Guest Post by Bob Tisdale
Please see the Update at the end of the post to avoid confusion.
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The paper Purkey et al. (2014) Relative contributions of ocean mass and deep steric changes to sea level rise between 1993 and 2013 was recently accepted for publication at the Journal of Geophysical Research: Oceans. The abstract reads (my boldface):
Regional and global trends of Sea Level Rise (SLR) owing to mass addition centered between 1996–2006 are assessed through a full-depth SLR budget using full-depth in-situ ocean data and satellite altimetry. These rates are compared to regional and global trends in ocean mass addition estimated directly using data from the Gravity Recovery and Climate Experiment (GRACE) from 2003–2013. Despite the two independent methods covering different time periods with differing spatial and temporal resolution, they both capture the same large-scale mass addition trend patterns including higher rates of mass addition in the North Pacific, South Atlantic, and the Indo-Atlantic Sector of the Southern Ocean, and lower mass addition trends in the Indian, North Atlantic, South Pacific, and the Pacific Sector of the Southern Ocean. The global mean trend of ocean mass addition is 1.5 (±0.4) mm yr-1 for 1996–2006 from the residual method and the same for 2003–2013 from the GRACE method. Furthermore, the residual method is used to evaluate the error introduced into the mass budget if the deep steric contributions below 700, 1000, 2000, 3000, and 4000 m are neglected, revealing errors of 65%, 38%, 13%, 8% and 4% respectively. The two methods no longer agree within error bars when only the steric contribution shallower than 1000 m is considered.
The full paper (preprint) is here.
I suspect the high rate of sea level rise east of Indonesia the Philippines (shown in the trend map below from the University of Colorado) is the reason the North Pacific trend discussed in the paper is so high with respect to the South Pacific. That pocket of exceptional sea level rise in the western tropical North Pacific looks suspiciously like an ENSO residual (the residuals from a series of off-equatorial Rossby waves returning leftover warm water from El Niño events). I’ve always wanted to remove that portion of the data to see its impact on global sea levels.
Sea Level Map from University of Colorado.
I recently expressed my opinion about sea level in the post Maybe It’s Time We Stopped Wasting Money Studying a Problem And Spent That Money Adapting to It. I’ll let you provide additional comment on this paper.
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UPDATE: Please read the paper carefully. The 1.5mm/year trend is the MASS component. In other words, it’s the TOTAL rate of sea level rise MINUS the STERIC (thermal and saline) component.
Went through the paper. My only non-expert comment is that the Figures were pretty p*ss-poor graphics.
Coincidentally, this morning the California Water Plan eNews announced release of the Governor’s final update of the 2013 water plan. The link to the 12-volume opus is here:
http://www.waterplan.water.ca.gov/cwpu2013/final/index.cfm
Page 23 of the 35-page executive summary (“Highlights”) summarizes sea level rise up to 66 inches by 2100. This is about ten times the number(s) reported in this WUWT post. Not to worry. The CA policy at:
http://www.coastal.ca.gov/climate/slr/guidance/CCC_Draft_SLR_Guidance_PR_10142013.pdf
is to attribute the difference between measured sea level and computer-modeled sea level as “latent” sea level rise. See Page 124 of the guidance for this summary:
“Ranges of sea-level rise projections that do not start at the year 2000
“The NRC sea-level rise projections use the year 2000 as the base year. Since there has been little, if any, measureable (sic) rise in sea level since 2000 for most locations in California (Bromirski et al., 2011; NOAA Tides and Currents, 2013), there is little reason or justification for adjusting sea-level rise projections from 2000 to a more current start date. All of the latent sea-level rise might occur quickly, providing sea level conditions consistent with the future projections. Thus, when the needed sea level value is a projection of the future sea level that will be experienced by a proposed project for a proposed planning situation, there is no need to adjust the 2012 NRC projections for a different project starting year.”
Their statement makes sense because they treat sea level rise as a planning parameter to be applied regardless of the existing data or trends. This is sort of like the use of 60 degrees C to define standard conditions for gases. It’s an arbitrary decision.
The use of sea level rise without an associated 100 (or 500) year storm surge is a bit dumb. Do they include the storm surge?
No. But FEMA does, without future sea level rise. FEMA uses a 50-year hindcast of tide gauge measurements over the last ~two tidal epochs to estimate the current 1% annual chance extreme high water including storm surge. The two methods are not compatible. There are other complexities and inconsistencies like ad hoc variable future sea level rise. The one I mentioned is only the latest. There are many more official sea level rises going back to the 2001 official state policy of about 36 inches by 2100.
This is the kind of thing that drives me crazy. Whenever some hired gun climatologist or politician quotes SLR , they always use the 90% confidence interval high point and portray it as the most probable value. Even then its not scary enough, so they invoke collapse of the West Antarctic Ice Sheet.
66 inches of “latent” sea level rise? That is approximately equal to a third of all ice in West Antarctica. That ain’t gonna melt quickly.
Simon I am quite confident we had nothing to do with the Ozone hole, It has not change since we started measuring it and we have only been measuring it with any accuracy for about 40 years. The Ozone crisis is another clear case of blame man first, learn later it is nature, not man. I expect that will take another fifty years though. God only knows what future generations will think about the collective stupidity of my generation.
“God only knows what future generations will think about the collective stupidity of my generation.”
Probably they’ll wonder how we ever survived driving places, when all we had was ABS, 12 airbags, auto lane correction, adaptive cruise control, backup cameras, or cars that can only park themselves? Then they’ll ponder how we all survived with cell service that could only provide lethargic 4G coverage on a paltry 95% of the CONUS.
I often wonder what imaginary crisis future generations will be force fed? Global Cooling maybe?
“I often wonder what imaginary crisis future generations will be force fed? Global Cooling maybe?”
… and the terror threat presented by home schoolers, church-goers, raw milk providers, defenders of the Constitution and, of course, anyone who questions climate alarmism.
“It’s Time We Stopped Wasting Money Studying a Problem And Spent That Money Adapting to It….”
thank you!
here in the Netherlands we spent billions of public money in keeping the rising sea out…
again thank you for your advice
The graphic is simply not creditable. Unless some cogent explanation can be given for these bizarre variations, it seems more likely that the data reflects something besides sea level, meaning that the signal has some unrefined noise in it.
The map is interesting. Note the area east of Japan. It looks like a hot spot with ocean current carrying the water to the east. Another spot east of Madagascar. Even the area around the Philippines could have a similar cause as it is sitting north of the equator.
The most recent data on the West Atlantic Ice Shelf is published in Geophysical Research Letters Vol 41,Issue 5,p1576, 2014. If read carefully, Figure 4 shows that the ice shelf as a whole has stabilized(no acceleration) since 2007, and is indeed not collapsing.
Of that mass component of 1.5 mm/year about 0.4 mm/year to 0.9 mm/year can be attributed to groundwater extraction. See: Global depletion of groundwater resources by Yoshihide Wada et al in Geophysical Research Letters, Vol 37, Issue 20.
Also: International Geophysics Volume 75, 2001, Pages 97–119 by Vivien Gornit: Chapter 5 Impoundment, groundwater mining, and other hydrologic transformations: Impacts on global sea level rise
Its it to much to ask how much actual ‘data ‘ they had on sea levels compared to area covered ?
I’m not entirely clear what you are asking, but the answer might be that GRACE coverage was basically global (i.e. the satellites flew (almost) over the poles, thus sweeping a swath of the entire planet from pole to pole and back again every 90-100 minutes. A quick Google search didn’t reveal how often samples were reported, but I’d guess several times a second — which would translate to sampling every few kilometers along the orbital path.
Short answer: Looks to be lots of data covering the whole planet.
Am I correct in thinking 1.5mm is good news if you look at the trend over the last 20,000 years with a 395 ft rise? Height in mm = 395 x 12 x 25 = a rise of 118,500mm in 20,000 years. = 5.925 mm per year. Food for thought?
Oh dear – I’m not sure why Bob T bothers. Please see the update to his post:
And?
Search this title “The Budget of Recent Global Sea Level Rise 2005-2012”
Which is the official NOAA 2012 report written by Eric Leuliett.
Summary
Steric (Argo) 0.2 ± 0.8
Mass (GRACE, Paulson GIA) 1.0 ± 0.2
Steric + mass (Paulson GIA) 1.2 ± 0.9
Total sea level (Jason-1 and Jason-2) 1.6 ± 0.8
Units are mm per year plus or minus the 95 percent confidence interval.
I think Soon has criticized the altimeter calibrations (Jason)
The paper includes full references, including the Paulson GIA. GIA is the so called “glacial isostatic adjustment” that claims that the ocean basin size is increasing.
Thus the need to add another 0.3 millimeters per year to the real data.
Would one of you geniuses please tell me what the REFERENCE POINT is for all these mm/yr measurements? There’s no place on Earth where the tectonic plates are so stable you could use it to measure such a tiny measurement against the scale of the Earth. The shape of the planet is also well known to wobble around on its axis, being pulled and pushed and squeezed by the VARIABLE nearby thermonuclear star and its various planets. How, in hell, do you say this rose 2.25mm/yr when your reference point is jumping up and down who knows how much up and down and sideways in every plane?
What nonsense!
What is of most interest is the total sea level rise, and the contribution of the steric and the mass components, and the heat expansion on different depths. That can tell us about how energies are stored.
“Steric expansion is estimated globally to be adding 1.1 (±0.3)mm yr t SLR from 1993 -2010 [e.g., Cazenave et al., 2009; Church et al., 2011; 2013; Levitus et al., 2012; Rhein et al., 2013]. In the global mean, most of the steric contribution is from anthropogenic warming, with freshening having little net effect on the global mean [Lowe and Gregory, 2006].”
“The upper ocean has expanded the fastest, with warming between the surface and 700 m contributing an estimated 0.7 mm yr from 1993– 2008 to global sea level rise, and the portion between 700 and 3000 m contributing an additional ~0.1 mm yr-1 [e.g., Church et al.,2011;2013]. Below 3000 m, the deep ocean is occupied by two water masses exhibiting different steric trends. ”
“suggest an increase in global ocean mass at a rate of 1.8 (±0.5) mm yr-1 from 2003–2012, accounting for both internal variability and uncertainty in the Glacial Isostatic Adjustment (GIA) [Chambers, 2009; Chambers et al., 2010; Johnson and Chambers,2013]. This result is in good agreement with estimates in changes in land freshwater storage owning to glacier retreat, polar ice sheets loss and anthropogenic freshwater storage of 1.66 (±0.73) mm yr -1 between 1993–2008, despite the difference in time periods [Church et al., 2013].”
“The deep ocean steric contribution is found to add 0.78, 0.40, 0.36, 0.07, 0.06, and 0.05 mm yr-1 from 300–700, 700–1000, 1000–2000, 2000–3000, 3000–4000, and 4000–6000 m, respectively.”
“Finally, we have also estimated the relative importance of the deep ocean to the SLR budget, with the deep ocean steric expansion below 700m equivalent to 65% of the ocean mass contribution to sea level, and 13% below 2000m.”