Last night, Anthony alerted us to another sea level scare study. From EurekaAlert……
Sea levels around the world can be expected to rise by several meters in coming centuries, if global warming carries on.
While the findings suggest that even at relatively low levels of global warming the world will have to face significant sea-level rise, the study also demonstrates the benefits of reducing greenhouse-gas emissions. Limiting global warming to below 1.5 degrees Celsius and subsequent temperature reductions could halve sea-level rise by 2300, compared to a 2-degree scenario. If temperatures are allowed to rise by 3 degrees, the expected sea-level rise could range between 2 and 5 metres, with the best estimate being at 3.5 metres.
…… The new study is using a complementary approach, called semi-empirical, that is based on using the connection between observed temperature and sea level during past centuries in order to estimate sea-level rise for scenarios of future global warming.
That was parts of the press release. We had to wait for the study to be published. Today, you can find it here. The authors are
- Michiel Schaeffer, William Hare, Stefan Rahmstorf, & Martin Vermeer
Our friend Rhamy has been very busy lately. Recall he and Tamino came up with the insightful paper stating that if things were different, our temps would be different. And, that just because the thermometers aren’t showing a rise, it doesn’t mean we’re not getting warmer! I love that piece of work.
Today, I’m a bit torn, while I don’t think they’ve outdone Tammy and Rahmy, I think it is on par with it. I was especially interested in two things the press release stated. One, I wanted to know what “semi-empirical” meant, and I wanted to know how they could use the plural of century when discussing observed temps and sea level. I’m fairly familiar with the various records of thermometers and tidal gauges. There isn’t any data set of observed values which go back centuries which could have the necessary coverage.
So, now I’ve got the paper. To understand semi-empirical, I think it proper to review what empirical means. A dictionary puts it this way…..
- based on observation and experiment: based on or characterized by observation and experiment instead of theory
- derived solely from experience: derived as knowledge from experience, particularly from sensory observation, and not derived from the application of logic
- based on practical medical experience: based on practical experience in the medical treatment of real cases, and not on applied theory or scientific proof
It lists some synonyms as observed, pragmatic, practical, realistic, firsthand.
In the main body of the paper, directly after the abstract, we see this……
Here we examine how emission reductions over the course of the twenty-first century may affect global mean SLR up to AD 2300. We assess a range of scenarios with emission reductions sufficient to meet the global warming goals in the Cancún Agreements with different probabilities. We then analyse the divergence in SLR and rates of SLR by 2100 implied by these and a broader set of emission pathways. The difference in rates of twenty-first century SLR is found to be an indicator for the divergence in post-2100 SLR, but is also important in its own right: higher rates of rise pose a greater challenge to adaptation by ecosystems and socioeconomic systems in the coastal zones.
Multi-century sea-level projections have previously been attempted by process modelling for only the steric component1, 6, by expert opinion7 and with a single-timescale semi-empirical model8. Here we present projections using a semi-empirical model2 for the total SLR, which accounts for multiple timescales of sea-level response and has been calibrated with sea-level proxy data for the past millennium, as well as with tide-gauge data for the past 130 years (Supplementary Sections S1 and S5). On this basis, sea-level projections beyond the year 2100 can now be explored with the semi-empirical method. The finite response timescale accounts for SLR gradually slowing down as it adjusts fully to a temperature change (see Fig. 1 of ref. 9). We used probabilistic parameter estimates derived from palaeodata sets of temperature and sea level over the past millennium (as in ref. 2) to estimate sea level over the coming 300 years (Supplementary Section S2). The sea-level projections are driven by temperature projections of the MAGICC6 climate/carbon-cycle model10, 11. Projection uncertainty ranges here represent 90% uncertainty intervals.
Okay, we have the answers to our questions. Semi-empirical means splicing paleo data to observed readings. They’ve done this with both temp and tidal gauge. So, they’re going back 1000 years using paleo, but adding the last 130 or so with observations. Now, this is funny. First of all, apparently, semi-empirical can mean ~1/8th observation 7/8th extrapolation and fantasy. I’ll explain in a minute.
But, this is what they’re attempting to do. They are projecting various emission scenarios. The problem arises, on this step, is trying to quantify the warming or lack of warming based on emissions. There is no agreed upon x amount of warming with y amount of GHG emissions(sensitivity). Then, they’re gaining a value by trying to establish a relationship between past temps and sea-level response to those temps. First, let’s discuss the instrument record going back 130 years. It has been well documented that global coverage of the thermometer record was too poor to have any useful meaning to any supposed global temperature. To give you an idea on how poor the coverage was for the Southern Hemisphere, here’s a map from GISS from 1880.
For expedience, I borrowed that from Bob Tisdale. Now, Schaeffer uses HadCrut, but there’s almost no difference in the coverage of stations of GISS and HadCrut, especially from the 1880 period. The sea level coverage is worse. One can’t even come up with a proper estimation of sea level using the tidal gauges of today. Here’s a map of the tidal gauges from 1981-2008 with only one year of missing data or less.
We can’t get a proper estimate from the last 30 years, we darn sure wouldn’t be able to get one for the last 130. It’s pure fantasy to believe one can get a global temp or mean sea level from mechanical readings going back this far.
Now we could stop there, but for completeness, why don’t we venture to see what paleo they used. …… this is where it sorta gets fun! You see, Schaeffer et al didn’t really do any of this historical temps to sea level work. They rely on another paper! The paper is Kemp et al 2010. Here are the authors of this paper….. Andrew C. Kemp, Benjamin P. Horton, Jeffrey P. Donnelly, Michael E. Mann, Martin Vermeer, and Stefan Rahmstorf Funny stuff.
Lol, whoa!!!! They’re using the oft discredited works of Mann! It’s fascinating. There has been a plethora of established information, which adequately disputes Mann’s work. But, the alarmists blithely ignore it and pretend this is a factual representation of our past temps. Hilarious. But, that’s not where the hilarity ends….. nope, not by a long shot. We still haven’t found out where they got their sea-levels from. Kemp et al state this in their abstract…..
We present new sea-level reconstructions for the past 2100 y based on salt-marsh sedimentary sequences from the US Atlantic coast. The data from North Carolina reveal four phases of persistent sea-level change after correction for glacial isostatic adjustment.
Okaaayyy… So, we find one place on the earth, based on proxy sea level measurements, (not forgetting the GIA) and then declaring we can know the relationship between sea level rise and temps and then the climate sensitivity to various emission scenarios and how sea level would relate to the precise temps around the globe. Lol, sure they can. On an aside, Kemp et al do run comparisons from their findings of North Carolina to other sea level reconstructions. And after applying different GIA values to the various sites, they say they’re in general agreement with the other sites. (LMAO!!)
Now, clearly, some may be a bit skeptical about the application of proxy temps to proxy sea levels to find such a clear relationship and clear findings as to the sea levels and temps. There should be an outside group look into this and validate the processes. And, there almost is! Here’s a paper………
In it, the authors find…… well I’ll let them tell it…….
We determine the parameters of the semi-empirical link between global temperature and global sea level in a wide variety of ways, using different equations, different data sets for temperature and sea level as well as different statistical techniques. We then compare projections of all these different model versions (over 30) for a moderate global warming scenario for the period 2000–2100. We find the projections are robust and are mostly within ±20% of that obtained with the method of Vermeer and Rahmstorf (Proc Natl Acad Sci USA 106:21527–21532, 2009), namely ~1 m for the given warming of 1.8°C.
Well, that’s good the authors have validated the method of Vermeer and Rahmstorf……… cause they got mostly within +/-20%. Hey! It works for horseshoes! So, who were the fellows who validated the methods of Vermeer and Rahmstorf? Which would, in turn validate Andrew C. Kemp, Benjamin P. Horton, Jeffrey P. Donnelly, Michael E. Mann, Martin Vermeer, and Stefan Rahmstorf ? Which then would validate the most recent publication of Michiel Schaeffer, William Hare, Stefan Rahmstorf, & Martin Vermeer? Well, if you haven’t peeked yet, I’m sure you’ve guessed a couple of them by now, Stefan Rahmstorf, Mahé Perrette and Martin Vermeer.
Semi-empirical? No, you can’t even state that 1/20th of the data as empirical. Not that it matters. The use a highly questioned temp proxy, alongside one site on the earth, to gain the sea level. It agrees with other places when one applies a variable GIA, which ranges from 0 to 1.7mm/yr! FFFF……FFFF….. HAHAHAHHAHA!!!! But, all of this is okay, because Vermeer and Rahmstorf have deeply looked at the work of Rahmstorf and Vermeer and have determined that alls well.
This paper is so deeply flawed we can see there isn’t any pretense to objectivity, or diligence. The error bars on each study are so great that when you combine them we see the margin of error increase to the point that the paper is of no utility. The side issue of applying the GIA at such a range is another hilarious aspect of these papers.