By Julius Sanks
A good way to distinguish between a reasonable climate discussion and fear-mongering is to examine the data. Fear-mongering will contain incomplete data, or none at all. The person mongering fear expects us to take the claim on faith. But we don’t have to. Sometimes it is ridiculously easy to check the claim.
A case in point is a recent article titled “How map of Britain will change in next 80 years as towns and cities fall into the sea” [sic] by Sam Elliott-Gibbs. Note the headline emotionally and deceptively implies they will “fall,” but the text goes on to discuss sea level rise based on air temperature. The article cites Climate Central to claim large areas of England will be under water by the year 2100. The only evidence provided is a couple of maps built on Climate Central’s interactive mapping tool. Climate Central uses topographic data to forecast flooding based on sea level, and blames sea level rise on climate change.
Climate Central bases its sea rise forecast on material that is mostly speculative. It cites the IPCC and a NOAA report. The NOAA report is actually a group effort involving several government agencies, none of which, except NASA, are directly involved in atmospheric science. The NOAA contribution comes from the National Ocean Service, not the atmospheric side. These sources extrapolate sea level rise from 2020 into the future.
But sea level change is something we can check and compare with Climate Central’s claims. We have used radar aboard satellites to measure sea level quite accurately since 1992, when the TOPEX/POSEIDON satellite was launched. That was the first time we could collect worldwide data. All earlier information is based on point, not worldwide, sources.
According to Climate Central, Peterborough, England will be on the coast in the year 2100. The town is 8 meters above current sea level, so that is how much the ocean must rise. Will it?
Climate Central claims the red area will be under water in 2100. 80 years of ocean rise? Probably not. Source: Climate Central.
According to NOAA’s Laboratory for Satellite Altimetry — unsurprisingly, not one of Climate Central’s sources — sea level rise is quite linear. The actual rate is 3.1 ± 0.4 millimeters per year. At that rate, it would take 2,580 years for the ocean to reach Peterborough. The ocean would have to rise 100 millimeters per year — more than 30 times faster than it actually does — to soak the town in 2100. It is worth noting the NOAA report does not predict anything near an 8 meter rise in 80 years. Its worst, and therefore least likely, case is 1 to 2 meters.
30 years of actual sea level rise. The colored bars indicate service lives of four satellites used to get the data. JASON-3 remains operational. Source: Laboratory for Satellite Altimetry.
Climate Central needs more than a fancy interactive map to make a convincing case sea level will change that drastically.
Julius Sanks is an engineer with experience developing weather satellites and weather forecasting systems for the US Air Force and NOAA.
This prediction too will fail like all the ones before it. Moving the end/cataclysmic date beyond what anyone today is expected to live is a common ruse that must be noticed by everyone since it keeps moving.
Apparently the sea rise halts in 2100. I moved the needle to 2150 and it stayed the same as 2100.
Or they haven’t programmed it to show sea level past 2100.
Or it’s all just stupid nonsense by lying nitwits.
Julius Sanks is an engineer.
Of course.
Thank you for sharing all that excellent, precise, analysis, Mr. Sanks.
Thank you!
🙂
The sea level rise is the Achille’s heel of the IPCC’s theory regarding the so called CAGW since the GPS-corrected tide gauges utterly disagree with the purported 4mm/year sea rise, in acceleration, that the IPCC satellites are recording.
Then if the 2022 sea level rise yearly rate is almost the same as that the first tide gauges recorded by the middle of the 19th century (end of the Little Ice Age) this means that the mountains glaciers and ice caps of the Antarctic and Greenland are not as catastrophically melting as the IPCC is claiming.
There is a tide gauge in Immingham on the coast near Hull, north of Peterborough. Its sea level records are almost steady since 1960:
Immingham, UK (NOAA 170-061, PSMSL 286) – SeaLevel.info
The interesting question is why the interesting questions are not answered.
1. What is the accuracy of satellite distance measurements?
2. Are different satellite measurements stitched together raw or after adjusting?
3. What measurements allow the assumption of static basin geometry or volume?
4, What is the magnitude of level change from transfer of water from land to ocean?
5. What mechanism explains a systematic difference between tide gauge and satellite measurements?
6. Why to so many tide gauges have a linear pattern of change over many decades?
7. What is the uncertainty of estimates of global land ice melting and accumulation?
8. Can changes in volume of ocean biota affect apparent sea level measurements?
9. Can changes in sedimentation rates create measurable ocean level changes?
10. Readers’ choice?
………
What poor research we have when a non-specialist geochemist onlooker like me can pose so many questions from memory.
Why have so many climate researchers forever responded to valid questions with no useful answers? IMore widely, it seems like a recent disease of the mind has affected a majority of our citizens to avoid a straight answer to a straight question.
So, Julius Sanks, author, are you going to try for answers here?
Geoff S
Some of those questions have been discussed, and even answered, in previous WUWT articles.
AndyHce,
Yes, I think I have read every WUWT post for the last decade.
There are “answers” that are simply repetitions of the findings of others and there are “answers” that give the method of derivation, its pros and cons and a genuine uncertainty estimate. There are many past articles claiming that satellite radar altimetry has a basic uncertainty of a couple of cm and there are others like the above Sanks post leading to an estimate of +/-0.4 mm/year.
These are clearly incompatible, not resolved by reading past WUWT posts and hence seeking answers by experts.
Geoff S
That is for the trend line, not individual measurements. However, when I see the uncertainty envelope for a trend line, I expect to see something with an approximately hyperbolic shape, not a single number or two linear boundaries paralleling the trend line.
My reading on discussions of the technicalities of sea level measurements (by tidal gage and satellite) say that the numbers I quoted are in the NOAA and/or NASA user instruction manuals. I must admit that I did not try to verify the quoted uncertainties by seeking out those manuals. However, none of the responders who disputed those articles’ conclusions disputed the quoted measurement uncertainties. Their arguments were all along the line that statistical analysis made those large uncertainties moot.
Sam Elliott-Gibbs! Attenti!
GREAT list, Mr. Sherrington. That was clearly compiled by a bona fide scientist. I seriously doubt that author Sam Elliott-Gibbs could answer any of them.
Well, Geoff, I’ve said what I have to say about Climate Central’s highfalutin claim of extreme sea level rise. Nor was I trying to explain why sea level changes; only wanted to check Climate Central’s work. I will say much of what is touted as sea level rise is actually land subsidence. But that’s not the point of what I wrote here. Since you asked me some specific questions, here are my replies:
1. What is the accuracy of satellite distance measurements?
• Per the graph, the accuracy is ± 0.4 mm/year. Unlike most environmental satellites, these use active radar to measure spacecraft altitude above the water, and that is used to compute mean sea level. I’m greatly oversimplifying how that is actually done. If you hit the link to the Lab for Satellite Altimetry, you will find a map of average worldwide sea level change. LSA is part of NOAA-NESDIS-STAR. STAR, an org I know well, is dedicated to figuring out how to use satellite observations to generate data useful to the public.
2. Are different satellite measurements stitched together raw or after adjusting?
• Note the graph shows overlap between satellites. Every instrument on every satellite is processed separately. The instruments are so sensitive those in a single production block often have unique characteristics that are addressed in ground processing. Their behavior also changes as they age. Ground processing addresses these issues. Sometimes data from more than one instrument are used to produce useful environmental data. Data from separate spacecraft are often compared as part of what’s called calibration/validation, and to provide continuity over time frames that exceed a particular spacecraft’s life.
3. What measurements allow the assumption of static basin geometry or volume?
• These spacecraft cannot do that. All they do is measure the distance to the water from orbit. Ground processing turns that into worldwide mean sea level (among other useful info such as wave height). The sea level alarmists don’t seem to publish such measurements, though the data might live in their sources. Their graphs look like the NOAA graph above, though they all show massive acceleration in sea level.
4, What is the magnitude of level change from transfer of water from land to ocean?
• Same as #3, irrelevant to the measurements I shared. Please keep in mind evaporation also dumps H2O onto the land. Also, changes to the ice packs will affect sea level. NASA & a German group operate the GRACE satellites. GRACE uses gravimetrics to measure that sort of thing. I don’t know how accurately they measure the water flow.
5. What mechanism explains a systematic difference between tide gauge and satellite measurements?
• Several reasons. Instrument error, especially for older data that was recorded manually. Land subsidence, as I mentioned above, which creates the appearance of sea level rise where it does not exist. Ditto for places where the land is rising, as it is doing where the glaciers have receded. Also, the data comparisons cannot identically match; a tide gauge is a point source, but the satellite will measure a grid, not a point.
6. Why to so many tide gauges have a linear pattern of change over many decades?
• Beats me. I know satellites. I don’t do much with in situ data. In situ and orbital data provide different types of understanding. That’s usually a good thing.
7. What is the uncertainty of estimates of global land ice melting and accumulation?
• Don’t know. The National Snow & Ice Data Center tracks this. I will say several years ago I used NSIDC & other data to compute how much the ocean would rise if all the land-based ice melted (floating ice does not change sea level). My number: about 61 meters. NSIDC said 70 at the time, but they didn’t show their work so I don’t know why we differ. But I’m guessing we just started with different estimates of ice or ocean area. The algebra is simple.
8. Can changes in volume of ocean biota affect apparent sea level measurements?
• Don’t know. I speculate the effect is small if it exists at all.
9. Can changes in sedimentation rates create measurable ocean level changes?
• Of course, but the effect is small. River deltas are tiny; the ocean is huge.
10. Readers’ choice?
• Don’t know what you mean by this.
The problem is, the satellite moves up and down depending on mascons encountered below, or what the average density is below. That varies with the depth of water and the kind of rocks not only in the oceanic crust, but in the mantle below. Furthermore, as the satellite changes speed, the horizontal sampling distance changes, meaning that the sensitivity to waves of different wavelengths changes. Over land, one can obtain a true altitude for the satellite. However, over the oceans, a gravity model is usually used to estimate the altitudes, unless GPS is used, but GPS has its limitations because differential GPS cannot be employed. With all of the uncertainty in the true altitude of the satellite above the centroid of the geoid, a continuously varying water surface has to be averaged! I don’t honestly trust that everything has been done properly because of the missing error bars in the data points.
Hmm. As I said above, JASON-3 (and at least some of the earlier radar satellites) does not depend on GPS alone. The ground team also gets accurate data about its orbit from the DORIS and LRA payloads. Look them up. DORIS ground stations are located worldwide, including polar and Pacific sites, and JASON is not the only satellite using it. So it’s not an estimate over ocean. It’s direct measurement from more than one source. BTW, RSAT requires an orbit altitude that is much tighter than needed for imagers or sounders. The team is well aware of that. When I worked NPOESS, which was scheduled to carry a radar altimeter for ocean measurements, the program viewed getting the bird to the proper altitude within tight limits as a serious launch challenge. Regarding accuracy, please keep in mind the graph I shared is a yearly average of millions of worldwide measurements. Not sure how useful an error bar would be on an average. Error bars are generally applied to statistical estimates, and an average of actual data is not an estimate. On that graph error bars would apply to the linear curve fit, but I don’t think it would add much. As I said, NESDIS-STAR is dedicated to accurate data. They do not publish “iffy” data. Regarding the data off the spacecraft, the ground team — actually all ground teams — check data quality as part of ground processing and tag bad data records before they go into the rest of the process to create useful info. Environmental satellite data processing is a complex and very structured process, unique to every on-orbit instrument, that would take too long to describe here. But every ground team I have ever seen puts a lot of effort into collecting and reporting accurate data. Why would they not do that? If you want to run the numbers yourself, here is where you can download JASON-3 and JASON-2 data to crunch your own numbers & check errors (this also applies to the question about 1-sigma error on the actual measurements). JASON-1 and TOPEX data are surely also available from NCEI. This is all I have to say about data accuracy.
https://www.ncei.noaa.gov/products/jason-satellite-products
I would disagree. Within a nominal 50 million years, a mountain range 3-5 miles high and thousands of miles long can be reduced to a peneplain near sea level. Consider the Gulf of Mexico where oil companies have drilled through sediments over 35,000 feet deep and less than 65 MY old. A rough back of used printer-paper calculation suggests that is an accumulation of about 0.2mm/yr, not accounting for volume changes with comminution. Then, consider the Amazon river delta, Mekong, Ganges, Nile, and Yellow rivers, etc., along with dust blown out of Mongolia and the Sahara and the amount being added to the oceans is likely in the range of what the satellites are claiming to be measured.
Consider that the lateral motion of tectonic plates is about an order of magnitude greater than the claimed rise in sea level.
These spacecraft are not designed to measure anything but sea the sea surface. Neither they nor the ground team care why the level changes. They just report from what they see.
Geoff, I answered all 10 of your questions in a long reply, but I’m not sure you can see it. I had to log back in to see it. Sheesh. Please confirm whether you (or others) can see my response. Thanks.
Julius,
Please accept my apologies for the hard wording of my queations. It is quite frustrating when trying for answers that I have been experimenting with options to improve answer rates.
Yes, you answers came through clearly. Thnak you for an uncommon response.
I shall not try to address all here, wrong forum, but we can start with Q1 “1. What is the accuracy of satellite distance measurements?” where you answered in part “Per the graph, the accuracy is ± 0.4 mm/year.”
I do not fully understand the mm/year bit, as distances are commonly given in mm only.
There are several corrections applied to altimeter raw data. There was a surge of interest in the topic of corrections in coastal areas around the 2010-2020s, but it is likely that instrument performance alone has improved since then. By how much, I do not know, hence I question.
One correction relates to air humidity in the path of the radar beam. Dr Roy Spencer wrote about this in
https://www.drroyspencer.com/2019/03/is-satellite-altimeter-based-sea-level-rise-acceleration-from-a-biased-water-vapor-correction/
He concluded in an afterthought that
“The altimeter correction made for water vapor is about 6 mm in sea level height for every 1 mm increase in tropospheric water vapor. The trend in oceanic water vapor over 1993-2018 has been 0.48 mm/decade, which would require about [6.1 x 0.48=] ~3 mm/decade adjustment from increasing vapor. This can be compared to the total sea level rise over this period of 33 mm/decade. So it appears that even if the entire water vapor correction were removed, its impact on the sea level trend would reduce it by only about 10%.”
It seems to me that uncertainty of humidity corrections alone is greater than your claimed accuracy, but I hate to write “seems to me” because a straight numerical comparison is clearer.
Can you please enlighten? Thanks Geoff S
I was fine with your questions. The mm/year in the graph is a worldwide average per unit time of 12 months, not any particular individual reading. Different units, but similar to kilowatts versus kilowatt-hours. Regarding accuracy, I take STAR at its word, because it works very hard to deliver accurate data. STAR also works data assimilation, i.e., figuring out how to use satellite data to initialize the supercomputer models the NWS uses for daily forecasting. That is very difficult science. STAR is an operational, not a research, organization. Their primary goal is accuracy. That said, the radar satellites don’t just carry radar. JASON-3 also carries a microwave radiometer to measure atmospheric humidity. It also carries DORIS, the Laser Retroflector Array, & GPS for precise orbital measurement. I think the team on the ground knows how to compensate for humidity as well as orbital perturbation. I have a lot of respect for Dr Spencer, but he has many caveats in the link you shared. Most importantly, he questions claims sea level is accelerating because of his questions about humidity; and the data he uses do not come from any of the satellites the LSA uses. I do not know anything about those other satellites, or the specific data Dr. Spencer was using.
Dear Mr Sanks
Imagine that I am an inhabitant owning a seashore-close villa. Which sea level measurements should I take in account with the aim to worry or on the contrary to find myself reassured about a possible future flooding of my home:
Why such huge discrepancies between the satellites and the planet’s many GPS-corrected tide gauges have not yet been solved ?
Don’t you think that the choice of the IPCC to keep only the satellite records and rejecting the tide gauges is risky regarding its credibility within some years when for example some recent studies have found that Pacific And Indian Ocean sea levels are rising much slowly, or not at all rising, than their projections.New Study: Pacific And Indian Ocean Sea Levels Rising ‘Much Slower Than Climate Model Predictions’ – Watts Up With That?
Jack, as I said above, tide gauges and satellites do not measure or report the same data. Gauges measure a point. Satellites measure a grid, based on the instrument’s resolution. Smaller is always better but the grid is never, ever, a point. It is useful to compare the data during analysis, but analysis must be aware of the technical differences in the measurements.
10. What is the one-sigma precision of individual satellite distance measurements?
But, but, but, didn’t Obama proclaim, Canute-like upon nomination in 2008 that it “was the moment when the rise of the oceans began to slow and our planet began to heal”? What happened?
This low estimate suggests at least 18.1 billion tons of water (14.5 water, 3.7 chemically transformed by photosynthesis) is being retained by the land biosphere, more than 18.1km^3 per year of water. That’s 10% of total annual glacier melt and possibly more than melt from climate change.
Gravimetric data shows substantially more water be retained by land. The 18.1 billion tons implied by just photosynthesis is only 23.5% of the additional 77 km^3 being retained by land each year, which is more than half of total annual glacier melt.
https://twitter.com/aaronshem/status/1594718627525283840?s=46&t=c-zZlljW5DmZwyeSRwM14g
https://www.pnas.org/doi/full/10.1073/pnas.1704665115
https://www.nature.com/articles/ncomms13428
aaron,
The 2010-11 shift of water onto the Australian land mass appears to have been large enough to be measured. Maybe.
Question is, how many experts in sea level rise predicted beforehand that this mechanism could be significant or observable?
Geoff S
I did at least as recently 2014ish, but I’m not an expert. Carbon sink implied a big shift.
As NASA GISS researcher Vivien Gornitz reported in the Science Brief “Sea Level Rise, After the Ice Melted and Today” back in 2007 (and since
archivedscrubbed from the GISS website), sea level was 4 to 6 meters higher during the warmest phase of the prior interglacial period 125,000 years ago. At the current rate of sea level rise, we have another 2,000 years of sea level rise if it follows the pattern of the last interglacial, which it very likely will not. There is a lot of variance between the several cool/warm glacial/interglacial cycles of the last 800,000 years. If adding CO2 to the atmosphere will slow the return to the next glacial period, we should be doing everything we can to emit more CO2 because glacial periods are devastating to flora, fauna, and humans.I would question the use of the word “accurately” in the description of satellite-derived sea level estimates. Note in particular the region of the included NOAA graph showing the overlap between Topex and Jason 1, 2002-2004. The absolute maximum difference in the two curves (~2mm) is about the same magnitude as the tide gauge annual average increase in SL and, similarly, about the same magnitude as the current difference between the regression line prediction and the most recent satellite estimates. Kip Hansen [on WUWT] has previously critiqued the probable performance of the satellites based on the design specifications. My recollection is that it appears that more accuracy and precision are being claimed than is warranted. In any event, as is all too often the case, there are no error bars provided for the data on the NOAA graph, or for the derived linear trend line.
The rise is not equal everywhere on Earth, both because of different rates of subsidence and uplift of coastal land and, because gravity varies over time and location, there are lumps and depressions over the oceans that are of no consequence to people living in coastal areas. Yet, the satellite average takes into account what is happening in the middle of the oceans. The established tide gauge stations around the world are superior for answering the question of what might happen in the future because the measurements are taken where the results actually matter.