Melting Ice/Rising Sea Levels/Warming Climate

[Procrustes Stretched]

How is it that people here and elsewhere get away with saying things like... they do not believe a melting ice cap will raise sea levels, because like melting ice in a glass, melting ice caps will not add volume or raise sea levels?

 

[Baruch Menachem]

Much of the ice is on places lie Greenland and in mountains like mt Hood, which most summers nowadays only has very small glaciers.

But you are right, the hysterics haven't read about Archimedes.

But, if the hysterics were right, given the supposed level of melting in Greenland and Antarctica ,most of florida should be underwater now.



However, most of the ice in the Arctic is floating on the ocean. The weight of the ice is the same as the water it displaces, so when the arctic ice melts, it is, as you say, like an ice cube melting in a cup of water. As it melts, the volume of water does not change.

 

[CrusaderFrank]

It's so funny, we had the Wisconsin deglaciation that cause the sea to rise 500 feet, drowning whole cities and civilizations and now if the tempo rises .5% anywhere on the planet, people get hysterical.

 

[Toronado3800]

How is it that people here and elsewhere get away with saying things like... they do not believe a melting ice cap will raise sea levels, because like melting ice in a glass, melting ice caps will not add volume or raise sea levels?

Melting ice does not give the world as a whole more h2o. It can however move it from ice on mountains as mentioned earlier to ice in the sea which would raise sea level.

 

[ReAmericaNow]

Much of the ice is on places lie Greenland and in mountains like mt Hood, which most summers nowadays only has very small glaciers.

But you are right, the hysterics haven't read about Archimedes.

But, if the hysterics were right, given the supposed level of melting in Greenland and Antarctica ,most of florida should be underwater now.



However, most of the ice in the Arctic is floating on the ocean. The weight of the ice is the same as the water it displaces, so when the arctic ice melts, it is, as you say, like an ice cube melting in a cup of water. As it melts, the volume of water does not change.

First, 98% of Antarctica (fifth largest content) is covered with ice appx. 1 mile thick.

Second, I am glad of that you have heard of Archimedes, but have you heard of Newtonian Physics? It is impossible to accurately measure sea level because there is a giant celestial body that is orbiting our planet roughly 400K km away. As a result, and because of Newtonian Physics, it tends to pull on the oceans (tides). Because Earth is not spherical, and the moon does not travel at the same speed compared to Earth’s speed of rotation. The effect of the moon’s gravity on tides will always be different, so sea level data is worth less. Now your could do a mass balance, or even a volume balance. If you take 100 oz and add a 10oz ice cube to it, you will get a 10% increase in the amount of water.
See isn’t science fun. =P

 

[Luissa]

Much of the ice is on places lie Greenland and in mountains like mt Hood, which most summers nowadays only has very small glaciers.

But you are right, the hysterics haven't read about Archimedes.

But, if the hysterics were right, given the supposed level of melting in Greenland and Antarctica ,most of florida should be underwater now.



However, most of the ice in the Arctic is floating on the ocean. The weight of the ice is the same as the water it displaces, so when the arctic ice melts, it is, as you say, like an ice cube melting in a cup of water. As it melts, the volume of water does not change.

I remember when you could ski Mt Hood at the beginning of the summer.

 

[Baruch Menachem]

Much of the ice is on places lie Greenland and in mountains like mt Hood, which most summers nowadays only has very small glaciers.

But you are right, the hysterics haven't read about Archimedes.

But, if the hysterics were right, given the supposed level of melting in Greenland and Antarctica ,most of florida should be underwater now.



However, most of the ice in the Arctic is floating on the ocean. The weight of the ice is the same as the water it displaces, so when the arctic ice melts, it is, as you say, like an ice cube melting in a cup of water. As it melts, the volume of water does not change.

First, 98% of Antarctica (fifth largest content) is covered with ice appx. 1 mile thick.

Second, I am glad of that you have heard of Archimedes, but have you heard of Newtonian Physics? It is impossible to accurately measure sea level because there is a giant celestial body that is orbiting our planet roughly 400K km away. As a result, and because of Newtonian Physics, it tends to pull on the oceans (tides). Because Earth is not spherical, and the moon does not travel at the same speed compared to Earth’s speed of rotation. The effect of the moon’s gravity on tides will always be different, so sea level data is worth less. Now your could do a mass balance, or even a volume balance. If you take 100 oz and add a 10oz ice cube to it, you will get a 10% increase in the amount of water.
See isn’t science fun. =P

The tides don't change the volume of the water. Sea levels are a tidal average.

The arctic ice cap, which everyone talks about is not adding to the cup of water, it is the ice on top of the cup of water. If it is ice or water does not matter, as the level does not change if the ice cube melts.

Now the ice on Greenland, and on Antarctica does matter, as that is not sitting in the ocean, and if that melts, then the sea level should increase. And according to the hysterics, it has been melting, and a lot of water is/was contained in that ice.

But average sea levels have not been rising as much as the hysterics predicted. That means that the amount of water coming off the glaciers is less than they predicted. Which means the melt is less as well.

That doesn't mean there isn't climate change. Louissa remembers being able to ski on Mt. Hood in the summer. These days the amount of snow Mt Hood gets is such that you can't even ski at timberline until October. And I think the Ski Bowl has shut down as it never gets enough snow to make it worth while to operate anymore.

It is just important to remember what is part of the normal workings of the natural system, and that the amount we can do for good or ill, is relatively minor.

 

[k2skier]

Much of the ice is on places lie Greenland and in mountains like mt Hood, which most summers nowadays only has very small glaciers.

But you are right, the hysterics haven't read about Archimedes.

But, if the hysterics were right, given the supposed level of melting in Greenland and Antarctica ,most of florida should be underwater now.



However, most of the ice in the Arctic is floating on the ocean. The weight of the ice is the same as the water it displaces, so when the arctic ice melts, it is, as you say, like an ice cube melting in a cup of water. As it melts, the volume of water does not change.

I remember when you could ski Mt Hood at the beginning of the summer.

You still can. Timberline has skiing all summer long on the Plamer glacier, they only close in October for maintenance.

 

[saveliberty]

Maybe we can kill more whales and haul them on shore to offset the displacement of glaciers sliding into the ocean. Yes! Man can save the planet. Sorry whales.

 

[Toronado3800]

I don't even think us super monkeys have to do anything as heroic as save the planet.

We just have to not mess it up.

 

[American Horse]

<SNIP>
It is impossible to accurately measure sea level because there is a giant celestial body that is orbiting our planet roughly 400K km away. As a result, and because of Newtonian Physics, it tends to pull on the oceans (tides). Because Earth is not spherical, and the moon does not travel at the same speed compared to Earth&#8217;s speed of rotation. The effect of the moon&#8217;s gravity on tides will always be different, so sea level data is worth less. Now your could do a mass balance, or even a volume balance. If you take 100 oz and add a 10oz ice cube to it, you will get a 10% increase in the amount of water.
See isn&#8217;t science fun. =P

The standard deviation of sea level values is 0.8 cm, an outstanding result. In fact the values are not spread like noise: successive values are consistent to within 0.4 cm on average, close to the formal error. The spread of the points suggests a small seasonal signal, of 0.6 cm amplitude, with fluctuations whose period is around 50 days and amplitude around 0.5 cm.
....
The surprising thing is that we can actually talk about millimeter-type variations. The annual mean could be even better, so that secular drift in sea level, on the order of 1.5 mm a year, could be detectable in a few years by T/P and its follow-ons, providing the signal is not hidden by interannual fluctuations or errors that we still know nothing about.

Outstandingly accurate mean sea level: Aviso

AND

MSL means the "still water level"&#8212;the level of the sea with motions such as wind waves averaged out&#8212;averaged over a period of time such that changes in sea level, e.g., due to the tides, also get averaged out.
....
Each year about 8 mm (0.3 inch) of water from the entire surface of the oceans falls into the Antarctica and Greenland ice sheets as snowfall. If no ice returned to the oceans, sea level would drop 8 mm every year. To a first approximation, the same amount of water appeared to return to the ocean in icebergs and from ice melting at the edges. Scientists previously had estimated which is greater, ice going in or coming out, called the mass balance, important because it causes changes in global sea level. High-precision gravimetry from satellites in low-noise flight has since determined Greenland is losing millions of tons per year, in accordance with loss estimates from ground measurement.

 

[Old Rocks]

The rise in sea level is much faster than the 'alarmists' estimated. Given the melt in the Arctic Ice Cap, and the resultant warming of the Arctic, which is resulting in outgassing both of the permafrost and the artic ocean clathrates, I think this estimate is also much too conservative.

http://www.ccrc.unsw.edu.au/Copenhagen/Copenhagen_Diagnosis_LOW.pdf

&#10063;&#10063; Satellite measurements show sea-level is rising at 3.4 millimeters per year since these
records began in 1993. This is 80% faster than the best estimate of the IPCC Third
Assessment Report for the same time period.
&#10063;&#10063; Accounting for ice-sheet mass loss, sea-level rise until 2100 is likely to be at least twice as
large as that presented by IPCC AR4, with an upper limit of ~2m based on new ice-sheet
understanding.

 

[Old Rocks]

Rising sea levels are not the only problem created by increasing CO2 levels created by the combustion of fossil fuels.

http://www.ccrc.unsw.edu.au/Copenhagen/Copenhagen_Diagnosis_LOW.pdf

New in-situ evidence shows a tight dependence between
calcification and atmospheric CO2, with smaller shells evident
during higher CO2 conditions over the past 50,000 years (Moy
et al. 2009). Furthermore, due to pre-existing conditions, the
polar regions of the Arctic and Southern Oceans are expected to
start dissolving certain shells once the atmospheric levels reach
450ppm (~2030 under business-as-usual; McNeil and Matear
2008: Orr et al. 2009).
There is new evidence for a continuing decrease in dissolved
oxygen concentrations in the global oceans (Oschlies et al.
2008), and there is for the first time significant evidence that the
large equatorial oxygen minimum zones are already expanding
in a warmer ocean (Stramma et al. 2008). Declining oxygen is a
stress multiplier that causes respiratory issues for large predators
(Rosa and Seibel 2008) and significantly compromises the ability
of marine organisms to cope with acidification (Brewer 2009).
Increasing areas of marine anoxia have profound impacts on the
marine nitrogen cycle, with yet unknown global consequences
(Lam et al. 2009). A recent modeling study (Hofmann and
Schellnhuber 2009) points to the risk of a widespread expansion
of regions lacking in oxygen in the upper ocean if increases in
atmospheric CO2 continue.

 

[CrusaderFrank]

The ocean is choking on 100/ppm additional CO2?

It's not a 1% increase, it's not 1/10 of 1% it's at most 1/100 of 1% and the ocean is choking on it.

 

[Old Rocks]

Fucking dumb, Frank. What is the base of the oceanic food chain?

 

[CrusaderFrank]

Fucking dumb, Frank. What is the base of the oceanic food chain?

Please set this experiment up at the San Diego Zoo in 2 100,000 gallon tanks and see what happens when the amount of CO2 increases by 1/100 of 1% of the atmosphere in the second tank.

 

[Baruch Menachem]

Fucking dumb, Frank. What is the base of the oceanic food chain?

Please set this experiment up at the San Diego Zoo in 2 100,000 gallon tanks and see what happens when the amount of CO2 increases by 1/100 of 1% of the atmosphere in the second tank.

Has anyone tried an experiment like that? I wonder where the formula came from.

 

[Liability]

Much of the ice is on places lie Greenland and in mountains like mt Hood, which most summers nowadays only has very small glaciers.

But you are right, the hysterics haven't read about Archimedes.

But, if the hysterics were right, given the supposed level of melting in Greenland and Antarctica ,most of florida should be underwater now.



However, most of the ice in the Arctic is floating on the ocean. The weight of the ice is the same as the water it displaces, so when the arctic ice melts, it is, as you say, like an ice cube melting in a cup of water. As it melts, the volume of water does not change.

If I fill a tumbler with ice cubes and add enough water to float them and then bring the water level to the very brim, then, as the ice melts, the water doesn't over-flow BECAUSE that ice is floating. In that case, as YOU correctly noted, the ice displaces the same volume of water whether in its solid or in its liquid state. So intuitively, melting water in that case doesn't seem to pose a threat of raising sea levels.

However, if the ice isn't floating, but is "anchored" to the bottom or to dry land, when it melts and the water gets added to the sea-levels, the volume of water in the seas does increase.

I have a related question.

If the polar ice in the Arctic is getting smaller (i.e. global climate change is melting it), but the polar ice in the Antarctic is increasing (i.e., global climate change is adding to it), then isn't it possible that we could eventually see sea levels being REDUCED?

 

[Procrustes Stretched]

hmmm, interesting thread.

 

[Procrustes Stretched]

Greenland And Antarctic Ice Sheet Melting, Rate Unknown

ScienceDaily (Feb. 25, 2009) — The Greenland and Antarctica ice sheets are melting, but the amounts that will melt and the time it will take are still unknown, according to Richard Alley, Evan Pugh professor of geosciences, Penn State.

In the past, the Greenland ice sheet has grown when its surroundings cooled, shrunk when its surroundings warmed and even disappeared completely when the temperatures became warm enough. If the ice sheet on Greenland melts, sea level will rise about 23 feet, which will inundate portions of nearly all continental shores. However, Antarctica, containing much more water, could add up to another 190 feet to sea level.

"We do not think that we will lose all, or even most, of Antarctica's ice sheet," said Alley. "But important losses may have already started and could raise sea level as much or more than melting of Greenland's ice over hundreds or thousands of years," Alley told attendees Feb 16 at the annual meeting of the American Association for the Advancement of Science.

Warming is expected to cause more precipitation on Greenland and Antarctica, adding snow. Previously, many scientists suggested that this would offset increasing melting. However, recent studies show that the ice sheets on both Greenland and in Antarctica are melting faster than the snow is replacing the mass.

A number of things can contribute to the increased rate of melting in Greenland and Antarctica. Large lakes of water on the ice in Greenland pose a problem. This water, by wedging open a crack or crevasse in the ice, quickly flows through to the bottom, melting the bottom of the ice sheet and causing it to move more rapidly toward the ocean. Observers have seen lakes on the Greenland ice sheet drain at the speed of Niagara Falls.

All ice sheets spread due to their large mass, but friction from the rocks beneath slows the ice's motion. Water beneath the ice allows the ice to move more rapidly.

"Right now, the center of the Greenland ice sheet is frozen to the rocks," says Alley. "If the melt water moves inland as the world warms and gets to the bottom, it will thaw the bottom and unstick the ice from the rocks."

Another contributor to the melting ice sheets is the warming of the ocean. When ice shelves -- ice still connected to the ice sheet but floating over water -- melt, they also cause the ice sheet to flow faster. In Greenland, the Jakobshavn ice shelf has retreated more than 5 miles since 1992. Rocks and cliffs on the sides of fiords or inlets slow the seaward movement of the ice shelves. If these shelves break up and melt, the ice streams behind them move more rapidly.

Ice shelf failures have also occurred on Antarctica where, for example, most of the Larsen B ice shelf disintegrated in March of 2002 and increased the rate of ice stream flow eight times.
"Water temperature is more important than air temperature in melting the ice shelves," says Alley. "However, both contribute."

Warmer oceans, caused by general global warming or local events can trigger more breakups of ice shelves and faster flow of ice streams in Antarctica. In Greenland, sustained increase in temperatures of only a few degrees will remove the ice.

Alley believes he knows the direction to go to gain a better understanding of the ice sheets, how they work and the effect they have on climate change. Although those who study ice sheets have long modeled ice sheet behavior, simulations of the whole earth system typically have not included ice sheets along with the atmosphere, oceans and clouds, in their models. Past atmospheric modelers usually treated the ice sheets simply as white mountains.

"They are not white mountains and they need to be modeled," said Alley. "We need to have them in the models to figure out how the system works."

Alley notes that a collaboration of government and academic scientists created the atmospheric and ocean models, but collaborations to model the ice are only just being developed.

-Greenland And Antarctic Ice Sheet Melting, Rate Unknown