By Larry Kummer. From the Fabius Maximus website.
Summary: Rising sea levels have become a core element — perhaps the core — of climate activists’ warnings. What do scientists say? Should we worry, panic, or despair? Here is a brief answer, plus much supporting evidence.
As so many of the predicted effects of climate change have failed to appear on time (e.g., the end of winter, more and stronger hurricanes), rising sea levels have become the focus of climate activists. It creates easy (if unscientific, even daft) graphics of global flooding — hopefully panicking insurance companies and landowners. Unfortunately, as so often the case, the science has not supported their screams of “Wolf!”
Now a new cycle begins, with the first salvo being Jeff Tollefson’s “Satellite snafu masked true sea-level rise for decades” in Nature, 17 July 2017 — “Revised tallies confirm that the rate of sea-level rise is accelerating as the Earth warms and ice sheets thaw.” A mild tone, as such articles go. The mainstream news stories to follow, fed by activists, probably will be lurid — or even hysterical. People will be running for the hills if they take them seriously (but they don’t; even believers see them as entertainment).
Spoiler – Conclusions
Below you will find six charts and 2750 words from major institutional science websites plus eight works of cutting edge research. It describes the scientific basis for the terrifying news stories you have seen and will continue to see in the major news media. I’ll save you some time. Here are the four conclusions relevant to the public policy debate about climate change.
(a) The seas are slowly rising and will continue to do so. Europe is preparing many of its coastal cities for this. America is not. Unless we wake up, the results will not be pretty. Slow and stupid are the sins “Nature’s god” always punishes.
(b) There are some tentative signs that the rate of increase is already accelerating, rather than just fluctuating. But the data is noisy (lots of natural variation) and the (tentative) acceleration is small — near the resolving power of these systems (hence the significance of the frequent revisions).
(c) Graph E in paper (5) is the key. As the world continues to warm, the rate of sea level rise will accelerate (probably slowly). Understanding the four scenarios used in the IPCC’s AR5 is an essential first step to making sense of the stories in the news about rising seas (discussed below).
(d) Bottom line: activists are attempting to incite hysteria by exaggerating and misrepresenting what science tells us about rising sea levels.
What do the scientists say about the rising seas?
We start, as always, with the Working Group I of the IPCC’s Fifth Assessment Report: Chapter 3 – Observations: Oceans. The oceans have been rising at varying rates for a long time.
“It is very likely that the mean rate of global averaged sea level rise was 1.7 [1.5 to 1.9] mm/yr between 1901 and 2010 and 3.2 [2.8 to 3.6] mm/yr between 1993 and 2010. Tide gauge and satellite altimeter data are consistent regarding the higher rate during the latter period. It is likely that similarly high rates occurred between 1920 and 1950.”
The chapter also discusses at length the high degree of “interannual-to-multi-decadal variability” due to climate modes (e.g., the North Atlantic oscillation, the Atlantic multi-decadal oscillation, the Pacific decadal oscillation, and the El Niño–Southern Oscillation) which obscure long-term trends.
Also see NASA’s website about sea level projections. The rise over the past 25 years is aprox. 3.2 mm/year (12.6″ per century). Red emphasis added
“High quality measurements of (near)-global sea level have been made since late 1992 by satellite altimeters …This data has shown a more-or-less steady increase in Global Mean Sea Level (GMSL) of around 3.2 ± 0.4 mm/year over that period. This is more than 50% larger than the average value over the 20th century. Whether or not this represents a further increase in the rate of sea level rise is not yet certain.”
Now let’s look at research since AR5’s WGI report was published in 2014.
What do the satellites say?
The major databases of global mean sea level show no acceleration in recent years. Here are two of them.
(a) AVISO – through 25 March 2017.
AVISO shows a 1993-2017 rise at a rate of 3.28mm/year (12.9″ per century) – and no acceleration. They are confident of their data. Aviso distributes satellite altimetry data from Topex/Poseidon, Jason-1, ERS-1 and ERS-2, EnviSat, and the Doris precise orbit determination and positioning products. It is a partnership of these major science institutions. They have not updated their graph since March 2017. See their interactive tool here. Click the graph to enlarge.
“Comparisons between these altimetry data and those obtained using independent techniques, such as the drifting buoys of the Argo network, the GRACE gravimetry satellite, or the network of tide gauges, can not only corroborate these results but also help us establish which of the possible sources of variation in mean sea level might explain the rise observed.”
(b) Colorado University Sea Level Research Group (SLMG).
The CU SLMG provides another graph showing rising sea levels — but no acceleration. They have not updated it since June 2016, probably waiting for recalculation of satellite data. The trend is 3.4 mm/year (11.8″ per century).
“Since 1993, measurements from the TOPEX and Jason series of satellite radar altimeters have allowed estimates of global mean sea level. These measurements are continuously monitored against a network of tide gauges. When seasonal variations are subtracted, they allow estimation of the global mean sea level rate. As new data, models and corrections become available, we continuously revise these estimates (about every two months) to improve their quality.”
Global Mean Sea Level. Seasonal signals removed (10mm = 0.4″.).
Where do activists get those scary scenarios?
The climate change debate has entered what we might call the “Campfire Phase”, in which the goal is to tell the scariest story. /1
— Oren Cass (@oren_cass) July 12, 2017
When climate activists do not just make up stories, they use the worst-case scenario in the IPCC’s AR5: RCP8.5. Like a good worst case analysis, it assumes large changes in current trends in population (high) and technology (stagnant in the 21st century). The scenario is unlikely and becoming more so every day. RCP8.5 assumes that coal is the fuel of the late 21st century. Coal companies are going bankrupt now, replaced by natural gas and renewables. Electric cars are already commonplace in Europe, with mass production coming to America eventually as the technology matures (it’s in the early stages now). The potential solar and even fusion remains bright for coming generations.
Scientists are responding to this, with papers increasingly focused instead on the middle scenarios (RCP4.5 and RCP6.0). With continued technological progress, we might reach the RCP2.6 scenario in the mid 21st C – with negative greenhouse gas emissions. For details see Manufacturing climate nightmares: misusing science to create horrific predictions.
Recent papers about new analysis of the data
Unlike what you read in the mainstream media about climate and economic data, collecting this data is not like counting apples. Hence the role of revisions and reanalysis of the data. The graphs of global sea level and atmosphere temperatures result from mind-blowingly complex calculations, whether based on instruments on satellites or Earth’s surface. See this presentation describing some of this complexity.
Improvements are an ongoing process, as seen in “Orbit related sea level errors for TOPEX altimetry at seasonal to decadal time scales” in Ocean Science, in press. The TOPEX mission ended in January 2006.
Scientists have attempted to understand the dynamics of rising sea levels, unlock their history, and detect the expected acceleration in the rate of rising sea levels. Here are samples of their recent work. Red emphasis added.
(1) “Timescales for detecting a significant acceleration in sea level rise” by Ivan D. Haigh et al in Nature Communications, 14 April 2014.
“Our results imply that if/when the currently understood components of the variability in the records are removed, then accelerations significantly different from zero are likely to become detectable in individual tide gauge records later this decade or early next decade, using the methods considered here.”
(2) “Unabated global mean sea-level rise over the satellite altimeter era” by Christopher S. Watson et al in Nature Climate Change, June 2015. Gated. Abstract…
“The rate of global mean sea-level (GMSL) rise has been suggested to be lower for the past decade compared with the preceding decade as a result of natural variability, with an average rate of rise since 1993 of +3.2 ± 0.4 mm yr−1. However, satellite-based GMSL estimates do not include an allowance for potential instrumental drifts (bias drift). Here, we report improved bias drift estimates for individual altimeter missions from a refined estimation approach that incorporates new Global Positioning System (GPS) estimates of vertical land movement (VLM). …
“Applying the bias drift corrections has two implications. First, the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1, depending on the choice of VLM applied. These rates are in closer agreement with the rate derived from the sum of the observed contributions, GMSL estimated from a comprehensive network of tide gauges with GPS-based VLM applied and reprocessed ERS-2/Envisat altimetry.
“Second, in contrast to the previously reported slowing in the rate during the past two decades, our corrected GMSL data set indicates an acceleration in sea-level rise (independent of the VLM used), which is of opposite sign to previous estimates and comparable to the accelerated loss of ice from Greenland and to recent projections, and larger than the twentieth-century acceleration.”
(3) “Refining satellite era estimates of global mean sea level rise” by Christopher S. Watson et al, slides presented at the International GNSS Service Annual Workshop in February 2016. This is an excellent introduction to the complexities of calculating sea levels from satellite data. A few of their conclusions.
- “Our work suggests TOPEX is yet to be fully understood and is presently slightly overestimating the trend in GMSL. {The TOPEX mission ended in January 2006!}
- “Our revised record seems more consistent with the sum of the observed contributions to GMSL. While not yet statistically significant, we see the emergence of an acceleration.
- “Further reprocessing of TOPEX is currently underway by mission agencies, first results seem commensurate with our findings, but this remains in progress.”
(4) “Revisiting the contemporary sea-level budget on global and regional scales” by Roelof Rietbroeka et al, PNAS, 9 February 2016 — “The simultaneous combination of sea-level anomalies from satellite altimetry and data from satellite gravimetry allows a partitioning of the sea-level rise into the different contributions.” Abstract…
“Dividing the sea-level budget into contributions from ice sheets and glaciers, the water cycle, steric expansion, and crustal movement is challenging, especially on regional scales. Here, Gravity Recovery And Climate Experiment (GRACE) gravity observations and sea-level anomalies from altimetry are used in a joint inversion, ensuring a consistent decomposition of the global and regional sea-level rise budget. …”
The thick grey line is the total change in sea level over the 2002–2014 period: 2.74 mm/year (10.8″/century).
(5) “Temperature-driven global sea-level variability in the Common Era” by Robert E. Kopp et al in PNAS, 15 March 2016 —
“We present the first, to our knowledge, estimate of global sea-level (GSL) change over the last ∼3,000 years that is based upon statistical synthesis of a global database of regional sea-level reconstructions.
“GSL varied by ∼±8 cm over the pre-Industrial Common Era, with a notable decline over 1000–1400 CE coinciding with ∼0.2 °C of global cooling. The 20th century rise was extremely likely faster than during any of the 27 previous centuries. Semiempirical modeling indicates that, without global warming, GSL in the 20th century very likely would have risen by between −3 cm and +7 cm {1.2″ to 2.8″), rather than the ∼14 cm {5.5″} observed. Semiempirical 21st century projections largely reconcile differences between IPCC projections and semiempirical models.”
“Graph A: Global sea level (GSL) under prior ML2,1. Note that the model is insensitive to small linear trends in GSL over the Common Era, so the relative heights of the 700–1000 CE and 20th century peaks are not comparable.” The sea level values are with respect to 1900 CE baseline. This graph is widely used, seldom with this important caveat. (1.0cm = 0.4″.)
“Graph E: 21st century projections for RCPs 2.6, 4.5, and 8.5. Red lines show the fifth percentile of RCP 2.6 and 95th percentile of RCP 8.5. …Sea level values are with respect to 2000 CE baseline.” By roughly 2025 the rate of sea level rise accelerates substantially under all four RCPs. (10cm = 3.9″.) The acceleration is steep only under the unlikely worst-case RCP8.5 scenario.
(6) “Is the detection of accelerated sea level rise imminent?” by J.T. Fasullo et al, Scientific Reports, 10 August 2016 — Abstract.
“Global mean sea level rise estimated from satellite altimetry provides a strong constraint on climate variability and change and is expected to accelerate as the rates of both ocean warming and cryospheric mass loss increase over time. In stark contrast to this expectation however, current altimeter products show the rate of sea level rise to have decreased from the first to second decades of the altimeter era. Here, a combined analysis of altimeter data and specially designed climate model simulations shows the 1991 eruption of Mt Pinatubo to likely have masked the acceleration that would have otherwise occurred. This masking arose largely from a recovery in ocean heat content through the mid to late 1990 s subsequent to major heat content reductions in the years following the eruption.
“A consequence of this finding is that barring another major volcanic eruption, a detectable acceleration is likely to emerge from the noise of internal climate variability in the coming decade.“
Unpublished research, new fuel for scary stories.
Tollefson’s Nature article mentioned research presentations at the “Regional Sea Level Changes and Coastal Impacts” Conference in July 2017 (see the abstracts here). The eventual papers published from these might have a large impact on the public policy debate. Here are two. First, the one by Nerem that Tollefson mentions.
(7) “Understanding the Acceleration of Sea Level Rise During the Altimeter Era” by R. Steven Nerem et al. Nerem had given a presentation with the same title at a CMCC seminar in February. Tollefson says that “Nerem’s team calculated that the rate of sea-level rise increased from around 1.8 millimetres per year in 1993 to roughly 3.9 millimetres per year today as a result of global warming.” Oddly, this isn’t in the abstract. This will be important if this work leads to the revision of the sea level histories so that they show an acceleration in recent years.
“Over the last 25 years, data from TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3 have been used to observe changes in global mean sea level. A rate of rise of 3.4 ± 0.4 mm/year has been observed. However, observing a possible acceleration in the rate of sea level rise is more challenging and pushes the limits of the observing system accuracy. This presentation will examine the feasibility of detecting an acceleration in the altimeter sea level record.
“First, the available evidence for estimating how big of an acceleration might be expected in the altimeter record will be reviewed. Next, the errors in the altimetry will be discussed in the context of tide gauge validation of the altimeter record. The role of interannual variability in GMSL in measuring the acceleration will be addressed.
“We will also discuss the role of decadal variability and how it might influence the determination of acceleration, including the role that the 1991 eruption of Mount Pinatubo might have had on the altimeter sea level record.
“Finally, we will discuss progress towards understanding the acceleration of GMSL over the 25-year record, based on consideration of all of these issues, including the importance of using the tide gauge validation to understand the errors in the acceleration estimate.”
(8) “Sea Level Budget of the Altimetry Era Revisited” by Anny Cazenave el al. Gavin Schmidt tweeted a graph (below) which I believe is from this presentation, similar to but apparently better documented than in previous paper associated with Cazanave (#2 above). This shows a slight acceleration during the past two decades, and a small acceleration since 2014 (to 0.14″/year). But the former might be natural variation and the latter might be a temporary effect from the 2014-2016 El Nino period.
“We revisit the global mean sea level (GMSL) budget during the whole altimetry era (1993 – present) and show that using a large number of data sets to estimate the different components of the sea level equation improves the budget closure. Moreover, the budget approach allows to detect bias and drifts in the observations.
- Six different altimetry-based sea level data sets have been considered over the period January 1993-December 2015. They include the Climate Change Initiative (CCI) sea level products from the European Space Agency (ESA).
- The steric data include three data sets for January 1993-December 2004 and four Argo data sets afterwards.
- Three glaciers time series are considered. For the ice sheets, the IMBIE data set is used until December 2003 and the CCI ice sheet products afterwards. Both IMBIE and CCI products combine a large number of individual data sets.
- Changes in land water storage and atmospheric water vapour content are also accounted for.
“For each term of the sea level equation we use the mean of available data sets. The sum of components agree very well with the altimetry-based GMSL except at the beginning of the record (1993-1998). During the later period a single altimeter (Topex A) was operating. Moreover Topex A suffered significant instrumental drift. Previous studies attempted to estimate this drift by comparing with tide gauges and the experimental Poseidon altimeter data onboard the Topex/Poseidon mission.
“Here we use another approach and estimate the Topex A drift from the sum of components over January 1993-December 1998. Accounting for this correction leads to much improved agreement between observed sea level and sum of components. Using ensemble means for the GMSL and components rather than individual data sets leads to closure of the sea level budget.
“The trend of the residual time series is 0.0 +/- 0.2 mm/yr. The RMS is 2.4 mm/yr for the whole altimetry record. It decreases to 1.7 mm when the steric sea level is estimated with Argo (as of January 2005). We attribute the slightly larger RMS of the first decade to uncertainty of the steric component.
“For the whole altimetry period (January 1993-December 2015), the GMSL rate is now close to 3 mm/yr. However, significant GMSL rate difference is found between the 1st and 2nd decade of the altimetry era (2.7 mm/yr and 3.5 mm/yr respectively), suggesting sea level acceleration in the recent years.”
“We don’t even plan for the past.”
— Steven Mosher (member of Berkeley Earth; bio here), a comment posted at Climate Etc about our unpreparedness for the inevitable repeat of past weather.
For More Information
There is a serious problem with Earth’s seas: we’re killing them. See the ugly details here, and more here.
For more information see The keys to understanding climate change, all posts about computer models, and especially these about rising seas…
- Good news: rising seas might not cover these Pacific islands.
- Assigning blame for the flooding of Pacific atolls.
- A massive melting problem in Antarctica!
- The New Yorker’s “The Siege of Miami” reveals a serious problem.
- Rising seas alert! Watch how science becomes a sensational news story.
- Focusing on worst case climate futures doesn’t work. It shouldn’t work.
And what should one expect nearing the end of an 11,300 year inter-glacial period? Wait awhile and the sea level will lower.
According to a book I am reading named, “13 Facts That Prove Humans Don’t Cause Global Warming”, twelve thousand years ago the oceans were 400 feet lower than they are today. In comparison, an inch or two in todays world is nothing. It probably comes from all the water pumped out of the deep wells in California that will take a hundred years to refill.
Willis, ignoring any/all data prior to 1950 makes your analysis worthless.
Ignoring satellite data makes you look stupid.
…
Isn’t “satellite data” the gold standard?
@ur momisugly Steve Heins –
Try harder to be more polite, I’m sure you can.
Serious question: do you think the satellite data shows an acceleration signal?
“In sharing their story, the team remains cagey on one crucial detail: the precise location coordinates of the site.”
No doubt-
http://www.msn.com/en-au/news/techandscience/underwater-forest-preserved-since-ice-age/ar-AAoqFNS
Perhaps the author(s) are unaware of the Gregory et al. assessment from a few years ago:
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00319.1
Abstract
Confidence in projections of global-mean sea level rise (GMSLR) depends on an ability to account for GMSLR during the twentieth century. There are contributions from ocean thermal expansion, mass loss from glaciers and ice sheets, groundwater extraction, and reservoir impoundment. Progress has been made toward solving the “enigma” of twentieth-century GMSLR, which is that the observed GMSLR has previously been found to exceed the sum of estimated contributions, especially for the earlier decades. The authors propose the following: thermal expansion simulated by climate models may previously have been underestimated because of their not including volcanic forcing in their control state; the rate of glacier mass loss was larger than previously estimated and was not smaller in the first half than in the second half of the century; the Greenland ice sheet could have made a positive contribution throughout the century; and groundwater depletion and reservoir impoundment, which are of opposite sign, may have been approximately equal in magnitude. It is possible to reconstruct the time series of GMSLR from the quantified contributions, apart from a constant residual term, which is small enough to be explained as a long-term contribution from the Antarctic ice sheet. The reconstructions account for the observation that the rate of GMSLR was not much larger during the last 50 years than during the twentieth century as a whole, despite the increasing anthropogenic forcing. Semiempirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the authors’ closure of the budget is that such a relationship is weak or absent during the twentieth century.
Notice the final sentence. Such honesty is rare these days.
Kurt,
“Perhaps the author(s) are unaware of the Gregory et al. assessment from a few years ago:”
As the post says, the papers cited were from after AR5. Gregory was received in 2012 and published two months before AR5. But that’s a trivial point.
More important, Gregory 2013 is one of a long series of papers attempting to “close the budget” so that the components of sea level rise add up to the observed sea level rise. The papers cited here show that during the past five years that has been done (as always, more can be done to better understand this).
This is a common problem in these threads — people cite old papers (in climate science 4 years is often old — as representing the current state of knowledge. Lots of money and many scientists are working on these problems, and the frontier of knowledge is moving.
Larry,
Thank you for your feedback. I take your point, … but…:
co-authors to the Gregory paper were both Church and White, whose earlier papers have been quoted as much as anyones that their IS a separate and detectable man-made sea-level rise signal. The Gregory paper (from 2012, published in 2013) says the OPPOSITE. Apparently the experts at the IPCC WG1 chose to ignore this inconvenient bit of information.
You can’t have it both ways: either the sea level rise rate is accelerating (ostensibly to increased human CO2 emissions) or it is not. Claiming a doubling in sea level rise rate late 20th Century vs entire 20th Century (as the IPCC does) is duplicitous at best, fear-mongering at worst.
Until a more recent paper demonstrates that Gregory, White, Church, … was in error, I will continue to doubt any claims that there exists a man-made signal.
Any “acceleration” signal is purely due to short-term noise and/or natural fluctuations. Most of the problems with the satellite record (showing about 3 mm/y) are probably due to drift, since the satellite signal shows no acceleration, either (same for the tide gauges), but the difference of 1-2 mm/y between the two needs to be reconciled eventually.
There does not exist a long-term anthropogenic sea-level rise contribution, not in the data at least.
Kurt,
“Claiming a doubling in sea level rise rate late 20th Century vs entire 20th Century (as the IPCC does) is duplicitous at best, fear-mongering at worst.”
It would be helpful to quote sources when you make claims about them. Let’s replay the tape to see the money quote from AR5 Chapter 3 (italics added):
“Likely is AR5’s lowest level of confidence.
“Any “acceleration” signal is purely due to short-term noise and/or natural fluctuations. ”
Yes, AR5 says that might be so. But they respect the data and express conclusions in terms of uncertainty. I am astonished at how often in this thread people give conclusions as if God just whispered in their ear.
“is duplicitous at best, fear-mongering at worst.”
I suspect if deuling was still in style, comment threads would have more careful accusations. Remarks like that in 1880 Dodge City might have you on the street looking an IPCC lead author in the eyes. Given the state in 1880 of pistols, holsters, and medical tech — making outcomes somewhat random — I suspect you would be wondering it “duplicitous” was really the best word to use.
Larry,
You’re missing the forest for the trees.
Re-read the following:
You can’t have it both ways: either the sea level rise rate is accelerating (ostensibly to increased human CO2 emissions) or it is not.
Decide which position you’re attempting to defend, then provide data to support it.
Gregory, White and Church are all believers in human-caused catastrophic global warming. Yet they wrote a paper five years ago saying they found no (or extremely weak) evidence of the same in the sea level record, even though one must certainly manifest itself… eventually.
The much-expected and hoped-for increase in sea level rise rate (acceleration) has been curiously absent from the data until now. Much like Trenberth’s “travesty”… What could one possibly conclude from such a record?
Kurt,
“You can’t have it both ways: either the sea level rise rate is accelerating (ostensibly to increased human CO2 emissions) or it is not.”
You appear unclear about how the real world works. While the reality is either X or not X, today’s available observations are often unable to determine which is true. Today’s research is clear — there are only tentative signs that sea level rise is accelerating. For those who rely on science, not revealed wisdom, observations are often in the grey zone of uncertainty. AR5 honestly and professionally reflects that uncertainty.
You have given not the slightest basis for your claims of “duplicitous”, nor for your misrepresentation of what AR5 said.
“Decide which position you’re attempting to defend, then provide data to support it.”
This is science, not a baseball game.
“What could one possibly conclude from such a record?”
It means that the acceleration might have become detectable. Further observations will give answers. But continued warming — and the evidence is overwhelming that the world will continue to warm for the foreseeable future — means that the rate of sea level rise will eventually accelerate.
Observations and research will tells us about magnitudes and timing. How much and when. Those provide the basis for effective public policy action.
All of these seems clear. Your comments appear to show some objection to this, but do not convey what that is.
Larry,
At this stage it is perhaps best to agree to disagree and move on.
You seem wedded to the meme that human CO2 emissions will {eventually} manifest themselves in an increase in sea level rise rate, despite the utter lack of evidence to support that claim.
But I wish you well in your efforts to “effectively seek the truth.” Sometimes that includes seriously questioning one’s most deeply held beliefs.
[duplicitous – ADJECTIVE FORMAL: behaving dishonestly in order to trick someone]
Since Gregory, Church and White were Lead Author, Coordinating Lead Author and Contributing Author, respectively, to AR5 WG1, Ch. 13 “Sea Level Rise”, one would expect that these individuals would have argued for accurate representations of the scientific conclusions from their own paper(s) — could we at least agree on that?
Gregory, White, Church et al., published 2013, stated (final sentence of Abstract): “Semiempirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the authors’ closure of the budget is that such a relationship is weak or absent during the twentieth century.”
In IPCC AR5 (2013) WG1, Ch. 13, Sea Level Rise – Executive Summary, Church (as Coordinating Lead Author) stated the following: “It is very likely that the global mean rate was 1.7 [1.5 to 1.9] mm yr–1 between 1901 and 2010 for a total sea level rise of 0.19 [0.17 to 0.21] m. Between 1993 and 2010, the rate was very likely higher at 3.2 [2.8 to 3.6] mm yr–1.”
Taken together, these two statements are incongruent. The claim of a rise from 1.7 to 3.2 mm/y can only be made if one grafts satellite readings (which show no acceleration) onto tide gauge readings (which show no acceleration either). This is duplicity. Once again, you can’t have it both ways. This isn’t quantum physics, where Schrödinger’s Cat can be both dead and alive simultaneously.
BTW, the range of acceleration rates listed also include deceleration (negative values). Rather humorous. And the range given for the would-be acceleration signal (-0.002 to +0.019 mm y -2) is itself less than the tolerance in the actual sea level rise rate, even after a century of said “acceleration”.
Your comment, “You appear unclear about how the real world works” is particularly entertaining. Is this anything other than your personal effort to insult or falsely condescend to one who disagrees with you, since you apparently don’t seem willing or able to detect the logical fallacy in your own position?
Respectfully, I believe you are the one lacking in scientific acumen (and/or common sense) here. In the real world (as well as in “real” science), a claim must be backed up by data in order to have credibility. Perhaps an illustration from the banking world would help clarify.
Let’s say you were a bank executive. A branch office manager had instituted a scheme to improve profits at his local office some ten years ago. He was confident it was working. He even reported that his analysis, over the ten year period to date, showed that the profit margin was increasing year-on-year, on average (with 66%+ likelihood). Surely you would continue to support his scheme, for over the coming ten years, the signal of increased profits would certainly manifest itself in the statistics. So you wait another ten years. And your branch manager says it is now very likely (90%+ likelihood) that there had been an increase in profits, maybe in another ten years or so it would really take off. But it WAS somehow possible, but statistically unlikely, that profits were not increasing at all, or even in fact decreasing. Hmmm.
Perhaps you fail to realize just how important the detection of a human-signal in sea level rise is to the entire premise (that CO2 emissions need to be curbed as soon as possible). How can you even begin to discuss ‘effective public policy action’ if you can’t even detect a climate signal associated with inaction?
I live about 5 miles west of Lake Michigan. My house sits on top of a massive, ancient hill left behind by the last glacial retreat.
I will only be concerned about this if I see a cargo ship sailing along in the spot where the train tracks are now over by the harbor. The beach would be about 50-some feet higher than the current beach.
I wonder how much the total amount of moisture in the atmosphere above the earh’s and sea level surfaces fluctuates in all reasonable time scales and if this has any impact on sea level.