70 Metre Rise In Sea Level?

stilicho

Trurl's Electronic Bard
stilicho
Joined
Feb 6, 2007
Messages
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Using my handy slide rule and easy-to-find calculations of the volume of the land-based icecaps, I came up with a 70-metre sea level rise if the Greenland and Antarctic sheets melted. I did not factor in the density of H2O in different states at various temperatures, nor did I include the change in elevation of the land masses currently icebound. I also figured that the time it will take is about 125 years, if the one-metre projected rise in the next twenty is accurate, and if the rate of melting increases exponentially. I did not include other high elevation glacial melting but the volume of glacial non-polar ice is small compared to those two regions.

Apart from the mere inconvenience of adapting to a 70-metre rise in the sea levels, is there any good reason we couldn't accommodate that? It sounds like an astonishing opportunity for capital investment, and the rate is not fast enough to outweigh the returns.

Alternately, is this 'worst-case' scenario flawed, and if so how? My casual reading of 'worst-cases' in the Ordovician and other eras show that sea levels could be higher but only if somehow the continents sank instead of rose.
 
Somewhere in that range but 1 meter puts 1 billion at risk - 70 meters is unimaginable - you'd be looking at a totally altered continental look.

Even worst case tho puts that millenia out - far longer than modern civilization has been around.

The kicker in this tho is that the ice is a terrific climate moderator.

Without that ice even now th eextra energy iont he geophysical system would make for rather ..ahem..interesting times.....:boggled:
Here - go nuts

http://flood.firetree.net/

Kiss london goodbye at 14 meters

Picture73-2.jpg


and New York

Picture74.jpg


and Tokyo even at 14 meters...grab a water taxi..

Picture75.jpg


at 70 meters.....all gone.

oh yeah = Miami and the Bahamas at 14 meters - our newest diving parks.

Picture76.jpg
 
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macdoc said:
Somewhere in that range but 1 meter puts 1 billion at risk - 70 meters is unimaginable - you'd be looking at a totally altered continental look.

Even worst case tho puts that millenia out - far longer than modern civilization has been around.

The kicker in this tho is that the ice is a terrific climate moderator.

Without that ice even now th eextra energy iont he geophysical system would make for rather ..ahem..interesting times.....:boggled:
Here - go nuts

http://flood.firetree.net/

Kiss london goodbye at 14 meters

http://i106.photobucket.com/albums/m269/macdoc/Picture73-2.jpg

and New York

http://i106.photobucket.com/albums/m269/macdoc/Picture74.jpg

and Tokyo even at 14 meters...grab a water taxi..

http://i106.photobucket.com/albums/m269/macdoc/Picture75.jpg

at 70 meters.....all gone.

oh yeah = Miami and the Bahamas at 14 meters - our newest diving parks.

http://i106.photobucket.com/albums/m269/macdoc/Picture76.jpg
Click to expand...

London doesn't always have to be London. Were my estimates too quick? Do we have the allocation of capital to make my scheme work?
 
macdoc said:
Somewhere in that range but 1 meter puts 1 billion at risk - 70 meters is unimaginable - you'd be looking at a totally altered continental look.

Even worst case tho puts that millenia out - far longer than modern civilization has been around.

The kicker in this tho is that the ice is a terrific climate moderator.

Without that ice even now th eextra energy iont he geophysical system would make for rather ..ahem..interesting times.....:boggled:
Click to expand...


Cool...did you make those pics, or is there a site where you put in the rise in sea level and it shows the result?
 
Wanna try Bangladesh

http://flood.firetree.net/

It's max is only 20% of the OPs postulate - Kennedy Space Centre would be a hour's boat ride offshore at 14 meters.

Picture77.jpg


At OPs level - Florida is no more.

nor is Bangladesh even at 14 meters.

Picture78-2.jpg


even at 7 m Bangladesh is gone -with 1 meter - 100 million have to move

Picture79.jpg
 
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Hope you all like Denver! Population : 75 Million
 
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Nice pictures Macdoc.

What you put me in mind of is that before modern technology, living by major waterways (large rivers, oceans) was practically a requirement for civilization. As a result most major population centers can be found in such locations.

I have not looked at the numbers, but I would not be very surprised if over 75% of the world population would be displaced by a 70-meter rise in sea level.
 
cwalner said:
Nice pictures Macdoc.

What you put me in mind of is that before modern technology, living by major waterways (large rivers, oceans) was practically a requirement for civilization. As a result most major population centers can be found in such locations.

I have not looked at the numbers, but I would not be very surprised if over 75% of the world population would be displaced by a 70-meter rise in sea level.
Click to expand...

I know more than that percent of Aussies would be displaced. I'd estimate 85%.
 
Damien Evans said:
I know more than that percent of Aussies would be displaced. I'd estimate 85%.
Click to expand...
I wonder: is there another country with a higher %age of its population living on the coast, i.e. with x miles of the sea (where x is, say 5 or 10 miles)?

At least they have plenty of land to move into.
 
It would be messed up to have to take a submarine down to where your hometown was...

INRM
 
cwalner said:
What you put me in mind of is that before modern technology, living by major waterways (large rivers, oceans) was practically a requirement for civilization. As a result most major population centers can be found in such locations.
Click to expand...

It's also worth noting that the most fertile soils (apart from volcanic deposits, which have their own obvious problems) are on floodplains and river deltas.
 
stilicho said:
Using my handy slide rule and easy-to-find calculations of the volume of the land-based icecaps, I came up with a 70-metre sea level rise if the Greenland and Antarctic sheets melted. I did not factor in the density of H2O in different states at various temperatures, nor did I include the change in elevation of the land masses currently icebound. I also figured that the time it will take is about 125 years, if the one-metre projected rise in the next twenty is accurate, and if the rate of melting increases exponentially. I did not include other high elevation glacial melting but the volume of glacial non-polar ice is small compared to those two regions.
Click to expand...

I don't see why the rate of melting should increase exponentially. Also, "one metre in twenty years" is a pretty extreme forecast - a metre this century is more mainstream. A seventy metre rise would take many centuries, if not thousands of years. We could maybe lose most of Greenland's ice in a few hundred (most of Greenland is below sea-level so once the ocean breaks in things will really get moving) but it's physically difficult to get all that ice off East Antarctica - it all has to come off one side because of the Antarctic mountain range on the other.
 
At 14 m, half of Philadelphia is gone. But not only is my house safe, it becomes a waterfront property!
 
CapelDodger said:
I don't see why the rate of melting should increase exponentially. Also, "one metre in twenty years" is a pretty extreme forecast - a metre this century is more mainstream. A seventy metre rise would take many centuries, if not thousands of years. We could maybe lose most of Greenland's ice in a few hundred (most of Greenland is below sea-level so once the ocean breaks in things will really get moving) but it's physically difficult to get all that ice off East Antarctica - it all has to come off one side because of the Antarctic mountain range on the other.
Click to expand...

If greenland melts slowly enough the land mass will rise somewhat blunting that effect. Most of the northern land massed sunk under the weight of ice and in fact Scandinavia is still rising from it at a rate we can now measure with modern satellite geodesy.
 
Move to Toronto and you will be saved! Lake Ontario is 75m above sea level. :)
 
CapelDodger said:
I don't see why the rate of melting should increase exponentially. Also, "one metre in twenty years" is a pretty extreme forecast - a metre this century is more mainstream. A seventy metre rise would take many centuries, if not thousands of years. We could maybe lose most of Greenland's ice in a few hundred (most of Greenland is below sea-level so once the ocean breaks in things will really get moving) but it's physically difficult to get all that ice off East Antarctica - it all has to come off one side because of the Antarctic mountain range on the other.
Click to expand...
What do you mean by "breaks in"? As I understand it, Greenland is dished due to the weight of ice, with the centre the furthest below sea-level. It would take a lot for the ice to get into the sea, and if it melted in situ a huge lake would form.
 
BenBurch said:
If greenland melts slowly enough the land mass will rise somewhat blunting that effect. Most of the northern land massed sunk under the weight of ice and in fact Scandinavia is still rising from it at a rate we can now measure with modern satellite geodesy.
Click to expand...

Scotland is still rebounding from the last glaciation, which is an indication of how slow the process is. It's not nearly rapid enough to make any difference in Greenland.
 
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