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Thread: What if all the ice melted...

  1. #31
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    Quote Originally Posted by samsara15
    If seeding the ocean with rust is so easy, then why shouldn't we consider it a practical means of tailoring our climate to whatever we define as desirable?
    One reason is that it isn't so easy. It isn't clear that this is either practical or effective. At the very least, it needs much more research.

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  2. #32
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    I think the ice in antarctica was caused by snowfall. However, Antartica is mostly a desert since little precipitation actually occures there at present. BTW, some people think there may be dry ice (frozen CO2) there because it gets so cold, but I don't know if it would be seasonal or permanently sequestered if it was true. There are also oil and coal deposits in Antarctica, so these might somehow end up in the atmosphere eventually from human mining and burning or from other mechanisms (natural underground coal fires).

    I'm all for humans changing the environment. But we need to make sure we know the ramifications of those acts. Only a few Mississippi levees failed in the 1993 flood, the others were intentionally destroyed intentionally, to relieve pressure on downstream localities. I think some of the problems with that levee system was its lack of defense in depth. I think there should be pocket levees or levee cells, that allow for a main riverside levee to be opened with limited range and damage potential. Or were you referring to NOLA and the failure of non-Mississippi River levees? (Actually, I'm not sure if you are using them as good examples or bad examples.)

    I think the Hoover Dam has been a success, hasn't it?
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  3. #33
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    BTW, if some of you are interested in sea level fluctuations in general take a look at this NOAA map of exposed land 18kya at the end of the last ice age.
    The FTP link is at the bottom of this page.
    Et tu BAUT? Quantum mutatus ab illo.

  4. #34
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    are there any maps of what the world would look like with a 200-foot rise in sea level?

  5. #35
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    This site has maps that only go up to a maximum of 6 meters, but have some nice viewing tricks:

    http://www.geo.arizona.edu/dgesl/res...level_rise.htm

    Edited to add:

    Here's one that is supposed to be 100 meters (very unlikely, of course)

    http://resumbrae.com/archive/warming/100meter.html

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    Thanks Van Rijn, I guess he didn't read through the OP. I had the same link, but it's 328ft. Comparing with the 30m should give an approximation.
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  7. #37
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    Quote Originally Posted by Ara Pacis
    Thanks Van Rijn, I guess he didn't read through the OP. I had the same link, but it's 328ft. Comparing with the 30m should give an approximation.
    Heh. It is easy to miss links. I thought the 100 meter was more fun than the 30 meter (roughly 100 feet) so I picked that.

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  8. #38
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    Quote Originally Posted by Doodler
    We're really not that good at it. I believe the Hippocratic "first do no harm" rule should apply.
    Damn right.
    The lithosphere, atmosphere, hydrosphere and biosphere are all chaotic systems
    and they all interact with each other in ways we don't quite understand.
    Short of a few simple rules of thumb (pollution=bad, green stuff=good),
    we simply don't know for sure what the ultimate consequences of our actions will be.

  9. #39
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    The largest problem with the ice sheets melting with regards to civilization and humanity is this: we have built our civ on the principle that this world will never change dramatically.

    The change in sea level rise will do more than dislocate people - it will have profound effects on the gulf stream system and possibly the jet stream system.
    Take the atlantic as an example. Raising the sea level will increase the amount of ocean surfcae. If nothing else, this will increase the amount of area which can feed hurricanes. So in addition to huricanes not being stopped by Florida (which will be underwater), and making landfall 20 - 40 miles farther inland, it will also have the added strength from the extra ocean it will cover. A category three hitting Mobile may become a 3.5 hitting baton rouge.

    Take into account Panama. It is very possible that a 100m sea level rise will reconnect the atlantic and pacific oceans. It is unclear what, if any, the effects on the ocean currents will be (either locally or farther). It is unliklely though that the net result will be *no change*. Not only will water be exchanged, but so will local fish populations, further upsetting local ecosystems.

    Now take into account what a strengthened hurricane system might do to the jet stream across the US. Crops might be drowned out in the heartland, other systems might be deflected or pushed northward or stalled in the west. Again, we cannot say for certain, but change seems likely.

    Then there is the change in salinity to consider and which species of marine life it will favor. There is the possibility of a partial breakdown of the gulf stream, locally chilling the northernmost atlantic.

    In short, building walls to keep out the sea will be the least of our problems. While technology, even present technology is theoretically capable of meeting this challenge, the political will combined with the engineering challenges lead me to conclude that a simple solution is unlikely and a uniformly agreed upon solution is next to impossible.

    Again, this is mostly because we've built our society on the idea that things will always stay the same - a dangerous and possibly foolish move.


    Oh, and a brief comment about sea level rise. I've done some thinking about this in the past and I have two questions about the modeling. One: do the heightened levels take into account the increased surface area as the seas rise? and Two: are the possibilities of new freshwater lakes and seas taken into account on the Antarctic continent? Granted, this would probably account for less than 5% of the total level in meters of rise, but if you're living in that 5%, you'd want it taken into account! lol

  10. #40
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    That's a good question. I don't know. The articles, FAQs and studies I've read do not specify the sea area or change in area as it affects the volume of meltwater. But I haven't located or read many in depth articles about it. Perhaps it's not important at this stage. The most likely scenarios are relatively minor and so a rise of 5-7 meters is a small enough physical range to guestimate (even if it represents a large margin of error or discrepancy between studies). However, the long term catastrophic scenario of losing all the ice requires so many estimates for so many parameters that any discrepancies may be subsumed by the margin of error. I don't even know what all the parameters necessarily are, but I can guess:

    Phase of material: Does it quickly melt and interfere with salinity levels or does it stay ice for a long time while still raising sea levels via displacement?
    Density of ice: The denser the ice the more water will eventually be released when it melts or floats free.
    Depth of ice: How much ice is actually in the ice sheets.
    Istostatic Adjustment: How much and how fast will Antarctic land rise displacing more seawater raising sea levels?
    Isostatic Adjustment: How much and how fast will increased water cause ocean bottoms to sink and cause the other dry continents to rebound?
    Thermal Expansion: How will melting ice effect the anticipated expansion of water from expansion from other GW scenarios? Will the ocean waters contract from cooling to offset some of the rise? How long will that cooling last?
    Regolith: How much material will be removed into deep water from melting and calving ice that would otherwise be left high and dry after the melt?
    Saturation: How much water will be absorbed by newly inundated ground that will not increase sea level?

    BTW, here is an image at Wikipedia showing the land under the ice.

    this NASA article mentions volcanism may be driving ice streams in the antarctic ice sheets.

    BTW, the Panama Canal is only 85 feet above sea level at it's highest point (Gatun Lake), so the artificial ditch would be open between both oceans, but I'm not sure if there are any natural low spots on the isthmus.
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  11. #41
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    Quote Originally Posted by hewhocaves
    Again, this is mostly because we've built our society on the idea that things will always stay the same - a dangerous and possibly foolish move.
    well we could all have chosen to remain hunter-gatherers and pick up our digging stick and move on when things change.

    As it is, most of us live in permanent settlements and enjoy a somewhat higher standard of living as a result.

    Dangerous and foolish? hum...no sure about that.

  12. #42
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    Quote Originally Posted by ArgoNavis
    well we could all have chosen to remain hunter-gatherers and pick up our digging stick and move on when things change.

    As it is, most of us live in permanent settlements and enjoy a somewhat higher standard of living as a result.

    Dangerous and foolish? hum...no sure about that.
    We could also have a little respect for the fact that the world does change, and that there are probably places its not too smart to inhabit permanently.

    Even worse is the delusion that not only will the world not change, but that we can somehow modify it to be what we want, when we want.

  13. #43
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    A lot of 'new' island communities would start fighting for independence?

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    Maybe... but a lot of those new island will go through a period where they are dependent on the mainland for food and other resources before climates are conducive to agriculture.
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  15. #45
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    Ice is less dense than water. Do an experiment and fill a glass full of ice and add water to it, right to the top. Wait for it all to melt.

    If the oceans were to rise then the melted ice should make the water overflow out of the glass. But all of you know that that does not happen. Not one drop will go over the edge and not one melted ice cap would do a thing to the ocean levels. They will remain the same just like the glass of water does.

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    Your analogy is true for the Arctic icecap as it sits on water but the Greenland icecap and Antarctica's ice sheets are all on land. If Greenland/Antarctica melted then the sea levels would rise dramatically.

  17. #47
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    Blueshift, do this experiment. In the winter, if it snows where you are, measure the amount of snow on your roof. After it melts, measure how much water comes out of your gutter spouts. If it is more than zero then you'll see how ice caps can affect sea levels.
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    Revisiting this idea

    So, this idea has been at the back of my mind for a few years and I was thinking about it again, for a possible series of stories. I'm postulating a setting at least 1000 years in the future where a lot or all the ice has melted and humanity has suffered several major catastrophes that have reduced much of the population.

    I have a few questions and thoughts:

    Does anyone know why the USGS and the IPCC have different estimates for ice volumes and Sea Level Rise (SLR) heights?
    - USGS estimates a total ice volume of 32,328,300 km and a SLR of 80.32 m
    - IPCC estimates a total ice volume of 28,740,000 km and a SLR of 68.8 m
    - I get different results using their numbers (USGS glacier ice density .89% of water) = 79.67 m SLR (USGS) and 70.66 m SLR (IPCC) although if the ice is denser (at the normal ice density of .917) then the results are 82.09 m SLR (USGS) and 72.80 m SLR (IPCC).
    - Both of these calculations only include melting/floating ice and not thermal expansion, which I've read could be from .5 m to 2 m (maximum total), which at a future maximum at equilibrium may increase SLR to either 70.8 m or 82.32 m.

    The IPCC lists the ocean area as 362,000,000 km. I don't know what ocean area the USGS used for their calculation, however the USA's CIA World Factbook lists ocean area at 361,132,000 km. The difference is 868,000 km. Additionally, the IPCC states that this rise includes isostatic adjustment, but I couldn't find any specifics. It's not clear if the difference is just a rounding, or due to flooding of Antarctica and Greenland or general flooding of low lying areas around the world, but if it is, it may only be for a very small area of flooding for a small SLR over the next century. Even so, the area of land inundation listed by the USGS is much higher than the difference:
    • 5 m = 5,431,902 km
      10 m = 6,308,676 km
      20 m = 7,888, 233 km
      30 m = 9,459, 562 km


    I don't know what is the exact amount of land beyond 30 m SLR, but this mapplet (different than posted previously) allows you to select any SLR. At 80m there's a lot of land under water.

    Of course, there are local variations to consider.
    Post-Glacial Rebound/Isostatic Adjustment
    From what I've read the crust directly under the ice may rabidly rebound as fast as the ice is unloaded due to pressure, if I understand correctly, and this can occur at rates of meters per year. After this mechanism, the flow of the mantle attempting to reach equilibrium would proceed at slower rates that can still occur at rates meters per century, reducing to near 0 at the former ice margin and then becoming negative beyond the margin (1-2 mm/yr south of the Great Lakes, 5 mm/yr in southern Great Britain) . Currently, parts of the recently glaciated north (Hudson Bay, Fennoscandia) are experiencing uplifts of 11-13 mm/yr (1.1-1.3 meters/century). Some of what I've read refer to uplift and subsidence in terms of the mass change of mm of water, referring to gravimetric data from GRACE, while others state mm change in height of the land directly (using GPS and/or GRACE) but they seem to arrive at the same value, so I'm not sure if the mass of water in mm is equivalent to a change in height precisely or not. Additionally, there are horizontal adjustments too, which seem to suggest the crust is moving north, relatively speaking.

    Gravitational adjustment
    The movement of mass from the poles may result in less oblateness of the planet due to mantle flow moving back to the poles in the long-term. However, the water might find its way to the equator in the short term, or will it? This will affect the speed of planetary rotation. Additionally, the change in mass locations will cause the polar axis of rotation to shift, but I'm not sure how far (hundreds of meters for the West Antarctic Ice Sheet (WAIS) only, but how much more and in what direction for all the ice?). This would alter the geoid and affect SLR distribution globally

    A recent article I read suggested that in a scenario where the WAIS melted, instead of a uniform 5 m SLR, the gravitational pull in the North Atlantic would increase the SLR by 1.3 m (to 6.3 m) while the sea level near Antarctica and perhaps elsewhere in the southern hemisphere would actually drop. Of course, if all the ice melted, those signals would be even more variable, but the indication is that SLR will be measured higher near shores because continents have stronger gravitational gradients than ocean basins and will alter the geoid to pull more of that new distribution of water towards and over land. I wonder how high that will increase shoreline SLR over a future MSL. (Incidentally, that article came out in 2010 and the author was stating that he didn't realize it was an issue. Yet, I was asking that question years before, so maybe I should be a climate scientist *grin*)

    Water Flow
    The Tradewinds create a bulge in the western Pacific of about .2 m, but this could change with differences in wind patterns.

    An alteration of the thermohaline current in the North Atlantic would result in the Gulf Stream backing up as high as .6m, in a moderate warming scenario. However, as far as the long-term result of deglaciation goes, I assume there would be a new equilibrium and the flow would start up again in some way to reduce the blockage and its local SLR, but I could be wrong.

    Interstitial Fluid Extraction
    Some locations are experiencing subsidence due to the removal of oil and gas and groundwater. It has been claimed that Louisiana is sinking 10 mm/yr due to this. Of course, there's a finite amount of extractable fluids and therefore a maximum amount of subsidence this can cause. However, it should be noted that extraction of groundwater that is later flushed down rivers to the ocean or evaporated into the air to later precipitate into oceans is also a non-zero component of SLR. However, on the global scale of things it may be negligible. Furthermore, this suggests one avenue for reducing SLR, by sequestering water underground or even above ground. Indeed, some researchers have claimed that it was the boom of dam & reservoir building during the 20th century that masked what should have been a SLR due to the melting of alpine glaciers.

    Possible Inundation Mitigation Strategies/ Mega-Projects
    I say inundation instead of flood, since I think of flood as a temporary weather phenomenon instead of a change in climate. Also, for the purposes of the discussion here I use Levee for river water barriers and Dikes for sea barriers and Dams for either type (or substructures thereof) that allow for controlling flow instead of merely impeding it.

    Mediterranean Sea Dams and Dikes and Locks
    One proposal would be a dam at the strait of Gibraltar and at the Suez. There are several possible reasons for this. An 80 m SLR would flood a fair amount of land in the Med, but it would also flood inland into parts of eastern Europe and even into the Caspian sea. The salinity of the Med also affects the thermohaline current in the Atlantic and some claim there would be local and global environmental benefits to this. In addition to those reasons, it might also be used to provide power by allowing some sea water in to generate hydroelectricity and serve as a road and rail connection with Africa. (The Med has a net loss of water from evaporation, so it will need to be replaced or else the level of the sea will reduce naturally, see Messinian Salinity Crisis) Locks may be part of the dams or constructed elsewhere in either Spain or Morocco or both for the Strait of Gibraltar and again for the Suez Canal. If the sea were prevented from flooding the Mediterranean (and using the current extent of the Med as part of the area of the Ocean used for SLR calculations) we can conclude that damming and maintaining the current MSL in the Med would result in a global increase in SLR of .53 to .55 m. If the Med sea level is lowered, intentionally or through evaporation, then this can be increased and if we use the Atlantropa parameters of a 200m reduction in Med sea level, then the global SLR would increase an additional ~1.86 m (.53 m + 1.33 m).

    Mississippi River and Gulf of Mexico Dam, Dike and Levee system
    At 80 m, a lot of land would be inundated from the Gulf on up the lower Mississippi Valley to New Madrid, Missouri. There would be a narrowing of this "Gulf of Mississippi" at about the 31st Parallel where a dike might be constructed that would only need to be ~120 km long and hold back waters ~70 m deep (and able to survive strong hurricanes with storm surges over 8.5 m, similar to Katrina). With the river located near the eastern edge, it would be simple to construct a single levee west of it for the entire length of the inundatable area, with an eastern levee existing only in the Mississippi Delta region from Vicksburg to Memphis. I guestimate that restraining this water might contribute an additional ~10 mm to global SLR.

    On the other hand, perhaps dikes could be constructed along the entire Gulf and Atlantic coasts to restrain SLR inundation. I don't know enough engineering to figure how plausible this, or the dikes and levees mentioned above, might be and what sort of maintenance they would require.

    California Central Valley Dams and Dikes and Locks
    A series of dams, at the Golden Gate strait, with a backup at the Carquinez Strait might prevent sea from inundating the Central Valley. A dike or Locks and Dam might be constructed to block the sea from entering near Daly City, south of that area. The same might be done for the various valleys that would become straights flooding the San Francisco Bay basin up to 60 miles north of the Golden Gate.

    However, this might result in freshwater flooding of the area, unless levees and a canal and/or pumping to the sea were done. Or perhaps it could be completely diverted for agriculture or to reservoirs in other basins. Perhaps a related project would be to intentionally inundate parts of the Basin and Range region into freshwater lakes, re-establishing Lake Lahontan and others. This might be especially useful if climate change results in one or more ARkStorm related flooding episodes.

    ***

    BTW, this is all background. It is unknown if such megaproject structures would survive various plausible catastrophes. Climate change may induce stronger and/or more hurricanes. Mass shifts from Post Glacial Rebound and inundation of dry land might induce earthquakes. These might induce tsunamis and mass shifts might induce landslides causing megatsunamis. Volcanism is expected to be induced by mass shifts. Warming climates may spread the incidence of mosquito born diseases and other parasites and diseases. Droughts and floods may cause malthusian shifts in human populations and subsequent conflicts may reduce populations further either directly (nuclear war and fallout) or indirectly by malnutrition and infrastructure failures (natural, such as by a strong geomagnetic storm, and man-made calamities) that make people susceptible to disease. I don't know if a super-volcano will be induced, but it's a possible stand-alone option for a fictional story. If all these things reduce human technological capabilities, a further calamity due to the impact of Asteroid 1950DA in 800 years may not be averted. On the bright side, I posit that humanity continues throughout much of the world, but at low subsistence populations (.5 Billion perhaps?) with a few technologically-advanced but isolated enclaves that re-establish the capability of spaceflight. Of course, this would be a fictional story. It may seem post-apocalyptic, but it may show a rebound from such a nadir in contrast to its depths.

    Any comments on the physical aspects of geophysics or engineering, or answers to any of my questions would be welcome.
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  19. #49
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    If all the ice sheets melt, wouldn't the sea levels just go back to what it was before the last bout of global cooling >2.5 million years ago? I'd imagine it would look like this:




    A major inconvenience requiring quite a bit of public works to keep our major cities from being submerged to be sure, but hardly the end of the world. After all if the Belgians could do it for hundreds of years, why can't we?
    Last edited by aquitaine; 2012-Apr-16 at 05:55 AM. Reason: Image fail

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    The Dutch, not the Belgians. And I'm pretty sure there'd be more desertification than shown on that map

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    Quote Originally Posted by parallaxicality View Post
    And I'm pretty sure there'd be more desertification than shown on that map
    I've read that there's an expectation of more desertification, but I haven't looked into it too much yet. A lot of the talk of desertification I've seen refers to near-term climate change proposals, as opposed to a future equilibrium state at a maximum sea level. From what I've read, there's an expectation of a reduction of mid-latitude cyclones because the poles are not as cold and that reduces the potential temperature gradient. On the other hand, warmer seas may induce more tropical cyclones that bring lots of rain at a time. I'm not sure how monsoons would be affected.

    Incidentally, if certain basins were dammed against a sea level rise of 80+ m, I calculate they might experience about 1F rise in temperature from adiabatic heating. I wonder how much difference that would make on desertification (and how it would affect the fog in San Francisco).
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  22. #52
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    Quote Originally Posted by aquitaine View Post
    If all the ice sheets melt, wouldn't the sea levels just go back to what it was before the last bout of global cooling >2.5 million years ago? I'd imagine it would look like this:
    According to the creator, that's 20 million years ago, not 2.5 Million. A lot's happened since then, geographically speaking. It's not just the amount/height of the water, but also of the land. Although, looking at topography now makes that sea level look like it's only about 20 m higher than current, not the estimated 70-80 m potential.

    A major inconvenience requiring quite a bit of public works to keep our major cities from being submerged to be sure, but hardly the end of the world.
    We might. And it might even work. I'm not an engineer, so I'm unsure what it would take to construct a dike to hold back 80+ m of sea water, not to mention all the freshwater that might build up behind it from rain and rivers. This site suggests a sea dike 100 m tall would need a width of >500 m to >900 m (I'm not sure how wide the top needs to be). Perhaps a river could be walled up behind two levees 80+ m high for hundreds of miles upstream of its mouth, or the river could flow through a huge elevated aqueduct. Or a river might be allowed to flood the area behind the dike to create a freshwater lake, or allowed to mix into a estuary. How would a dike react to a hurricane storm surge? How would would react to a tsunami, or a mega-tsunami? This are the questions I ponder because I want my fiction to reflect real human choices. So, I'm wondering if we'd build and maintain these mega-structures or if we'd simply retreat. After all, we'd not only have to build one, but probably a second behind the first, just in case it failed.

    However, I don't think anyone would plan to build it since no one would expect all the ice to melt. It might be a gradual process of adding on height over time. When we factor in human behavior and natural disaster probabilities, I suspect that at some point in 1000+ years most of the coastal dikes will have failed. Locations where a singular structure might be built from the beginning, in San Francisco and Gibraltar/Suez, might they survive natural disasters and neglect.
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  23. #53
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    I've read that there's an expectation of more desertification, but I haven't looked into it too much yet. A lot of the talk of desertification I've seen refers to near-term climate change proposals, as opposed to a future equilibrium state at a maximum sea level. From what I've read, there's an expectation of a reduction of mid-latitude cyclones because the poles are not as cold and that reduces the potential temperature gradient. On the other hand, warmer seas may induce more tropical cyclones that bring lots of rain at a time. I'm not sure how monsoons would be affected.
    Why is desertification going to increase?

    According to the creator, that's 20 million years ago, not 2.5 Million. A lot's happened since then, geographically speaking. It's not just the amount/height of the water, but also of the land. Although, looking at topography now makes that sea level look like it's only about 20 m higher than current, not the estimated 70-80 m potential.
    I tried finding a more recent map before the ice age but it was extremely pixelated. But even so, the entire state of Florida is at or near sea level, enough to sink it.

    We might. And it might even work. I'm not an engineer, so I'm unsure what it would take to construct a dike to hold back 80+ m of sea water, not to mention all the freshwater that might build up behind it from rain and rivers. This site suggests a sea dike 100 m tall would need a width of >500 m to >900 m (I'm not sure how wide the top needs to be). Perhaps a river could be walled up behind two levees 80+ m high for hundreds of miles upstream of its mouth, or the river could flow through a huge elevated aqueduct. Or a river might be allowed to flood the area behind the dike to create a freshwater lake, or allowed to mix into a estuary. How would a dike react to a hurricane storm surge? How would would react to a tsunami, or a mega-tsunami? This are the questions I ponder because I want my fiction to reflect real human choices. So, I'm wondering if we'd build and maintain these mega-structures or if we'd simply retreat. After all, we'd not only have to build one, but probably a second behind the first, just in case it failed.
    If it takes sea levels a few decades to rise to that point then it should be possible to build a sea wall of that size around the major coastal cities of the first world. Small communities in danger of flooding would be exacuated (not enough economic value to make it worthwhile), as would Florida. The reason being is that amount of land needing to be preserved is too great. It is questionable to what extent the third world will be able to save its coastal cities, more than a few would likely be abandoned.

    If you're interested in the topic then I suggest reading up on New Orleans, at its lowest point it is 6 meters below sea level, and so the city is protected by levees and dikes. What happened with hurrican katrina was the levee system was badly neglected. Otherwise it would have likely been able to hold during the hurricane.

  24. #54
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    71% of the planet is ocean, more than double total land area. If we can avoid major catastrophes, it may be possible for human population to increase considerably by moving to the sea, maybe to 50 billion people. A mile wide sphere of fresh water could support a high rise city and float around the ocean currents. Greenfield ocean cities floating on fresh water bags could optimise law to be very pleasant places to live. Most of the ocean is several kilometers deep, so the floor's the limit for scale of water balls. Algae farms in the ocean could prevent runaway arctic ice melt and methane release while also providing a sustainable low cost energy and food supply. 0.1% of ocean covered in high intensity industrial algae production facilities could soak up more CO2 than total emissions, reducing the likelihood of tipping point catastrophes like methane release or acidification or massive Antarctic melt. If we work out how to use algae intensively for carbon based construction, we will have incentive to mine CO2 out of the air.

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    Ironically, melting of the polar caps has a short-term temperizing effect upon sea levels - Cold water currents sinking into the oceans lower temperatures. Thermally contracting the net volume. Once the caps are gone, it will be Katy-bar-the-door.

    Today is 'Connect the Dot Day'; linking climate change to world-wide weather extremes, including damaging tornados, extreme droughts in Africa, 'heat stroke' death of coral reefs and new extreme records all over the planet. See Jeff Masters blog on Wunderground.com for more links and details.

    Since the first warnings in the early 70's; it has been interesting watching both the effects of climate change and the reaction to the greatest anthropothic event in the history of the earth. In the late 80's a petition was circulated in the research laboratory in which I worked disparaging gw science. The petition was tied to papers popularized at the time because they highlighted weather events and indices that ran counter to gw theory. Many of my peers, much to my dismay, signed the petitions. But as the evidence mounted; there was a feeble attempt to welcome the anthroptic change as a welcome reprieve. Today, as Jeff Masters observed; there is a growing trend in the world media to 'ignore the dots'.

    What worries me most is that the climate changes I am We are living through the worst-case senarios painted four decades ago. The worst-case predicitions for the next 100 years are horrendous. James Hansen is worried we will Venusify the atmosphere - creating world-wide winds that are not broken-up by land masses.

    Meanwhile - the Kentucky derby is being drowned in another severe weather event.

    Connect the dots.

  26. #56
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    I see three serious errors in this article from Yahoo!

    Can anyone else see them? Dark doesn't necessarily mean heat if it's converting sunlight into chemical energy; it premises that people will stop migrating, something that's never happened in human history; their "big surprise" shouldn't be, as plants have always reacted that way, particularly in environments of increased CO2 (also ignores buffering effect of plants).

    @Jerry: The Earth has weathered far more extreme periods of both warmer and cooler weather without Venusifying or Plutoing itself...

  27. 2012-Jun-04, 09:00 AM
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    request by DoggerDan to delete (accidental post)

  28. #57
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    Quote Originally Posted by DoggerDan View Post
    I see three serious errors in this article from Yahoo!

    Can anyone else see them? Dark doesn't necessarily mean heat if it's converting sunlight into chemical energy;
    White snow/Ice tends to reflect many wavelengths, but darker rocks and biological material tend to absorb them. Absorbing more energy into the system results in a net increase of energy into the system. Sure, some of the photons are used in endothermic reactions, like photosynthesis, but eventually that energy will be released back into the system by fire or digestion. Meanwhile the dark parts of the plant absorb the other frequencies and emit that energy as IR. Just like eleewhere on the planet, some of that IR energy escapes and some is blocked.

    it premises that people will stop migrating, something that's never happened in human history;
    No, it doesn't premise that, it just says that people will be at risk. There are many risks which may not be mitigated by migration. And every location is bound to be exposed to at least one of a number of risks. It's not just sea level rise, it's drought and inland flooding and fires and migrations of insect pests and diseases and war over dwindling or variable resources.

    their "big surprise" shouldn't be, as plants have always reacted that way, particularly in environments of increased CO2 (also ignores buffering effect of plants).
    I didn't realize that established plants that are stunted due to environmental variables could suddenly enter a growth spurt in better conditions either. Maybe they thought the plant stunting was genetic instead of merely morphological.
    Et tu BAUT? Quantum mutatus ab illo.

  29. #58
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    Sorry for the delay.

    Quote Originally Posted by aquitaine View Post
    Why is desertification going to increase?
    Apparently, there will be a general increase in warmth, causing more evaporation and precipitation is expected to vary, with droughts and floods, neither of which is good for plants and both of which result in erosion of good soil.

    I tried finding a more recent map before the ice age but it was extremely pixelated. But even so, the entire state of Florida is at or near sea level, enough to sink it.
    There are high points over 200ft. A total melt might flood even those.

    If it takes sea levels a few decades to rise to that point then it should be possible to build a sea wall of that size around the major coastal cities of the first world. Small communities in danger of flooding would be exacuated (not enough economic value to make it worthwhile), as would Florida. The reason being is that amount of land needing to be preserved is too great. It is questionable to what extent the third world will be able to save its coastal cities, more than a few would likely be abandoned.
    Florida currently has some decent agricultural land and climate, so part if it would be desirable to save, unless we knew the land would become useless for those purposes due to climate. The idea that land is not worth preserving is backwards. The larger the swath of land, the more likely it is to be worth preserving. A lot of it depends on the elevation and how big and strong a seawall or dike might need to be to resist flooding even in hurricanes. You might want to save cities on the coast, like Miami, but realize that you'll have to replace the beach and several blocks of building with a huge dike over 300 ft tall.

    If you're interested in the topic then I suggest reading up on New Orleans, at its lowest point it is 6 meters below sea level, and so the city is protected by levees and dikes. What happened with hurrican katrina was the levee system was badly neglected. Otherwise it would have likely been able to hold during the hurricane.
    I'm not sure what your point is, that writing and resurrecting a thread where I post detailed analysis of flooding and dike and dame mitigation strategies doesn't mean I'm interested, or that I've not heard about New Orleans and Hurricane Katrina.
    Et tu BAUT? Quantum mutatus ab illo.

  30. #59
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    Quote Originally Posted by Robert Tulip View Post
    71% of the planet is ocean, more than double total land area. If we can avoid major catastrophes, it may be possible for human population to increase considerably by moving to the sea, maybe to 50 billion people. A mile wide sphere of fresh water could support a high rise city and float around the ocean currents. Greenfield ocean cities floating on fresh water bags could optimise law to be very pleasant places to live. Most of the ocean is several kilometers deep, so the floor's the limit for scale of water balls. Algae farms in the ocean could prevent runaway arctic ice melt and methane release while also providing a sustainable low cost energy and food supply. 0.1% of ocean covered in high intensity industrial algae production facilities could soak up more CO2 than total emissions, reducing the likelihood of tipping point catastrophes like methane release or acidification or massive Antarctic melt. If we work out how to use algae intensively for carbon based construction, we will have incentive to mine CO2 out of the air.
    It's not enough to find room for people, we have plenty of room for 50 billion people on land. The problem is finding room to grow food. Besides, if we were going to construct mile-wide sphere's for mobile human habitation, we may as well float up.

    Also, it's not clear that CO2 sequestration will be able to stop arctic ice melt and/or methane release if we're already past the tipping point. We'd need to affect precipitation patterns to increase the mass balance of the ice sheets. After all, despite the title of the thread, sea level can rise without all the ice actually melting. It's enough for it to calve ice mass into the oceans.

    Anyways, this thread is about a post-event, not about preventing an event. But I appreciate suggestions for potential mitigation attempts in the fictional account that will have failed.
    Et tu BAUT? Quantum mutatus ab illo.

  31. #60
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    Quote Originally Posted by Jerry View Post
    Ironically, melting of the polar caps has a short-term temperizing effect upon sea levels - Cold water currents sinking into the oceans lower temperatures. Thermally contracting the net volume. Once the caps are gone, it will be Katy-bar-the-door.
    Or at least reducing the positive rate of expansion due to thermal increase, even if it doesn't go negative. Of course, the ice doesn't have to melt, it just has to displace water in order to raise sea level. The circumpolar current might, fictionally, if not conceivably, prevent some temperature mixing while allowing volume increase system-wide.
    Et tu BAUT? Quantum mutatus ab illo.

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