Slashdot Mirror
Global Warming To Leave North Pole Ice-Free
cwolfsheep writes "Tonight, Yahoo & AFP news are
reporting on a study, further backing up a
previous report, that suggests the North Pole will be ice-free in the summer by the next century. Oddly enough, they say the melting will not
add to the sea-level of the ocean (since the ice is already in the ocean) and that the extra water will help absorb more greenhouse gases. Maybe we need to start using more
aerosols."
No, the ice displaces an amount of water equal to it's on weight, and that's why some of it sticks out above the water.
Anything floating in water displaces a volume of water EXACTLY equivalent to its own weight. If ice melts, the part that was above the water is exactly equal to the reduction in volume, and there is exactly no change in the water level.
On the other hand, if the non-floating ice on Antarctica or Greenland melts, since it wasn't displacing any water, the ocean levels will rise. And there is a LOT of ice on Antarctica.
The melting of floating ice makes little difference to sea temperature since it is water at close to 0 degrees, but melting glacial ice generally runs off into warmer water, causing sea temperature reduction with potentially catastrophic effects (e.g. stopping of the Gulf Stream).
Panurge has posted for the last time. Thanks for the positive moderations.
Unlike the North Pole where the ice floats on the sea Antartica is a big land mass with lots of ice on top. If the Antartic ice melts, sea levels will rise.
Omnis amans amens
The rub is, Desert begets desert. As the land becomes arid, it heats up the surrounding land, causing the desert to spread.
Now one thing not helping the situation is Man. Certain agricultural practices accellerate desertification.
Indeed, start looking for deserts to form in Brazil. Rain forests don't really build good soil, and when you slash and burn the rainforest down to form farmland you only get a few good years out of it before the soil breaks down. Rain Forests generate their own weather patterns, and with no forest, no rain.
"Learning is not compulsory... neither is survival."
--Dr.W.Edwards Deming
http://www.physicstoday.org/vol-56/iss-8/p30.html
Todays sea ice maps: http://www.seaice.de
Two things:
1 Ice floating in water displaces as much water as it mass. So when it melts the volume will not change.
2 The interesting thing is that water shrinks when you heat it from 0C to 4C so in that traject it will take up less space. Continue heating above 4C it it starts expanding again.
Warmer oceans will mean higher sea level because warmer water is less dense.
Nyh
How do they figure melting ice won't raise sea levels? even if the glacier is 20 feet above water, won't the excess buoyant pieces of ice melt down into the ocean?
Actually no. Water is more dense than ice (this is why it floats above the water in the first place). So so far this theory seems ok.
What they don't account for, and what makes this bunk is that it doesn't account for the huge amount of landlocked glaciers (The south pole, Greenland, etc.).
Someone kindly explain how you propose to melt just the floating ice and not the rest of it?
This crap is posted just to further the official slashdot agenda of:
"I'll do whatever the hell I want to and I'm sure it'll have no consequences whatsoever on the environment. And if it has, it's my lazy worthless childrens problem!
You'll pry the steering wheel of my SUV from my cold dead fingers, commie-boy!"
Now go ahead and label me a crazy environazi, if you like.
It doesn't make my point any less valid.
"First lesson," Jon said. "Stick them with the pointy end."
The interesting bit here is that the normal state of the earth is to be completely ice-free, which means that the sea level would be some 250 feet higher than it currently is. We're presently still in an ice age, which was probably caused by the American continents blocking off equatorial sea currents, and the transfer of heat to the colder parts of the globe. One exception is the Gulf Stream, which is responsible for the very mild climate in much of northern Europe.
Did you know you can fertilize your lawn with used motor oil?
I'm not really sure where your physics comes from, but the principle isn't all that complicated. Anything that floats on water displaces a volume of water where the mass of the water displaced is the same as the mass of whatever is floating.
When the ice melts, its density becomes 1 therefore its mass = its displacement (1kg of water will displace the volume of water which weighs 1kg).
So there is no "approximately cancel each other out." As the parent stated the net change in sea level will be exactly zero. Excepting for minor changes due to temperature or evaporation. Ice currently sitting on a land mass will change the sea level since it is not displacing more or less water.
Education is a better safeguard of liberty than a standing army.
Edward Everett (1794 - 1865)
Heck here everyone. http://www.penguins.cl that should give everything anyone will want to know about penguins. has them all, galapagos, blue, gentoo. check it out
Thanks that was almost what I wanted to say.
one other big factor that dosn't seem to have been mentioned yet is that ice is very good at reflecting light and water is not so good. If the planet is covered in ice it gets very cold if the ice melts it takes less energy to heat it up. Take a look at the snowball earth theory.
First of all, Sahara was at one time reasonably fertile. Or at least parts of it were. In a similar way, we could point out that the America's Midwest is potentially a desert: those are sand dunes we're farming on, and we'd better take care of it if we want to keep on farming it.
And yes, political strife makes it so people, desperate to eat today, don't take care of tomorrow. And the Saharan region *did* go through political strife: the conquest by Islam. [and no, not all religions are equal, or as you seem to think, equally bad. Some shed more blood, some less. Some have peaceful periods, some don't.]
You're also wrong that there were no dictatorships. Some of the dunes have completely covered old Roman forts. Rome was definitely a dictatorship.
But I don't think it was politics or religion that did the Sahara in. I think it was the introduction of grazing animals. You see, the earlier (Christian) and primitive (animist) cultures that existed in the region before that were mostly farmers. But grazing animals represented wealth to the incoming Islamic "missionaries". So they brought that in with them (but not because of their religion; just because of their culture.)
The grazing animals overgrazed the land, and destroyed the plant life, freeing up the dunes.
Further, plants tend to regulate the water; so the Sahara then had no further regulation.
But no, this also isn't Western capitalism that did it. This is an extension, if you will, of the Mongol invasion, and the imposition of a new culture upon a region that was not suited to it.
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
Exactly. I had one professor who claimed you could link the increasing effects of global warming with "research" groups fighting for funding in congress. He even had charts. ;)
1 /fig2_en.html
The temperature of the earth has been hotter then this before, and it has been colder. Yes, we may be in a time of man-made temperature increases, but we still don't know for sure. What all the global-warming zealots ignore is the fact that in the hundred thousand year global temperature cycle, we are IN A WARMING TREND. This is to be expected. If you look at the ice age cycles, they follow similar temperature trends. Yes we may be causing some of the temperature increase - but at the same time, a good deal of it is most likely normal, natural, and to be expected.
I wish people would stop looking at the last 50-100 years, and get it through their heads that to understand climate modeling, you need to look at eons. The ice ages do have some meaning - they weren't random events that happened due to man not burning fossil fuels.
Since nobody seems to be doing this, here are some pretty charts and discussions about why the current hype about global warming is, at minimum overrated, and at max completely bogus:
Ice ages and inter-glacial warming periods:
http://www.ocs.orst.edu/forum/BigPicture.htm
Thermodynamics coupled with solar radiation fluctuations:
http://64.21.37.2/~rhailey/archives/001402.htm
Temperatures since the last ice age:
http://www.gfz-potsdam.de/pb3/pb33/kihzhome/kihz0
While I don't claim that these are all 100% correct and relevant, they should at least get you to question the current global-warming mentality of "we did it and it's here now". Yes, we may be responsible for some global warming. But until we can tell for sure, THROUGH SCIENCE, people need to take a deep breath and calm down. Ask for the facts, ask for the numbers, look at the charts.
Few of you believe manufacturers when they claim speeds for things - you go look at benchmarks. Why would you then automatically accept claims of massive global warming, especially from groups with obvious agendas? Ask to see the data. Ask to see *all* of the data. Get angry that much of the "temperature increase of y degrees in the last x years" "data" came from limited readings in some of the coldest places on earth, because it showed the greatest change, instead of from a representative sample across the entire planet.
Yes, we should pollute less, and yes, we should take responsibility for our environment. However, we shouldn't run around screaming "the ice is melting, the ice is melting". If it is, then it very well might do that every so often, humans, fossil fuels, or not. But using junk or no science to promote a phenomenon which might or might not exist is just not cool...
Velociraptor = Distiraptor / Timeraptor
I've seen the details on nuclear plant saftey with the new post-3 Mile Island saftey designs. Does it include a 747? Yes. Actually, four seperate possibilities were detailed: 1) a 747 (cargo haul version, taken over by terrorists and carrying non-nuclear explosives in a fair portion of the cargo hold) 2) a fully laden B-52 with non-nuclear weapons, 3) a flight of F-15C Strike Eagles and 4) the worst combination of the three, specifically 2 and 3.
Why non-nuclear? Because if you drop a nuclear bomb on a nuclear plant, the bomb effects dwarf the nuclear plant effects. The result is almost the same as dropping a nuclear bomb on a coal plant.
The results with the new design in the worst case? The reactor shuts down and is entombed in a concrete/ lithium half-sphere. The underground shielding remained intact. Radiation leakage? The lithium allows only short-term low-effect leakage.
My backyard is fine with me and apart from the amount of space required, densely populated areas are safe.
So long and thanks for all the fish . . . !!!
We should use more aerosols?
Um, how do I say this... aerosols, by which I assume you mean CFC-based aerosols, float to the upper atmosphere and catalyze the very thin layer of ozone that sort of floats like a skin over the whole planet. This causes sporadic thinning of the ozone layer, which is usually not a big deal, since ozone regenerates. But the CFC's float about for a while, and do persistent damage until they disappate.
Ozone depletion is a different problem than the greenhouse effect, which is caused by increased amounts of CO2 in the lower atmosphere caused by burning fossil fuels and of all things, flatulence of our herd animals.
The confusion of CFC pollution which causes ozone depletion and the global warming engendered by CO2 seems to widespread everywhere. I can't count the times I've seen intelligent people mix this up.