[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. Here is a paper from MIT that describes Earth’s gravity anomaly and sea level differences. – Anthony
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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 equilibrium—in 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. 😉
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 – 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 Earth’s 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 10’s 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 don’t 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.