from CO2 Science: The authors write that “satellite altimetry measurements since 1993 have provided unique information about changes in global and regional mean sea levels,” suggesting a mean rate of rise of 3.2 mm/yr for global sea level over the period 1993-2012 (Boening et al., 2012; Cazenave et al., 2012), which “notably exceeds the estimate of 1.8 mm/yr sea level rise for the 20th century (Bindoff et al., 2007).”
So which rate is closest to the truth?
What was done
In a study designed to answer this question, Jevrejeva et al. (2014) say they “renew the global sea level [GSL] reconstruction by Jevrejeva et al. (2006), using monthly mean sea level data collected by the Permanent Service for Mean Sea Level (PSMSL) covering the observations from 1807 to 2010,” thereby improving the GSL reconstruction by increasing data coverage “by using many more stations, particularly in the polar regions, and recently processed historic data series from isolated island stations,” as well as by extending the end of the reconstruction from 2002 to 2009.
What was learned
Quoting the five researchers, “the new reconstruction suggests a linear trend of 1.9 ± 0.3 mm/yr [7.5 inches per century] during the 20th century” and “1.8 ± 0.5 mm/yr [7 inches per century] for the period 1970-2008.”
Global sea level reconstruction since 1807, blue shadow represents 5 and 95% confidence interval
What it means
Although some regions have recently experienced much greater rates of sea level rise, such as the Arctic (3.6 mm/yr) and Antarctic (4.1 mm/yr), with the mid-1980s even exhibiting a rate of 5.3 mm/yr (Holgate, 2007), this newest analysis of the most comprehensive data set available suggests that there has been no dramatic increase – or any increase, for that matter – in the mean rate of global sea level rise due to the historical increase in the atmosphere’s CO2 concentration.[Therefore, there is no evidence of any human influence on sea levels]
The paper:
Trends and acceleration in global and regional sea levels since 1807. Global and Planetary Change 113: 11-22. Jevrejeva, S., Moore, J.C., Grinsted, A., Matthews, A.P. and Spada, G. 2014.
We use 1277 tide gauge records since 1807 to provide an improved global sea level reconstruction and analyse the evolution of sea level trend and acceleration. In particular we use new data from the polar regions and remote islands to improve data coverage and extend the reconstruction to 2009. There is a good agreement between the rate of sea level rise (3.2 ± 0.4 mm·yr− 1) calculated from satellite altimetry and the rate of 3.1 ± 0.6 mm·yr− 1 from tide gauge based reconstruction for the overlapping time period (1993–2009). The new reconstruction suggests a linear trend of 1.9 ± 0.3 mm·yr− 1 during the 20th century, with 1.8 ± 0.5 mm·yr− 1 since 1970. Regional linear trends for 14 ocean basins since 1970 show the fastest sea level rise for the Antarctica (4.1 ± 0.8 mm·yr− 1) and Arctic (3.6 ± 0.3 mm·yr− 1). Choice of GIA correction is critical in the trends for the local and regional sea levels, introducing up to 8 mm·yr− 1 uncertainties for individual tide gauge records, up to 2 mm·yr− 1 for regional curves and up to 0.3–0.6 mm·yr− 1 in global sea level reconstruction. We calculate an acceleration of 0.02 ± 0.01 mm·yr− 2 in global sea level (1807–2009). In comparison the steric component of sea level shows an acceleration of 0.006 mm·yr− 2 and mass loss of glaciers accelerates at 0.003 mm·yr− 2 over 200 year long time series.
Full paper with figures is available here: http://www.sciencedirect.com/science/article/pii/S0921818113002750#f0015
Is there any way to tell in which areas the coast and sea bed dropped, accounting for these changes?
Gregory said at 6:09 pm
Is there any way to tell in which areas the coast and sea bed dropped, accounting for these changes?
Try this link:
http://www.psmsl.org/train_and_info/geo_signals/gia/peltier/
Gregory says:
========
http://www.sonel.org/IMG/png/ulr5_vvf-2.png
Someone tell Gov Brown that he can leave his wading boots and life preserver at home
now. And scrap those plans for relocating LAX.
Reblogged this on Power To The People and commented:
@TomSteyer Buys @HarryReid http://freebeacon.com/blog/tom-steyer-buys-harry-reid/ All the money on earth can’t control #climate only God http://youtu.be/OP3bRZl8Xmk
This is going to raise h*ll with the alarmists… Bummer!
They never got the memo, “It’s worse than we thought. Or else.”
If you look up Colorado Univeristy’s Sea Level Research Group
http://sealevel.colorado.edu/
on the Internet WayBack Machine
https://archive.org/web/web.php
and look up the data from March 27 2004 (#version_2004_rel1.2) and do an analysis you will find that in 2004 the rate of sea level rise for 1992.928 – 2003.842 was 2.6 mm/yr.
Today (#version_2014_rel3) you will find that the rate of sea level rise for that same time series 1992.96 – 2003.819 is 3.5 mm/yr. A change of nearly a millimeter per year.
The historical data has been rewritten.
@Steve Case I noticed once that the rate seemed to increase between datasets, too. You can play with the URLs and go back at least 3 years, ex:
http://sealevel.colorado.edu/files/2014_rel3/sl_ns_global.txt
http://sealevel.colorado.edu/files/2011_rel1/sl_ns_global.txt
I plan to make a page that will let you analyze rates between different versions of their dataset over the same time period of data, I just haven’t gotten around to it yet.
From what I understand about things like the viscosity of water & gravity, the actual rate of sea-level rise can’t vary between locations on any long-term basis. Now, you do have things like isostatic rebound & subsidence, but those should tend to average out over a large enough number of tide gauges.
That is, unless the Earth itself is changing size.
*cue spooky music*
The paper does quote an acceleration, but for the period 1807-to 2009, which seems an odd period to quote as we’d be most interested in whether or not anthropogenic emissions had caused an acceleration in sea level rise. Comparing 1900-1950 and 1950-2009 would seem sufficient.
“So which rate is closest to the truth?”
NONE !
They are error ! and the papers are dog-s[..]t (a lower and more disgusting form of Bulls[..]t) !
[language. Mod]
Stark Dickflüssig says:
May 20, 2014 at 6:45 pm
That is, unless the Earth itself is changing size.
*cue spooky music*
===================
The underlying assumption is that the basin is a fixed size, which is preposterous. There are 15,000 volcanoes in the oceans. Tectonic plates are sliding all over the place. Rivers dump mountains of sediments into the seas. MSL is a concept, not a value.
Tide gauges without GPS for tectonic uplift/subsidence can say nothing on average. And GPS without local correction is not designed to be this accurate. And the rates found here disagree with the NASA sat altimetry data that everybody else uses. Just wrote for the next book about that.
All of which just proves the uncertainty monster is alive, well, large, and very scary.
Well I wouldn’t exactly say that “this newest analysis of the most comprehensive data set available suggests that there has been no dramatic increase – or any increase, for that matter – in the mean rate of global sea level rise due to the historical increase in the atmosphere’s CO2 concentration.”
The authors themselves say:
“We estimate an acceleration of 0.02 ± 0.01 mm·yr− 2 in global sea level by the conventional method, defining the acceleration as the second derivative of sea level with time (twice the quadratic coefficient), measured in mm·yr−2.”
“long term estimates of time variable sea level acceleration in 203 year global reconstruction are significantly positive, which supports our previous finding (Jevrejeva et al., 2008a), that despite strong low frequency variability (larger than 60 years) the rate of sea level rise is increasing with time.”
“The contribution from two components of sea level—melting of glaciers, and thermal expansion of the ocean, provide evidence of acceleration of 0.006 mm·yr− 2 and 0.003 mm·yr− 2 respectively (Fig. 16) since 1800. …At the same time steric sea level rise during the 20th century is determined mainly by increased anthropogenic forcing (Gregory et al., 2006).Greenland mass loss since 1840 shows an acceleration of 0.002 mm·yr− 2 (Box and Colgan, 2013). We cannot fully account for the 0.02 mm·yr−2 acceleration in the GSL12 reconstruction with these contributions alone. Accelerating mass loss from Antarctic and Greenland ice sheets since 1992 [Rignot et al., 2011] is an additional source of the recent sea level acceleration.”
They also point out that the choice of glacial isostatic adjustment datasets make a difference in the estimates and that better estimates are needed, especially in the Arctic and Antarctic.
I wish I could find the letter from BOM some years ago. They stated that sea levels would rise 177MM by 2050. It could have been 2100 for all I can remember. So where is the panic. Land does sometime sink, not much. Well done those people?
Figure 3 seems to show a leveling off in the past ten years or so (!).
Here’s the full text of the paper:
http://nora.nerc.ac.uk/504181/
Bush Bunny, a number of recent SL studies show a deceleration in SLR and the current rise is about 177mm or about 7 inches by 2100. ZIP difference to the 20th century.. And the 2014 Leclercque et al world glacier study shows that glacier retreat has slowed since 1950 or exactly the opposite to CAGW theory. IOW there’s ZIP evidence to show for CAGW at all.
somewhere on the Colorado University Sea Level site I saw where it says that their numbers are not meant to be used to gauge the relation of sea level to land. I cant seem to find it now…
I very much like that the seal level rise estimated in this study very closely matches the SF tide gage rate of 1.92 mm/yr since 1897. The NOAA data for SF also shows no discernible acceleration over time and the last 10+ years look look a decrease in rate (could be flat or dropping).
Neville yes I know, this letter, that I can’t find, but it wasn’t destroyed, is millimetres less than CM.
I seem to have found deaf ears with Tony Windsor stating this fact. He wiped me off years ago and I was once one of his staunch supporters and workers.
I have been searching for a sea level rise at the end of the 20th century that would reconcile the 20th century’s average rise rate of 1.8mm/year with the satellite era average of about 3mm/year.
My findings so far have been published in a series of posts, with more to come. An index of these posts can be found here…
http://climatesanity.wordpress.com/the-search-for-acceleration/
No Correlation Between Man-Made CO2 and Sea Level Rise Acceleration
According to the latest IPCC report (2013), sea levels rose at a rate 1.7 mm per year, or at a rate of 6.7 inches per century, between the years 1901 and 2010.
If Antarctica is melting faster because of man-made CO2, we should have necessarily seen a steep acceleration of sea level rise in the scientific record since about the 1950s to the present, as anthropogenic CO2 began it’s steep rise in the late 1940s, early 1950s, as shown on this epa.gov graph:
http://www.epa.gov/climatechange/images/ghgemissions/TrendsGlobalEmissions.png
But we don’t see that. Instead, peer-reviewed scientific papers tell us that, from the 1950s to the 2000s, sea level rise rates have slowed, or decelerated.
http://onlinelibrary.wiley.com/doi/10.1029/2006GL028492/abstract
The rate of sea level change was found to be larger in the early part of last century (2.03 mm/yr 1904–1953) in comparison with the latter part (1.45 mm/yr 1954–2003).
So, from 1904 to 1953 (50 years), CO2 ppm levels increased by ≈15 ppm, and sea levels rose by 2.03 mm/yr.
From 1953 to 2003 (50 years), CO2 ppm levels increased by ≈75 ppm, and sea level rose by 1.45 mm/yr.
Thus we can conclude that sea level rise decelerated by 40% during the same span of years that CO2 levels were increasing by 500% (15 ppm to 75 ppm), an inverse correlation.
This establishes a strong lack of correlation between CO2 amplification and sea level rise acceleration.
And if there is a lack of correlation between CO2 amplification and sea level rise acceleration, then it cannot be said that CO2 absolutely causes sea level rise acceleration. Further, it may be concluded that man-made CO2 does not cause accelerated rates of ocean heating, ice sheet and sea ice melt, or surface temperature heating.
Further peer-reviewed papers (abstract summary highlights) that have determined a deceleration trend since anthropogenic CO2 emissions began rising:
http://multi-science.metapress.com/content/q7j3kk0128292225/
For the last 40-50 years strong observational facts indicate virtually stable sea level conditions….contradicting all claims of a rapid global sea level rise, and instead suggests stable, to slightly falling, sea levels.
http://www.bioone.org/doi/abs/10.2112/JCOASTRES-D-10-00141.1
The analysis reveals a consistent trend of weak deceleration at each of these gauge sites throughout Australasia over the period from 1940 to 2000.
http://www.sciencedirect.com/science/article/pii/S0378383912000154
However, long term tide gauges, recording sea levels worldwide, as well as along the coastline of Australia, and within the bay of Sydney, do not show any sign of accelerating sea level rises at present time.
http://multi-science.metapress.com/content/k3xg21881l4k0161/
The paper shows that locally and globally measured data, collected over short and long time scales, prove that the claim of sea level sharply accelerating is false.
http://www.eike-klima-energie.eu/fileadmin/user_upload/jaeger/Moerner_Parker_ESAIJ2013.pdf
We revisit available tide gauge data along the coasts of Australia, and we are able to demonstrate that the rate may vary between 0.1 and 1.5 mm/year, and that there is an absence of acceleration over the last decades.
http://www.bioone.org/doi/abs/10.2112/JCOASTRES-D-10-00157.1
We analyze monthly-averaged records for 57 U.S. tide gauges in the Permanent Service for Mean Sea Level (PSMSL) data base that have lengths of 60–156 years…and 25 gauge records having data spanning from 1930 to 2010 are analyzed. [W]e obtain small average sea-level decelerations.
http://multi-science.metapress.com/content/575k5821r2w23t73
Morphological and stratigraphical observational facts in the Sundarban delta provide data for a novel sea level reconstruction of the area. This sea level documentation lacks traces of a global sea level rise. This implies totally new perspectives for the future of Bangladesh. No longer are there any reasons to fear an extensive sea level inundation in the near future.
All this stuff is hard to believe for a numbnuts like me. The seas are constantly moving up and down – waves and swells, and moving around with tides, the land is rising and falling in different places, and so presumably is the seabed, so for someone to measure the total to within millimetres boggles the imagination, if they could get it within the nearest couple of feet with any accuracy I would be surprised. (sorry for the long sentence)