However, other analyses show the opposite…
Correcting estimates of sea level rise
Acceleration in sea level rise far larger than initially thought
The acceleration in global sea level from the 20th century to the last two decades has been significantly larger than scientists previously thought, according to a new Harvard study.
The study, co-authored by Carling Hay, a post-doctoral fellow in the Department of Earth and Planetary Sciences (EPS), and Eric Morrow, a recent PhD graduate of EPS, shows that previous estimates of global sea-level rise from 1900-1990 had been over-estimated by as much as 30 percent. The report, however, confirms previous estimates of sea-level change since 1990, suggesting that the rate of sea-level change is increasing more quickly than previously believed. The new work is described in a January 14 paper published in Nature.
“What this paper shows is that sea-level acceleration over the past century has been greater than had been estimated by others,” Morrow said. “It’s a larger problem than we initially thought.”
“Scientists now believe that most of the world’s ice sheets and mountain glaciers are melting in response to rising temperatures.” Hay added. “Melting ice sheets cause global mean sea level to rise. Understanding this contribution is critical in a warming world.”
Previous estimates had placed sea-level rise at between 1.5 and 1.8 millimeters annually over the 20th century. Hay and Morrow, however, suggest that from 1901 until 1990, the figure was closer to 1.2 millimeters per year. But everyone agrees that global sea level has risen by about 3 millimeters annually since that time, and so the new study points to a larger acceleration in global sea level.
“Another concern with this is that many efforts to project sea-level change into the future use estimates of sea level over the time period from 1900 to 1990,” Morrow said. “If we’ve been over-estimating the sea-level change during that period, it means that these models are not calibrated appropriately, and that calls into question the accuracy of projections out to the end of the 21st century.”
To obtain their improved estimate of 20th century global sea level, Hay and Morrow approached the challenge of estimating sea-level rise from a completely new perspective.
Typically, Hay said, estimates of sea-level rise are created by dividing the world’s oceans into sub-regions, and gathering records from tide gauges – essentially yard-sticks used to measure ocean tides – from each area. Using records that contain the most complete data, researchers average them together to create estimates of sea level for each region, then average those rates together to create a global estimate.
“But these simple averages aren’t representative of a true global mean value” Hay explained. “Tide gauges are located along coasts, therefore large areas of the ocean aren’t being included in these estimates. And the records that do exist commonly have large gaps.”
“Part of the problem is related to the sparsity of these records, even along the coastlines,” Morrow said. “It wasn’t until the 1950s that there began to be more global coverage of these observations, and earlier estimates of global mean sea-level change across the 20th century were biased by that sparsity.”
“We know the sea level is changing for a variety of reasons,” Hay said. “There are ongoing effects due to the last ice age, heating and expansion of the ocean due to global warming, changes in ocean circulation, and present-day melting of land-ice, all of which result in unique patterns of sea-level change. These processes combine to produce the observed global mean sea-level rise.”
The new estimates developed by Hay and Morrow grew out of a separate project aimed at modeling the physics that underpin sea-level “fingerprints” – explainer from previous story.
“What we were interested in – and remain interested in – was whether we can detect the sea-level fingerprints we predicted in our computer simulations in sea-level records,” Morrow said. “Using a global set of observations, our goal has been to infer how individual ice sheets are contributing to global sea-level rise.”
The challenge, Hay said, is that doing so requires working with a “very noisy, sparse records.”
“We have to account for ice age signals, and we have to understand how ocean circulation patterns are changing and how thermal expansion is contributing to both regional patterns and the global mean,” she explained. “We try to correct for all those signals using our simulations and statistical methods, then look at what’s left and see if it fits with the patterns we expect to see from different ice sheets.”
“We are looking at all the available sea-level records and trying to say that Greenland has been melting at this rate, the Arctic at this rate, the Antarctic at this rate, etc.” she continued. “We then sum these contributions and add in the rate that the oceans are changing due to thermal expansion to estimate a rate of global mean sea-level change.”
To their surprise, Hay said, it quickly became clear that previous estimates of sea-level rise over most of the 20th century were too high.
“We expected that we would estimate the individual contributions, and that their sum would get us back to the 1.5 to 1.8 mm per year that other people had predicted,” Hay said. “But the math doesn’t work out that way. Unfortunately, our new lower rate of sea-level rise prior to 1990 means that the sea-level acceleration that resulted in higher rates over the last 20 years is really much larger than anyone thought.”
###
[UPDATE] My sub-oceanic source has sent me a copy of the actual study. Here is the abstract:
Estimating and accounting for twentieth-century global mean sealevel (GMSL) rise is critical to characterizing current and future human-induced sea-level change. Several previous analyses of tide gauge records1–6—employing different methods to accommodate the spatial sparsity and temporal incompleteness of the data and to constrain the geometry of long-term sea-level change—have concluded that GMSL rose over the twentieth century at a mean rate of 1.6 to 1.9 millimetres per year. Efforts to account for this rate by summing estimates of individual contributions from glacier and ice-sheet mass loss, ocean thermal expansion, and changes in land water storage fall significantly short in the period before 19907. The failure to close the budget of GMSL during this period has led to suggestions that several contributions may have been systematically underestimated8. However, the extent to which the limitations of tide gauge analyses have affected estimates of the GMSL rate of change is unclear. Here we revisit estimates of twentieth-centuryGMSL rise using probabilistic techniques9,10 and find a rate of GMSL rise from1901 to 1990 of 1.260.2 millimetres per year (90% confidence interval). Based on individual contributions tabulated in the Fifth Assessment Report7 of the Intergovernmental Panel on Climate Change, this estimate closes the twentieth-century sea-level budget. Our analysis, which combines tide gauge records with physics-based and model-derived geometries of the various contributing signals, also indicates that GMSL rose at a rate of 3.060.7 millimetres per year between 1993 and 2010, consistent with prior estimates from tide gauge records4. The increase in rate relative to the 1901–90 trend is accordingly larger than previously thought; this revision may affect some projections11 of future sea-level rise.
Regards to all,
w.
And today’s headline, worldwide, reads: The sea is rising faster than we thought, experts say. That is as far as most readers will dig into the story, though I doubt for those who choose to read the article that there will be a link to the full text, let alone the abstract.
And yet, even the guys on Bondi beach didn’t see it coming.
http://media.zenfs.com/en_us/News/Reuters/2014-11-13T074931Z_1448044381_GM1EABD17SO01_RTRMADP_3_AUSTRALIA-PROTEST.JPG
Good time for a tsunami.
For beaches like this picture, where the beach is flat and high and low tides really swing the water line, if sea level has risen 8 inches over the last 100 years like they say then this beach would have looked A LOT different 100 years ago.
Ok, got it. There was just a missing +-character and I missed closing blockquote
But what about these sealevel stats:
http://jeremyshiers.com/sealevels/20140814/rlr_monthly/summary_rlr_monthly.html
“But these simple averages aren’t representative of a true global mean value”
This is truly bizarre. Why would anyone care about their abstract global mean value when the only thing that is potentially important is measuring sea level rise around coastlines?
If increases in sea levels are accelerating faster than anyone thought, it should become apparent in just a few years because “acceleration” implies an ever-increasing rate. It cannot help but become unequivocal soon, unless there is a “pause” in sea-level rise. Then they’ll have to explain the pause. But any claims that the sea-level rise is hiding in the deep oceans won’t cut it this time.
“Here we revisit estimates of twentieth-century GMSL rise using probabilistic techniques9,10 and find a rate of GMSL rise from 1901 to 1990 of 1.260.2 millimetres per year (90% confidence interval). ”
90% confidence interval? It’s been quite a few decades since my last stats class but as I recall that’s basically the description of a totally meaningless result. And BTW, what the Hell is 1.260.2 millimetres exactly?
http://www.osdpd.noaa.gov/ml/ocean/J2_handbook_v1-3_no_rev.pdf
OSTM/Jason-2 Products Handbook
2.3.1. Accuracy of Sea-level Measurements
Generally speaking OSTM/Jason-2 has been specified based on the Jason-1 state of the art,
including improvements in payload technology, data processing and algorithms or ancillary data
(e.g: precise orbit determination and meteorological model accuracy). The sea-surface height shall
be provided with a globally averaged RMS accuracy of 3.4 cm (1 sigma), or better, assuming 1
second averages.
The abstract says 1.2 ± 0.2 mm, I suggest you find a better source.
though not a scientist a bit of simple “high school logic” counters this claim:
a little thought about TOPEX/JASON vs tidal gauges: the satellites measure the whole sea and thus the overall sea level rise very accurately. ways more accurate then tidal gauges. Now comes the logic:
it is logic that satellites can measure an acceleration if the preceeding data are tidal gauges..Why?
tidal gauges are land based, region based: put all the tidal gauges in alaska and in scandinavia and the “global sea level would fall (measurements are taken in region with isostatic uplift from the last glacial)
put it in Greece and the sea level would rise faster then the satellites measure (Greece “sinks or subsides)
the satelite measurement is the real “right measurement” but only starts in 1990
this implies using standard logic:
1 you only can speak of satellite data since 1990 All the data from tidal gauges are deemed incorrect compared to this different type of measurement Thus the satellite data can only speak for 1990-present
This data however covers only a short time and shows no real acceleration. However logically speaking for warmist logic: 25 years of data is for such a statement too little; we need at least a double timespan to see if this is real
2 plotting the satellite data after the tidal gauge data (even if it is adapted) is measuring apples and then suddenly follow it up by measuring bigger pears and say “the apples became bigger” Does tidal gauge measurements follow the satellite measurements? No even here on WUWT this has already been shown with plenty of tidal gauge data.
3 Of course we know why this discrepancy between tidal gauge and satellite measurements exist: tidal gauges are exposed to land changes (beach erosion,subsidence, isostatic uplift, coastal earthquakes,….) while satellite records are not.
now comes the conclusion with a fictional very exaggerated what if example to illustrate the point i try to make by using simple logic:
Isn’t the tidal gauge data the “real real life situation data”? in my opinion, though maybe not scientifically correct, it does correlate more correctly to real life situation, the tidal gauge data would show what happens on your coastline. so in real life for isostatic rebound regions the sea level is “dropping”, for subsiding regions the sea level is “rising faster”. this even if the satellite mesurements show a general rise.
the exaggerated what if example: if your region has an uplift of 1 meter (1 yard) a year in a few years your port would be dry and have to move to the new waterline, if your region subsides 1 meter (1 yard) a year you got every few years a “Noah’s flood” even if the satellites measure only a rise of 3 mm a year, it is not what these regions are experiencing.
In short: when the IPCC claims that coastal regions will be flooded then it is more important to look at what tidal gauges are telling you in these regions. they show what’s really going on in that region.
this illustrates my thought about sea levels: even if the satellite measurements are superior to the older mesurement method, it does not always say what is really happening.
Honey. Honest, it’s rising a lot higher than you think. So stop laughing.
To be honest, as soon as I saw “Harvard” I switched off. What a sad state one of the previously most respected educational establishments in the world has come to that almost everything that emanates from it these days is utter garbage. I was going to try to get my daughter in there, but it looks like it will be Oxford or Cambridge now.
The author claims that “other analysis shows the opposite” but that chart is quite outdated (only up to about 2011).
Current data from the cited source http://sealevel.colorado.edu/files/current/sl_global.txt is 73.090mm or quite literally “off the chart”
Time for an update.
I believe, despite the “current” in that URL, that the following is actually the current data:
http://sealevel.colorado.edu/files/2014_rel5/sl_global.txt
Accessible from this page:
http://sealevel.colorado.edu/
When this alarmist climate warming pack of cards comes crashing down will anyone believe real scientists ever again.
Why always discuss without seeing ?
Here is what is available about sea level since 1700. Of course more recent data is better, so what! For centennial climate change we have to work with what we have.
http://climate.mr-int.ch/images/graphs/sea_level.png
Note the rise around 1800, for about 30 years it was fast, and this was before the industrial era.
Note in green the swinging rate of change, amazingly with a period close to that of oceanic multi-decadal oscillations.
And yes, apparently recent satellite observations seem to show a faster rate of rise, but they are recent and we have to wait centuries to know what are the variabilities due to things that we don’t understand.
Short term thinking and climate are like oil and water, they don’t mix.
see also: http://climate.mr-int.ch/index.php?option=com_content&view=article&id=40&Itemid=442
Does anyone have the polynomial equation for the fit to the blue curve in the figure at the top (from Colorado.edu)? What is the quadratic term of the SLR deceleration?
Using the annual averages for 1993-2013, I get -0.023mm/yr/yr
-0.023*yr^2 + 96.92*yr – 100310
Thanks. If SLR is 2-3 mm/yr, that suggests we have 100-150 years before SLR overturns. This may signify the start of the Holocene interglacial at that time.
It hasn’t been long since the U. Colorado Boulder folks had to add a significant “fudge factor” to their sea level readings in order to account for a decline in the rate of absolute sea level rise they were measuring and restore it to its previous rate. As I recall, they attributed that rate decline to “depression of the sea beds caused by the increased weight of additional sea water”. I yowled at the time that in so doing they were mislabeling “volume” as “level” and that they had no rational basis for calculating that convenient fudge factor in any event.
Am I now being told that sea level rate of rise was INCREASING DURING THAT PERIOD when the U.C. Bolder folks thought it was declining?
Don’t worry, they’re working on another adjustment for that. Soon they’ll have really good data, like this:
https://stevengoddard.wordpress.com/2013/12/21/thirteen-years-of-nasa-data-tampering-in-six-seconds/
Is that 3 years or less of post doc work for Carling Hay? Would that be 2 years or less for “Eric Morrow, a recent PhD graduate of EPS”?
I don’t like pointing to experience or qualifications but YOU have forced me to look into it. You brought it up after all. What should matter is if someone’s evidence is right or wrong.
Didn’t look very hard, otherwise you would have found out that the two senior authors had been left off the list in the head post!
I don’t care about the 2 senior authors. I am worried about those two and their ‘extensive’ published works.
Why?
Facts and figures on sea level rise
Those that allege that climate change poses an imminent threat often cite rising sea level and/or its indirect effects. Rising sea level is, of course, said to result from rising global temperatures caused by man-made emissions of carbon dioxide and other gases. This article will present some facts and figures relating to the specific claims regarding sea level rise.
The scientific facts regarding climate change in general should be pointed out. The global warming hypothesis claims that man-made emissions of carbon dioxide and other gases have caused global temperature to increase in the 20th century and will cause further increase in the 21st century, with abundant negative side effects. This hypothesis is not supported by scientific observations. The 20th century temperature increases largely occurred prior to the largest increase in atmospheric carbon dioxide. The widely-acclaimed temperature increases in the 1980s and 1990s most likely are flawed readings affected by urban heat-island effects: independent atmospheric readings show relatively constant global temperatures for the past 50 years. Despite claims to the contrary, a majority of scientists (both in general and in fields related to atmospheric physics) do not accept the global warming hypothesis as fact.
Even though the claims of future sea level rise hinge on this hypothesis, examination of these claims is useful to clarifying some popular misconceptions.
The United Nations International Panel on Climate Change is an international group of scientists, politicians, and others which have met several times, each time producing a “consensus” statement regarding predictions and proposed responses regarding climate change. The last few statements are tied to the Kyoto Protocol treaty, which would selectively restrict carbon dioxide emissions and other activities. The politicized nature of this “scientific” conference has been addressed by others; what follows are its claims regarding sea level rise.
The IPCC’s 2001 report predicted that global average sea level will rise by 10 to 80 centimeters (median estimate 48 centimeters) by the year 2100. This will result from thermal expansion of ocean waters, net melting of glaciers, and net melting of polar icecaps. Predicted consequences include coastal flooding, incursion of salt water into coastal freshwater supplies, and a host of other effects. It might also be noted that environmental organizations have extended these predictions. For example, the UCS and ESA predicted sea level increases of up to 1 meter along the US Gulf Coast by combining IPCC predictions with ground subsistence projections. By combining well-established effects with highly questionable predictions, they prevent straightforward testing of their predictions.
There are 28,700,000 cubic kilometers of icecaps and glaciers in the world. This includes grounded ice in Antarctica and Greenland; floating ice shelves in the Arctic Ocean and seas near Antarctica; and glaciers in various mountain regions of the world. This represents the remaining unmelted ice from the last ice age, when total ice volume was about 3 times greater and when world sea levels were about 120 meters lower.
Calving of icebergs from floating ice sheets is periodically cited as an indicator of “climate change.” Regardless of the cause, even the complete melting of the ice sheets would have no effect on sea level. This is a consequence of Archimedes’ principle of buoyancy. The mass of floating ice (above and below water both) is identical to the mass of the water displaced. If the ice melts into water, its density decreases but is mass is the same, and water level is unchanged. [Yes, I know, I know, you have heard it all before but the climate hysterics should have yet another opportunity to get their facts straight.] There are potential side effects to large scale melting of ice sheets. One is a decreased reflectivity of the Earth’s surface; due to clouds and low sunlight angles near the poles the consequences are minimized. Another is a change in ocean currents in the Arctic Ocean.
Those that express concern over an increase in sea level make the implicit assumption that the current stability in sea level is normal. Currently the Earth is exiting a period of glaciation. Rising sea level has been the norm for the last 20,000 years, not the exception. The average rate of sea level rise in this period was 60 centimeters per century.
Consider the following: in the IPCC’s predictions, 20% of the expected sea level rise over the next century is due to net melting of continental ice (outside Greenland and Antarctica). This would require that 20% of the Earth’s continental ice melt in the next century. This ice is the remnant of the ice cover from the last ice age; what remains is 0.4% of the ice cover at the last peak of glaciation. On one hand, for this ice to melt in the next century would involve a rate of melting only one-fourth of the average over the last 20,000 years. Probably more relevant is the fact that this ice has apparently been hard to melt.
Limited data suggests that around the mid 1800s the rate of sea level rise increased to about 15 centimeters per century. This rate has apparently remained constant for the past 150 years; various tidal gauge measurements over a 20-year period give results comparable to this rate. While some suggest a link between this and current man-made carbon dioxide emissions, note the following: the observations suggest a constant rate of sea level rise for the past 150 years, while rate of man-made carbon dioxide emissions has increased over 100-fold. Additionally, most of the cumulative rise in sea level preceded the majority of cumulative carbon dioxide emissions. Global temperature change and sea level rise do correlate with each other, but not with human activities; thus it appears that both temperature and sea level are changing principally due to natural phenomena.
Note that there are uncertainties even with these modern measurements of sea level change. Tide gauge measurements for the past 150 years show rising sea level at some locations and dropping sea level at others. The primary factor is sinking and rising of the ground, respectively. The 15cm per century sea level rise incorporates model-based adjustments for these ground motions. Parts of Europe and North America are still rising in adjustment to the removal of the ice sheets by melting over the past several thousand years. Some sources question the accuracy of these sea level rise rates because of limits in our understanding of this isostatic rebound.
The IPCC predictions heavily depend on models that have limitations. It is first necessary to model global climate change; these models make assumptions regarding future increases in atmospheric carbon dioxide and proceed to model global and regional changes in temperature, precipitation, and other climatic factors. Models of sea level rise use these results and further model mass-balance for the icecaps (considering precipitation and melting) and thermal expansion of the oceans (requiring modeling of changes in temperature-depth relations for the global oceans). These models involve a high degree of uncertainty. The models for temperature change fail miserably to predict temperature changes for the last 35 years, yet their predictions for the next 100 years are still assumed valid. Nearly all the models require “fudge” factors to correctly simulate a steady state situation. The fact that the various models cited by the IPCC give relatively consistent predictions does not reflect reliability; the models have been “adjusted” to conform to each other, but fail to conform to real-world observations. When regional climate changes are considered, the models give inconsistent and sometimes dramatically contradictory results. Further, the models are modeling global carbon dioxide balance, which is very poorly understood at this time. Sea-level change models likewise attempt to model icecap mass balance, also poorly constrained by current observations.
file storage
http://www.filedropper.com/ratesofsealevelrises
Thanks, Sasha.
===========
The United Nations International Panel on Climate Change is an international group of scientists, politicians, and others which have met several times”.
Make that”Intergovernmental”. (IGPOCC)
People don’t read articles. We simply need to figure out how to write “Climate alarmists full of shit” as many different ways as possible in 144 characters. Yeah, stoops to their level but we’re right they’re wrong.
You make a compelling argument. On the other hand, I’m right and you’re wrong. Check and mate!
Oh noes! In twenty years the water has risen from under my foot level almost up to my ankle! Whatever shall we do?
Many commenters not happy with this. I wonder why.
Is is problematic that according to this estimate the sealevelrise the last century is smaller than other estimates?
Is it problematic that this estimate shows more sealevelrise and acceleleration during warming periods? Like the thirties. And less sealevel rise during periods with less temperature rise. And close to no rise in sealevel during periods with no warming.
What is the problem?
Notice the Abstracts states:
“Estimating and accounting for twentieth-century global mean sealevel (GMSL) rise is critical to characterizing current and future human-induced sea-level change.”
Implicitly their goal is to prove a point, not to get the metric correct for its own sake.
One thing has been overlooked here – the exponential rise in Global Warming Drivel (GWD). Suppose GWD doubles every year. Start with 1000 liters or 1 cu meter of GWD. Since doubling every year means an increase of 1000 every 10 years, after 30 years the 1 cu m of GWD will have increased to 1 cu km. After 40 years we will have a 1 sq km x 10km deep volume. After 70 years we will have 1 billion square km x 10 km deep of GWD -NOAA’s great flood! We are all going to drown in GWD – NOAA needs more money to build NOAA’s Ark! 🙂
You could do the same calculation with US Government regulations or the Federal debt.
Or with your mortgage, compound interest, which is also exponential. Fortunately interest rates are only ~4%, so the annual multiple is ~1.04. Reducto ad absurdum doesn’t work in this case.
Same Old Story
Measured sea level rise isnt alarming so we must ignore and trust a computer model
As the French would say – Merde
Seems like your take on this is that a smaller rise the last 100 years is more alarming.
What would the French say to that?
Here’s a purely pragmatic, and possibly naive view:
Forget about global sea level rise for a moment. It really doesn’t mean anything except as an indicator. The threat is local so we should be considering local implications.
Looking at this graph in isolation:
http://tidesandcurrents.noaa.gov/sltrends/sltrends_global_station.htm?stnid=822-071
There is a clear 30cm rise above the trend in the late 1990s. Was there disastrous flooding in Vancouver that year? Was a single square metre of usable land lost to the sea? I’ve not been able to find anything that suggest there was a marine inundation. The threat seems to be from rain rather than seawater flooding. If not, we know that at that location we have at least 30cm of headroom. So eyeballing the trend line consider that between 1900 and 2000 we have a trend of about 3cm/century. Which gives us a millennium until the trend reaches the levels we know are not disastrous. So this could be treated as a long term threat and monitored and adapted to as technology develops.
The numbers in Texas (Galveston Pleasure Pier) give a different picture.
http://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=8771510
Using a similar approach to the Vancouver numbers the known headroom is less than 15cm based on the 2010 peak, This could be eaten up in 20 years based on the 2000-2020 part of the trend line. Starting to adapt now might be a good idea. They could do worse than look at the Low Countries where they have been living with the threat of inundation for a hundreds of years.
http://news.bbc.co.uk/1/hi/sci/tech/8362147.stm
For some islands the picture might be worse and one form of adapting might be to stop building waterfront properties and importing tons of concrete to do it.
http://www.factfish.com/statistic-country/maldives/tiles+and+flagstones+of+cement,+concrete,+artificial+stones,+import+value
That’s a lot of investment for islands that will be uninhabitable in 15 years. Unless all that concrete is going into sea walls of course. I can’t seem to find out. The see defences mentioned here are not imported but made from local sand.
http://news.bbc.co.uk/1/hi/world/south_asia/7946072.stm
Disclaimers:
* I can’t look at other locations right now.
* All the numbers are eyeballed from a small graph, I’m supposed to be working 😉
* The trend line does not take into account spikes which might take the headroom away in a sudden and unpredictable way.
* This is based on not losing usable land to the sea. It might be that the local geography can limit the losses.
Old Man: concerning the Galveston data, the trend of the past 15 years is nearly flat, contrasted with the previous trend, which is much steeper. This change in the trend reflects subsidence and counter measures taken to arrest subsidence.
The Harris/Galveston Subsidence District was established in the nineties to address this problem and have restricted ground water withdrawel to good effect in Galveston.
Other Gulf Coast tidal guages show a flat trend except at Grande Isle, La., which is subsiding and shows a rising sea level.
I thought it better to take the long trend to avoid cherrypicking.
“The past not only changed, but changed continuously.” ~George Orwell 1984~
The leftist/progressive/Marxists in society believe in moral relativism…that “the ends justify the means”, thus any act, including lying, cheating, stealing, and even killing, is perfectly justified if it is done to advance the agenda; to achieve the desired end. The so-called climate scientist who change the past in order to advance the man-made global warming/climate change agenda are only acting/lying to advance the agenda, so in their mind it is perfectly acceptable behavior, in fact it is expected of ‘true believers’.
FWIW, the chart Willis tacked on is for satellite data whereas Hay & Morrow work with tidal gauge data. There are actually two independent sets of satellite data — Topex/Poseidon which shows roughly 3.3mm/year with (IHMO optimistically) small estimated error margins and GOES which showed 2 mm/yr with large error margins due largely to uncertainties in ionospheric delay modeling. Tidal gauge data is not great but it seems to show around 2mm/yr. Going from memory the First IPCC assessment report (pre satellite) acknowledged that nothing adds up and the second said there had been progress. I am going off to download and read the third/fourth/fifth reports. Doubt I’ll be back any time soon because reading and digesting sections of the assessment reports is slow work