Can someone please explain this to me?
If an iceburg is 90% below water then the water has already been displaced by that amount correct?
That leaves only 10% of the iceburg that would contribute to a rise in sea level. Also water expands when frozen which means that if it melts it takes up even less area.
So even if the whole Arctic melts how would that account for enough of a rise in the sea level to flood all of New York, Florida, etc.
Answer:
You're mostly right, although the current IPCC report suggests a 8 - 24 inch rise over the next 100 years. Knowing that the IPCC has been backpedaling with every new revision, it'll probably be down to 4 inches pretty soon. And Antarctica is actually increasing in ice thickness, only a small portion has experienced and significant warming. Once winter gets into full swing, it will be interesting to see how much new ice is put down.
the Greenland and Antarctic glaciers are on land, not water, these are the big problems
You're right about the displacement. However, The ice that will melt and cause sea levels to rise are not already in the water. It's the glaciers scientist worry about not the icebergs.
None of the ice in the ice berg would add to the water level. It is already displaced when it goes in to the water. You can try to fill a cupwith water and then place a peice of ice in it. Mark the water level. Then let the ice melt and see what happens. There is a difference when icebergs on land melt and the water flows in to the ocean.
You're partly right. First--the projection is for a rise of roughly 4-8 FEET by the end of the century-not 4 inches.
I think one repsponse alreaedy point out most of the ice is in the form of glacial masses on land--so of course, any melt from them isn't already displaced, as is Artic pack ice or icbergs.
But here's two more factors--
a) although its very unlikely that more than a few percentage points of the icecaps will melt, evenin 2-3 centuries, remember that that average temperature is jsut tthat--an average. In summer, the surface ice is much warmer in any case--and that's where melting occurs.
b) you are correct that the volume of water at just above freezing is actually smaller than that of ice. BUT--as water warms to higher temperatures, it again expands. Not by a lot--but even a few degrees can cause an expansion of one part in 2-3000--and with the whole ocean doing that over time--even that much is enough to cause a rise of several feet in average sea levels. Here's an example to illustrate:
Given an avrage ocean depth of 10,000 feet ( its even more, but I don't feel looking it up) :)
A rise of 2-3 degrees (Centigrade) can produce about a 1/5000 expansion in water volume--but do the math--that's about 2 feet. And that's on top of the rise due to melt runoff.
Sea ice is not the issue---melting sea ice does not cause any rise in sea level. It's the Greenland ice cap and the Antarctic ice cap that will cause 150 meter rises in sea level, several thousand years from now.
Forget sea level rise, forget the hurricanes, forget the mosquito-borne diseases. The real danger is that the Earth may continue to warm over the next few thousand years, as a result of burning all the fossil fuel, and become not just a few degrees hotter but a few tens of degrees hotter. That's enough to wipe out almost all life on Earth.
The hulking southern glaciers of Greenland are melting rapidly -- at a rate quicker than previously thought.
In only five years, the amount of freshwater the melting glaciers have dumped into the Atlantic has nearly doubled, which has caused many scientists to conclude that current projections of how fast sea levels will rise have been too low.
The melting glaciers, moving quickly across the ocean, may account for about 17 percent of the estimated one-10th of an inch annual rise in sea levels, according to a study released today by Eric Rignot, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., and his co-author, Pannir Kanagaratnam, of the University of Kansas.
An increase in surface air temperatures appears to be causing the glaciers to flow faster -- at up to 8 to 9 miles a year at their fastest clip. They have also been dumping increased volumes of ice into the Atlantic.
"The behavior of the glaciers that dump ice into the sea is the most important aspect of understanding how an ice sheet will evolve in a changing climate," Rignot told The Associated Press. "It takes a long time to build and melt an ice sheet, but glaciers can react quickly to temperature changes."
That stepped-up flow accounted for about two-thirds of the net 54 cubic miles of ice Greenland lost in 2005. That compares with 22 cubic miles lost in 1996, Rignot said.
Details of the study were presented Thursday at the annual meeting of the American Association for the Advancement of Science. The study appears Friday in the journal Science.
The increased rise in sea level could have possible runaway effects that could produce a dramatic rise in sea levels, potentially making storm damage far worse, by the time today's toddlers reach middle age, some scientists predict.
Scientists also worry about the effect all this fresh-melt water will have on the Atlantic's Gulf Stream "conveyor belt" currents. These currents have long kept the northeastern United States, Britain and northwestern Europe relatively warm for their northern latitudes by transporting heat up from the tropics. Too much freshwater slows these currents, said scientists.
A few weeks ago, scientists announced a surprising discovery -- currents have slowed by 30 percent in recent years.
A dramatic sign of Greenland's melting is the speeding up of the glacier "tongues" of the ice cap as they push down to the sea, and the disintegration of their front walls, which means they spill out even faster. This acceleration has been recorded in several tongues on Greenland's southern coast and is beginning to happen farther north as well, the scientists said in their report.
This is the latest confirmation that global warming is now accelerating and involving interconnected "positive feedback" effects in which the warming in different Earth systems reinforces overall warming, and it is all now happening faster than scientists recently thought possible, according to the report.
The only way to stem the loss of ice would be for Greenland to receive increased amounts of snowfall, said Julian Dowdeswell at the University of Cambridge, in an accompanying study.
"Human activities are releasing greenhouse gases more than 30 times faster than the natural rate of such emissions that produced a similar period of extreme warming in ancient times," according to his study, which is based on evidence from studies of sediment cores.
Ancient natural warming events started slowly and then accelerated -- worrisome evidence that there are natural "positive feedback loops," such as the release of the greenhouse gases carbon and methane as the frozen ground and seabeds that have trapped them thaw, that become "runaway effects" at some point, his study found.
What this article is basically explaining is that whatever happens in one part of the world has an effect on the entire globe... yes ice is melting is Greenland but its slowing down the currents world over, affecting the climate globally.
Besides the answers given by all those people above. Global warming will also produce a lot more rain globally. And as in England at the moment it will cause flooding of inland low lying areas. This in turn means people will be without water to drink and will also help spread diseases by flooding sewer systems. Not to mention the panic, chaos and looting. But life threatening? Nothing to worry about for our generation i shouldn't think. But the Governments of the world need to put pressure on countries to do all they can to fight this issue for the sake of our children and grandchildren.
Okay well The Ozone layer is breaking from all of the polution. But the ozone layer is what helps us from the sun coming to close and burning everyone. So without the ozone layer we will be fried! do you get it or do you think it is a myth. cause if you think it is a myth just wait and see what happens.
The best gauge would be the Isthmus of Panama.
That would be the first to flood over before any other mass flooding.
Have there been any alarms sounded in that location?
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