3:11 pm
strange that NASA uses satellites for sea level, but ignores them for temperature. since NASA is supposed to be about space, even has “space” in the name, why doesn’t it use satellites for both sea level and temperature? why does it still rely on ground stations that give only partial coverage of temperature?

Why hasn't ferdberple bothered to find out the reasons for himself. The answer is fairly obvious. There are a lot of challenges to overcome before satellites can be used to measure the temperature on the surface with the necessary accuracy or consistency. It is much easier and much more accurate to use thermometers that are located on the surface. (See this paper for a list of some of the problems.) As for using satellites to measure sea level change, the instruments used for that are quite different and the technology is well-developed (and relatively simple). There's a great introduction to the subject by François Parisot that you can listen to and watch. There's more here, from Aviso, which describes how the altimeters work.


Greg is suspicious and senses another conspiracy - and needs new spectacles (the tide gauge chart goes to 2000):

April 7, 2016 at 5:22 pm
It is also very suspicious why the CSIRO tide gauge graph cuts off in 1995 , just about the point where the satellite graph starts.
Does the CSIRO graph really end in 1995 or have they just truncated it avoid publishing two totally contradictory graphs, covering the same dates and avoiding commenting the fact is their text.

Rob Morrow is a full-blown conspiracy fruitcake, thinking all scientists are "charlatans and liars". What a fearful life he must live:

April 7, 2016 at 6:58 pm
The institution which achieved the greatest engineering triumph in human history has been co-opted by charlatans and liars. NASA’s the same as any other government institution, such that it often lives on as a vampire after it’s mandate has shrunk or vanished. How did NASA react to shrinking space exploration budgets? They adopted the climate scare narrative to keep that juicey government money flowing. 

Evan Jones decides to join in the conspiracy building game:

April 7, 2016 at 4:28 pm
Another hack you may or may not have noticed is that they selected a start point so as to ensure a predominantly positive PDO.

Seriously? The first satellite with an altimeter was Topex/Poseiden and it was launched on 10 August 1992, toward the end of the last warm phase of the PDO. The first full year of data was 1993, right when the graph commences. The PDO entered a warm phase in 1976, and shifted to a cool phase in 1998 after the El Nino (click to enlarge the chart below).

Figure 4 | Global mean surface temperature (GISTemp) with La Nina years (blue) and El Nino years (orange/tan) and the PDO index, with PDO phases marked. Data sources: GISS NASA (temperature), BoM(ENSO years), JMA (PDO index), Trenberth15 (PDO phases) 

Ray Boorman displays the logical fallacy of personal incredulity. He probably thinks that NASA faked the moon landing too. (How could anyone have measured the trajectory so precisely that the astronauts didn't end up in the next galaxy?) He's right that for most people they will only care about sea level if they live on the coast. And then only about how much the sea level will change where they live.

April 7, 2016 at 8:37 pm
If you live beside the ocean, the only tide gauge that matters is the one nearest you. Who gives a rip if 100 miles away the land is sinking fast, while you are enjoying steady sea levels? Like global average temperature, global average sea level is impossible to measure. Anyone who earns a living by making claims about either is a charlatan.

expat suffers the same ailment as Ray Boorman. If someone told him an earthquake was imminent he'd probably shrug and go stand in the middle of a bridge to prove he knew that scientific signals are all wrong.

April 7, 2016 at 5:39 pm
I heard part (couldn’t stand the whole thing) of an NPR broadcast the other day The interviewed scientist (and another sycophant NGO individual ) had developed a model (based on a model based on a model of a model) that the ocean would raise at least 1 meter or 6′ (moderator) in the next 100 years. 10 meters or 50′ (moderator) in 500. They then proceeded to learnedly discuss what a disaster that would be. No discussion of the accuracy of the initial models. A classic SISO operation but funded anyway. Gotta love taxpayers paying for quality stuff like this.

JohnWho asks the right question, though he could have looked up the answer himself. (It's both.)

April 7, 2016 at 3:07 pm
Are they saying the oceans are deeper
or just that the top of the oceans are higher?
/huh? 

daveburton belatedly writes something sensible as a comment. If he'd not been so intent on his conspiracy theory, claiming all the scientists were tricksters, he might have thought to be clear about this in his article. He might have even educated some of the WUWT ignoramuses:

April 7, 2016 at 4:21 pm
They’re saying that when the great northern ice sheets melted ca. 7K – 10K years ago, raising the oceans, the weight of that additional water caused the ocean floor to slowly sink — so slowly, in fact, that it is still sinking, to this day.
It certainly sounds reasonable. Prof. Peltier estimates, from computer models, that the ongoing sinking of the ocean floor causes an annual reduction in global sea-level of 0.3 mm/yr, and that seems to be the figure that just about everyone uses, though there’s no way to check it.
When NASA (and others) add that 0.3 mm/yr to sea-level measurements, the sum is potentially useful for water mass budget calculations, and that sort of thing, but it’s not truly sea-level. It’s what what sea-level probably would be, if the ocean floor were not sinking.

Scratch the comment I made about something sensible. Say Dave gets out his tape measure and stops Jack in the stairwell, measures him head to toe as being 6' tall. Then Jack step down to the next step, say it's a 6" step - Dave measures him again. Dave would then solemnly inform Jack that he's found Jack suddenly shrank six inches and is now only 5' 6" tall.  Jack would probably retort that Dave is a stairwell denier :) (Added by Sou sometime after re-reading what Dave Burton wrote.)

nobodysknowledge wants to be spoonfed. I doubt too many people from WUWT have gone to the NASA page, even after reading Dave Burton's article. Nor would most of them ever go to a science site, of their own volition.He or she has a point that the NASA page could have used more recent data. It might be that the scientists suggested they wait (given the caution on the CSIRO website).

April 7, 2016 at 3:18 pm
The fastest sea level rise measured from satellites has come the last 5 years with over 5mm pr year. This support the idea of accelleration. But tide gauge data is not presented for the last years. It is up to everybody to try to find out. It is a shame that the tide gauge presentation stops in 2000, as it is impossible to compare the last years with satellites. With all the effort laid down in all kind of measurements, why this neglect of tide gauges.
Latitude: Tide gauges show sea level rise, no doubt. The gauges (the ground) have vertical movements that are measured by gps. So it is easy to correct the measurements with the movement of the stations. 

Interesting too that there is a lot of faith put in satellite GPS but not so much in satellite altimeters.

adjacentworlds has lots of questions, most of which have answers if he or she cares to do their own research:

April 7, 2016 at 3:18 pm
To find the number for figuring out how much to adjust the satellite data for ocean floor dropping do the use the increase in altitude of the land? Or do they just reach behind them to pull a number out for adjustment?
Besides an adjustment for ground water extraction; shouldn’t they also have a number for sediment run off since this would also increase the volume in the oceans? Wouldn’t the lose of mass on the land slow the up welling of the land? It might be a micron or so every hundred years.

Willis Eschenbach did his duty as the keeper of honesty of scientists, or something. He considers himself exempt from any such code of behaviour, along with everyone else at WUWT. It's known as DDS or denier double standards.

April 7, 2016 at 3:36 pm
I went to their site, and I said I hoped the omission wasn’t deliberate … we’ll see how that plays out.
w.

Dan Pangburn scolds the WUWT-ers (that is who he's talking about, isn't it?)

April 7, 2016 at 4:03 pm
People can be ignorant, or stupid, or blinded by ideology but, worst of all, they can be intentionally deceitful.

Patrick Moore (@EcoSenseNow), who recommends a glass of glyphosphate a day as a pick-me-up /sarc, wrongly thinks that the oceans are outgassing more CO2 than they're absorbing. He failed arithmetic as well as science.

April 7, 2016 at 5:03 pm
I love how NASA always talks about warming seas expanding but never about warming seas outgassing CO2. It conflicts with the Ocean “Acidification” fabrication.

Nick Stokes provided evidence that the tide gauge data was consistent with the satellite altimetry data (the same as above), to which Rud Istvan (ristvan) weirdly responded with:

April 7, 2016 at 8:35 pm
NS, please provide some traceable evidence. Cause I looked hard and did not find any, exxept for the geostationary tide gauge/sat alt discrepancy discussed elsewhere. Verifiable data only.

Talk about nutters! Here's another. joelobryan realises he's in conspiracy theorists' heaven at WUWT and writes:

April 7, 2016 at 9:17 pm
NASA, NOAA, IRS, Dept of Labor/Bureau of Labor Statistics, DHS/Customs and Border Protection, Dept of Labor, EPA, FCC, …just to name a few of the politically corrupted agencies in the current US executive branch where the leadership are political appointees doing the political bidding of a politicallly corrupt President, who also happens to be a serial liar himself. Tom Karl and NOAA & NASA are just doing what Lois Lerner et al at the IRS were encouraged to do… that is lie for the cause, and subjugate your honor for the President’s ego.

References and further reading

Church, John A., and Neil J. White. "Sea-level rise from the late 19th to the early 21st century." Surveys in Geophysics 32, no. 4-5 (2011): 585-602. doi: 10.1007/s10712-011-9119-1 (open access)

Church, J. A., and N. J. White (2006), "A 20th century acceleration in global sea-level rise", Geophys. Res. Lett., 33, L01602, doi:10.1029/2005GL024826. (open access)
CSIRO sea level data website - with links to papers and data

Sea Level - on NASA's Global Climate Change website

Li, Zhao-Liang, Bo-Hui Tang, Hua Wu, Huazhong Ren, Guangjian Yan, Zhengming Wan, Isabel F. Trigo, and José A. Sobrino. "Satellite-derived land surface temperature: Current status and perspectives." Remote Sensing of Environment 131 (2013): 14-37. doi:10.1016/j.rse.2012.12.008 (open access)


From the HotWhopper archives

• Sea level for dummies - a video by MinutePhysics - November 2013
• WUWT readers are too scared to read about rising sea levels in National Geographic - November 2013
• Sea levels and global ice volumes over the past 35,000 years - October 2014
• The stupid: a prediction fulfilled at WUWT (and sea level) - January 2015