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Arctic Ice May Melt By 2040
Dekortage writes in with a new study by the National Center for Atmospheric Research suggesting that the North Pole may be clear of ice in summer as soon as 2040, decades earlier than previously thought. From the article: "'As the ice retreats, the ocean transports more heat to the Arctic and the open water absorbs more sunlight, further accelerating the rate of warming and leading to the loss of more ice,' Holland said in the statement. 'This is a positive feedback loop with dramatic implications for the entire Arctic.'"
Except ice is less dense than water...
Yes, which means the same mass takes more volume. When submerged ice (the majority of the ice in question) melts, it becomes more dense (same mass, less volume) which means it actually LOWERS the water level. Add in the amount of ice that is above water in the Artic channel, and the total change in water levels will be negligible.
-Rick
"Most people in the U.S. wouldn't know they live in a tyrannical state if it walked up and grabbed their junk." - MyFirs
Because of bouyancy, melting the ice which is floating in water will not raise sea level. The ice is less dense than water, ergo it floats on the water, but it displaces an amount of water equal to its mass. So when it melts into water, the level will stay the same.
You can try this yourself with a glass of water and ice cubes. Mark the water line with the ice cubes floating, then let the ice melt and notice that it hasn't moved. This is elementary school physics.
There are two things that will raise sea level: First, any ice that is on land (not displacing sea water) that melts and flows into the ocean. Thus why Antarctica is a much bigger concern as far as rising sea levels are concerned. Second, thermal expansion of the ocean as it becomes warmer. I believe that the latter will actually end up being the dominant effect.
The enemies of Democracy are
The ice in the arctic is fresh water, the ocean it is floating in is salt.
http://www.physorg.com/news5619.html
-- perl -e'print pack"H*","6e656d6f406d38792e6f7267"'
You can try this yourself with a glass of water and ice cubes. Mark the water line with the ice cubes floating, then let the ice melt and notice that it hasn't moved. This is elementary school physics.
And by the time you get to college, you should have learned that the experiment does not work with saltwater.
If I have been able to see further than others, it is because I bought a pair of binoculars.
There is a slight difference in the academic and scientific quality between the reports appearing in major scientific journals that note the correlation between record high levels of CO2 in the atmosphere and increasing global temperatures, compared to the sort of "research" that appears on Fox news.
The story appeared on "Fox news" in the USA, and references a story appearing in the British newspaper "Daily Telegraph", both of those news organisations are known to be the main global warming deniers in each of those countries. They both love running sensationalist, unscientific articles in order to discredit the real scientific research going on.
No it is not, according to RealClimate. Snowfall may be increasing at the interior of Greenland, but it's offset by an accelerated dumping of ice into the ocean at the periphery.
From RealClimate:Emphasis added by me.
uhg, my inability to express this analogy is frustrating me. Your first paragraph is what I was posting about. If the only change enacted on the environment is to melt either the submerged, or non-submerged ice, and no other effect is allowed.
While I was writing it, I was applying the logic such that you could replace the submerged half of the formula with dry land. If you break it out into two sperate formulas (submerged ice melting reduced total volume, non-submerged ice melting increases total volume) and you can assume that the volume of water displaced equals the total volume of the ice above and below the water line, then you can state that: ice that is not submerged will increase the volume of water by the same amount as what it would have displaced if it were partially submerged, and the inverse of that for finding the volume of water displace by the submerged ice. When dealing with the two formulas together, the net change in a controled environment is 0.
Since you can then figure out water volume of non-submerged ice, you can then figure out how much volume you are adding to the water body by melting ice that is on dry land.
-Rick
"Most people in the U.S. wouldn't know they live in a tyrannical state if it walked up and grabbed their junk." - MyFirs
Also, it wasn't scientists who were talking about global cooling in the 70's. It was some of the same media types who now think that "both" sides of the global warming "debate" need to be discussed. I.e., journalists who didn't understand science, but want to sell subscriptions. I challenge you to find a single peer-reviewed article supporting global cooling in the 70's. In fact, you'll find that scientists in the 70's were already warning about global warming.
Ben Hocking
Need a professional organizer?
I was thinking for some dumb reason that the ice cap would be frozen salt water.
Well, taken literally, that is true. The problem is that when salt water freezes, most of the salt is left behind. The explanation is fairly simple: The water starts forming crystals, and the salt (mostly Na and Cl ions) don't fit into the crystal structure very well. So at the surface, the water molecules slowly join the growing crystal, while the dissolved salt ions don't. You do get some salt in the ice, because ice usually consists of a lot of crystals that grew together, trapping salt in the pores. But usually there's not enough salt for the ice to taste salty.
This phenomenon is used sometimes. It's often called "freeze distillation". One way it has been used is to concentrate wine. For instance, people used to leave jugs of apple cider out on below-freezing nights. In the morning, they'd remove the layer of ice at the top. The liquid left would be thicker, and would contain most of the alcohol, because ethanol also doesn't join into ice crystals. The resulting concentration is more like alcoholic syrup than brandy, but due to the high alcohol content, it doesn't spoil.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
Actually, no. Sea level will still rise: though only by a little. The water from the ice is less dense than the sea water around it because the sea ice typically contains less salt. Hence, more floats up above the water than bouyancy would suggest, which reduces the water level as it gets frozen, and increases the water level when the ice melts again.
l
Search for 'salinity' in http://www.radix.net/~bobg/faqs/sea.level.faq.htm
Must admit I accepted this too until the argument was put to me recently. Fact is of course that the ice is fresh water (less dense) than the sea water it floats in. Check out the links posted elsewhere to physorg about this. Archimedes principle is about the force of the ice pushing down and displacing an equal weight of sea water. But since the ice is lower density then the volume of sea water displaced is less than the volume of the fresh water in the ice ... even after melting. So when floating ice melts in sea water the sea level goes up. Check here, not just the reasoning but also the actual experiment to prove it.
Bitter and proud of it.
I don't know, did they ? : Rearing cattle produces more greenhouse gases than driving cars, UN report warns. Note the un.org domain in my link.
Here's the full abstract. Note that 1 of 7 computer models showed total ice melt by 2040... the worst case scenario. Gotta love how the media grabs the flashy stuff. Holland, Marika M.; Bitz, Cecilia M.; Tremblay, Bruno Future abrupt reductions in the summer Arctic sea ice Geophys. Res. Lett., Vol. 33, No. 23, L23503 http://www.agu.org/pubs/crossref/2006/2006GL028024 .shtml
Abstract
We examine the trajectory of Arctic summer sea ice in seven projections from the Community Climate System Model and find that abrupt reductions are a common feature of these 21st century simulations. These events have decreasing September ice extent trends that are typically 4 times larger than comparable observed trends. One eventexhibits a decrease from 6 million km2 to 2 million km2 in a decade, reaching near ice-free September conditions by 2040. In the simulations, ice retreat accelerates as thinning increases the open water formation efficiency for a given melt rate and the ice-albedo feedback increases shortwave absorption. The retreat is abrupt when ocean heat transport to the Arctic is rapidly increasing. Analysis from multiple climate models and three forcing scenarios indicates that abrupt reductions occur in simulations from over 50% of the models and suggests that reductions in future greenhouse gas emissions moderate the likelihood of these events.
1975 quote is a lie.
Acid rain has had many negative effects.
The ozone hole DID get worse. As a New Zealander I've grown up with it. We have soaring melanoma rates in our country due to it. It may still be another few decades before it shrinks enough to lessen risk.
Bird Flu is a danger, and there WILL be a flu pandemic in the future. We don't know when, but we do know that many of the flu pandemics of the past occurred due to changes in viruses from jumping between porcine, avian and human populations. But there will definitely be a pandemic in the future.
The debate over climate change never really existed. The so-called "debate" has been a generated controversy of American corporate and right-wing interests.
As for your opinion that concerning anything happening globally "we can't change anyway" I have to say, you're an idiot. Please take an hour or two to look into humanity's effects globally on fishing stocks, the current human-caused mass extinction, pollution etc. Humans have a huge impact on this planet, and this also indicates that we can also take action to prevent global changes of our own making.
(Perhaps you should think before you post)