[insert your own caption here]
Vancouver Sun/Reuters
ANTARCTICA — Sea levels will rise at varying rates around the world because of a quirk of the earth’s gravity linked to global warming, a leading glaciologist said.
“Everyone thinks sea level rises the same around the world,” David Vaughan, of the British Antarctic Survey, said on Tuesday at the Rothera Base on the Antarctic Peninsula. “But it doesn’t”.
Rises could vary by tens of centimetres from region to region if seas gained by an average of one metre by 2100 as temperatures rise, he said. Worst-affected nations would have to budget billions of dollars more than others on coastal defences.
Vaughan said big ice sheets on Antarctica and on Greenland have a gravitational pull that lifts the seas around them — water levels around Antarctica, for instance, are higher than if the frozen continent were an open ocean.
As ice thaws, Antarctica would get smaller and its gravitational tug would diminish.
UPDATE: With the humorous photo I chose, I may have unintentionally implied that the gravitational effect described is not true. It is and the simplest physics. The likely magnitude and the suggestion of Antarctica melting are the main issues.Ā Here is a paper from MIT that describes Earth’s gravity anomaly and sea level differences. – Anthony
Oh we all know that Antarctica is wasting away. Every couple of years they have to go out and place new towers for automated weather stations because the disappearing snow causes the old towers to fall over. Antarctic stations deep in the interior now stand dozens of feet above the surface they were built on as the surface snow and ice disappear.
Just today the mercury shot up to a blazing -49F at Amundsen-Scott station at the South Pole. With temperatures like that, all the ice should be gone in only eleventy zillion years!
/sarc
Your mama’s so fat she has to wear wellies in the Sahara.
Regards
Andy
lol @crosspatch. Man this is probably one of the most ridiculous (and DESPERATE) attempt at warning people of the dangers of AGW. Now GRAVITY is the cause, what next, TV SHOWS?!
That is what I call a fat cat!
I’ve found the right song lyrics..
“We’re clutching at straws
We’re still drowning
Clutching at straws”
: The Last Straw, Marillion
Problem is… they probably Believe in AGW
So, if I took the ice tray out of my freezer, I wouldn’t be drawn to eat so much food??
David Vaughn is a clown. Really.
I have proof that David Vaughn is a clown……..
“Clown at airport made to take off plastic handcuffs, a bubble-blowing saxophone and metal bits on his costume.
60 year old, childrenās entertainer David Vaughan, aka PC Konk the clown, who dressed in full clown costume was taken to a room and strip-searched by Birmingham airport security after a piece of metal on his costume set off the security alarm.”
Computers predict there is a match.
You do realise that is Cat Porn…and is illegal in 27 states.
Well, if I alter Vaughn to Vaughan, it matches.
A I read this, countries with massive mountains would be mostly affected of a sea level rise. Does that mean I have to take all my money out of my Swiss bank account because Switzerland will be flooded?
What is funny about it is that it says “water levels around Antarctica, for instance, are higher than if the frozen continent were an open ocean.”
Which would seem to imply that it is the landmass itself … the continent … not the freezing part that seems to increase ocean levels … or something.
So how hot does it have to get to melt the continent in addition to the ice?
…. Now that the full gravity of the situation has been exposed ; )
On the BBC news last night there was a reporter with a tape measure reporting from somewhere on the English coast. He was standing on top of a coastal defence wall, some feet above the beach, and playing with his tape measure. Placing the tip on the wall, the highest point of the sea defence, he demonstrated how high the seas might rise (around a metre) due to the advanced effect of glabal warming. “This is how high the sea could rise”, he assured us. I’m surprised he wasn’t deafened by people yelling at the screen, advising the stupid prat to measure the alleged rise in sea level from…sea level, aka the beach still visible at high tide, several feet below the wall!
Much was made of footage of a train running along rails adjacent to a sea wall. There was heavy spray hitting the train. This was treated as if it was an unusual event but not unusual enough to stop the train from running. Maybe reporters needs to visit the North West Coast of England where we often get howling gales blowing in off the Irish sea along with the accompanying storm surges. It’s called British weather and there isn’t anything unusual about it.
This photo was taken at Blackpool when the high tide was being whipped up by a moderate gale force wind. The figures give some perspective although I question taking a young child out fishing on such a day. There is a real risk of a very large rogue wave sweeping them out to sea.
http://www.sxc.hu/photo/742427
During a real blower the waves are much higher and where the man and boy are sitting can flood, especially during an exceptional high tide (spring tide) driven by gale force winds. I don’t photograph storms like this because the wind can gust to 90-100mph, hard enough to blow double decker trams weighing several tons over onto their sides and lift roofs from buildings.
Weather like this is not unusual and has been going on for a very long time. It isn’t caused by global warming. Nor is the sea level rising in this part of the world. I’d know because I live a few minutes walk from the beach in a small coastal village and very close to a river estuary. Storm surges are a fact of life and an act of nature. We protect ourselves against them and no amount of carbon cutback will stop them. So where’s the beef?
All,
What is said by David Vaughan is a scientific fact, already found out 50 years ago… Has nothing to do in itself with global warming, but with gravity changes.
Huge land based ice sheets attract water molecules, which pile up against their coast. IF (and only if) the ice sheet (3,000 m high at Greenland) melts, the water pile fades away, causing a sea level sink around the melting ice sheet and a sea level rise farther away. The no level change point is about 6,000 km from the ice sheet away. That means that if Greenland melts completely, Florida will see a significant sea level drop (!) and Amsterdam a modest drop, while the SH will see a significant rise. The opposite happens if the WAIS should melt…
REPLY: Yes I know it is a fact, I was just having a little fun with the imagery. Such sea level variances are well documented and measurable today via satellite sounders, albeit small.- Anthony
Re: UK Sceptic: I saw the same bulletin; it was a major piece, and it was the biggest collection of lies and distortions as I have seen. At one point the reporter (over pictures of flooding in tuvalu) said “increasing temperatures driven by man-made CO2 are causing sea levels to rise around the world”. I don’t need to point out here how many factual inaccuracies and massive assumptions he managed to squeeze into such a short sentence.
Often I see on web sites like this one that ‘surely this or that fact or event is the last nail in the coffin of AGW’, but such things rarely get an airing in the mainstream media, where AGW is more certain and urgent than ever.
Ferdinand is right.
Brian Johnson, amongst others…, I used to think myself silly to think people at WUWT would dispute gravity if it was mentioned at the same time as AGW – but now we see truth is far stranger than fiction…
“water levels around Antarctica, for instance, are higher than if the frozen continent were an open ocean.”
But…but…bu….you said when the icecaps MELT, the sea level will RISE, and millions will DIE.
This isn’t one of those global warming means it gets colder things is it?
You scientists…such a clever lot.
“Ferdinand Engelbeen (00:44:55)
That means that if Greenland melts completely, Florida will see a significant sea level drop (!) and Amsterdam a modest drop, while the SH will see a significant rise. The opposite happens if the WAIS should meltā¦”
So if they both melt at the same time, do they cancel everything out, and we end up with no sea level increase?
Nothing to see here…move along, move along. Return to your sea-side homes and villages.
JimB
Re: UK Sceptic (00:30:47) :
One thing they always fail to mention when talking about sea level rises in the south of England is that due to the disappearance of glaciers from Scotland, Scotland is rising and England is sinking. This exaggerates any rise in the south.
The Guardian continues its usual 5 to 6 Alarmist articles per day.
There’s been a spate of extremist alarm stories in the UK Press in the last couple of days.
Greenland ice sheet melting will cause ‘far greater sea level rises’ by 2100 is the gist of it.
All kinds of ridiculous scaremongering contained in the stories as a result.
Key question: how likely is it? What were the measurements used? And is this yet another example of extrapolation of short-term data into runaway models which aren’t based on self-correcting systems?
Look at http://www.independent.co.uk, http://www.bbc.co.uk/news etc and you’ll find the stuff. It’s getting a bit repetitive. Boring. Are their grants up for renewal sometime soon?
I have another theory:
The centrifugal force on the oceans around the equator is much greater than at the poles, causing sea levels to be higher in the tropics.
But if the gravity of the ice sheets causes sea level rise at the poles, then levels rise all over the globe.
Oh dear me, another perpetual motion machine.
Mr Vaughan must have a computer model to tell him this effect is catastrophic bordering on armageddonoid. I can’t believe his numbers, given the masses involved.
āEveryone thinks sea level rises the same around the world,ā David Vaughan, of the British Antarctic Survey, said on Tuesday at the Rothera Base on the Antarctic Peninsula. āBut it doesnātā.
AND THEY DON’T
But what we need is a new GRAVITY TAX, encouraging people to relocate to higher altitudes in order to pay less.
Cats would be exempt.
Two friends of mine were once discussing what one called “penal taxation.” The other moaned, “O God, they’re not taxing that now, surely.”
Rhys Jagger:-)
You’ve hit the nail right on the head. It’s a funding issue, 1st April around the corner, local authorities spending their left-over cash on silly schemes ready for the new financial year to start, so to for the AGW scientists. As I have said several times before, if the science is settled, why pay them to keep working?
An entirely reasonable effect, having nothing directly to do with global warming. The interesting question is: are we talking about a change in sea level of millimeters or centimeters or what?
Don’t you need another factor in there to properly apply the monkey wrench?
If you have a mile or two of ice sitting on top of the crust, and the ice melts, the geologic potential is for the crust to rise, which in effect will raise the coastline out of the water in the general vincinity of the landmass (like Greenland).
You do know that the crust floats in the mantle, and the structure of a mountain/island/continent is of a ship floating in the ocean. Part of it is submerged. Ballast. Unload the cargo and it bouys up higher. Load it up with cargo and it sits lower in the water. Glaciate a mountain off and it wants to pop up when the ice has melted.
None of which has anything to do with global warming or cooling caused by CO2. Ice Ages exist, and so do interglacials. They just don’t happen in 10-30 years. Really.
The relationship between gravity and sea-level is well known to geophysicists. The relationship between continental glaciers and gravity is also well known.
Nils Axel Morner retired in 2005. A key feature in his efforts to educate sea-level modellers was his insistence that sea-level change is affected by the complex interaction of many factors, including gravity. You can read about his career here, including why he ojected to alarmism concerning sea level: http://en.wikipedia.org/wiki/Nils-Axel_M%C3%B6rner
A major research project under his direction was conducted in the Maldives. (URL: http://www.pog.nu/02projects/1_maldives.htm), a group of islands in the Indian Ocean located at he bottom of a gravity well. This project illustrated the impact gravity both upon sea level and upon the shape of the geoid itself.
That continental glaciers distort the shape of the continents has been known for over a hundred years. That the change in ice volume over time changes the topography of the continents is similarly well established.
The phenomenon may seem strange, but gravity exerted by continental glaciers can also distort the topography of the ocean,
The real issues are: first whether or not the effect is great enough to pose any threat.
I think the are looking for a way out… By publishing ever more ludicrous articles, these pranksters are really saying “hint, hint, use your head, it’s all a giant practical joke”. They are probably trying to find out what level of stupidity finally triggers the average person to a mental “tipping point” where people finally say “um, am I on TV or something?”
TerryS. It seems to be the norm to shove inconvenient realities such as glacial isostatic adjustment aside and blame everything on AGW. After all, they can’t tax us if geology insists on keeping people’s feet dry. :0)
Sorry your local geology seems to be working at odds. It only gives them an excuse to tighten the political screw. :0(
And to apply the monkey wrench even more, when sea-levels rise the pressure of the additional water will press down the continental shelves a bit, making sea-levels an extra bit higher (hydroeustasy), while on the fourth hand much of the West Antarctic Ice is under sea-level and will be replaced by salt water which is ca 15 % denser than the ice, which will partly offset the gravitational effect this thread is all about, and furthermore….
In short the effect on sea-level by melting glaciers is a rather more complex affair than it might seem from BBC:s clownery with a measuring tape.
BS
Great! Does this mean that I shouldn’t go on a diet? or I should? in order to mitigate against climate change I mean?
Okay, would someone please tell me if anywhere in the world has there been a low-lying Island go underwater, or lose a significant portion of it’s above-water land mass? Surely there has to be at least one? Maybe an atoll ? Something?
Hmm. One of our icy issues of our time is water lubricating glaciers causing them to surge forward and do bad things. So, as ice in Antarctica gets more massive, it will attract water to the coastline and lift the glacier there. I never realized ice could lift itself by its bootstraps. Or that it has bootstraps!
In the extreme, this could be another tipping point – ice attracts more water, the additional mass attracts still more water, and before you know it all the water on the planet will be on Antarctica.
Anthony, don’t you think we have enough to worry about already?
Saying there will be a 1 or 2 meter rise in 100 years (91 now I guess) is easy, since they won’t be here to say “oops, I was wrong” …
In terms of ice causing earths gravity to shift, that is a stretch beyond anything I have read in Sci-Fi.
Ron de Haan (22:32:36) :
“That is what I call a fat cat!”
No, that is what I call a gravitionally challenged ticking CO2 time bomb…
Woman’s Alien Baby Is Reincarnated Elvis!
Soon these Global Warming scare stories will be lumped in with the National Enquirer headlines.
Looks like Tibet and Nepal are going to be flooded because of their excess mountainous gravity…
….global warming, a leading glaciologist said.
Isn’t it interesting how the media portrays all alarmists, scientists that have something bad to say as “leading” in their field.
and all skeptics are “crackpots” or some other negative connotation.
BTW, isn’t there more gravitational pull at the poles because the Earth bulges at the equator, therefore you are further from the center of the Earth.
This is truly catastrophic news.
Well, maybe not. Even the ipcc’s AR4 said the rise will only be somewhere between 7 and 23 inches, a far cry from the 1 meter Vaughan posits. Actually, it is more likely to be 4 to 6 inches, the same rate of increase it’s been in recent centuries. But, also from the above article: Their biggest finding, however, was that although the glaciers are fast to respond to rising temperatures, they rapidly reach a new equilibriumāin other words, the rapid rates of retreat are not sustained.
So, this claimed variation in sea level rise due to gravitational changes will actually be far less than his “tens of centimeters”.
Of course, man is not responsible in any way whatsoever for the sea level rise in the past or future, and simply needs to do what he has always done – adapt.
That, of course, is not what climate fat cats like Gore want to hear, though.
Okay. I’ll bite. Is that a Cat As trophy?
A point of order to all you brits; If your courts ruled, as I recall they did, that ALgore’s craptacular film was so factually wrong that schools using it had to present the counter-argument, then can they not order the BBC to quit showing blatant AGW balderdash? Or are education and propaganda still two different things? lol
hehe I’m naming the cat little Al
OMG! (as my daughter would ‘text’). Does no one ever check this sort of statement out with some simple physics?
Density of ice = 920 kg/m3, volume of Antarctic ice (from USGS http://www.smith.edu/libraries/research/class/idp108USGS_99.pdf) = 3 x 10^7 km3 =
3 x 10^16 m3 . So mass of Antarctic ice = 27.6 x 10^18 kg
Now gravity being a central force, and Antarctic being roughly circular, for this back-of-the-envelope calculation we can consider all the ice to be at the center of a circle of radius (estimated from maps) to be 2000 km = 2 x 10^6 m
So the ice will exert a force on 1 kg of ocean water, which lies on the shore of Antarctica, of
F = G*Mice*Mwater/r^2 = (6.67×10^-11)*27.6×10^18*1/ (2×10^6)^2 = 4.6 x 10-4 N
which also is the net acceleration on this 1 kg of water, vis, .00046 m/sec2. This is 5/1000 of 1 percent of the earth’s gravitational acceleration (9.8 m/sec2)!
And this number is too big! This 1 kg of ocean water is not isolated. It is being pulled by the gravitational attraction of the mass of all the other ocean water it sits in opposite to the attraction of the ice. I could do that calculation, but I don’t see much point as the basic number above is so small, that to make it more realistic, and thus even smaller, seems pointless.
Melting glacial ice due to AGW will lead to a gravity shift which will raise the waters even more around what was once ice covered land. Do I have that right? True or not, someone needs to add this one to the “list”. Now if they can just put this scientific discovery to use in a bra.
So this means that if we irrigate more, take water/mass from the continents, they will rise and we can avert the sealevel catastrophe. š
It may be that many of you are confusing what is meant here. Gravity is one of the fundamental forces and I don’t think anyone is suggesting that will change.
The Earth has a specific gravitational field that depends on its unique distribution of mass ā yes, this is well known. See http://en.wikipedia.org/wiki/Earth's_gravity . So increasing or decreasing the size of glaciers will cause local changes in Earthās gravity.
Is this a significant change? Even at 3000M thick, the mass of the glacier will be very, very small compared to that of the Earth.
Will it mean 10ās of centimeters of change in sea surface level? Somehow it seems very unlikely the difference will be that great, or that it would result in significant sea surface changes thousands of miles form the glacier. I would expect it to be more like millimeters or smaller.
Sorry, I donāt have the answers,
MikeEE
To UK Sceptic
Obviously, you are not a TV person. That poor reporter had to stand well away from any danger area, as health and safety rules demand at Beeb, since he might have been endangered by the forthcoming Arctic ice melt, which could easily happen by the time TV crew finished their umpteen re-takes.
Crosspatch
TV shows = millions of viewers = More electricity = more CO2 = more money for Al Gore. That’s why he made that DVD.
Schrodinger’s Cat Found Dead or Alive
What evidence is there that the Greenland and Antarctica Ice are melting or are going to disappear would me my first question. I thought it was very very cold at these locations or am I wrong?
Are there any Physicists who could calculate the gravitational pull of the Antarctica Ice cap and calculate whether the effect would be significant?
We know? That the moon and to a lesser extent the sun affects the tides, intuitatively I think Mr Vaughan is incorrect because the mass is not sufficient to have a significant effect.
One of the contributors above is correct that if you remove a large mass from the surface the ground will heave I think, but I am not sure that there is also corresponding settlement remote from the removal of the mass?
Is there anyone who could calculate the volume of the Antarctica land ice and compare it to the volume of the Oceans and surface area of the seas.
If someone postulates an effect due to a belief that something may happen it is best not to deal the belief better to deal with the consequences. Firstly.
In other news, farmers in Iowa grow more corn than if the North American continent were an open ocean. Panama authorities expect the income from the Panama Canal would be less if the North American continent were an open ocean.
@This is, again, “Hollywood science”, as professor Khabibulo Abdusamatov characterized global warming theory.
Link to a Abdusamatov’s paper:
http://www.giurfa.com/abdusamatov2.pdf
wait, we better calulate the effect of large cities on sea level rise. I wonder what the mass of coastal cities like New York City have on the sea level. I mean, asphalt/steel/concrete and eveything else we’ve added must have brought up the sea level [/sarc off]
Thanks Mike Monce for busting their hypothesis. Anyone with half a brain should realize that the mass of the ice is in no way comparable to the mass of the Earth, and should make little difference to sea level changes.
Global Warming – The New Baking Soda!
Is there NOTHING it can’t do????
Re: Mike Monce (05:52:27) :
Exactly – simple physics that these virtual land of nod climatologists appear to either ignore or don’t understand.
The computer says….
This is what happens if you drop your bonzaicat onto a concrete floor!
not only is that cats name is Al, i bet it invented the cartoon Garfield…
I have a theory. The true cause of Anthropogenic climate change is not CO2, water vapour, or any of that ‘scientific’ stuff. Nothing to do with the laws of physics at all. It’s caused by lazy journalism, poor fact checking, bandwagon jumping, and political manouevring.
More news as research funding comes in.
This was a cartoon interlude, right?
Or are people really this ignorant.
Allan M (02:24:14) :
It’s not a theory it’s a fact. If you want to lose weight quickly, fly from either pole to the equator and weigh before yourself leave and when you land.
Dave in Canada (04:48:13) :
No because maximum gravitational force is at the surface and not the center. This is because the maximum mass is between you and the other side of the planet.
NOTE:
With the humorous photo I chose, I may have unintentionally implied that the gravitational effect described is not true. It is and the simplest physics. The likely magnitude and the suggestion of Antarctica melting are the main issues. Here is a paper from MIT
http://ocw.mit.edu/NR/rdonlyres/Earth–Atmospheric–and-Planetary-Sciences/12-808Fall-2004/A740D69D-9E59-401D-89E9-BE2F0EFD0194/0/course_notes_3b.pdf
that describes Earth’s gravity anomaly and sea level differences.
BTW my entry for the caption would have been:
“Above: the gravity well of canned tuna”
– Anthony
Where did you get the picture of Lucias cat?
Here is a project that may interest WUWT readers:
Climate researchers seek citizen scientists
http://seattletimes.nwsource.com/html/localnews/2008838705_buds11m.html
Yes Anthony the effect of gravitation is certainly real, I remember reading the reports form the 2005 tsunami in southeast asia, the first thing people noticed was that the sea level was actually lowering, the water seemed to dissapear. I thouhgt about this and came to the conclusion that the enormous mass of the tsunami wave was attracting the water in front of it, this probaly amplifies the effect of a tsunami. Gravitation is sometimes hard to grasp, we never really have to think about it, it’s just there, not much to do about it.
We should fund ocean cruises for obese people. Not only will they sequester more carbon at the buffet table, but the gravity from their bulk will help draw ocean water away from the coasts. This will be at least as effect as cap-and-trade for slowing the rise of the sea level.
Caption: Jim Hansen and Al Gore are investing millions of dollars in a new carbon storage technology that will be more efficient than underground storage… cats will save the planet.
Steve M. (06:46:40) I know you posted re: sinking cities in sarcasm, but I read where Manhattan is sinking from the buildings there, and Shanghi is sinking at 1.5cm/yr, ie. 15mm/year, a lot faster than the sealevel increase at 3.3mm/yr.
MartinGAtkins (08:13:17) I want to know who cloned our cat Buckey before he passed on a couple of years ago. We adopted him at 8yrs and 27lbs with the name ‘Volleyball’. I thought he was humiliated by his name and named him a more obscure allusion to a spheriod as ‘Bucky’, with reference to fullerenes.
The only effect that could arise from the melting of the Antartic would come from 1. the volume of liquid water added to the oceans and 2. the lift of the continent from not having this mass of ice on top of it. But there might also be something about the increased level of water at the equator from the centrifugal pull du to the rotation of the earth. Would the earth turn slower though if the ocean level rises?
But regardless of Peter Pan science, do we have any proof that Antartica ever completely melted in the past?
Ice sheets and gravity are discussed in “Polar Wander, Sea-Level Variations and Ice Age Cycles” by L.L.A. Vermeersen and R. Sabadini, Surveys in Geophysics 20; 415 – 440, 1999.
In their paper they acknowledge the work of R.S Woodward “On the form and position of mean sea level” in 1888 USGS Bull 48, 87-170. He goes thru derivations for the gravitational attracton of an ice sheet.
So, it isn’t new, but it is good to see the idea get more exposure. We do live in a complicated place
By logical extention we could assume that everyone that arrives in Antarctica automatically weighs more when arriving. Does anyone know where on earth is the location with the least gravity? We should set up a weight loss spa there where you are guaranteed to lose weight immediately upon arrival. Technically true but scamfull nonetheless.
Ray (08:49:46)
Yes certainly, but how much I don’t know. Think of an ice dancer doing a piruette, he or she controls the rotational speed of the piruette with the arms, when they raise there arms and hold them closer to theire vertical mass center the rotational speed increses if they hold the arms out from their body it decreases, all to keep the living energy constant. Besides the hockey finals soon start here in Sweden, so by by for me!
MartinGAtkins
“BTW, isnāt there more gravitational pull at the poles because the Earth bulges at the equator, therefore you are further from the center of the Earth.”
In your reply you said
“No because maximum gravitational force is at the surface and not the center. This is because the maximum mass is between you and the other side of the planet.”
I’m pretty sure this is incorrect the controlling factor is that at the pole you are closer to the center of mass therefore the force of gravity is greater. The amount of mass involved and it’s position relative to you is not different. Additionally the rotation of the earth gives you some momentum that tends to reduce the net force of gravity, this reduction is greatest at the equator. In short you weigh more at the poles.
Oh wow Ray!
I guess the world really would turn slower if the ice caps melted… how much slower? this is most cool you have given me a wonderful rotational dynamics problem to use on my students next semester.
Glad I could help you Wondering Aloud. It’s something else they will have to add to the dooms… we will have to change all of our clocks or add another day tyo the calendar… like February 30th every 4th years…
Mike Monce
Thanks for the calculation, you must have been in moderation before I posted.
Fellow citizens of the world.
Please grant us your sympathy. All of us in the UK have to pay a significant mandatory tax that allows the BBC to transmit this rubbish. I guarantee that ICCC will not get a mention – they don’t do facts.
Furthermore, if the world slows down due to the increased diameter from water volume increase, the days would get hotter and the nights colder…. OMG, we have a new catastrophic positive feedback loop!!!!
[insert your own caption here]
Han, my boy, you disappoint me . . .
MartinGAtkins (07:51:43) :
Gravitational force is weaker at the equator due to equatorial bulge, (with is caused by centrifugal force), which causes objects at the equator to be farther from the planet’s center than objects at the poles.
force due to gravitational attraction between two bodies varies inversely with the square of the distance between them.
Ric Werme (04:09:10) :
“Hmm. One of our icy issues of our time is water lubricating glaciers causing them to surge forward and do bad things. So, as ice in Antarctica gets more massive, it will attract water to the coastline and lift the glacier there. I never realized ice could lift itself by its bootstraps. Or that it has bootstraps!
In the extreme, this could be another tipping point – ice attracts more water, the additional mass attracts still more water, and before you know it all the water on the planet will be on Antarctica.”
Great stuff. Have we found another form of positive feedback; this time it’s gravity? “We’re all doomed!” Negative feedback has been made illegal, because our glorious leaders think it reflects badly on them.
If only Max Escher could have been around to do the artwork for the AGW crowd.
Richard111 (05:16:03) :
No, your spelling is bad. It is a “Cat Ass Trophy”
Ferdinand (00:44:55) :
Not just 50 years ago!
In 1867 Victorian scientists discussed the likely effect that unloading of ice from Antarctica would have on the surface of the global ocean. In this paper by James Croll, published in the Transactions of the Geological Society of Glasgow, (see page 194 inside pdf) he estimates that the centre of gravity of the whole planet would be altered by loss of ice from the Antarctica.
He suggests that this change would alter the geoid, in particular the height of the water surface of the northern hemisphere Arctic Ocean above the ocean floor, and lead to a rise in the sea level distributed across the whole of the northern hemisphere. This rise is in addition to the change in volume due to the extra water derived from the melting of the Antarctic ice.
From Croll J. 1867 ā On the Change in Obliquity of the Ecliptic; its Influence on the Climate of the Polar Regions, and the Level of the Sea. Trans Geol Soc Glasgow Session 1866-67 p194:-
If 470 feet were melted off-and this is by no means an extravagant supposition, when we reflect that for every 18 pounds of ice presently melted an additional pound or two pounds, or perhaps more, would then be melted, and that for many ages in succession-the water thus produced from the melted ice would raise the level of the sea 18 feet 5 inches. The removal of the 470 feet of solid ice-which must be but a very small fraction of the total quantity of ice lying upon the antarctic continent would shift the earthās centre of gravity about 7 feet to the north of its present position. The shifting of the centre of gravity would cause the sea to sink on the southern hemisphere and rise on the northern.* And the quantity of water thus transferred from the southern hemisphere to the northern, would carry the centre of gravity about 1 foot further, and thus give a total displacement of the centre to the extent of about 8 feet. The sea would therefore rise about 8 feet at the North Pole, and in the latitude of Glasgow about 6 feet 7 inches. This, added to the rise of 18 feet 5 inches, occasioned by the melting of the ice, would give 25 feet as the total rise in the latitude of Scotland 11,700 years ago.
pdf file
Wondering Aloud (09:42:30) :
MartinGAtkins
āBTW, isnāt there more gravitational pull at the poles because the Earth bulges at the equator, therefore you are further from the center of the Earth.ā
In your reply you said
āNo because maximum gravitational force is at the surface and not the center. This is because the maximum mass is between you and the other side of the planet.ā
Iām pretty sure this is incorrect the controlling factor is that at the pole you are closer to the center of mass therefore the force of gravity is greater. The amount of mass involved and itās position relative to you is not different. Additionally the rotation of the earth gives you some momentum that tends to reduce the net force of gravity, this reduction is greatest at the equator. In short you weigh more at the poles.
The last is correct, the recommended expression is as follows:
gt = 978.0327(1.0+0.0053024 sinĀ²(Īø) – 0.0000058 sinĀ²(2Īø))
so at the poles it’s 983.2186
Philip Mulholland (14:35:04) :
We can suppose that if the Antactic ice melts, the Artic ice, Greenland’s ice and as well as all the mountain ice must also melt. The release of pressure on the crust from the redistribution of the mass and the slowing down of the rotational speed of the earth will surely make that distribution more uniform.
I don’t think in 1867 they had a whole and precise picture of the planet… we still don’t!!
Anthony – Many thanks for that update. Most enlightening.
The problem I see isn’t with the science per se, but with the way it seems so many scientists try to link everything to AGW. Once AGW is debunked, all science will likely suffer from a backlash.
An interesting twist from a science view is that Swedish scientist Celsius actually is more renowned for his participation in a French led expedition in northern Sweden to prove Newtons theory about the equatorial bulge, rather than his thermometer. Here’s a link about him:
http://www.astro.uu.se/history/Celsius_eng.html
Oh and my team won again!
Time for the chubby feline to cut back on the Meow Mix.
I would recommend a 42D. The rib cage measurement seems slightly larger than the typical proportion so I recommend the larger band size but stick to a D cup with side gathering capability. I would also choose a padded shoulder strap. The larger measurement bra can dig into your shoulders without that extra wide protection. Three hooks would be a must.
My former life. Department Head in the Lingerie Department for The Broadway Clothing Store Chain. It was my job to solve the brazier problems of all the older ladies who came in to be measured.
Are You Being Served?
Pamela G
Let’s not start the personals thing again mmmkay?
Caption for cat pic…
“Get ready, kitty… when I pull this plug anything could happen…”
Jeez, jeez, lost your funny bone? It was a parody of the CAT! You know. The cat in the photo. See photo in this post. Prepared and presented to us by the blog owner. To give us a smile. A bit of levity. To turn us from a sour puss into a happy cat. God knows the amount of testosterone, chest thumping, tree branch rattling, and head butting here can be overdone on a regular basis. Granted in a cerebral way, but nonetheless…
No Pamela, apparently you have lost yours. We are sooo done.
And I had such high hopes…wimper.
Phil. (14:42:41) :
If you were at the center of the mass then you would be weightless (and dead). This is because the mass of the planet is surrounding you and attracting you more or less equally in all direction. It’s true that the core is denser but the earth is not a perfect sphere. It’s wider at the equator and so has more mass in that plane. It’s the rotation of the earth that makes you less heavy not the distance from the center of the mass. Remember the question was.
āBTW, isnāt there more gravitational pull at the poles because the Earth bulges at the equator, therefore you are further from the center of the Earth.ā
I maintain that the answer is no because there is less mass between you and the other side of the earth at the poles than there is at the equator.
Down with gravity, up with levity.
Philip Mulholland (14:35:04) :
Thanks for the update! Didn’t know it was that long ago that the scientists came to the same conclusion… Anyway an interesting extra…
MartinGAtkins (18:09:51)
Sorry Martin the mass between you and the other side of the earth is the same in either case, and it is distance between your center of mass and that of the earth that rules here. Phil posted just after me above with the actual accepted values for the equator and poles.
However, as I mentioned the rotation of the earth not only creates the bulge it is part of the difference in the net force.
Wondering Aloud (05:15:02) :
Sorry Wondering, but you are in error. It’s true that that the center of gravity is at the center of the earth but that is only because it is the center of the mass of your body and all the mass between you and the other side of the earth. Now let me remind you of the original question.
āBTW, isnāt there more gravitational pull at the poles because the Earth bulges at the equator, therefore you are further from the center of the Earth.ā
He is not asking if you would weigh less at the equator because of the rotation of the earth. If he had so, my answer would be yes because the rotation of the earth has the in effect of moving us in a straight line through space but on a curved body. The curvature would appear to fall away from us because we are traveling in a straight line through space. The gravity of the planet counteracts this tendency but the two forces compete, with the net effect being you would weigh less.
Now we have that out of the way we can get back to the original question which deals only with the effects of gravity and the shape of the planet.
Gravity is the product of the two bodies masses. If you were in space then it would be the entire mass of the earth that would be the attractor. You would be attracted to the center of earth because that is the maximum point of it’s diameter in relation to you and so it has the maximum mass and gravitational pull.
It’s maximum mass is not a straight line from you to the center of earth. It is a straight line from you to the opposite side of the earth.
It’s the same at the surface. You must take into account the gravitational attraction of the mass beyond the gravitational center.
Due to the rotation of the earth it is slightly oblate and so is wider at the equator than it is at the poles. It therefore has more mass between the surfaces of equator than it does between the surfaces of the poles.
If you could take a core drilling through the entire planet, then the equatorial core would be longer than the polar core. So which one would have the most mass?
Even if you only took a core drilling to the center, the equatorial core would be longer than the polar core and so would have more mass.
Thanks Anthony. Is it Al’s preincarnation?
Tom Bakewell (09:14:23) :
Ice sheets and gravity are discussed in āPolar Wander, Sea-Level Variations and Ice Age Cyclesā
http://www.gps.caltech.edu/~jkirschvink/pdfs/SeaLeveliitpw.pdf (6 pages + refs)
What are the conclusions? Heavier or lighter at the poles ignoring centrifugal force and not ignoring?
Is the planet cooling? I believe it is with little to zero ocean stored heat. That would negate any relevance melting has to present times wouldn’t it?
The following may be of interest but don’t answer my question(s)-
http://www.gps.caltech.edu/~jkirschvink/pdfs/SeaLeveliitpw.pdf
A sea level test for inertial interchange true polar wander events
http://www.ias.ac.in/currsci/oct/articles7.htm
True polar wander and marine transgressions
http://books.google.com/books?id=ez5LlQZ3MfAC&printsec=frontcover#PPR9,M1
Global Dynamics of the Earth