Global Warming: Earth 10,000 AD

[GreyArea]

This image shows what Earth would look like following a 100 meter rise in sea level. Not nearly as dramatic as the first image I posted

Looking at that map, I see two flaws. Antarctica is not shown at all. And Greenland has a very high altitude. If all the ice melted, Antarctica would be an archipelago of large islands, and Greenland wouldn't be so tall.

I found some more maps from an AGW-denier's website here: (see Section III) http://www.johnstonsarchive.net/environment/waterworld.html

But I still think that's not what Greenland would look like. I remember one of those old National Geographic maps from the 60's showing the world without the oceans. Greenland had a hollow center filled with a large bay, making the island look like a backwards "c" or a question mark.

Geology magazine's website has a map of a hollow Greenland here:
http://geology.gsapubs.org/content/36/7/539/F1.large.jpg

Does anyone know if this is still the current understanding of what's under the ice?

Meanwhile, looking for a timeframe, Greenland might take 3,000 years? The article that the picture accompanied wasn't specific about timeframes, so I only have the diagram to go on here.
http://www.nytimes.com/imagepages/2005/10/24/science/20051025_ARCTIC_2.html

 

[lomiller]

I found this interesting and at least plausable

http://www.worlddreambank.org/D/DUBIA.HTM

 

[aleCcowaN]

I found this interesting and at least plausable

http://www.worlddreambank.org/D/DUBIA.HTM

I rather suggest skipping that link (Two of a hundred examples: Malebo Pool -former Stanley Pool, I presume - is more than 200 meters above sea level; Antarctic ice melts by heat but Lake Chad becomes a sea)

Anyway, I'm not opposed to take 100 meters for the sake of speculation. Although the complete melting of ice implies a raise of about 73m (?), thermal expansion of sea water could add 10 to 20 meters more (this relates to floe-free polar seas)

 

[lomiller]

I rather suggest skipping that link (Two of a hundred examples: Malebo Pool -former Stanley Pool, I presume - is more than 200 meters above sea level; Antarctic ice melts by heat but Lake Chad becomes a sea)

The have lake Chad becoming the largest lake in Africa due to shifting monsoons. While I can’t say whether that specific shift would happen monsoons moving north/south is certainly a major prediction of climate change. Neither Malebo Pool or Stanley Pool are mentioned, at least they don’t show up in a search.

 

[aleCcowaN]

The have lake Chad becoming the largest lake in Africa due to shifting monsoons. While I can’t say whether that specific shift would happen monsoons moving north/south is certainly a major prediction of climate change. Neither Malebo Pool or Stanley Pool are mentioned, at least they don’t show up in a search.

My friend, you almost always get meaningful material. But ...

All that is more than 230m above sea level. The same dramatic licenses are taken all over the world. For instance, the remaining part of Uruguay is shown as an island. Not only the sea raises 110m but many parts have to drop from 140, 200 and even 250m to that level just to conform that fantastic map (otherwise much better that the one in the OP). There is a dramatic varnish all over the map, a Liberace quality, so I suggest to discard that source for the purpose of this analysis.

This map is better, though it contains a few endorheic basins become lakes or seas with water at the same level of the "future" oceans.

 

[macdoc]

Meanwhile, looking for a timeframe, Greenland might take 3,000 years?

Not sure where you got that but Greenland AFAIK has about 3 million cu km and at a current melt rate of 200 cu km per annum that gives 15k years not 3k.

That is also within my understanding.

 

[GreyArea]

Not sure where you got that but Greenland AFAIK has about 3 million cu km and at a current melt rate of 200 cu km per annum that gives 15k years not 3k.

That's what I got from the New York Times graphic showing Greenland in 5005. The link is below my comment.

 

[Trakar]

...This map is better, though it contains a few endorheic basins become lakes or seas with water at the same level of the "future" oceans.

Seems like a reasonable map, presumably it is tied to a class or lecture somewhere that specifcs and details could to dredged forth from?

~100m generally considered a reasonable estimate.
~ 65m for EAIS
~ 7m for Greenland
~ 8m for WAIS
~ 2m assorted other mountainous icecaps and snowpacks
~ 25% for thermal expansion at equilibrium

Many recent studies are shifting the expectations for 2100 sealevel rise, with 2m being the current "best guess" maximum. 6 feet of water in 9 decades is a lot, and will impact a lot of major US(world) cities and population centers.

 

[aleCcowaN]

~ 25% for thermal expansion at equilibrium

This relates with something I've been thinking regarding this thread and that one. It is known that thermal expansion for sea water under high pressure (like a -1000m level) varies from about 240x10^-6 at 0° to 310x10^-6 at 20°. Nowadays the temperature at that level is 2° or so. What temperature do different analysis expect? I know it has little to do with continental ice -maybe only the "valley" between West and East Antarctica-, but melting ice suppose higher atmospheric temperatures and the collapse of sea ice, doesn't it? And warmer polar oceans wouldn't imply less cold water to replenish the deep ocean? So the temperature of equilibrium would be?

 

[oddboyout]

You may want to check out AlternateHistory.com. Not often scientific, but they do have a penchant for maps. I am sure you could find some similar topics there.

 

[macdoc]

Meanwhile, looking for a timeframe, Greenland might take 3,000 years? The article that the picture accompanied wasn't specific about timeframes, so I only have the diagram to go on here.
http://www.nytimes.com/imagepages/20..._ARCTIC_2.html

They postulate a high C02 climate - not our current one.
That said - given the rate of acceleration of loss over the last 30 years it's notoutside of possibility that the loss could be that high as of course the intermediate increase in sea level would rapidly increase ice loss both in Greenland and West Antarctic.

 

[casebro]

Is the fact that the warmer atmosphere, plus the greater surface area of oceans and seas, mean that here would be more water tied up in the atmosphere? Any numbers on volume? Any appreciable affect on sea levels?

 

[macdoc]

Atmosphere of Earth - Wikipedia, the free encyclopedia
The atmosphere has a mass of about 5 × 10¹⁸ kg, three quarters of which is within about 11 km (6.8 mi; 36000 ft) of the surface

The total mass of the hydrosphere is about 1,400,000,000,000,000,000 metric tons (1.5×1018 short tons) or 1.4×10²¹ kg, which is about 0.023 percent of the Earth's total mass. Less than 3 percent is freshwater; the rest is saltwater, mostly in the ocean.

Pretty minor given the disparity in mass, and water vapour only a portion of the atmosphere content.

 

[Trakar]

This relates with something I've been thinking regarding this thread and that one. It is known that thermal expansion for sea water under high pressure (like a -1000m level) varies from about 240x10^-6 at 0° to 310x10^-6 at 20°. Nowadays the temperature at that level is 2° or so. What temperature do different analysis expect? I know it has little to do with continental ice -maybe only the "valley" between West and East Antarctica-, but melting ice suppose higher atmospheric temperatures and the collapse of sea ice, doesn't it? And warmer polar oceans wouldn't imply less cold water to replenish the deep ocean? So the temperature of equilibrium would be?

Good question, I don't recall any predictions of that level of specificity (which is probably why we don't see a lot more concrete estimations and one of the main factors behind the rather large range figures given for sealevel rise predictions). ISTR, arguments supporting a variety of estimation percentages but to tell you the truth, I wasn't paying that close attention to that line of the discussion so I'd really have to look into the issue in more depth before I could really lend strong voice to the issue one way or the other. I'll give a look-see in my free time over the next few days and see if I can find anything that addresses the issue in a bit more detail.

 

[Trakar]

They postulate a high C02 climate - not our current one.
That said - given the rate of acceleration of loss over the last 30 years it's notoutside of possibility that the loss could be that high as of course the intermediate increase in sea level would rapidly increase ice loss both in Greenland and West Antarctic.

I was going to comment on this earlier, but my connection dropped out and I see that you've now strengthened your statement. We do seem to be in an accelerating warming/melt rate. If we pop up to the +6-10° C range over the next couple of centuries and hang out in that range for a few millenia (or so), we might see some rather dramatic melt rather abruptly.

WE can hope that we have the will and ability to keep that type of change from occurring, but I grow less confident of that rosy future with each year that passes.

 

[macdoc]

I'm too lazy to chase the paper the NYT used for the map.

Given the growing suspicions about rapid collapses of vulnerable ice sheets even on a massive scale....3k years will see a very different planet.

 

[plumjam]

Thanks to everyone for the imaginary-world heads up.
Now I have eight thousand years to find a hill to live on.
Plus, fish will be cheaper, (though you never know, with inflation).

 

[Dinwar]

Plus, fish will be cheaper,

More reefs, too. I'm hoping that barnacles get to make them this time. Almost every other group has made reefs--let the decapods have their chance!

but melting ice suppose higher atmospheric temperatures and the collapse of sea ice, doesn't it? And warmer polar oceans wouldn't imply less cold water to replenish the deep ocean? So the temperature of equilibrium would be?

There are specific structures in the Arctic (polynyas) that generate a HUGE amount of the water in the thermohaline circulation right now. The way it works is (simplified) you get a hole in a bunch of ice for some reason. It's cold, so the water freezes. Thing is, freezing is a type of fractional distillation--the ice will be largely fresh water, and the remaining water will become increasingly saline. Water's freezing point lowers with the addition of more dissolved ions--meaning that the water is super-salty and super-cold. It drops like a rock and starts flowing.

If you eliminate polynyas some other area on Earth will generate the densest water (densest is a relative term, so it necessarily has to exist unless all water is equally dense). If it's cold Arctic or Antarctic water it won't bother things too much. If it's warm water (say, from the Med. Sea), things have the potential to get weird. And if the densest water comes from a place with low oxygen (remember, gas solubility is inversely related to temperature) life has a hard time existing. Plus the whole thing with the oceans basically sitting on a heating coil. That would be bad. They'd warm from the top (sunlight, heat transfer from the air) and the bottom (deep warm water).

So basically how cold the deep water will be depends entirely on where the new source of densest water comes from.

 

[casebro]

How would the decreased salinity effect the co2 binding of the oseans? 80 meters of fresh water into um 2,000 meter avg ocean depth= 4% dilution of salinity? = I dunno effect on CO2 sequestration.

 

[zaphod2016]

Thanks to all for the great discussion.

I see a few people assuming a 100m rise in sea level, and citing maps which have used this assumption + elevation to predict future coastlines.

However, as I understand it:

a) the Earth is supposed to be getting cooler right now, not hotter, so assuming we curbed CO2 emissions it would be possible to see the recent warming phase reverse within a time frame of a few hundred years

b) assuming the warming continue unabated, Greenland would only be 2/3rds melted by the year 10,000 AD. Antarctica would take hundreds of thousands of years to melt entirely.

Therefore, assuming we fail to stop this warming trend, how much sea level rise would we expect within 10,000 years? 100m? That seems extremely high, considering the amount of time needed for everything to melt.

Am I mixed up?

EDIT: assuming 18 feet rise per 1,000 years (according to NPR projections), we would expect sea levels to have risen 8*18=144 feet = ~44 meters

Is that a more reasonable estimate than 100m?