Discussion > A Debating Motion- Sea level rise is a threat.
Nowadays my wisest response to stress is to disengage.
Dec 16, 2014 at 9:47 AM Entropic man
"In psychology, cognitive dissonance is the mental stress or discomfort experienced by an individual who holds two or more contradictory beliefs, ideas, or values at the same time, or is confronted by new information that conflicts with existing beliefs, ideas, or values."
Martin A
Martin A:
Nowadays my wisest response to stress is to disengage.
Dec 16, 2014 at 9:47 AM Entropic man
One of the problems with the likes of Entropic Mann is that they have allowed their mental processes to ossify. They are stuck in one way of thinking, and nothing will make them change their minds/views. Personally, I prefer to keep my thinking fluid, to allow my mind to explore new avenues, and to constantly question every view that I do have. I might accept whatever I am told, but that does not mean that I believe it; I will store the information away, for later verification. In spite of the British education system, I have never had a fear of being wrong, or of failing, or of asking silly questions; it is far less stressful, and considerably more entertaining. I accept that I am not alone in that thinking, as many others on this site display similar attitudes. It is probably the first phrase of that last sentence but one where Entropic Mann is failing; he has been within that system for at least part of his career, on his own admission, which probably leaves the later parts of the sentence inaccessible to him.
Radical Rodent
RR - Yes, I too have never hesitated to ask the potentially dumb question. Surprisingly often, either:
- The lecturer says something like: "Um ,yes. Interesting question. I must think about that. Something doesn't quite add up there".
- Another member of the audience comes up to me afterwards and says "You know, I'm really glad you asked that question. I couldn't understand the point but I assumed it was just me".
Staying in one position for ones's entire career, especially one where the people you are dealing with are not empowered to answer back nor equipped to ask difficult questions can induce a false belief in one's infallibility. It leads to mental ossification as you point out. An awful lot of university lecturers stay in that position all their career - and still republishing essentially the same paper as their first.
Martin A
Latimer Alder, the heat-hiding-in-the-deep-ocean theory does have one thing in its favour: Because the deep ocean is cold, the density changes for a fractional increase in temperature mean that the heat would produce a much smaller volume change than it would if it warmed the, already warm, surface waters. Thus a smaller sea level rise.
Presumably that is why Kevin liked the idea as a place to hide his missing heat. But the other side of the coin is, of course, less alarm about rising sea levels. It's a cruel world.
Because the putative temp changes are so small and of unknown location, it also highlights how truly difficult it is to really account for the multiple variables with one number. But that doesn't stop the people with the models.
michael hart
@Martin A
'Staying in one position for ones's entire career, especially one where the people you are dealing with are not empowered to answer back nor equipped to ask difficult questions can induce a false belief in one's infallibility'
Yep. It's remarkable just how ill-equipped the academics and pedagogues and their hangers-on are when they have to step out from behind the lectern and field questions from all-comers or to a blog where they are not in control of the moderation or the 'ban' button.
The cynical observer might liken them to a football team that plays all its matches at its home ground, against its own reserves and behind closed doors. And then are surprised and terrified to discover that there are plenty of good players outside the stadium who can give them a very good game and win.
Without control of the discussion they flounder and splutter. Or try to take their ball home and refuse to play on the grounds of injury.
Latimer Alder
"Without control of the discussion they flounder and splutter. Or try to take their ball home and refuse to play on the grounds of injury."
And declare victory all the same.
not banned yet
Latimer Alder
When I looked at the sea level rise earlier this year/last year when EM raised the spectre of accelerating rises via the University of Colorado data which, at the time, was showing an acceleration. This later returned to below average. I took the sealevel in the UC data as zero and worked out the annual rises. Then I used Mike's Nature Trick and spliced the two sets. As you say the "acceleration" was greatly reduced suggesting natural variability rather than anything else.
The other puzzle I haven't found an answer to yet is Richard Betts' Lag, which I have seen him mention twice on different blogs.
sandyS
Latimer Alder
You asked about estimating the link between CO2 and sea level rise.
If you make the simplifying assumption that rate of rise is proportional to forcing this calculation can be done.
We estimated current forcing at 0.3W/M^2 as sea level rise at 3.2mm/year.
Using 5.35ln(C/Co) the forcing at 560ppm (one doubling since 1880) increases to 5.35ln(560/400) = 1.8w/M^2.
Rate of rise becomes 1.8*3.2/0.3 = 19.2mm/year. Under "business as usual" that would occur about 2060.
That is 1.9M/century, close to the estimate Richard Betts quoted earlier.
Entropic man
We estimated current forcing at 0.3W/M^2…Nice to have an estimate, but what is the actual figure?
Also… who be “we”?
(Mind you, as you have yet to answer any of the other, quite simple, questions I posited earlier, I do not expect an answer here, either.)
Latimer – you never know, it might be under an "X" somewhere. Let’s face it, that is as likely as any other that has been mooted.
Radical Rodent
What's a good place to search (or ask) for the answer to RR's question - How much sea level rise can be attributed to sediment dumped in the sea by rivers?
Martin A
EM,
So your latest post seems to agree with the "con" position: Since your proffered link between CO2 and slr is fantasy, can we finally conclude that slr is not a threat to civilization? Would you like to debate sea ice, or hiding heat, or ocean acidification? Or possibly something else?
hunter
There's something very wrong in EM's equation. This is my busiest time of the year and I'm too knackered to get my brain working properly, so perhaps one of you engineers could look at it. We're still 160 odd ppm away from a doubling of CO2 since 1880. On what planet will an increase of 160ppm lead to a six times increase in this assumed current 0.3w/M2 “forcing” (God, how I'm coming to hate some of this terminology)? Also, under BAU, it'll be more like 2080 (not 2060) before a doubling is reached, even allowing for an increase in the current 2ppm a year.
Laurie Childs
Martin A
According to Wiki, us humans are to blame for most erosion
Each year, about 75 billion tons of soil is eroded from the land—a rate that is about 13-40 times as fast as the natural rate of erosion
Again from Wiki the density of soil, which is basically what we're talking about is
The density of quartz is around 2.65 g/cm³ but the (dry) bulk density of a mineral soil is normally about half that density, between 1.0 and 1.6 g/cm³. Soils high in organics and some friable clay may have a bulk density well below 1 g/cm³.
So if you used a figure of about 2 g/cm³. and that 90% of the erosion ends up in the sea you'll get the figure for land erosion*. I haven't looked for the data for coastal erosion and volcanic eruptions.
*Numbers plucked from the air by me; if we could link this to Climate Change I'm sure there'd be a research grant in the offing to get a definitive value. Is Climate Change making Soil Erosion more severe and Increasing Sea Levels by an unprecedented amount has a certain ring to it.
SandyS
“forcing” (God, how I'm coming to hate some of this terminology)?
Dec 20, 2014 at 1:16 PM | Laurie Childs
Yes. You are not alone. Hard to say why the term is so vomit-inducing. But a year or two back a nu,ber of BH readers expressed much the same reaction. "a feedback" is almost as bad.
SandyS -
Thanks for that. Yes I think we should hold the inaugural conference on this threat in Rio de Janeiro.
"Soils high in organics and some friable clay may have a bulk density well below 1 g/cm³."
So they will float on water?
With the estimate for the mass of soil erosion (75 billion tons) its density (2 g/cm³),
the volume of water in the ocean (1.3 billion cubic kilometers )
the surface area of the ocean (~3.6×10^8 km2)
it should be possilbe to get an estimate for the mean change in depth. I'll try to do it when I don't have things urgently awaiting my immediate attention.
Martin A
Martin A
As I recall dry peat certainly floats, not sure about anything else.
sandyS
@entropic
'If you make the simplifying assumption that rate of rise is proportional to forcing this calculation can be done'
Sure. And If I make the simplifying assumption that I've just bought the winning lottery ticket, I can guarantee to be richer by Christmas.
But your 'simplifying assumption' misses out the hard bit that ATTP said could be done. All I ask is to see it - all the way through. Not just the easy bits. And some historical confirmation that the metjod in question provides good predictions of sealevel rise.
Good to see that you feel able to rejoin the fray.
Latimer Alder
Sorry - my last post wasn't specific enough to be easily understood.
The calculation in question is to start with a given level of CO2 and from that derive the appropriate sea level rise. We can then check back into history (where we know both) and see how good a predictor the method is.
Latimer Alder
Once again, apologies. I was over hasty. Half an eye on the footie on twitter was not a good study buddy.
Entropic
Please can you work your sums backward and show that they fit the historical record of SLR?
Latimer Alder
Entropic man (9:56 AM): "We estimated current forcing at 0.3W/M^2 as sea level rise at 3.2mm/year. ...Rate of rise becomes ...19.2mm/year"
I'm afraid you're in the deep rough with this one.
First, current anthropogenic forcing is around 2.3 W m-2. [AR5 WG1 Chapter 8 summary] Second, it seems incorrect to attribute the entire sea level rise rate to the anthropogenic forcing, as sea level has been rising fairly steadily since the mid-19th century. [Cf. Jevrejeva et al, cited upthread.] Let's say 1.5 mm/yr is the anthropogenic effect. Then the anticipated sea level rate change due to a further forcing of 1.8 Wm-2 would be 1.8 Wm-2 * (1.5 mm/yr / 2.3 Wm-2) ~ 1.2 mm/yr. Making the total 4.4 mm/yr.
HaroldW
As I recall dry peat certainly floats, not sure about anything else.
Dec 20, 2014 at 4:20 PM sandyS
Yes - I didn't think of dry peat as 'soil' but I suppose that's what it is.
Martin A
Latimer Alder
From AR5.
"These results all indicate that for the past 3,000 to 5,000 years oscillations in global sea level on time-scales of 100 to 1,000 years are unlikely to have exceeded 0.3 to 0.5 m. Archaeological evidence for this interval places similar constraints on sea level oscillations (Flemming and Webb, 1986). Some detailed local studies have indicated that fluctuations of the order of 1 m can occur (e.g., Van de Plassche et al., 1998) but no globally consistent pattern has yet emerged, suggesting that these may be local rather than global variations."
Jeyrwjeva et al describe a continuing acceleration from 1850. Of ours, Law Dome and the Keeling curve describe a similar increase in CO2.
I'll have to do some rate and forcing calculations and think a little.about a hindcast.I'll get back to you.
Entropic man
HaroldW
I'm behind the times. 2.3W is higher than I realised. If it is that high I am indeed overestimating the effect.
If you think 1.5W of that is anthropogenic, the problem becomes, "Where is the other 0.8W coming from?".
Entropic man
Martin A, Radical Rodent
I can save you some time. From previous calculations I know that a 1mm rise in sea level is equivalent to a volume increase of 360 cubic kilometres, or 360 billion cubic metres.(Feel free to check.)
Your 75 billion tons of sediment becomes 37.5 billion cubic metres. This would produce a sea level rise of just over 0.1mm, 3.3% of the current rate of 3.2mm/year.
Entropic man
Entropic man: 'If you think 1.5W of that is anthropogenic, the problem becomes, "Where is the other 0.8W coming from?" '
I didn't say that. 2.3Wm-2 is the AR5 estimate of anthropogenic forcing. Let's take that as a given.
What I did say is that it doesn't seem appropriate to consider all of the 3.2 mm/yr sea level rise rate as a linear response to the forcing, because prior to the forcing (or at least when the forcing was much less), there was a significant sea level rise rate. Jevrejeva et al. 2013 shows a substantial rise rate from 1860-1900: the slope appears to exceed 2 mm/yr, but for the sake of argument I've postulated that 1.5 mm/yr of sea level rise rate is anthropogenic.
[Even allowing all 3.2 mm/yr as anthropogenic, the incremental rise rate attributable to 1.8 Wm-2 of additional forcing would be 1.8 Wm-2 * (3.2 mm/yr / 2.3 Wm-2) or around 2.5 mm/yr. Which would give a rate of 5.7 mm/yr.]
By way of comparison, AR5 WG1 Fig. 13.11 projects (using GCMs) a sea level rise rate in 2060 of around 5 mm/yr for RCP6.0, and 8 mm/yr for RCP8.5.
HaroldW
@harold w
Thank you for drawing our attention to the work of Jevrejeva et al who have extended the sea level reconstructions to 2009.
Remarkably, they seem to show a levelling off in SLR since 2000 rather than the acceleration that some have (wishfully?) thought is happening.
This would seem to be a problem for those who believe that the 'missing heat' that is not showing up in the atmospheric readings is 'hiding in the deep ocean'. Based on this data it ain't showing up as thermal expansion of seawater either.
So if it's not in the atmosphere and not in the oceans, there aren't that many places for it to be concealing itself.
Suggestions anybody? The adjudicators regret that entries containing a map of an island with 'X marks the spot' will not be accepted.