20 Nov 19
@metal-brain saidWhy? I don't think it is unusual. That's at least partly because its consistent with the proven fact that CO2 is a greenhouse gas.
Now you have to prove that is unusual.
What good is your argument if it is a normal cyclical pattern.Which "normal cyclical pattern" would that be of then? Name it...
@humy saidLook up 60 year oscillations.
Why? I don't think it is unusual. That's at least partly because its consistent with the proven fact that CO2 is a greenhouse gas.What good is your argument if it is a normal cyclical pattern.Which "normal cyclical pattern" would that be of then? Name it...
"I don't think it is unusual."
Then we agree. That is normal.
@metal-brain saidWhy? The rate of increase in sea level rise has been increasing for well over 60 years so no 60 year oscillation can explain that one.
Look up 60 year oscillations.
@metal-brain saidIt was a simple question. You copied this specific article into threads on at least three occasions. Typically when choosing a reference to make a point, there is a reason to select a particular one instead of another. In this case, apparently, there was no rationale?
I don't know. Every excerpt that has been posted is consistent with the data. I have not seen a contradiction so far, just bias based on cherry picked irrelevancies.
I'm asking you a question. What distinguished Holgate (2007) from other Sea Level Studies? You seem to be implying there is one, so you tell me.
It seemed suspicious since Holgate is a 12 year old study. Similar to your frequent jag about the heat island effect, some of the buoys used to calculate GMSL are contaminated by local effects. To correct this Holgate removed low quality buoys from the analysis and concludes that only a few buoys are needed to make the same conclusion, although to me their reasoning for removing 95% of the buoys is confusing. I was not previously aware that sea level rise is non uniform and highly dynamic, even on short time scales.
However, there is a problem with the figures in Holgate. In fact this enigma was well appreciated years prior (e.g. [1]). A rise of 1.6-1.9 mm/yr indicates a discrepancy in the earth's bank account. As detailed in Gregory et al [2], there isn't enough water displaced from thermal expansion and deglaciation to account for that rise. In other words, if you accept the figures from Holgate, early in the 20th century something other than thermal expansion and deglaciation must have been contributing.
What explains it? Volcanic activity? Maybe aliens? In Hay et al. [3] they use much more comprehensive approaches relative to Holgate to propose that the earlier figures were wrong. They conclude that GMSL increased more slowly in the early 20th and is increasing 3X faster now. For obvious reasons, this has implications for future predictive algorithms, especially in low-lying areas. Consider using this reference instead of Holgate for future discussions.
(not that you'll read them, but for anyone interested in learning new things.... For those who love physics, the PNAS article is jargon-y.)
[1] https://www.pnas.org/content/99/10/6550
[2] https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-12-00319.1
[3] https://www.nature.com/articles/nature14093
20 Nov 19
@metal-brain saidThey used 9 rather than 170 buoys, their conclusion was that based on their data there was no observable acceleration of sea level rise. The purpose of the study was to see if one could use a small number of high quality data sources to measure sea level rise. More recent studies that built on their work have observed an acceleration. @wildgrass pointed this out in the first post on page 8.
I don't know. Every excerpt that has been posted is consistent with the data. I have not seen a contradiction so far, just bias based on cherry picked irrelevancies.
I'm asking you a question. What distinguished Holgate (2007) from other Sea Level Studies? You seem to be implying there is one, so you tell me.
In their conclusions they make an important point about volcanism:
[20] Although the mean rate of change of global mean sea level is found to be greater in the first half of the twentieth century, the two rates are consistent with being the same at the 95% confidence level, given their individual standard errors. However, a greater rate of rise in the early part of the record is consistent with previous analyses of tide gauge records which suggested a general deceleration in sea level rise during the 20th century [Woodworth, 1990; Douglas, 1992; Jevrejeva et al., 2006]. A twentieth century deceleration is consistent with the work of Church and White [2006] who, although finding evidence for a post‐1870 acceleration based on an EOF reconstruction of global sea level, found that much of the overall acceleration occurred in the first half of the 20th century. Church and White [2006] suggested that the greater rate of sea level rise observed in the first half of last century was due to reduced volcanic emissions (and hence also lower variability in sea level) during the 1930s to 1960s. This idea is supported by results from the HadCM3 model which suggest that the simulated global mean sea level did not accelerate through the twentieth century due to the offsetting of anthropogenic warming by reduced natural forcing [Gregory et al., 2006].
Holgate (2007).
Bold my emphasis.
Hay et al come to a different conclusion regarding acceleration of sea level rise:
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 3.0 ± 0.7 millimetres per year between 1993 and 2010, consistent with prior estimates from tide gauge records. The increase in rate relative to the 1901–90 trend is accordingly larger than previously thought;
Hay et al, (2017), Abstract.
Bold my emphasis
So they are saying that there has been a recent acceleration, due to the absence of those factors which offset anthropogenic global warming being reduced compared with the first part of the twentieth century.
20 Nov 19
@deepthought saidThe OP will be happy to know that we've finally revealed truth.
They used 9 rather than 170 buoys, their conclusion was that based on their data there was no observable acceleration of sea level rise. The purpose of the study was to see if one could use a small number of high quality data sources to measure sea level rise. More recent studies that built on their work have observed an acceleration. @wildgrass pointed this out in the ...[text shortened]... et anthropogenic global warming being reduced compared with the first part of the twentieth century.
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Just as a recap, did anyone answer if they believe science may someday help reveal absolute truth? What sciences are not fundamentally reductionism?
It seems to me that when we uncover another layer our information grows, and yet our sum total of knowledge shrinks. Does anyone else kind of see what I'm saying?
20 Nov 19
@joe-shmo saidOur knowledge grows with new information, but along with that our realization of the magnitude of what we do not know grows as well.
Just as a recap, did anyone answer if they believe science may someday help reveal absolute truth? What sciences are not fundamentally reductionism?
It seems to me that when we uncover another layer our information grows, and yet our sum total of knowledge shrinks. Does anyone else kind of see what I'm saying?
21 Nov 19
@wildgrass said"They conclude that GMSL increased more slowly in the early 20th and is increasing 3X faster now."
It was a simple question. You copied this specific article into threads on at least three occasions. Typically when choosing a reference to make a point, there is a reason to select a particular one instead of another. In this case, apparently, there was no rationale?
It seemed suspicious since Holgate is a 12 year old study. Similar to your frequent jag about the heat i ...[text shortened]... nals.ametsoc.org/doi/full/10.1175/JCLI-D-12-00319.1
[3] https://www.nature.com/articles/nature14093
Bullcrap!
That is not the overall trend. You can cherry pick 17 year accelerations in sea level rise to falsely represent a trend, but when put in the correct context it is normal. What if I cherry picked a period in time when a deceleration took place? Would that be a fair representation?
What is good for the goose is good for the gander.
21 Nov 19
@deepthought said"More recent studies that built on their work have observed an acceleration."
They used 9 rather than 170 buoys, their conclusion was that based on their data there was no observable acceleration of sea level rise. The purpose of the study was to see if one could use a small number of high quality data sources to measure sea level rise. More recent studies that built on their work have observed an acceleration. @wildgrass pointed this out in the ...[text shortened]... et anthropogenic global warming being reduced compared with the first part of the twentieth century.
What study is that? Assertions are worthless without an actual study to prove it. People make lots of assertions that are false.
You can cherry pick 17 year accelerations in sea level rise to falsely represent a trend, but when put in the correct context it is normal. What if I cherry picked a period in time when a deceleration took place? Would that be a fair representation?
What is good for the goose is good for the gander.
21 Nov 19
@metal-brain saidYou'll have to read the papers first. I don't know what you mean by normal or overall trends. Neither of these terms are mentioned in these articles. Are you talking about geological time scales?
"They conclude that GMSL increased more slowly in the early 20th and is increasing 3X faster now."
Bullcrap!
That is not the overall trend. You can cherry pick 17 year accelerations in sea level rise to falsely represent a trend, but when put in the correct context it is normal. What if I cherry picked a period in time when a deceleration took place? Would that be a fair representation?
What is good for the goose is good for the gander.
21 Nov 19
@wildgrass saidYou'll have to read the papers without prejudice. Nothing you have pointed out is an unusual trend.
You'll have to read the papers first. I don't know what you mean by normal or overall trends. Neither of these terms are mentioned in these articles. Are you talking about geological time scales?