Slashdot Mirror
Arctic Sea Level Falling?
HRH King Lerxst with a link to BBC News' report that "Arctic sea level has been falling by a little over 2mm a year — a movement that sets the region against the global trend of rising waters. ... It is well known that the world's oceans do not share a uniform height; but even so, the scientists are somewhat puzzled by their results."
Funny things happen when you have solid H2O in liquid H2O that, on a large scale, are probably not well understood. I'm not a physicist but you have heat dissipation as Newton's Law of Cooling goes into effect and a multitude of climate issues. I can speculate on a few things:
- As the water becomes warmer, it is more prone to evaporation on the surface from the sun. Previously, less water would evaporate and keep the water levels slightly higher but now the difference in temperature at the surface is less making the water more easily transferred into a vapor.
- Gravity pulls down on the free floating icebergs and it displaces the water. These icebergs are shrinking or being reduced greatly so the water height in the vicinity lowers slightly while the water levels around the world rise slightly.
- The tides are becoming stronger and as the amount of water on the surface of earth increases, so does the effect of the moon on it. The moon pulls least on water at the caps and even more so on water near the equator.
- Some force (moon, internal gravity, spinning of the earth, sun, etc.) is causing the water to accumulate at the equator which in turn reduces the water at the poles.
Like I said, this is pure speculation and I haven't thought out in advance the above propositions. But I'm going to speculate that there's an unknown effect that occurs when massive bodies of ice are half submerged in water on a planet. The basis of this effect is probably known in physical and chemical fields of science but we just haven't put them together to figure it out. Hopefully we can figure it out as these "discoveries" are oftentimes the foundation for more work and more discoveries that benefit mankind. Translation: curiosity spurs innovation.If there's one thing that Slashdot is good for, though, it's testing half cooked theories! My fellow colleagues, I welcome you to point out the scientific flaws in my above hypotheses!
My work here is dung.
May be connected to a slowdown of the Gulf Stream?
Nuffsaid
________
Don't know about his cat, but Schroedinger is definitely dead.
...What?... I was THIRSTY, okay?
A computer once beat me at chess, but it was no match for me at kick boxing.
There has been periodic change in water levels for thousands, if not millions of years. While it may seem alarming, and probably does have a large effect on our climate, it is not just CO2 emissions to blame. I'm sure the tectonic plates shifting (I'm no geologist) and various other natural phenomena contribute a significant amount to the change in the earth's water level, just like they have for a long time before we were around.
The arctic icepack is melting at an accelerated rate, due to global warming. Once the ice is gone, it is no longer displacing so much water, and so sea levels drop.
Nice speculation. But since the end last ice age most of the coastlines surrounding the Arctic Ocean have undergone isostatic rebound. Most of these areas were highly glaciated and heavily loaded with ice. Once the ice was rapidly removed the land maintained bouyant equilibrium by rising. Apparent sea levels have been falling in these areas for 1000's of years. The only question is how long it will continue and how isostacy and sea level rise interrelate in different areas.
an ill wind that blows no good
" The polar caps are actually *growing* this year, as they have been recently, not shrinking."
if you want to be a pedant, parts of the middle of certain ice sheets are thickening do to increased precipitation, which is due to excess evaporation from warming. the rest of these ice sheets are melting, and more is melting than is thickening.
but thanks for playing "clouding the issue with Dan Grossman" Don, tell him what he didn't win!
Aaaaaah! Panic! Global cooling is BACK!!!!!
Time,
Newsweek,
etc.
-Peter
http://en.wikipedia.org/wiki/Global_dimming [Wikipedia on Global Dimming]
Quote: Some scientists now consider that the effects of global dimming have masked the effect of global warming to some extent and that resolving global dimming may therefore lead to increases in predictions of future temperature rise.
Hmmm...but this article says that the glaciers in Greenland are melting and retreating from the sea, not growing larger.t m
http://news.bbc.co.uk/1/hi/world/europe/3922579.s
Whoever am I to believe about this scientific issue...scientists from the Geological Survey of Denmark and Greenland, or a keyboard jockey from Slashdot?
Because they don't know how to swim?
They ate less than twenty minutes before entering the water?
Just too damned fat?
They're drunk?
Suicide pacts?
Forgot their water wings?
Their star is falling while their pollyanish wives are reaching the big time?
They were all carrying Hamlet's child?
#19845
I wouldn't take seriously any explanation posted here. I've read through a few of them, and although I myself am not a climatologists, they do strike me as being scientific-sounding rationalisations of an existing opinion.
Climate change is a kind of political topic, and this means that everyone who has a political opinion pretends to be an expert on the subject.
If we can put a man on the moon, why can't we shoot people for Apollo-related non-sequiturs?
Maybe global warming is causing an increase in the sponge population.
One thing I haven't seen mentioned recently in the comments on Slashdot is the idea of the Precautionary Principle (http://www.unu.edu/unupress/unupbooks/80841e/8084 1E0o.htm#12.%20The%20precaution%20principle/. By its very nature, good science is uncertain- its investigations rarely produce evidence that points in only one direction, and the whole point of the scientific method is to avoid coming to dogmatic, unjustified beliefs.
This produces problems when science and politics come together, because of the way science is treated by popular culture and popular politicians. Essentially, science is popularly viewed and portrayed as being a source of certainty. This is why the extremely small number of global warming naysayers always are referred to as scientists (irrespective of whether their credentials are respected or relevant). It creates the illusion that "science" has yet to arrive at its intended goal: absolute certainty. But as any good scientist will tell you, scientific truth is always provisional.
Thus, the trouble with doing something about global warming is that there is a disjunction between the sort of certainty (absolute) that politicians facing re-election and pressure groups want before acting, and the sort of certainty (provisional, always subject to revision) that scientists can, in good faith and following the strict methodology of science, give. Enter the precaution principle, which basically states that if you have a reasonably likely possibility of really bad future outcomes, you should try to do something about it, even if it's possible those outcomes don't come to pass. To me, global warming fits this scenario.
Except that weather is full of random fluxuations and anomylous local occurances. It is very bad science to say that every random weather patter that we can't explain is caused by global warming. It is fearmongering and political posturing, not science.
No, more water vapor = more clouds = more light reflectd -> cooling
First of all there was not scientific consensus for any of those straw-man arguments you mention. Science has know the world wasn't flat for thousands of years and any confusion over that is due to religion and stupidity; just check the wikipedia article. Religion and stupidity also were the culprits in blacks being supposedly 'inferior' (as opposed to the more accurate 'slightly different'). And it's religion and stupidity that said Iraq had WMDs.
.5 celsius is 1 degree. You reasoning is sound, but your conclusions are wrong because the so-called facts you are starting from are wrong. When this happens to an otherwise smart person there is one word for it: denial.
Second, get your facts straight. It's 1 degree celsius... just look at the damned graph... from -0.5 to
The artic ocean has not fallen 2mm. The sky has fallen 2mm. This gives you the impression the ocean is down 2mm. ;-)
RTFG - Read The F#$%ing Google!
But is taking "action" any better when we don't know the science behind it?
They don't know.
To take action when one doesn't know what is happening could make things worse.
Of course we know there are oddities occuring, but that is the key word - oddities. Its odd when we don't understand.
The problem with Climate science is that it hasn't been all that long since we had the tools to truly understand it. Hell we have had only a couple of decades where we could accurate measure temperatures around the globe. The accuracy increases each year and yes we will learn something from it. Some things we learn will proven "common" beliefs to be totally wrong, others may actually prove some concepts.
That is the crux of the Global Warming issue. We don't know enough to be sure what all the causes are and if actions we take will have the desired effect. If we knew the climate as well as some think they do then why are simple things like weather prediction difficult? Easy, its difficult and not simple, its difficult because we don't know all the variables. We know the obvious ones, well at least we think we do.
So before flying off the handle we need to realize we are not as smart as we think we are.
* Winners compare their achievements to their goals, losers compare theirs to that of others.
definitely, but the installation is difficult since Penguins aren't native to the Arctic and Polar Bears find them yummy.
Good bye and thanks for all the fish, now that all the mass of them darn dolphin's are gone, the water dropped by 2mm. Easy explanation.
The end is near - I knew it.
Custom electronics and digital signage for your business: www.evcircuits.com
Yes, but nearly all of the "actions" I've heard recommended for dealing with global warming are just common sense, and would have other benefits. It's not as though someone has decided we should take an enormous glacier from the arctic ocean and drive it down to the equator to try to cool things off, change the orbit of the earth to be further from the sun, or some other fanciful suggestion. They're suggesting things like using less fossil fuels, looking into alternative energy, and reducing pollution and industry waste. I mean you cannot deny that any of these things are positive unless you're an industry shill. And they're actions we can safely take today, until we understand fully the science tomorrow.
By no means am I an expert in the field, but I do have a firm head on my shoulders, and am confused by the lack of any "discussion" section in the BBC report. So here is a part of mine. Although it is common to say that the top of a continuous body of water is all at the same elevation (a fact surveyers use extensevly to reduce costs), that statement is wrong. The tops of water bodies follow an equipotential surface. This means that each top point will have the same potential energy. In small surfaces, such as lakes, the difference between the equipotential surface and the equi-elevation surface is nearly zero, so it is not taken into account. In larger bodies, such as the entirety of north America, or even the world, spherical coordinates are not as useful. Geoids have been used for many years to approximate the equipotential surface on the earth (search NAD27) but even they do not capture the peculiarities that occur with local lead outcroppings or other local density peculairities on the earth. Another coomonly understood fact is that water is most dense at 34 degrees farenheight. A not commonly understood fact is that the global ocean circulation patterns are very slow. Put these three ideas together and one can figure out that it is not the oceans that have been lowering, but that there is more cold water near the polar ice caps then there was before becasue of the increased rate of ice melt. This effect has increased the density of the polar ice cap region and decreased the elevation of local equipotential curve. The decrase in absolute elevation is true, but the equipoential elevation has been rising. If I am wrong on any of this, please correct me. Have a good day.
warmer = more evaporation = more water vapor in the air = more heat trapped and so on
... ... ... -> more cloud formation -> wetter weather -> more vegitation in once barren areas -> more CO2 uptake from vegitation -> less GHG and more O2
It means nothing of the sort my friend. In fact as scientists analyse global climate, they seem to be slowly, subtlely distancing themselves from the theory/term of "Global Warming". Have you noticed that authorities on the subject--even the most ardent supporters of things like the Kyoto initiative--now almost NEVER use the term anymore? The correct term is "Global CLIMATE CHANGE" because EVERYONE agrees that the earth is not universally warming up (some areas are, and others are getting cooler), and they aren't even convinced anymore that the AVERAGE gloabl temperature will continue to steadily rise. What they DO agree upon is that the climate is CHANGING--they point to evidence of changing weather patterns and more "extreme weather"--we'll get more Katrina's in the Gulf of Mexico and huge, freezing blizzards in maritime Canada and expanding deserts in Africa. The general consensus is still that CO2 from human activity exacerbates the problem--it's just that scientists now cover their butts with more general terms like "climate change" because truthfully, NOBODY has a handle on what exactly is going to happen.
The situation might go as you state, but there are a number or drastically different predictions as well:
warmer -> more evapouration -> more cloud formation -> sunlight blocked -> cooler
or
or
warmer -> melting polar ice -> lower ocean temperatures -> shifting weather patterns -> more "even" climate (warmer & wetter towards poles, cooler in the equatorial region)
NOBODY knows what will REALLY happen--it is all guesswork (albeit really educated guesswork). Although those who say human activity/CO2 emissions have no notable effect on the planet are generally dismissed as crackpots (and rightly so), the scientific community is finally acknowleging--at least a bit--that they don't know the ultimate effect, which is significant becasue high-profile research organisations really hate to admit they don't know something (almost as much as they hate admitting they're wrong). And here is one to cheer you up--there is a growing contingent of scientists that say "yes, human activity has altered our climate, but the can is open and the worms have long since escaped--we are past the point of fixing things".
The problem I have with Kyoto is that if we assume the worst case senario (that humans are the primary cause of global warming and the result is destruction of our way of life etc), that it still is a pretty inneffective way of reducing CO2 emissions. It would be far cheaper to give developing nations some of our pollution reduction technology and pay them to build their societies to function with less energy requirements (far cheaper to build a new building with efficiency in mind than retrofit existing buildings) yet the only nations required to cut emissions were the developed countries. I wish there had been some thought about cutting emissions in a more efficient manner globally.
Degaussing scares the bad magnetism out of the monitor and fills it with good karma.
I can make the entire thing make sense in a matter of seconds!
Change
Arctic sea level has been falling by a little over 2mm a year - a movement that sets the region against the global trend of rising waters. A Dutch-UK team made the discovery after analysing radar altimetry data gathered by Europe's ERS-2 satellite.
to
Europe's ERS-2 satellite has been falling by a little over 2mm a year. A Dutch-UK team made the discovery after analysing radar altimetry data gathered over the Arctic sea level.
You are checking your backups, aren't you?
They are changing their terminology simply because the general public did not get what they were saying. People hear "warming" and they think of spring and butterflies--sounds nice doesn't it?
But what it means in terms of climate is related to the true scientific meaning of the term temperature--a measure of the total energy in a system. "Warming" simply means that more and more energy is being stored by the system. Think of a fly wheel being spun up faster and faster.
EVERYONE agrees that the earth is not universally warming up (some areas are, and others are getting cooler)
Yeah, actually this has been understood from the very beginning. It's not exactly a revelation. When a system stores more energy, the oscillations of the system are like to become greater. Imagine that the flywheel is not well-balanced. The more energy you put into spinning it, the bigger the oscillations will be (both up and down). Now imagine trillions of those flywheels in one machine and you get an idea of the chaotic nature of what we're talking about. Scientists might not be able to predict when it will buck in a certain way, but they can predict an overall increase in activity.
they aren't even convinced anymore that the AVERAGE gloabl temperature will continue to steadily rise.
The annual mean temp rise steadily? Not steadily, no. But it looks like the mean delta over time is going to stay positive for a while.
What they DO agree upon is that the climate is CHANGING--they point to evidence of changing weather patterns and more "extreme weather"--we'll get more Katrina's in the Gulf of Mexico and huge, freezing blizzards in maritime Canada and expanding deserts in Africa.
Everything you just mentioned is driven by stored heat in the atmosphere and oceans. Change can't just happen, it has to be driven by something. In the climate that something is heat.
The general consensus is still that CO2 from human activity exacerbates the problem--it's just that scientists now cover their butts with more general terms like "climate change" because truthfully, NOBODY has a handle on what exactly is going to happen.
That's just not true. There are a ton of open-ended questions but you can build models based on the available data and produce approximations--think of the flywheel machine. Like all science you must qualify the precision of your results and not stretch beyond it (that's true when being critical as well). Luckily the system under study is enormous so even very imprecise results can indicate trends.
Also, you need to understand the physics of the reactions involved. It's not enough to say that CO2 is related to climate change, we need a cause and effect relationship. And there is one--a strong one actually--the "greenhouse effect."
which is significant becasue high-profile research organisations really hate to admit they don't know something
Where do you get that? The whole raison d'etre of high-profile research institutions is to ask the hard questions and seek answers. Their entire existence is based around what they don't know.
Build a man a fire, he's warm for one night. Set him on fire, and he's warm for the rest of his life.
This shouldn't really be a surprise - after all, it's been known for several years that the water level of the oceans is going down, due to the "leaky seas" phenomenon. See New Scientist article from a few years ago at http://www.newscientist.com/article/mg16322030.200 .html (used to be free, but no longer), or a CNN summary at the time: http://www.cnn.com/NATURE/9909/17/leaky.seas.enn/i ndex.html
No one knows why - forming mineral hydrates, some other form of leaking into the earth itself, or global cooling - it's all speculation right now, just like global warming. The truth: The world is a complex place and we're not even close to understanding it.
BTW: Remember when "all the world's climate experts" warned of global cooling and an impending ice age only around 30 years ago? (Which would, of course, require many of the same environmental policy changes wanted by the global warming crowd now.) Those who forget history are doomed to repeat it.
"The future's good and the present is nothing to sneeze at." - Roblimo's last
Here's a possible explanation: When water freezes it forms hydrogen bonds that produce a crystalline structure that is less dense than water (this is why water ice floats). In a body of water near the freezing point there will be many water molecules constantly moving in and out of this fozen state (because of local temperature fluxuations). Therefore as you warm such a body of water you would expect fewer and fewer water molecules to be cool enough to bond together temporarily in a less dense crystalline fashion. In other words, as you warm a body of water that's near the freezing point, it should become less dense, and shrink.