Forums > General Discussion   Shooting the breeze...

Rising seas, removing ships.

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Created by elbeau > 9 months ago, 22 Jul 2015
elbeau
WA, 988 posts
22 Jul 2015 8:17PM
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I have wondered with the possibility of the sea rising, what a difference removing all the ships would make?
Then a further thought occurred, what if we removed all the fish?
Wonder no further Seabreezers.
Here is the answer.
You're welcome

Ships How much would the sea level fall if every ship were removed all at once from the Earth's waters?-Michael TojeAbout six microns-slightly more than the diameter of a strand of spider silk. Archimedes' principle tells us that the water displaced by a ship weighs as much as the ship itself. If we can figure out the total weight of all the world's ships, we can figure out how much water they're displacing, then divide that volume by the surface area of the ocean to figure out how much the water level would drop.Weighing ships is confusing. There are a bunch of different measurements of the size of a ship, and many of them, like gross tonnage, are actually measures of the volume of the ship's rooms and other internal spaces, not its weight.The UN Conference on Trade and Development publishes estimates of the size of the world shipping fleet.What the UNCTD publishes is "deadweight tonnage", which is the maximum weight of the ship's fuel, cargo, and crew. What we want is "displacement". Unfortunately, comprehensive numbers for displacement are harder to find.Fortunately, we can estimate it. Brian Barrass's book Ship Design and Performance for Masters and Mates gives a table of ratios of deadweight tonnage to displacement for different types of ships.Extrapolating from the last few years of UNCTD data, and using the coefficients from the book, suggests that the world fleet weighs about 2.15 billion tons when fully loaded. The main component of the fleet by weight is oil tankers and bulk ore-carrying ships, which make up over two-thirds of the total. (The UNCTD data doesn't include small recreational boats or naval fleets. However, based on some numbers for naval fleets and recreational boats, neither one contributes much to the total.)A ton of water is about a cubic meter. 2.15 billion cubic meters divided by the surface area of the oceans equals about 6 microns (0.006 mm).But you don't have to worry about that six-micron sea level drop. The oceans are currently rising at about 3.3 millimeters per year due to global warming (through both glacial melting and thermal expansion of seawater).At that rate (normalized for seasonal variation and short-term fluctations), if you removed every ship from the ocean, the water would be back up to its original average level in 16 hours. Sea levels will likely rise a few feet by the year 2100. Current fish wet biomass is about 2 billion tons, so removing them won't make a dent either. (Marine fish biomass dropped by 80% over the last century, which-taking into consideration the growth rate of the world's shipping fleet-leads to an odd conclusion: Sometime in the last few years, we reached a point where there are, by weight, more ships in the ocean than fish.)And what about the old joke about how much deeper the ocean would be without sponges? While estimates of sponge biomass are hard to come by, the answer is probably that if you removed all the sponges, sea level would drop by no more than a few microns ... and much less if you squeezed them out first.

Pitbull
WA, 1267 posts
22 Jul 2015 8:20PM
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It appears the ICE epidemic has arrived on seabreeze.

elbeau
WA, 988 posts
22 Jul 2015 8:27PM
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Removing the ICE would make little difference because

Assume we have one cube of ice in a glass of water. The ice displaces some of that water, raising the height of the water by an amount we will callh .Archimedes' principle states that the weight of water displaced will equal the upward buoyancy force provided by that water. In this case,
Weight of water displaced=m water displaced g=ρVg=ρAhg
whereV is volume of water displaced,ρ is density of water,A is the surface area of the glass andg is acceleration due to gravity.Therefore the upward buoyancy force acting on the ice isρAhg .Now the downward weight of ice ism ice g .Now because the ice is neither sinking nor floating, these must balance.
Now when the ice melts, this height difference due to buoyancy goes to 0. But now an additional mass m ice of water has been added to the cup in the form of water. Since mass is conserved, the mass of ice that has melted has been turned into an equivalent mass of water.

Sailhack
VIC, 5000 posts
22 Jul 2015 10:45PM
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Cue macro...

lotofwind
NSW, 6451 posts
22 Jul 2015 11:02PM
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Remove the heavy large increasing numbered white pointers and the sea level would decrease by 30%.
Its not global warming that is increasing the sea levels, its the increased numbers of whites. True fact.
Oh,,and the chemtrails that slow the earth's rotation which reduces the gravitation pull = higher sea levels.

And people told me doing chemistry, marine studies and Biology in grade 12 wouldn't teach me anything.

CrossStep
SA, 210 posts
22 Jul 2015 10:51PM
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Desalination plants?

jn1
SA, 2685 posts
22 Jul 2015 10:55PM
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Select to expand quote
elbeau said..

Could you explain how dividing a sphere's surface area, by a cubic volume gives you a differential radius ?. Is this a known formula ?

J

Mark _australia
WA, 23532 posts
22 Jul 2015 9:41PM
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I say just throw more sponges in.


Dawn Patrol
WA, 1991 posts
22 Jul 2015 9:58PM
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Great post. It's an interesting thing to put into numbers, I know I've wondered similar things.

Select to expand quote
jn1 said...
elbeau said..

Could you explain how dividing a sphere's surface area, by a cubic volume gives you a differential radius ?. Is this a known formula ?

J


I'd say the volume errors in that calc would be negligible over these scales.

Cambodge
VIC, 851 posts
23 Jul 2015 12:11AM
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Select to expand quote
elbeau said..
Removing the ICE would make little difference because

Assume we have one cube of ice in a glass of water. The ice displaces some of that water, raising the height of the water by an amount we will callh .Archimedes' principle states that the weight of water displaced will equal the upward buoyancy force provided by that water. In this case,
Weight of water displaced=m water displaced g=ρVg=ρAhg
whereV is volume of water displaced,ρ is density of water,A is the surface area of the glass andg is acceleration due to gravity.Therefore the upward buoyancy force acting on the ice isρAhg .Now the downward weight of ice ism ice g .Now because the ice is neither sinking nor floating, these must balance.
Now when the ice melts, this height difference due to buoyancy goes to 0. But now an additional mass m ice of water has been added to the cup in the form of water. Since mass is conserved, the mass of ice that has melted has been turned into an equivalent mass of water.


Removing the ice from Antarctica could work, though, since it's ice sitting on a landmass. So, if we remove it then there's none left to melt and run into the ocean and raise the sea level. (Probably worth having a chat with Greenland, too). Rising sea levels solved! Someone call the Mad Monk!

Rex
WA, 949 posts
22 Jul 2015 10:38PM
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You could be on to something elbeau, the IMO register has more than 9 million ships on it, not sure how many of those are still displacing water though.

elmo
WA, 8879 posts
22 Jul 2015 10:51PM
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Australia's already ahead of the game on this one

Dig a dirty great big hole, or just join up the little ones the let the water fill them afterwards

tightlines
WA, 3504 posts
23 Jul 2015 12:00AM
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Ok confess, who's been pissing in there wetsuit?

kiteboy dave
QLD, 6525 posts
23 Jul 2015 9:40AM
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Given that the 16 biggest ships alone create the same sulphur pollution as all the cars*, removing all the ships would probably lower the global warming trajectory, slow glacier melting, and lower the projected sea level rise by more than microns.

For those interested, basically crude is boiled and as it heats up different parts evaporate and are taken off and processed, that's how the basic splitting into petrol/diesel/kero/lpg happens. The very thickest parts with all the crap in are called bunker oil or fuel oil and used as ship fuel.


*
www.dailymail.co.uk/sciencetech/article-1229857/How-16-ships-create-pollution-cars-world.html


Cambodge
VIC, 851 posts
23 Jul 2015 10:29AM
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kiteboy dave said..
Given that the 16 biggest ships alone create the same sulphur pollution as all the cars*, removing all the ships would probably lower the global warming trajectory, slow glacier melting, and lower the projected sea level rise by more than microns.

For those interested, basically crude is boiled and as it heats up different parts evaporate and are taken off and processed, that's how the basic splitting into petrol/diesel/kero/lpg happens. The very thickest parts with all the crap in are called bunker oil or fuel oil and used as ship fuel.


*
www.dailymail.co.uk/sciencetech/article-1229857/How-16-ships-create-pollution-cars-world.html




And with no shipping we also solve the issue of foreign-made goods since there'll be no sea-borne import/export...And there'd be no asylum seekers arriving by boat either...plus there'd be no boats for fishing so the fish stock will recover.

jonnulla
NSW, 74 posts
23 Jul 2015 10:57AM
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Removing all the rocks that i threw in the ocean trying to get the most 'skips' would make a bigger difference, I'm thinking roughly twice the width of spider silk

Mr Milk
NSW, 3121 posts
23 Jul 2015 12:14PM
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Select to expand quote
kiteboy dave said..
Given that the 16 biggest ships alone create the same sulphur pollution as all the cars*, removing all the ships would probably lower the global warming trajectory, slow glacier melting, and lower the projected sea level rise by more than microns.





Now I'm confused. I thought that sulfur dioxide was supposed to reflect sunlight, reducing global warming. Here I find out that is wrong. Somebody tell the geoengineers that they have to throw their plans out.

7tim
VIC, 89 posts
23 Jul 2015 12:44PM
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Select to expand quote
elbeau said..

I have wondered with the possibility of the sea rising, what a difference removing all the ships would make?
Then a further thought occurred, what if we removed all the fish?
Wonder no further Seabreezers.
Here is the answer.
You're welcome




At least put a link if you're going to copy and paste an entire post from xkcd.

33frupus
VIC, 118 posts
23 Jul 2015 1:04PM
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why carnt we just pull the plug out for a while and let a bit out?

pweedas
WA, 4642 posts
23 Jul 2015 11:45AM
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People should train their dogs a bit better.
They soak up gallons of water so if they ran up into the dunes to shake it out rather than shake it all out on the waters edge, it would evaporate into the air rather than run back into the ocean.
That would lower sea levels heaps, and it would make more rain.

Revhead
ACT, 372 posts
23 Jul 2015 2:14PM
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Also, we could do our bit by drinking more. Imagine if everyone took a gulp in 1 day, that'd be heaps off the sea level.
And lots of fountains all over the oceans, how good would it look and heaps of water would be up in the air.



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Forums > General Discussion   Shooting the breeze...


"Rising seas, removing ships." started by elbeau