|
Post by fascinating on May 19, 2013 13:21:40 GMT 1
"global warming should lead to a decrease in mean sea level." So you agree that sea level is a concept which can be usefully measured?
|
|
|
Post by alancalverd on May 19, 2013 23:59:47 GMT 1
It is an interesting concept, and in the absence of wind, waves, tides, tsunamis, tectonic shifts, seasonal fluctuations, and everything else that makes water move on a real planet, (a) it could have some practical value and (b) it would decrease if the floating ice sheets were to melt. But, to quote an Indian physics exam question, that would be"ignoring the weight of the elephant".
Fact is, it can't be measured globally to any useful degree of accuracy. The Ordnance Survey datum at Newlyn, which is very slowly recovering from the last ice age depression, is not rigidly coupled to the old (now abandoned) Japanese tidal datum which leaped about daily as the Pacific plates shift. The tidal range at the Rance estuary is 25 times that of Venice: a 1 cm change in the mean would have no impact on the output of the Rance barrage or the Venetian tourist trade, both of which depend on the local tidal range.
|
|
|
Post by mrsonde on May 20, 2013 19:15:14 GMT 1
It is an interesting concept, and in the absence of wind, waves, tides, tsunamis, tectonic shifts, seasonal fluctuations, and everything else that makes water move on a real planet, (a) it could have some practical value and (b) it would decrease if the floating ice sheets were to melt. How on earth have you reached that conclusion? The (b) part, I mean? However you did it, it's quite wrong. Modern sea level measurements are made by radar from satellites, ranging over the surfaces of the oceans.
|
|
|
Post by buckleymanor1 on May 20, 2013 22:29:16 GMT 1
Not so sure that it is wrong. Sea water reaches it's maximum density before it freezes. So frozen water is less dense, when it melts some of it becomes more dense than warmer water or frozen water so overall it takes up less room if only the floating ice sheets melt.
|
|
|
Post by mrsonde on May 21, 2013 3:41:45 GMT 1
Not so sure that it is wrong. Sea water reaches it's maximum density before it freezes. So frozen water is less dense, when it melts some of it becomes more dense than warmer water or frozen water so overall it takes up less room if only the floating ice sheets melt. Problem is, it's not sea water: it's fresh water. It's come from the atmosphere, originally from the sea, to where it returns if it melts. So, overall, no significant change - a very slight increase. But what most definitely will not happen is a fall in sea level. The big problem is if the Arctic melts, then ice on the land will melt too. Hence the increase in sea level since the end of the last ice age, 12,000 or so years ago - or glacial, strictly speaking, seeing as we're still in it. Then you've got the other big problem - if it's warm enough to melt the ice, the oceans will be continuing to warm, and as you say: warm water expands. Higher sea level.
|
|
|
Post by mrsonde on May 21, 2013 4:17:51 GMT 1
Not that I'm in the least bit worried about that possibility. If it turns out that the present cooling phase only lasts thirty years or so, instead of sixty or seventy, and if by that time, by some fantastical chance, no one has still not figured out how to split water with sunlight and almost instantly create the Hydrogen Age, and with it the rapid end of fossil fuels, then the effects of global warming - whatever the causes - can easily be completely reversed now we know for sure that clouds have an overall cooling effect. We merely have to make them.
There are several ways to do this. The scheme I like the most is John Latham's - generating sea-spray over the oceans using wind-powered turbines. Clean, simple, cheap. Latham calculates it would cost a few billion dollars to generate a 10-15% increase in ocean clouds and thereby completely counteract the past century's global temp rise, projected onto 2050 or so.
A few billion.
Al Gore doesn't like the idea. Nor does the IPCC. What a surprise.
|
|
|
Post by alancalverd on May 21, 2013 6:36:23 GMT 1
Physics. Observation. Textbooks on polar oceanography. All that kind of irrelevant stuff.
|
|
|
Post by rsmith7 on May 21, 2013 9:32:41 GMT 1
Not that I'm in the least bit worried about that possibility. If it turns out that the present cooling phase only lasts thirty years or so, instead of sixty or seventy, and if by that time, by some fantastical chance, no one has still not figured out how to split water with sunlight and almost instantly create the Hydrogen Age, and with it the rapid end of fossil fuels, then the effects of global warming - whatever the causes - can easily be completely reversed now we know for sure that clouds have an overall cooling effect. We merely have to make them. There are several ways to do this. The scheme I like the most is John Latham's - generating sea-spray over the oceans using wind-powered turbines. Clean, simple, cheap. Latham calculates it would cost a few billion dollars to generate a 10-15% increase in ocean clouds and thereby completely counteract the past century's global temp rise, projected onto 2050 or so. A few billion. Al Gore doesn't like the idea. Nor does the IPCC. What a surprise. Why on earth would one want to make it cooler???
|
|
|
Post by buckleymanor1 on May 21, 2013 9:55:29 GMT 1
The presumption that the oceans will continue to warm is just that. Initially there will be a drop in sea level ls if the floating ice sheets just melt. Temperature rises as a gradient.I am not sure if there is a sufficient amount of ice on the land in the Antarctic to cause a rise above the density increase. As an aside the warmest's will have you believe that it's the use of fossil fuels that are causing this.Well where does all the fossil fuels in the world come from.The ground on the earth or the ground under the sea.Nature does not like empty spaces, so the majority of those spaces, must eventually fill with water.It does not make any difference if it's sea water or fresh it just takes it out of the cycle and lowers the sea levels around the world.
|
|
|
Post by mrsonde on May 21, 2013 10:02:49 GMT 1
Physics. Observation. Textbooks on polar oceanography. All that kind of irrelevant stuff. As I say, you're wrong. You won't have read any physics or oceanography textbook that asserts sea level will fall if the Arctic melts; and you certainly won't have observed it! Given the relative densities, fresh water on salt water, there'd be a slight rise - negligible for all intents and purposes. The real problem will be the mass of land ice joining the sea, and the oceans expansion due to the warming that's caused the melt.
|
|
|
Post by mrsonde on May 21, 2013 10:10:08 GMT 1
Not that I'm in the least bit worried about that possibility. If it turns out that the present cooling phase only lasts thirty years or so, instead of sixty or seventy, and if by that time, by some fantastical chance, no one has still not figured out how to split water with sunlight and almost instantly create the Hydrogen Age, and with it the rapid end of fossil fuels, then the effects of global warming - whatever the causes - can easily be completely reversed now we know for sure that clouds have an overall cooling effect. We merely have to make them. There are several ways to do this. The scheme I like the most is John Latham's - generating sea-spray over the oceans using wind-powered turbines. Clean, simple, cheap. Latham calculates it would cost a few billion dollars to generate a 10-15% increase in ocean clouds and thereby completely counteract the past century's global temp rise, projected onto 2050 or so. A few billion. Al Gore doesn't like the idea. Nor does the IPCC. What a surprise. Why on earth would one want to make it cooler??? I said if. If the present cooling phase does not result in a significant drop in global temp - or, worse case, the AGW alarmists somehow have managed to blunder and guess their way through to an accurate prediction, if for the wrong reasons and by the wrong methods. If. for example, a doubling of CO2 actually does lead to a two or three degree rise; or if, for another example, the sun for some reason suddenly kicks into another very active phase, like the late 80s and 90s; or if our solar system happens to pass through a part of space unusually dense in plasma. Any number of possibilities - one of which is that despite being so amateurish and unscientific, the AGW proponents just happen to have got it right: it's important to keep an open mind, and remember that the future is not yet written. Anyway - if. That would be very, very bad news. But, fortunately, fairly easily and cheaply solved.
|
|
|
Post by mrsonde on May 21, 2013 10:20:15 GMT 1
The presumption that the oceans will continue to warm is just that. Initially there will be a drop in sea level ls if the floating ice sheets just melt. As opposed to do a dance or something? I don't know what you mean. You mean if just the floating ice sheets melt, perhaps? Well, going along with that physical impossibility for the purpose of argument, the sea level would rise very slightly. It's pretty basic physics. I don't know what you're referring to. What "density increase"? A temp rise of liquid water causes a density decrease. The amount of ice in the Arctic pack is a tiny fraction of the water in oceans. Do a google and take a look at how thick the ice is on Antarctica. Then factor in the Greenland cap, and the Siberian, and Canadian, and the Himalays, and the Alps, and all the glaciers around the world.
|
|
|
Post by buckleymanor1 on May 21, 2013 13:36:18 GMT 1
The presumption that the oceans will continue to warm is just that. Initially there will be a drop in sea level ls if the floating ice sheets just melt. As opposed to do a dance or something? I don't know what you mean. You mean if just the floating ice sheets melt, perhaps? Well, going along with that physical impossibility for the purpose of argument, the sea level would rise very slightly. It's pretty basic physics. I don't know what you're referring to. What "density increase"? A temp rise of liquid water causes a density decrease. The amount of ice in the Arctic pack is a tiny fraction of the water in oceans. Do a google and take a look at how thick the ice is on Antarctica. Then factor in the Greenland cap, and the Siberian, and Canadian, and the Himalays, and the Alps, and all the glaciers around the world. I don't dispute what you are saying there is a lot more water there. What I do dispute is that it is at the moment frozen and the oceans are in the meantime getting shallower because of extraction.
|
|
|
Post by alancalverd on May 21, 2013 18:50:50 GMT 1
No, it doesn't. Please read a physics textbook before making such assertions. The anomalous behaviour of water is enormously important to life on earth, and derives from the shape of the hydrogen bond, which is even more fundamental to the processes of life, even if AGW enthusiasts don't understand it.
And for what it's worth, satellite altimetry is referred to a hypothetical geoid that has to be revised every time the crust shifts - i.e continually. Just as well, because however high you fly from A to B, the last ten feet determines the rest of your life.
|
|
|
Post by mrsonde on May 22, 2013 11:47:42 GMT 1
Thankyou buckley, but as it goes I'm very familiar with all of the latest research on the properties of water: it happens to be peripheral but nevertheless essential to my own field. It would help more if you made your point.
I believe I have grasped it - what you've said, anyway. These latest claims are simply incorrect, I'm afraid. They might be if liquid water froze at 4 degrees - but it doesn't. Beyond that, it continues to get less dense as temp rises, until of course it turns to vapour.
You dispute that the ice caps and glaciers of Antarctica, Greenland etc are frozen? And you're claiming that the oceans are getting shallower? Have I grasped it?
|
|