I’m on a three week vacation in Norway. I’m programming to open another post in 10 days– so that long comments don’t get too long. Also so people who don’t want to discuss whatever is on a particular thread can switch to the other one.
Open thread: Behave!
Wow Norway. Have fun!
Wow have a wonderful time! Thank you for everything.
Enjoy the “white nights”! Perhaps you’ll get to see an aurora or two.
The Larsen-C shelf iceberg finally broke loose. Story here.
Wonders never cease, the story is actually pretty balanced.
mark –
Thanks for that link. Yes, the balance is surprising for the Guardian. Although they do manage to mention the fact that “[t]here is enough ice in Antarctica that if it all melted, or even just flowed into the ocean, sea levels [would] rise by 60 metres.â€
I was surprised at Luckman’s comment that “most of the shelf [is] thickening.” Hadn’t heard that before.
They’re also slightly inaccurate about writing
[Not the best wording there…the volume of water does increase, but the surface level stays much the same.] Shepherd et al, “Recent loss of floating ice and the consequent sea level contribution” claims a 49 ±8 um/yr increase in sea level due to floating ice melt, because of reduced salinity (decreased density).
mark bofill,
For The Guardian that was remarkably restrained. The saddest part of the whole climate change dogma to me is that it has stopped me from reading the environment section almost entirely, I just get fed up with the human lecturing that has nothing to do with the environment. Must they do this all the time? I’d much prefer circa 1970 Mutual of Omaha’s Wild Kingdom and The Undersea World of Jacques Cousteau to almost anything they put out today. I think it would be more effective and capture more viewers if they simply concentrated on the wonders of nature. There is a place for commentary on man’s impact but it can be handled better without the “woe is me, shame on you” attitude. This article is a good example of that.
lucia,
Enjoy a world where they don’t cover Trump 24/7 like the world is ending. It’s a better place.
Here is how one expects this to be covered by the usual suspects:
https://www.nytimes.com/interactive/2017/06/09/climate/antarctica-rift-update.html
.
Never let a (non)crisis go to waste.
HaroldW (Comment #164061)
“[Not the best wording there…the volume of water does increase, but the surface level stays much the same.]
Shepherd et al, “Recent loss of floating ice and the consequent sea level contribution†claims a 49 ±8 um/yr increase in sea level due to floating ice melt, because of reduced salinity (decreased density).”
–
what are you trying to say 49 Um/year is more or less the sea level staying the same within human eyeball powers.
From how much of the ice melting ?
The whole of the sea ice over 100,000 years.
The Arctic and Antarctic sea ice combined?
Into the whole volume of the earth’s oceans or just the top layer?
Be more precise.
I think the comment was fine.
angech,
Yes, 49 um/year is small potatoes with respect to the ~3 mm/year change in sea level. I recall that one paper estimated about 4 cm as the contribution to sea level if all sea ice disappeared entirely. Which, if it occurred at all, would likely occur in conjunction with a far larger change in sea level due to (land) icecap melt and thermosteric expansion.
One’s typical experience is of ice melting in a glass of water, which displays no change in level. But having read (in papers such as the one I cited) that there is a second-order effect due to salinity, I’m surprised when scientists express the opinion that no change results for the ocean context. It’s important to make a distinction between land ice and sea ice melt, which might not be apparent at first glance to a layman, but I expect to hear “almost no effect” rather than “no effect” from a scientist.
Actually, for the instance given — ice floating in a G&T — I’d expect that the secondary effect, due to diluting the alcohol in this case, would be the other way round, and the drink’s level would decrease marginally due to melting. I calculate about -6% of the ice volume for gin of 40% alcohol by volume (80 proof) sans tonic, or about -2% for a 1:1 (by mass) G&T. Does anyone wish to conduct this experiment? [I don’t happen to have any graduated cylinders at home.] The reward is self-evident, as the experimental matter must be taken care of afterward.
HaroldW,
:>
Busy schedule, but I’ll keep on the lookout for an opportunity to run that experiment for you.
What the icemelt analysis demonstrates rather well is the trivial and insignificant impact of melting sea ice.
Antarctic calving took place in winter, not summer, broke off, didn’t melt off, and while many shleves are long lived, these events are not surprising when ice rushes off the continent at a kilometer per year for much of Antarctica.
HarodW: “But having read (in papers such as the one I cited) that there is a second-order effect due to salinity, I’m surprised when scientists express the opinion that no change results for the ocean context.”
Scientists make mistakes all the time. Since you seem interested in the subject, I point out that equation (1) in Shepherd et al. is incorrect. The correct equation, using their symbols and in the form closest to what they give, is
delta_V = V_fw * (rho*f – rho_fw) / rho
The factor missing from their equation is
f = V_soln / V_pure
where V_soln is the partial molar volume of water in seawater and V_pure is the molar volume of pure water.
.
For ideal solutions, V_soln = V_pure. Then f=1 and the correct equation reduces to the one given by Shepherd et al. But salt solutions are not ideal. Since rho is only slightly different from rho_fw, even small deviations of f from unity can have a large effect on the result. And large deviations are possible; there is no guarantee that V_soln is even a positive number, although I know of no cases where is is negative for the solvent.
.
If people care, I can probably find some actual numbers for seawater. But it is a bit of a hassle.
Mike M. —
Thanks for that. I confess that I didn’t check their equations that closely at the time when I read that paper. I’ll go back and take another look.
By the way, my estimates for the G&T scenario were not based on that equation, but on a table of density vs. alcohol concentration. [Of course, I found that table on the web…]
HaroldW: “By the way, my estimates for the G&T scenario were not based on that equation, but on a table of density vs. alcohol concentration.”
The table of densities should work, but you would have to account for the amount of ice that melts and the resulting change in concentration of the solution. I suspect you would need a dilatometer rather than a graduated cylinder. Shouldn’t cost more than a few $K. 🙂
Mike M.,
I used this table, which gives density corresponding to integer alcohol-by-weight percentages. [The table is for 20°C temp, not quite what is desired. But it’s what I could find quickly.] 40% by volume is about 34% by weight, so I started with that, density=0.94847 g/ml.
Here’s an example of my method. To end up with an integer by-weight percentage, I chose 33 g gin & 1 g ice — after melting, it will be 33% alcohol by weight. Initial volume = 33 g / (0.94847 g/cc) for the gin, plus displacement due to ice of 1 g / (0.94847 g/cc), a total of 35.847 cc. After melting, there is 34 g of (weaker) gin, at a density of 0.95028 g/cc; volume = 35.779 cc. Change in volume is -0.068 cc. The initial ice volume is 1 g / (0.9 g/cc) = 1.1 cc, so the loss is about 6% of the ice volume.
Similar calculation with 24 g gin & 10 g ice (final concentration 24% alcohol by weight) gives a loss of about 5.5% of the ice volume.
HaroldW,
Your method looks correct to me, but I did not check your arithmetic. I note that the formula in Shepherd et al. would give -0.052 cc for your example, an error of 24%.
Alcohol strength is stated either by mass or by volume: If the strength of a mixture of alcohol and water is is stated as 80% by mass, it means that for every 100g of mixture, 80g is alcohol. If the strength of a mixture of alcohol and water is is stated as 80% by volume, it means that for every 100cm3 of mixture, 80cm3 is alcohol.
HaroldW (Comment #164074)
I am confused, nothing new.
Volumes and weights and substances all over the place. Not clear at all. You use mls and gms interchangeably when they are not the same at all if there is alcohol in the mixture.
How do you determine how much alcohol is in gin?
You seem to be using the term gin for pure alcohol by weight and then for an alcohol water mix interchangeably.
Alcohol in water
0.94847 density is for 40.7% volume, not 40%, important with these small numbers.
Ice will sink in 50% volume alcohol in water.
–
Hence 33 gms of gin is meaningless, you either mean 33 gms of alcohol by weight so 77 gms of water, add a Gm of water , 33 gms plus 78 gms is 32. something % by weight not 33%. The volume would be a bit over 101 mls, maybe 102 mls, maths too hard.
If, on the other hand you wish to use 33 mls of alcohol and water, so after melting there is 34 plus mls of weaker mixture, there is no way it can expand 1.847 extra mls to 35.847 mls.
Please redo/redefine your terms and maths.
angech –
Sorry for sneaking in that “ml” when elsewhere I used “cc”…
Let me try to clarify the values in the post.
Gin (in the US) is at least 40% alcohol by volume (abv). The table I used is given for integral percentages of ethanol by weight (ebw), and it contains no entry which precisely corresponds to 40% abv, but 34% ebw is close. The “gin” of the examples is defined to be 34% ebw (40.7% abv). The first example contains 33 g gin & 1 g ice. After the ice melts (and is mixed), the diluted drink is 34 g — total mass is conserved — and is 33% ebw. [The mass of ethanol remains unchanged at 34% of 33 g = 33% of 34 g.]
The initial volume of gin, given that the density of 34% ebw is 0.94847 g/cc, is (33 g)/(0.94847 g/cc) = 34.793 cc. When 1 g of ice is added, 1 g of gin is displaced, so the level in a graduated cylinder would rise by (1 g)/(0.94847 g/cc) to read a total of 35.847 cc. [The actual liquid volume is unchanged by adding ice, but the level in a graduated cylinder is what corresponds to “sea level”.]
When the ice melts, there is 34 g of a 33% ebw solution. Per the table, its density is 0.95028 g/cc. Hence its volume is (34 g)/(0.95028 g/cc) = 35.779 cc.
Hope that helps.
I note that the earlier post used a rough value for the density of ice, namely 0.9 g/cc, whereas a more accurate value per Wikipedia is 0.9167 g/cc. The level of the drink (before or after melting) isn’t affected by this, though. The ice density does enter into the expression of the “sea level” change as a fraction of ice volume. To one significant digit, though, it remains -6% for ice in 34% ebw gin.
thanks sorry to nitpick
angech, No worries. It helped me to write it out a second time, more clearly.
Regarding the huge iceberg which broke off Larsen C, Tom Scharf (#164064) posted about the NYTimes’ take on it. A CNN columnist weighs in, telling us that this event “should freak [us] out”.
….poor snow flakes freaking out bcuz an iceberg broke off from a place where giant icebergs have broken off for millions of years. A coup underway, N Korea doing a slow motion march towards nuke war, Europe committing cultural suicide, and am iceberg freaks out the CNN journalist. I wonder if the starving brutalized people of Venezuela would have any thoughts about the perspective of CNN?
Hunter, put a comment up at Judith’s saying that this event could lead to a small welcome decrease in SST in SH. Probably too small but still should halt any warming and may cause a SH temp drop?
15 years ago I remember an iceberg breaking off in Antarctica that was covered widely. Only later did I read that it was a regular occurrence. I thought the media had wizened up and stopped covering it, but now they are doing it again. Presumably because of the size of the iceberg.
hunter,
We don’t have to worry about nuclear war anymore because the UN just banned it!
https://www.nytimes.com/2017/07/07/world/americas/united-nations-nuclear-weapons-prohibition-destruction-global-treaty.html
Tom,
What a strange negotiation. The ultimate in kumbayah. But the present climate consensus grew out of something even sillier and took years and years of careful positioning and message shaping. The UN is clearly using truly world-class communications at least in respect to moving large groups if elites.
Speaking of scary stories, Hansen et al. claim it might take as much as $535 trillion to remove 1270 GtC from the air by 2100. (To maintain temperature +1.5 deg C above 1880-1920.)
This estimate uses the high end of CO2 extraction costs, and assumes an RCP8.5-ish scenario of ~50 years of 2% increase in emissions, total emissions ~1700 GtC. [Nit: The text says this scenario increases to 25 GtC/year emissions; figure 9 goes up to 27.5.]
Hawking, unlike Hansen et al, can plead that his irrational anti-scientific claptrap is a result of a tragic chronic disease. Hansen et al have no such excuse. Hansen has been given passes on his calls for criminalization of climate skepticism, his delusional garbage about Manhattan flooding regularly as well as saying almost the same thing Hawking (or his voice controller) said about Venus. But the climate hype community is largely silent. I guess only climate fear insiders get to push anti-scientific garbage. Hawking, an outsider, is held to a higher standard.
I dunno. I bet Hansen’s cost numbers aren’t too far off. I expect it *would* be crazy expensive.
Re: Hansen et al.
It’s strange…trying to see what they’ve done, I’ve failed to even reproduce their emissions scenarios of figure 9.
E.g., the “constant” scenario is (per the figure) 9.2 PgC/yr, but their table of historical emissions shows 9.8 Gt in 2015. [Presumably this is GtC, not GtCO2 which would be way off.] Similarly the “+2%/yr” should be double the 2015 value by 2050; the figure shows 18.5 but a spreadsheet says 19.7.
Not to mention the previously-mentioned fact that the high scenario is limited at 27.5 PgC/yr in the figure, but the text says 25 GtC/yr. [Unit note: Pg=Gt]
HaroldW,
Emissions aren’t increasing by 2%/year now. It’s more like 1%, and not even that recently. I’m also not convinced that the emission figures are particularly accurate. While fracking has made the Peak Oilers look foolish, there is a limit to how much, and probably how fast, fossil carbon can be extracted from the ground.
Mark Bofill (Comment #164088): “I dunno. I bet Hansen’s cost numbers aren’t too far off. I expect it *would* be crazy expensive.”
I’d say his numbers are off by 100%, since there will be no need to remove CO2 from the atmosphere.
It is long past time, if the clisci community wants to be credible, to toss Hansen, Romm, Oreskes, etc. under the bus. But they will dither as long as possible. When they finally do toss the anti-science kooks and fear mongers under the bus the gravy train derails.
DeWitt, Harold W,
The current rate of rise does appear to be increasing, but the noise is pretty high, so it is difficult to say for sure. In any case, substituting natural gas (fracked, everywhere!) for coal and rapid construction of nuclear capacity could bend the emission curve downward, especially if there is some progress on batteries for electric passanger cars, and plenty of nuclear power generation. The wild-eyed continue to fight these simple measures and insist on impractical and crazy-expensive solar and wind. Talk about cutting off your own nose to spite your face! The dilusional greens are their own worst enemy.
Mike M.,
Shrug. What it would cost and whether or not it’s needed or justified are separate things of course. I agree; I suspect humanity could come up with something better to do with 535 trillion.
$535 trillion US is a number from some sort of spy movie parody.
The +2%/yr scenario is as unrealistic as RCP8.5 or the 1988 scenario A. But I’ll wager it will be touted as the “business as usual” case.
Another point to bear in mind is that the $535 trillion figure — well, all the figures actually — are total expenditures between now and 2100. As such, they should be discounted when compared to current GDP figures, or compared to future GDP. It’s still a large number, even discounted. But it depends on huge increases in emissions. (And on climate sensitivity which is likely too high as well.)
Thanks for the links on the iceshelf. ( I’m guessing this will stick in moderation).
lucia,
So how us your vacation going?
HaroldW,
RCP 8.5 is very similar to the old A1F1 scenario for atmospheric CO2. At the time, A1F1 was considered worst case, not BAU. BAU was A1B. RCP 6.0 is below A1B for atmospheric CO2.
DeWitt,
If the IPCC would have created an RCP 20.0 scenario everyone would be quoting that as BAU. All emission profiles are technically BAU at this time as they started with the existing trajectory. Anytime I see BAU in the media I know propaganda is about to follow.
The intentional sleight of hand is that most causal readers would interpret BAU as keeping emissions at their current levels and any increases over current levels as exceeding BAU.
DeWitt,
I didn’t mean to imply that the +2%/yr scenario of this paper, or RCP8.5, *is* a business-as-usual case. And they were not referred to as such in the paper/AR5 respectively. In Hansen’s 1988 paper, Scenario B is described as “perhaps the most plausible.”
However, then comes framing. In his Congressional testimony, Hansen referred to his Scenario A as “business as usual”. Others have called RCP8.5 the business-as-usual scenario, or the no-action scenario, as if it represents the natural trajectory of things, absent concerted effort to limit fossil fuel consumption.
I predict that some of those same writers, given the 4 emissions scenarios of this new paper, will interpret the +2%/yr as BAU, rather than an upper bound. Indeed, much of what I have read already gives this impression, something on the order of “if we don’t do something drastic, our grandchildren will have to pay $535 trillion.”
They say that truth is the first casualty of war. In the “climate war”, truth may have been seriously wounded, but qualification, nuance, and even-handedness are DOA.
HaroldW,
I take it back. Two percent/year is about right for 1980-2015 for global emissions. However, it’s all coming from the emerging countries. The mature countries are very nearly flat over that time period. It’s unlikely, however, that the emerging countries will continue to increase emissions at 4-5%/year for another 35 years.
What I don’t get is the effusive praise for the PA and especially China’s actions and then in the next breath quoting RCP 8.5 as BAU. If in particular China can be believed, we are not on a RCP 8.5 trajectory. RCP 8.5 was never realistic for a lot of reasons that aren’t worth going over again. At some point you have to start assuming the world is actually doing something that will bend it off of RCP 8.5.
The litanies produced by the most extreme climate hypesters should really be strongly rejected by anyone who believes in the triumph of the rational and civil. Hansen and others if his ilk are making thinly disguised calls for xenocidal levels of killing of humans. And demanding a huge fraction of the wealth of humanity to achieve that destruction.
ERSST v5 has been released. Has anyone seen what the impact is on trend? Before someone said about 1/3 of trend would disappear.
Per this tweet, ERSST v5 is not much changed from v4 overall, and (by eye) trend difference is perhaps -.03 K over 30 years. Multiply by 70% to get its effect on global average.
Just got back from there on cruise – we stopped at Lofoton Islands, Honingsvaag, Tromso, and North Cape! From there to Iceland (highly recommended)! Land of the Midnight Sun indeed, I looked out of my window at 2:30 AM and the sun was shining.
Hope you are enjoying as much as we did.