Just like Archimedes discovered millennia ago, it is well known today that the Arctic ice cap displaces it’s own weight in the water so that when it melts it will not cause a rise in global sea level.
Surprisingly, the National Science Foundation has just figured this out (thanks to someone complaining about it) and has issued a correction to their sea ice page.
The error was first pointed out by commenter Steven Skinner on WUWT on March 25th 2010, who wrote:
The NSF, the U.S. Office of Naval Research, and the Japanese government cooperated in funding a research project called SHEBA (Surface Heat Budget of the Arctic) back in 1997. Considering the big names in funding I was surprised they allowed the conclusion in the last sentence past scientific proof reading before publication. The bit from ‘melting sea ice…’
It’s fixed now, see the BEFORE and AFTER.
WUWT reader Dave Burton, who called NSF on the error and asked for a correction writes in an email to them:
Since the error was on your site for over 6.5 years, misleading readers into believing that melting sea ice contributes to coastal sea level rise, I think it is important that you identify the error on your site, with a footnote which explains what was wrong with it.
I always wondered why I’d get the occasional angry email claiming melting Arctic sea ice would raise sea levels dramatically and “why don’t you get it?” …to which I’d reply “look up the principle of buoyancy”. Now I know.
Further suggested reading: 10 Scientific Laws and Theories You Really Should Know
This thread now resembles a French farce, improbable persons with suspect “explanations” jumping out of unexpected wardrobes… Good while it lasted. Time for my own melting ice cubes in a fine crystal beaker experiment and I won’t divulge the results in the face of any FOI sheet. Or the algorithms.
In light of the 6.5 years of sleepwalking at the NSF with respect to the sea ice, sea level non-relationship, I can see that it’s time to float the Larry Hypothesis:
Belief in AGW dramatically accelerates the progression of Alzheimers disease.
The logic of the experiment that finds an increase in water level escapes me.
Let’s try an experiment with seawater in a container. Fill container half full and seal, (with pinhole for air escape). Place in freezer and cycle to part frozen then to thaw. Find by observation the cycles it takes to fill the container. This is called a “making water” experiment. 😉
Well, I’m very disappointed. We have discussed this at WUWT twice before. Has everyone forgotten so soon?
The answer is, yes, if the sea ice has almost no salt in it (as we are told it doesn’t) then the sea level will in theory rise a few milimetres if all the Arctic ice melts. Which rise of course is negligible. Then it will freeze again next winter and the sea level will drop a few mm.
I even bothered to do the expriment, because it’s easy enough. Why do we talk about theory when we can test that theory? The theory is borne out.
Here is my experiment:
http://i43.tinypic.com/2dhsbyb.jpg
How can scientists get such basic physics wrong?
jaymam says:
October 11, 2011 at 12:32 am ,
“How can scientists get such basic physics wrong?”
What about the salt content of the ice that was lost as it was frozen? If it wasn’t salt water that was frozen, then the experiment is meaningless.
Thanks for the answers about CO2’s “buoyancy”. I cannot look at all the links right now. However…if say we have O2 and CO2 molecules with the same average kinetic energy, since CO2 has more mass it would have a lower average speed,making therefore the CO2 molecules more likely to stay near the ground (the effect should be vastly enhanced where the atmosphere is thin enough to let molecules fly unimpeded for longer times).
What am I doing wrong? (question)
Dave Springer says:
October 10, 2011 at 12:24 pm
mkelly says:
October 10, 2011 at 10:43 am
FrankSW says:
October 10, 2011 at 9:49 am
You can see the effect with simple experiment that can be carried out at home, just pour a gin and tonic, add ice and watch……
I have tried this experiment as stated and with other liquids. Beam, JD, Jameson, etc and I never am able to reach a conclusion as the liquid always vanishes prior to the ice fully melting. Any suggestions?
I have a suggestion. Piss on the ice cubes to fill the glass. Presumably that won’t disappear before the ice melts in the manner of the others.
Modified your suggestion slightly and went with a Salty Dog and instead of salt on lip of glass I put salt directly into glass. (A margarita may work also.) Still failed to get the end with ice completly melted. I cannot fathom want I am doing incorrectly.
Werner Brozek says:
October 10, 2011 at 10:19 pm
“Steve from Rockwood says:
October 10, 2011 at 2:09 pm
3. Volume of Arctic sea ice from PIOMAS is 2.87E+04 cu km.
8. If only 2.6% displacement occurs (fresh versus salt) then 80 x 0.026 = 2.09 mm.”
You seemed to have used only Arctic ice, but Noerdlinger says:
Our total estimate for floating ice in terms of displacement is then 660,000 km3.
So it seems as if he uses total earth floating ice which is 23 times more than your Arctic ice so he gets a number 23 times larger. But is his number correct?
—————————————————————————————
Werner:
Arctic sea ice is estimated by PIOMAS to be 27,800 km3.
Mueller estimates Arctic shelf ice at 575 km2 with an average thickness of 40 m for 23,000 km3
Using sea ice + shelf ice in the Arctic only gives a total 4 mm of sea level rise – the value quoted by Walt Meier.
The 660,000 km3 must include all Antarctic sea + shelf ice.
Anyway – the ‘warmists’ must be trying desperately to ignore the brisk rate at which the sea ice is increasing again this autumn…
“Steve from Rockwood says:
October 11, 2011 at 5:47 am
The 660,000 km3 must include all Antarctic sea + shelf ice.”
I quoted the following right from page 13 of their 28 page document:
“Our total estimate for floating ice in terms of displacement is then 660,000 km3.”
For some reason, I cannot get the URL, but when I google “total ocean sea ice volume”, the following is one of the things showing up:
[PDF]
Melting Sea Ice will Raise the Ocean Level
home.comcast.net/~pdnoerd/NoerdlingerBrower.pdf
File Format: PDF/Adobe Acrobat – Quick View
by PD Noerdlinger – Cited by 8 – Related articles
freezes into sea ice, a similar decrease in effective ocean volume, equal to 2.6% of … explicitly or implicitly, on the assumption that the total meltwater volume …
At http://www.johnstonsarchive.net/environment/waterworld.html
the following appears:
–floating ice only ~620,000 (km3)
Ferdinand – would you have the equivalent for inversion_co2.jpg for O2 or any other gas please?
Stephen Skinner – The settling out speed of CO2 in our atmosphere is too slow for the speeds with which the atmosphere circulates/moves/overturn – doesn’t that make the IR properties of CO2 hardly relevant, dwarfed by conduction/convection exchanges between CO2 and the other atmospheric gases?
It’s a cycle, dudes. When sea water freezes, it dumps most of its salt, slightly increasing the salinity and density of the remaining water, but also slightly increasing the volume. This is counterbalanced by the raising of some of the frozen water into the air, as it now occupies more volume than the water phase would have. So not much net change. Then, when it melts, it re-dilutes the water and all is as it was before. All in all, negligible effects all round.
re: the experiment at physorg.
I suspect that the ruler is placed backwards (if I was to do this experiment I would want my numbers to increase as water level rose and not decrease) so as we cannot make an assumption as to the depth of the beaker. Thus making approximation of the size of the ice cube pointless if trying to work out whether it was touching the bottom of the beaker at the start of experiment..
re: the experiment at physorg.
I suspect that the ruler is placed backwards (if I was to do this experiment I would want my numbers to increase as water level rose and not decrease) so as we cannot know the depth of the beaker. Thus making approximation of the size of the ice cube pointless if trying to work out whether it was touching the bottom of the beaker at the start of experiment. Also is that beaker getting narrower or is that an optical illusion? Lesser minds want to know.
PS: if allowed through moderation please delete my earlier similar comment as I made dumb grammatical errors
re: the experiment at physorg.
I’ve replicated the experiment, with (as I expected) the opposite result. I floated a big 18 oz chunk of ice on (simulated) sea water, sealed the container with plastic wrap (to avoid evaporation/condensation). I then photographed what happened.
What happened, of course, is that when the ice melted the water level was unaffected.
http://www.burtonsys.com/climate/sea_ice/
daveburton, I get the opposite result from you.
i.e. when pure ice floating in salt water melts, the level rises slightly – as physics predicts, and as we have thrashed out twice before at WUWT. Any experiment that does not show that is wrong.
http://i43.tinypic.com/2dhsbyb.jpg
I am not considering the levels before the ice cube was created, just pure ice in sea water. The whole effect on sea level is trivial at all times, but there is a slight rise. Let us be truly scientific and agree with that. Yes of course when the ice freezes in the first place (with or without salt in it) the levels will change. The original claim stated (deceitfully) that “when [Arctic ice] melts it will not cause a rise in global sea level” and did not consider level changes when the ice first froze.
jaymam, a few questions about your photos:
1. Are those two different photos of the same container, or two different containers?
2. Did you seal the container(s), to prevent evaporation/condensation from affecting the result? (A chilled glass can condense a lot of water out of the air in an hour!)
3. What is the salinity of the saltwater that you used? Was it a realistic approximation of seawater?
4. How much saltwater did you use, and how much ice did you float on the saltwater?
5. Why does the surface of the water in the 2nd photo appear to be uneven? Is it still frozen? Why?
6. It is important that you measure water-level far enough away from the ice that you’re not really measuring the top surface of the ice. In your right-hand photo, did you ensure that the ice was far enough from the edge of the container that it wasn’t causing a false elevation of the liquid water level? (I don’t think so!) You can see the effect I’m talking about, where ice close to the edge of the container causes a local increase in the (frozen!) water level, without affecting the liquid water level elsewhere, in this photo.
Let’s be truly scientific and agree with this: when water floating at the top of the open ocean changes in density (regardless of whether it is frozen, liquid or slush), it causes a purely local change in sea level. When the floating water’s density goes down (i.e., its volume goes up), as when it freezes or warms, it floats a bit higher, but its displacement does not change. Unless its density increases to above that of the surrounding ocean (which never happens), there can be no effect whatsoever on sea levels elsewhere when its density changes. When it freezes its density goes down, and when it melts its density goes up (and its top surface goes down), but those are a strictly local effects which do not change sea levels elsewhere at all.
Now there is a minute, theoretical, eventual, secondary effect, due to the fact that meltwater eventually mixes with the surrounding ocean, and reduces its salinity. As long as the less-salty water stays in the top layer of the ocean (as is its tendency, because it floats), it still has no effect on coastal sea levels. But when it eventually mixes into the ocean depths, and reduces the salinity of the water there, that water’s slightly reduced density will have a (very, very tiny) effect on coastal sea levels. But it takes hundreds of years for much of the surface water to find its way to the ocean’s depths.
jaymam says:
October 11, 2011 at 10:09 pm
“daveburton, I get the opposite result from you.
i.e. when pure ice floating in salt water melts, the level rises slightly – as physics predicts, and as we have thrashed out twice before at WUWT. Any experiment that does not show that is wrong.”
jaymam, not sure if you read in Richards post above: October 10, 2011 at 9:29 pm
“When sea water freezes there is “brine expulsion” which is supposed to make the floating ice almost pure water. I do, however, see a recent thesis saying this is not so:” – see also the link to the paper there.
Furthermore it was mentioned that ice density varies in ice shelves where lower levels are compressed by the higher level, not sure how significant this is but could be.
If all floating ice and shelves melts it was calculated it would increase sea level with 4 cm (all floating north hemisphere floating ice would generate 2 mm). If the above 2 mentioned points are taken into account not sure if there is anything left of the 4 cm. This is more or less a theoretical discussion as true as the one: when we all go to bath in the sea in summer sea level are rising with 4 microns.
May I suggest the following to be done in the experiment:
1. Use a calibrated laboratory cylinder in the first place, not that useless steel scale, which could be tilted.
2. Use a highly concentrated salt solution (after all you are trying to prove whether the effect is there and not measure the quantitative effect)
3. Use plenty of Ice (again for the above reason)
4. Mount your camera on a tripod at approx the water level. This will ensure the two pictures are taken at the same level
The water level should rise.
But as pointed out since the ice is frozen from the sea water and the salt is expelled and redissolved in the water the effect in the sea should be effectively negligible.
I thought that WUWT discussions had already settled this matter. Why do we bother having complex theoretical discussions at WUWT when we can’t even agree on one of the earliest scientific experiments, that of Archimedes?
Unlike the climate alarmists, I’m not prepared to use misleading facts to try to win an argument.
Please note well, I am ONLY talking about a lab experiment where pure ice melts when it is floating in sea water. I and others contend that the level of water rises slightly when the ice melts, and that physics predicts that, and that that physics is not wrong.
Granted that the sea level sank when the ice froze so there is no nett difference.
Granted that if the icebergs are as salty as the sea water there will be no change in sea level when they melt. Please let’s not revisit all that.
Granted that if Professor Andrew Shepherd’s worst fears happen and the sea level rises by 49 micrometers every year, after 20 years the sea level will have risen by 1mm, that’s
one whole millimetre. (How will we tell?)
It doesn’t matter whether or not Arctic ice freezes with salt in it or not, because we are talking about a simple experiment that you can all do at home. Please all do it and let us know your results. I’m redoing the experiment with sea water, not that the amount of salt actually matters since it’s a principle that we are discussing here.
And please read the earlier discussion where I thought we agreed that yes the level does rise when pure ice melts, particularly wayne’s comments:
http://wattsupwiththat.com/2010/04/30/climate-craziness-of-the-week-msm-jumps-on-alarming-headline/#comments
wayne says:
May 1, 2010 at 8:28 am
…
“You know, when I first read this article this morning I was saying the same thing you are saying. Archimedes wrong in this case, poppy cock! But I love physics and I just had to test this out. These are the weird things that make physics enjoyable and fascinating.
So I went to wiki and got the densities of ice, water, and sea-water. Set up a thought experiment with 10x10x10 cm cube beaker (1000 ml) with a 500 cm3 (or ml) cube of ice in it and then fill it to the brim with sea-water. Get that in your mind. The ice sticks ~10% above the rim of the beaker of coarse.
The rest is rather easy to calculate, but I will be darned, he is correct. The volume of the melted ice, even though it sticks out of the beaker will be larger than the “hole” that the floating ice creates and occupies in the sea water. Amazing. I spent a good bit of today checking and double checking the calculations. I kept coming up with 2.5%, not 2.6% difference. Close enough.
Now that’s interesting to me. If he’s right (and now me), and it appears it is so, and it’s proper physics, then he deserves at least a nod for his honesty and foresight. Here is some unexpected science. We have seen so many things coming out of the AGW camp that are blatantly distorted, manufactured, and manipulated in science and physics that is hard to believe that any thing coming out from that side is true. But this one does appear so.
But put it in perspective, I also calculated base on that 2.5-2.6% difference and the effect is TINY. As I stated above, ALL of sea ice in the entire world if melted at once would only raise the oceans 7 millimeters, not centimeters. That’s about the width of a pencil or the diameter of a pea. If you were standing at sea level the rise would barely cover the soles of your shoes. Now that’s comical! How do you make a scare story from that?
But if your interested in a quirk about Archimedes principle, here are the three densities to compute it yourself, 0.9167 for ice, 1.0 for water, and 1.025 for sea water all in g/ml (same as g/cm3). The key is the volumes, not the mass that does this since water expands when frozen and salt water is ~2.5% denser than water, so Archimedes was still right all along, he was only measuring mass.”
“so Archimedes was still right all along, he was only measuring mass”
Nope.
Yes Archimedes was still right all along, but he was measuring weight not mass. Archimedes principle doesn’t work in the absense of gravity.
And you do not need the density of ice to compute the %age volume increase. It is directly proportional to the density of the salt solution, so that is all you need (the density of the salt solution).
Re: “The volume of the melted ice, even though it sticks out of the beaker will be larger than the “hole” that the floating ice creates and occupies in the sea water…”
Your misconception, jayman, stems from your assumption that the lower-density meltwater will “push aside” (displace) as much normal seawater as an equivalent volume of normal sea water. It won’t. It displaces an equivalent mass of normal sea water.
The remaining volume of meltwater, or mixed melt and seawater, rises up, in place, creating a locally elevated sea level, but having no effect at all on sea levels beyond the area of ocean to which the meltwater actually flows/mixes.
In a beaker, the meltwater immediately flows throughout & mixes with the whole body of water. But that is not the case in the open ocean. There the lower density liquid water rises up in place, just as lower-density solid (frozen) water does.
It doesn’t matter whether the water is solid, liquid or slush, nor whether it contains voids/bubbles. Its displacement is the same in any state, because its mass is the same. As long as its density does not exceed that of the surrounding seawater (which it never will) its varying density has no effect whatsoever on sea level elsewhere.
Now, when the water is liquid, it gradually mixes with the surrounding ocean, and eventually (by which I mean hundreds of years) the lower density & salinity sea water which results from mixing with meltwater will find its way into the ocean depths. A reduction of density there will affect sea levels everywhere (to a miniscule extent). But density changes in water at the surface have no effect at all on sea level elsewhere.
Not just immeasurably small, but truly zero.
Now, if you do the experiment in a beaker, in the lab, there are important differences from the real ocean. Since the container is small, It takes very little time for the meltwater to mix with and reduce the salinity throughout the beaker. The small size of the beaker means that there’s really no such thing as locally elevated sea level unless some of the water is frozen solid; when the water is liquid, it quickly mixes throughout (unlike in the ocean). However, the effect on water density of the change in salinity is still small.
Take a look at these three pictures:
http://www.burtonsys.com/climate/sea_ice/PA110069_closeup3a.png
http://www.burtonsys.com/climate/sea_ice/PA110080.JPG
http://www.burtonsys.com/climate/sea_ice/PA110082.JPG
The first photo was taken shortly after 18 oz (by weight) of freshwater ice was added to 1 gallon of saltwater (at approx. ocean salinity). The ice had raised the water level by roughly 22 mm above the 1 gallon level.
The second photo was taken after the ice had nearly all melted (perhaps a teaspoon remains). In between the two photos, the container did not move, and it remained sealed with plastic wrap to prevent evaporation and condensation. The water levels appear to be identical.
The third photo was taken after the ice melted, and the water had been allowed to stand for a few hours, to approach room temperature. The water level still appears to be unchanged.
Here’s a water density calculator:
http://www.csgnetwork.com/h2odenscalc.html
In my experiment, I added 18 oz (by weight) of freshwater ice to 128 oz (by volume) of simulated seawater (128 oz of fresh water + 4.7 oz by weight of salt). When the ice melted, the water’s salinity was reduced by about 14%, from about 35g/L to about 30.68 g/L. Plugging in a temperature of 1C and the salinities into the water density calculator, and we get:
00.10 g/L NaCl -> 1000.008 kg/m^3 (typical tapwater at 1C)
35.00 g/L NaCl -> 1028.071 kg/m^3 (simulated seawater at 1C)
30.68 g/L NaCl -> 1024.598 kg/m^3 (after dilution with meltwater at 1C)
30.68 g/L NaCl @ur momisugly 15C -> 1022.672 kb/m^3 (after dilution at about 15C)
So, mixing 18 oz of tapwater into 128 oz of saltwater results in a (1028.071 – 1024.598) / 1028.071 = 0.338% reduction in density, or perhaps as much as 0.525% after warming.
The (unfortunately not quite uniform) water column is almost 20 cm high, so I would have expected a 0.0034 x 200 = 0.68 mm increase in depth. It surprises me that it isn’t visible in the photos, which are of sufficient resolution that you should be able to see differences of as little as ~0.3 mm.
daveburton says: October 12, 2011 at 6:01 pm –
Daveburton if pure ice water is floated on saltwater after it melts it will cause the water level to rise.
This is because before the ice melts it displaces its weight of saltwater as per Archimedes principle. This displaced volume of saltwater is less than the volume of melted ice (water) because it is denser. Therefore the total volume increases.
If you want to do the experiment accurately please read what I have written at 1:06 pm. However I have just completed the experiment using a glass measuring cup, using quite a concentrated salt solution and a trayful of ice from the freezer. The level is clearly higher. I have taken photographs which I shall post later.
As I have said the concentration doesnt matter for the effect to take place. The more the concentration the greater the percentage volume increase.
If you have a 1 litre measuring cup. Mix salt in water separately till it is saturated. Pour about 500 mL of the saturated salt water into the measuring cup. Then weigh 250 gms of ice and plonk it in. Wait for it to melt. The volume should increase by ~ 50 mL. You can easily see it and measure it.
Just do it and you can see you are wrong.
Richard says:
October 12, 2011 at 8:52 pm
daveburton says: October 12, 2011 at 6:01 pm –
“Daveburton if pure ice water is floated on saltwater after it melts it will cause the water level to rise.”
Regardless of any experiment that can demonstrate this the line that I took exception to was this:
“In addition to altering salinity, melting sea ice also raises worldwide sea levels, with POTENTIALLY SIGNIFICANT effects for coastal cities and towns.”
This statement and the experiment you carried out make no mention of what actual difference in densities are, in the Arctic. Also the Arctic is not a closed system and the there is no starting point where fresh water is introduced and then frozen. It is also not a salty ocean. What if this experiment started with salty water. Remove half/some and freeze that. Then introduce that to the remaining salty water and run the experiment. Otherwise we are in danger of comparing apples with oranges.
And… the sentance from the NSF is still wrong.
I meant “And… the sentance from the NSF WAS still wrong.