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View Full Version : What would Earth look like if the icecaps melted completely?



Bad Ronald
2010-Mar-15, 08:07 PM
And be like? What would the effects & fallout be longterm? I mean if overnight the Earth reverted to a mid-Cretaceous climate, which would persist for several million years to come.

Argos
2010-Mar-15, 08:19 PM
Ice-free Earth (http://www.johnstonsarchive.net/spaceart/earthicefree.jpg).

grant hutchison
2010-Mar-15, 08:51 PM
Ice-free Earth (http://www.johnstonsarchive.net/spaceart/earthicefree.jpg).Note that the Greenland elevation data haven't been adjusted in that map. Most of central Greenland bedrock is below sea level: we could expect to see ice-free Greenland as an archipelago with a central sea, if the ice-cap melted faster than isostatic rebound.

Grant Hutchison

cosmocrazy
2010-Mar-15, 08:53 PM
Is it me or does that map at first glance show the landmasses to be not much different than they are now?

grant hutchison
2010-Mar-15, 08:56 PM
Is it me or does that map at first glance show the landmasses to be not much different than they are now?Not much, in proportion to the total land area. A significant fraction of the world's population, in terms of inhabited territory.

Grant Hutchison

Argos
2010-Mar-15, 09:07 PM
Is it me or does that map at first glance show the landmasses to be not much different than they are now?

I think it is dramatic in many aspects. Florida and Louisiana are gone. Eastern US and California devastated. Interior seas appear in several regions. Bangladesh gone. Denmark gone. Pacific Isles gone. Cornwall becomes a big Bristish isle. Italy is almost severed from Europe [bye bye Venice]. China main industrial centers gone. Wherever you look youŽll find disturbing consequences.

Swift
2010-Mar-15, 09:08 PM
Is it me or does that map at first glance show the landmasses to be not much different than they are now?
One of the differences I note is that a lot of the river deltas, such as for the Mississippi, are now flooded completely and turned into very large bays. Basically, anything lower than a few feet above current sea level is flooded.

cran
2010-Mar-15, 09:47 PM
Note that the Greenland elevation data haven't been adjusted in that map. Most of central Greenland bedrock is below sea level: we could expect to see ice-free Greenland as an archipelago with a central sea, if the ice-cap melted faster than isostatic rebound.

Grant Hutchison

If I'm understanding the image correctly,
it shows central Greenland as a lowland plain, but not submerged ...
a lot of Antarctica, on the other hand, is wet ...

looking at Australia, there are large inland areas which should be under water
but are not (ie, areas which are currently below, or within a few metres above, sea level) ...

I would have expected a deeper incursion into the Congo, as well ...

the Aral-Caspian-Black Sea region looks about right ...

cosmocrazy
2010-Mar-15, 10:05 PM
I think it is dramatic in many aspects. Florida and Louisiana are gone. Eastern US and California devastated. Interior seas appear in several regions. Bangladesh gone. Denmark gone. Pacific Isles gone. Cornwall becomes a big British isle. Italy is almost severed from Europe [bye bye Venice]. China main industrial centres gone. Wherever you look youŽll find disturbing consequences.

yes, sorry on closer inspection I see what you mean.

neilzero
2010-Mar-15, 10:18 PM
Greenland and other Arctic locations may loose another 5% of their ice in the next 90 years. Antarctica will likely have little or no net ice loss. Snow fall typically replace the ice, that breaks off the Antarctic ice shelf. Oceans invading inhabited land, will likely be less of a problem than the previous century. If the ocean rises a millimeter per year, half of earth's population may move to higher ground over the next 10,000 years. A new iceage is likely in about 10,000 years and has possibly already begun. Neil

Nick Theodorakis
2010-Mar-16, 03:37 PM
Note that the Greenland elevation data haven't been adjusted in that map. Most of central Greenland bedrock is below sea level: we could expect to see ice-free Greenland as an archipelago with a central sea, if the ice-cap melted faster than isostatic rebound.

Grant Hutchison

Would there be some "rebound" in elevation of Greenland if you took the ice off it?

Nick

Edit: Bah! Apparently I didn't read all the way to the end of Grant's post.

eburacum45
2010-Mar-16, 04:29 PM
Oh yes, but it would be very slow. That map attempts to show what would happen if the ice magically melted in a short period. Antarctica would rebound too; I think much of central Antarctica, shown as underwater in that image, would also rebound somewhat.

chornedsnorkack
2010-Mar-16, 04:42 PM
Lower Congo cascades down Livingstone Falls about 280 m in the 350 km below Kinshasa. So little incursion there.

If the climate suddenly became warm, glaciers would melt several metres each year. But at that rate, melting several km thickness would take centuries.

cran
2010-Mar-16, 06:27 PM
Lower Congo cascades down Livingstone Falls about 280 m in the 350 km below Kinshasa. So little incursion there.

If the climate suddenly became warm, glaciers would melt several metres each year. But at that rate, melting several km thickness would take centuries.

you're right - I'd forgotten about the cascades -
knowing me, I was probably thinking about another river altogether ...

Delvo
2010-Mar-16, 07:33 PM
looking at Australia, there are large inland areas which should be under water
but are not (ie, areas which are currently below, or within a few metres above, sea level)But what elevation is the land between those places and the ocean?

novaderrik
2010-Mar-16, 08:18 PM
hmm.. what about all the predictions that the sea levels would rise hundreds of feet if only the Greenland icecap were to melt? i've heard this claim made by some environmentalist groups- if we don't stop what we are doing NOW, then we are all doomed.
going by this map, everyone that is along the coasts moves a few miles inland and resettles. since this is something that would not happen overnight- unless something really dramatic were to happen, in which case we'd all be wiped out immediately, anyways- i'd say that the human race would simply adapt over time and move their population centers farther inland as the flood waters show up.

danscope
2010-Mar-16, 08:49 PM
Answer: " WET " .

cran
2010-Mar-16, 09:33 PM
But what elevation is the land between those places and the ocean?
less than 50m ... and mostly less than 25m ...
between Spencer Gulf and the Lake Eyre Basin via the main Tertiary palaeochannel west of the Flinders Ranges and including Lake Torrens ... basically a refilling of the Tertiary Lake Dieri, or even the Late Cretaceous Lake Walloon ... and the submersion of Yorke Peninsula - effectively combining the Spencer Gulf and the Gulf of St Vincent

and similar inland from the mouth of the Murray River into the Riverland, cutting through the palaeobeaches (Tertiary coastal highstands - old sea levels) ... marked extension of Lake Alexandrina, and flooding of much of the Mallee ...

the Gulf of Carpentaria should extend further south across the grasslands (which are grass paddies - ie, the water table is at surface; this, like the coastal plains of Kakadu, is water buffalo country) and look more like an inverted oversized Spencer Gulf (ie, tapering to a point as it progresses inland) ...

I've been trying to find a map with fine enough elevation data to show,
but the digitals I've found don't include legends, and the maps with legends don't discern less than 150m ...


Elevation by percentage of land mass
ELEVATION.......AREA (km2) ... % OF AUS (CUMULATIVE %)
Below sea level .....8 500 ...........0.11 ........(0.11)
0 - 199m .......2 909 500 .........37.98 ......(38.09)
http://www.ga.gov.au/education/geoscience-basics/landforms/elevations.jsp

...........
but maybe some of these will help illustrate:

http://www.ga.gov.au/image_cache/GA11759.gif
(300m gradations)
...........

http://www.ga.gov.au/image_cache/GA11828.jpg
(finer definition, but no legend included on site)
...........

http://www.virtualoceania.net/australia/maps/elevation.gif
(ditto - but this is much closer to what I expected to see on the first global image/map)
...........

(there was another map, but the link doesn't want to work)
http://www.ga.gov.au/bin/mapserv40?

map=/public/http/www/docs/map/national/national.map&mode=map&apext=-3564133.333333+-5650000.000000+3654133.333333+-830000.000000&layers=bath_col&mapsize=580+550 (http://map=/public/http/www/docs/map/national/national.map&mode=map&apext=-3564133.333333+-5650000.000000+3654133.333333+-830000.000000&layers=bath_col&mapsize=580+550)

cran
2010-Mar-16, 09:38 PM
... everyone that is along the coasts moves a few miles inland and resettles. since this is something that would not happen overnight- unless something really dramatic were to happen, in which case we'd all be wiped out immediately, anyways- i'd say that the human race would simply adapt over time and move their population centers farther inland as the flood waters show up.

when I lived on the escarpment overlooking Perth, the locals would discuss the rising sea situation, the million-plus population living on "the big beach", and the need to practice defensive drills - "prepare to repel boarders!" ...

Bluevision
2010-Mar-17, 01:19 AM
Ice-free Earth (http://www.johnstonsarchive.net/spaceart/earthicefree.jpg).I'd call that pretty accurate.

Though that just seems like a map of the Earth shopped so the landmasses end at new places. You also have to remember that the Midwestern US would be almost a complete desert, the Sahara would have most of northern Africa, both of the Great Lakes would be smaller, the coasts of Australia would almost universally be like the East coast, and yes Greenland would be about 3 different islands.

cran
2010-Mar-18, 12:42 AM
I'd call that pretty accurate.

... the coasts of Australia would almost universally be like the East coast...

you'll have to explain what you mean by that -
because as a simple statement, it's rubbish ...

Noclevername
2010-Mar-18, 02:20 AM
hmm.. what about all the predictions that the sea levels would rise hundreds of feet if only the Greenland icecap were to melt? i've heard this claim made by some environmentalist groups- if we don't stop what we are doing NOW, then we are all doomed.
going by this map, everyone that is along the coasts moves a few miles inland and resettles. since this is something that would not happen overnight- unless something really dramatic were to happen, in which case we'd all be wiped out immediately, anyways- i'd say that the human race would simply adapt over time and move their population centers farther inland as the flood waters show up.

Don't underestimate it, though-- the affected areas are also among the most densely populated, and, for the most part, underdeveloped. Moving nearly half a billion (approx.) refugees would have a non-trivial effect on the entire world socially and economically, not to mention the massive loss of industry and shipping.

Craigboy
2010-Mar-18, 06:58 AM
Ice-free Earth (http://www.johnstonsarchive.net/spaceart/earthicefree.jpg).
Wouldn't there be less vegetation than that?

Argos
2010-Mar-18, 01:51 PM
Don't underestimate it, though-- the affected areas are also among the most densely populated, and, for the most part, underdeveloped. Moving nearly half a billion (approx.) refugees would have a non-trivial effect on the entire world socially and economically, not to mention the massive loss of industry and shipping.

I agree with your assertion on the non-trivial effects of refugees displacement. But, as you can see, lots of developed areas are going to suffer too, namely the US coasts and Europe. ItŽs gonna be a global mess.

Argos
2010-Mar-18, 01:55 PM
Wouldn't there be less vegetation than that?

hmmm, predicting the consequences of the sea level elevation is the hardest part of the problem. But at first glance it seems that the atmosphere will be more saturated with moist, which tends to favor vegetation.

A.DIM
2010-Mar-18, 02:53 PM
Cool, if such a thing happens I'll not have to go down the Tombigbee in my sailboat in order to get to bigger waters.
The "gulf" will have come to me!
:D

danscope
2010-Mar-18, 06:04 PM
You will have become " engulfed" .

crosscountry
2010-Mar-18, 06:07 PM
Ice-free Earth (http://www.johnstonsarchive.net/spaceart/earthicefree.jpg).

does that take into account isostatic rebound?

Argos
2010-Mar-18, 06:21 PM
does that take into account isostatic rebound?

It isnŽt clear to me. It depicts Antarctica as an Archipelago. IŽm not sure what it would be like after the rebound is complete.

Digix
2010-Mar-18, 07:58 PM
Don't underestimate it, though-- the affected areas are also among the most densely populated, and, for the most part, underdeveloped. Moving nearly half a billion (approx.) refugees would have a non-trivial effect on the entire world socially and economically, not to mention the massive loss of industry and shipping.

There should not be any problems:

if water rises slowly people will just abandon flooded areas.

It will take ages too flood all NY city. At first people may struggle fighting with water building dams but that will severely increase taxes and make area dangerous when water will rise severely, so people probably will leave until gradually all city will disappear and move in other place.

So basically nobody will even notice that flood.

maybe some exception will be japan and Europe, because land cost is enormous there and even little loss will be economic disaster for land owners.

Romanus
2010-Mar-18, 11:31 PM
I read once that during the peak of the deglaciation, sea level rose some 2 feet per century. While extremely rapid in geologic terms, in human terms this would be manageable. Difficult and costly, and probably ruinous to many areas in the long run, but by no means a dramatic flood.

cran
2010-Mar-19, 01:28 AM
I read once that during the peak of the deglaciation, sea level rose some 2 feet per century. While extremely rapid in geologic terms, in human terms this would be manageable. Difficult and costly, and probably ruinous to many areas in the long run, but by no means a dramatic flood.

it's not the overall rise rate ...
it's the storm surges and king tides ...