WatchYou're going to be seeing headlines on this in about two weeks. That's when I'm guessing the arctic ice melt will reach an all time record and most of the arctic ocean will be free of ice and navigable.
http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html
The blue starts in 1979. The more red the line, the more recent the year. (dark red is 2011) Each horizontal line is 1 million sq. kilometers. When the graph reaches the bottom, the north pole is completely melted. x-axis is day of the year.
Follow
Befriend (4)
2 threads
787 comments
which are blocks of fresh-water ice from the continent that are floating in salt-water sea. In this case, we must take into account that the salt water is denser than the fresh water. The fresh-water iceberg still weighs as much as the weight of the displaced salt water, but because of the difference in density, the volume of melted fresh water will be slightly greater than the displaced volume of salt water -- so when the iceberg melts, the water level will rise,
leoj707 says
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
xrpb11a says
Is there *enough* fresh water in that arctic sea ice to raise sea levels by that much? We need numbers. Compared to thousand-foot-thick continental ice in Greenland and Antarctica, how much of an effect will the melting Arctic sea ice have? Even w/o global warming, the Arctic sea ice pack would melt around the edges in summer, how much did global sea levels rise every summer? Probably not much.
When it comes to sea level rise, I'm more concerned about continental ice melt then sea ice melt.
I've read that almost half of the expected sea-level rise will come from thermal expansion alone, even w/o added mass from melting ice.
Follow
Befriend (4)
2 threads
787 comments
Actually, the difference in displacement is minimal. But enough to factually win my argument with Iwog.
But the loss of cooling that the icecaps currently provide will contribute to global warming, which affects other things that will also contribute to sea level rise...enough to worry Floridians...
freak80 says
Follow
Befriend (12)
10 threads
3,516 comments
Oakland, CA
leo707's website
Premium
xrpb11a says
Yes, when an item floats it displaces its same weight in fluid. Ice being less dense than fresh water is already displacing more salt water than the fresh water would. I am by no means an expert on this, feel free to tell me if I am getting anything wrong here.
Lets add another layer to the density numbers:
Sea water = 1020-1030 kg/m³ = at 1000 kg volume is 0.97561 m³ (assuming 1025 kg/m³)
Fresh water = 1000kg/m³ = at 1000 kg volume is 1.00000 m³
Ice water = 920 kg/m³ = at 1000 kg volume is 1.08695 m³
OK, so lets say you have a pool of salt water that weighs 4000 kg. The volume of that pool would be 3.90244 m³.
Then you add a 1000 kg ice block to the pool. 1000 kg of salt water is displaced and the pool volume increases by the volume of the ice block to 4.98940 m³.
The ice then melts into 1000 kg of fresh water. As the density increases from ice to water the total volume of the 1000 kg reduces, but still displaces the same 1000 kg of the salt water.
So, now you have a pool with 5000 kg of liquid with a total volume of 4.90244 m³. This is 0.08696 m³ less than the volume with the ice.
So, in the end you are actually lowering the depth in your pool.
Follow
Befriend (4)
328 threads
913 comments
Game Over,
I could not find the exact quote.
If all animals die ,man dies.
If all men die, life flourishes.
Follow
Befriend (48)
272 threads
12,452 comments
47 male
Lafayette, CA
Premium
freak80 says
The bottom line is what I said originally before xrp took us on a merry go round:
For all practical purposes, the north pole is ice cubes floating in a glass of water. They do not raise the level of the oceans by any measurable amount.
Greenland and the South Pole however will flood the coasts if they melt since they contain water on top of land.
Follow
Befriend (4)
2 threads
787 comments
I agree completely with the scenario you have laid out. [edit] no i don't.
Here is my initial argument:
xrpb11a says
Which is why when the icecap melts, pouring fresh water into the salty ocean, more volume is displaced thereby raising the level of the sea.
Under my scenario, global warming will cause more chunks of ice at the polar cap to break off, falling into the ocean as icebergs. When the ice hits the water, the ocean rises. Note this applies to ice at the caps that is not already floating.
leoj707 says
Follow
Befriend (4)
2 threads
787 comments
On second thought....
http://nsidc.org/news/press/20050801_floatingice.html
Looks like the portion of the iceberg not submerged is affecting your equations....
leoj707 says
Follow
Befriend (4)
2 threads
787 comments
Fail.
http://nsidc.org/news/press/20050801_floatingice.html
iwog says
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
iwog says
True. But only by a foot or two, right?
That's what I heard from credible sources: about a 1 foot rise, more or less depending on how much the planet actually warms. About half of that rise is from thermal expansion, the other half from melting continental ice.
So why are you buying up real estate near San Francisco Bay again? ;-)
It's my understanding that much of the land around it is "fill" that's not far above sea level.
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
GameOver says
Which is probably a good thing. Cannibal anarchy is oh so inconvenient.
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
xrpb11a,
Thanks for the link!
I also believed that floating sea ice displaced the same volume, since I believed that floating sea ice had the same salt concentration as the ocean (as most people would probably assume). But we all know what happens when we ass-u-me!
Follow
Befriend (48)
272 threads
12,452 comments
47 male
Lafayette, CA
Premium
freak80 says
If Greenland melted, the oceans would rise 7-8 meters or around 21-24 feet. It would be enough to flood most coastal cities on earth.
The only place that would not see a sea level rise would be Greenland.
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
iwog says
Correct. But no one is expecting *all* of the Greenland Ice Sheet to melt, right? Even the "worst case" model predictions don't even come close, as far as I know.
I'm more worried about killer droughts & heat-waves (like the one in the Midwest this summer) than the "sexy" stuff like sea level rise and hurricanes.
Follow
Befriend (48)
272 threads
12,452 comments
47 male
Lafayette, CA
Premium
freak80 says
I think it's safe to say that it will not melt in our lifetime. 100 years maybe. 200 years guaranteed. Most of the models have been broken already and no one knows exactly how this will play out.
My favorite scenario is that the Greenland ice sheet lubricated from the bottom by melting ice will slide off the landmass and cause a massive tidal wave which will wipe out the planet.
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
iwog says
Wow you're even more fascinated with "the end of the world" than I am! That's not healthy. ;-)
Maybe we should both go live in the woods with Apocalypsefuck.
Follow
Befriend (4)
2 threads
787 comments
Your welcome!
I'm just trying to get all my ducks in a row.....
freak80 says
Follow
Befriend (4)
117 threads
17,655 comments
Premium
iwog says
You are funnier than me after all!
How exactly will a tidal wave wipe out the planet? Unless you think humanity IS the planet. That is very arrogant. And still, you may be surprised how much of human population will remain.
I now think that humanity is quite resilient because of our diversity in culture. In some ways kind of like cockroaches. Almost as disgusting anyway.
Follow
Befriend (4)
117 threads
17,655 comments
Premium
freak80 says
Are you talking about voting for a certain mascot? LOL! This is not a political statement. :-)
Follow
Befriend (12)
10 threads
3,516 comments
Oakland, CA
leo707's website
Premium
xrpb11a says
FYI, here is a link to the original paper:
http://home.comcast.net/~pdnoerd/NoerdlingerBrower.pdf
I have yet to full digest it but after reading it last night it does suggest that there may be a slight increase in sea level due to floating ice. And, yes this would be due to the little bit of ice that is sticking out of the water. It seems that there might be just enough mass buoyed up by the salt water that it not only offsets the contraction of volume in my previous example, but adds a slight amount to the total volume of liquid.
However, one thing that struck me in the study is in their experiment they used salt water with a density of 1197 kg/m³, that is much denser than the normal sea water range of 1020-1030 kg/m³. It was a little silly to do this rather than use the same density of sea water because of course it buoys up the ice increasing the volume that is out of the water. Perhaps they did it because then they can take a dramatic picture of the volume level rising as the ice melts.
There is of course a "break-even" point where when the contraction of submerged melted ice is equally offset by the volume of the melted ice sticking above the water; all resulting in a net-zero change to the volume of the liquid.
If I have time later today I will redo my scenario to include the ice poking out of the water, but I suspect that Noerdlinger is correct in that the volume of ice that floats out of the water is just enough to actually increase the volume of the ocean slightly.
If all the sea ice melts Noerdlinger estimates that this would result in a 4 cm increase to the sea level.
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
So what are we going to do about this AGW problem?
"Everyone talks about Global Warming, but nobody does anything about it."
--Mark Twain
Follow
Befriend (4)
117 threads
17,655 comments
Premium
freak80 says
I plan on doing nothing. A tragedy of the commons is usually a comedy in disguise.
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
I plan on buying RE in Maine.
Want to join me, iwog?
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
The U.P. of Michigan would also be a good place...plenty of fresh water, the surrounding Great Lakes act as a heat sink in summer. And it's far from the future (present?) cannibal anarchy in Detroit.
Follow
Befriend (4)
117 threads
17,655 comments
Premium
It may be more profitable doing something about the scare before the fact than the aftermath. LOL!
Follow
Befriend (12)
10 threads
3,516 comments
Oakland, CA
leo707's website
Premium
freak80 says
Plan on having your children live in a world that looks like this.
Follow
Befriend (4)
2 threads
787 comments
Time to invade canada while we have the edge....
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
So...that's it...we're "giving up"?
And I thought *I* was the pessimist.
Follow
Befriend (12)
10 threads
3,516 comments
Oakland, CA
leo707's website
Premium
freak80 says
To change the direction of global climate change would require extraordinary effort, huge short term sacrifices and the entirety of humanity working towards that common goal. The longer we wait to tackle these issues the more painful the transition becomes.
We can not even get the US to acknowledge as a nation that the problem needs to be addressed.
I would not call it "giving up", but living with the reality that as individuals we need to plan on living in a world where global warming goes to its logical conclusion.
Follow
Befriend (4)
52 threads
4,416 comments
Corning, NY
Premium
leoj707 says
Or just a tax on carbon dioxide with the revenue used to subsidize nuclear power plant construction. Am I right?
Follow
Befriend (12)
10 threads
3,516 comments
Oakland, CA
leo707's website
Premium
freak80 says
Well... for that to work...
First: We would have to construct nuclear plants quickly enough to replace all our current fossil fuel power needs, and do this before we burn more than an additional 565-gigatons of carbon dioxide.
Second: The taxes would have to be significant enough to either entirely fund efforts to remove CO2 from the atmosphere -and/or- make fossil fuel so expensive that it is no longer worth pulling them out of the ground.
Third: There is also a finite amount of nuclear fuel on the planet, perhaps in as short of a time as a few decades we would have to come up with a more sustainable energy source to replace nuclear.
And a final caveat -- every country in the world would have to enact the same tax
Follow
Befriend (48)
272 threads
12,452 comments
47 male
Lafayette, CA
Premium
freak80 says
I hear Lobster has dropped to $2.75 per pound dockside in Maine because of too many fishermen.
I'm there buddy.
Follow
Befriend (48)
272 threads
12,452 comments
47 male
Lafayette, CA
Premium
Update: This is an extraordinary divergence, even compared to the previous record in 2007. With two more weeks of guaranteed melting, and an additional two weeks of possible melting, there is going to be less summer ice than ever before on the scale of half a million square miles.
About 2-3 more days until the record is broken and you start seeing the media go hog wild over this. Also expect Obama's poll numbers to climb. (sorry Republicans)
http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html
Follow
Befriend (4)
2 threads
787 comments
The real party is in about 4-5 billion years....
we are just showing up a little early...
leoj707 says
Follow
Befriend (12)
10 threads
3,516 comments
Oakland, CA
leo707's website
Premium
leoj707 says
xrpb11a, I am not going to redo my scenario, but I did run some more numbers on melting of ice in salt water and yes there is an increase in total liquid volume. So, I think that Noerdlinger's estimate of a 4 cm increase to the sea level could be right.
This is even when I used Noerdlinger's density estimate of 1007 kg/m³ for brine ice melt, however in this case the sea level rise would be somewhere less than 4 cm.
I did not go through the trouble of doing any calculations based on density changes due to temperature, etc.
The margins are pretty razor thin though. If the underwater part of the ice is >91.70% then the overall level would reduce. This is exactly the amount of ice that is underwater when floating in fresh water. When in sea water the ice is pushed up slightly to where it is about 89.38% under water.
Follow
Befriend (48)
272 threads
12,452 comments
47 male
Lafayette, CA
Premium
leoj707 says
A massive crash program to replace fossil fuels with nuclear energy would create a giant economic boom similar to post-world war 2.
3rd world nations would industrialize and take advantage of the cheaper fossil fuel prices left by the first world.
If there is any hope at all, it would almost certainly require a one world government and near dictatorial power. We'll see a new dark age before any of this happens.
Besides I have other reasons for believing this is the end........
Follow
Befriend (48)
272 threads
12,452 comments
47 male
Lafayette, CA
Premium
The end #1:
Have you ever thought why you exist now? At the peak of human technology and population and fossil fuel use? If the Human race is going to continue another 100,000 years and presumably keep increasing in numbers, why weren't you born in 3000AD? 30,00AD? 50,000AD? Do you think it's a coincidence that a mere 100 years after widespread use of oil and during the largest human population you just happened to come into the universe to watch this amazing period in history? Or is this period in history the top of the bell curve and this was always the most likely time to be born in?
A single data point cannot be used to prove anything, however if you have a bucket full of marbles, and 99 marbles are blue and 1 marble is red, and you're told you can pick one out blindfolded and infer something about what color the rest of the marbles are, what are the odds that you'd be wrong?
A 100,000 year modern human civilization and a 100 year lifespan means there are 999 blue marbles and 1 red marble. A 10,000 year modern human civilization means there are 99 blue marbles and 1 red marble. A 1000 year modern human civilization means there are 9 blue marbles and 1 red marble.
I personally don't think I got really lucky and pulled out the red marble. I think I'm alive right now because there isn't much human history left. I think I'm alive right now because throughout human history, there were 100 million or fewer humans alive, and during the modern age there are billions.
Or it could just be a coincidence. They happen, but not usually.
Follow
Befriend (48)
272 threads
12,452 comments
47 male
Lafayette, CA
Premium
The end #2:
Most scientists agree that if there were other modern technological civilizations in the galaxy, and they were transmitting radio and television, that we should easily be able to receive their signals.
Unfortunately the skies are silent. The SETI program started in 1971 and funded by NASA has been operating over 40 years, and the WOW signal not withstanding has found nothing.
The possible reasons for this include:
1. There is no other technological life in the galaxy.
2. Technological life tends to burn itself out very quickly. With a window of only a few hundred years, and the age of the universe being more than 10 billion years, the odds of us finding another civilization is practically zero. They don't last long enough.
One hypothesis is that the life curve of a planet is pretty much fixed, and that evolution will eventually result in an intelligent species who will utilize the planet's stored hydrocarbons all at once and wipe itself out. Failing this, they will accomplish it by nuclear holocaust.
I think this is probably the way things work, which is why we aren't receiving any radio signals from space. Earth is certainly not exempt from this.
Follow
Befriend
29 threads
1,473 comments
Bellingham, WA
Premium
3. EM broadcasting is a 19th century communications technology and there are better ways to communicate yet to be found, e.g.:
http://en.wikipedia.org/wiki/Quantum_entanglement
Follow
Befriend
29 threads
1,473 comments
Bellingham, WA
Premium
iwog says
http://en.wikipedia.org/wiki/Self-selection_bias