Originally posted by Roy
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THE thread for climate skeptics.
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Originally posted by Bill the Cat View PostExactly my question. If the massive ice sheets were basically melted, and the sea level raised that much that quickly, and it hasn't frozen back to prior levels, like when Canada was under ice, why should we expect a similar rapid changes as from 8K-7K years? It just seems to me that good ol' Mother Nature can do a far better job at raising the sea levels than humans are being accused of.
The reason we can see a repeat has to do with the topography of Antarctica. There are several ice filled basins that extend from the coast deep into the interior, all of which are below sea level. The ice within them is piled several kilometers above sea level.
Right now, the site where these meet the coast has what's called a "grounding line" - an area where there are features that are close to sea level, and the ice sits on that relatively stably. That's because the weight of ice above sea level is enough to force the entire ice sheet onto the ocean floor (which again, is relatively shallow at the site), even though water is more dense than ice, and would naturally float it off the grounding line.
Two things can happen to destabilize this: either the ice above thins so that there's not enough weight to force it to the bottom of the ocean, or warm water gets to the base of the ice at the grounding line. When this happens, the ice floats off and breaks up rapidly, and the whole thing quickly retreats back to the next grounding line. (We can see things like this in sediment records, and have watched it happen in Greenland).
The problem with lots of Antarctica: there are only a couple of grounding lines left before you get to the deep basins in the interior. In one case, there are none. If sea water invades those deep basins, then the whole thing breaks up rapidly, dumping those several-km high chunks of ice into the ocean. You get rapid sea level rise of a couple of meters - but that's just if a single basin goes. If several of them go in quick succession or there's some sort of chain reaction (the rise in sea level destabilizes other grounding lines), then we can get over 10 meters in a few centuries.
That's what the worry is.
Incidentally, this is not the mechanism by which there was rapid sea level rise at the end of the ice age. For that, look into the draining of Lake Agassiz."Any sufficiently advanced stupidity is indistinguishable from trolling."
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Originally posted by oxmixmudd View PostAntarctica and Greenland still have substantial Ice reserves. Where they all to melt, the sea levels would rise an additional 230 feet according to the sources I checked before writing this reply. That is quite a bit, though only about .6 what we saw after the ice age (380+ feet).Atheism is the cult of death, the death of hope. The universe is doomed, you are doomed, the only thing that remains is to await your execution...
https://www.youtube.com/watch?v=Jbnueb2OI4o&t=3s
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Originally posted by seer View PostThis is exactly what I think the problem is, these predictions. How much has the sea level risen in the last 130 years or so since the industrial revolution began? Inches, feet?
Originally posted by seer View PostAnd I can remember 12 years or so ago being told that Atlantic storms (hurricanes) would become more intense and more frequent - and just the opposite has happened.
Originally posted by seer View PostAnd on a personal observation, where I have been going to the ocean for 50+ years there hasn't been any change in the ocean level. On high tide it still comes to a certain point and at low tide. There could have been an inch or two of change but certainly not a foot or feet.
Have a look at the table at the end of this NOAA report on nuisance flooding:
http://www.noaanews.noaa.gov/stories...20Flooding.pdf
Nuisance flooding is caused by a mix of local sinking of the ground, and climate driven sea level rise. And it's happening much more often, as that table shows. But the magnitude of the increase varies from place to place. Wilmington, NC has seen a 40-fold increase; Providence RI has seen none. So you may just happen to be going to a place where the difference isn't as pronounced.Last edited by TheLurch; 09-12-2016, 11:15 AM."Any sufficiently advanced stupidity is indistinguishable from trolling."
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Originally posted by oxmixmudd View PostAntarctica and Greenland still have substantial Ice reserves. Where they all to melt, the sea levels would rise an additional 230 feet according to the sources I checked before writing this reply. That is quite a bit, though only about .6 what we saw after the ice age (380+ feet).
So we really don't want to warm things up enough to do that - otherwise we'd have to say goodbye to Disneyland, MGM studios, Sea World, the Statue of Liberty, Ocean City, The Baltimore Harbor, LA, and a whole host of other even more important places
JimThat's what
- She
Without a clear-cut definition of sin, morality becomes a mere argument over the best way to train animals
- Manya the Holy Szin (The Quintara Marathon)
I may not be as old as dirt, but me and dirt are starting to have an awful lot in common
- Stephen R. Donaldson
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Originally posted by TheLurch View PostA bit over a foot. It's going up by a bit more than an inch a decade at the moment, and accelerating.
That's not the opposite of what happened. Fewer have made landfall in the US, but hurricanes have changed. We're not seeing an increase in numbers (i can go into detail on this if you'd like), but we are seeing an increase of the category 4 and 5 storms.
Nuisance flooding is caused by a mix of local sinking of the ground, and climate driven sea level rise. And it's happening much more often, as that table shows. But the magnitude of the increase varies from place to place. Wilmington, NC has seen a 40-fold increase; Providence RI has seen none. So you may just happen to be going to a place where the difference isn't as pronounced.Atheism is the cult of death, the death of hope. The universe is doomed, you are doomed, the only thing that remains is to await your execution...
https://www.youtube.com/watch?v=Jbnueb2OI4o&t=3s
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Originally posted by Leonhard View PostHere you go sir. The answer is almost 8 inches, about 0.6 feet.
Atheism is the cult of death, the death of hope. The universe is doomed, you are doomed, the only thing that remains is to await your execution...
https://www.youtube.com/watch?v=Jbnueb2OI4o&t=3s
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Originally posted by seer View PostAccording to Lurch, they have not risen at all where I live. But Jim's prediction said they will rise 230 feet! Scare tactics?"Any sufficiently advanced stupidity is indistinguishable from trolling."
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Originally posted by TheLurch View PostRead what he said more carefully - it was "if all of Greenland and Antarctica melt." It's not a prediction or scare tactics; it's math.That's what
- She
Without a clear-cut definition of sin, morality becomes a mere argument over the best way to train animals
- Manya the Holy Szin (The Quintara Marathon)
I may not be as old as dirt, but me and dirt are starting to have an awful lot in common
- Stephen R. Donaldson
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Originally posted by seer View PostReally, I was speaking of Atlantic storms. There has been no increase in frequency or intensity. Where are all these Cat 4 and 5s in the last 12 years?"Any sufficiently advanced stupidity is indistinguishable from trolling."
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Originally posted by Bill the Cat View PostHave they all melted before?
To put this in perspective, most of Florida is built on top of former coral reefs."Any sufficiently advanced stupidity is indistinguishable from trolling."
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Originally posted by TheLurch View PostOut at sea, where you pay no attention to them. Or striking a Caribbean island that you don't pay attention to.Atheism is the cult of death, the death of hope. The universe is doomed, you are doomed, the only thing that remains is to await your execution...
https://www.youtube.com/watch?v=Jbnueb2OI4o&t=3s
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Originally posted by Bill the Cat View PostHave they all melted before?
The Laurentide Ice Sheet was the last major ice sheet collapse during our last glacial maximum. It covered all of Canada and many parts of the Northern US, and it was about 2.5 to 3.0 miles thick. It last collapsed after changes in the Earths orbit warmed global temperatures to a point that the ice sheet could not be sustained - see my previous post on the Milankovitch cycles.
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Originally posted by TheLurch View PostRead what he said more carefully - it was "if all of Greenland and Antarctica melt." It's not a prediction or scare tactics; it's math.Atheism is the cult of death, the death of hope. The universe is doomed, you are doomed, the only thing that remains is to await your execution...
https://www.youtube.com/watch?v=Jbnueb2OI4o&t=3s
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