Icemelt

Oh sorry ! Not you then http://www.advancedphysics.org/forum/archive/index.php/t-3503.html

Hi Norman Ah, I thought your name rang a bell. I remember you from absolute zero, if you know what mean Very interesting down there with becs Best wishes

Hey Neil You've certainly made some amazing progress over the past three months. I'm fairly blown away with your ideas, which have developed so much since our initial discussions. Well done mate, certainly a huge step from NetWare & GroupWise eh Great intuition and I love the diagrams which make it so much easier to follow your thoughts. Keep up the good work !

Anyone care to explain what's happening here ? http://prola.aps.org/abstract/PRL/v85/i9/p1795_1 Bose-Einstein condensation has been achieved in a magnetically trapped sample of 85Rb atoms. Long-lived condensates of up to 104 atoms have been produced by using a magnetic-field-induced Feshbach resonance to reverse the sign of the scattering length. This system provides new opportunities for the study of condensate physics. The variation of the scattering length near the resonance has been used to magnetically tune the condensate self-interaction energy over a wide range, extending from strong repulsive to large attractive interactions. When the interactions were switched from repulsive to attractive, the condensate shrank to below our resolution limit, and after ∼5 ms emitted a burst of high-energy atoms

Good grief ! That was nearly ten years ago ? So what's happened since ? "With improved frequency stability of our set-up and lower coupling intensities, even lower light speeds would be possible, perhaps of the order of centimetres per second"

There's an interesting book by George Smoot called "Wrinkles in Time" covering this subject. I like your ideas, I'm still digesting your PDF

Come on ! We discover something we can't properly measure, so by definition it must be identical to all other similar objects we can't measure ! This is one of the least acceptable arguments I've ever heard How about: "We are unable to measure the structure of an electron because it is continually changing its state. Therefore in this respect each electron is unique since its state can never be synchronized with another" To me this seems a much more plausible conclusion !

No ! I can't agree with that If the light was bouncing off the particles due to the high density of the condensate, then it would be scattered as it leaves the medium. But it isn't ! It leaves as the same nice concentrated tight laser beam exactly as it entered.

OK but we can measure this distance since it the condensate is trapped in a tiny magnetic bottle in a lab, and it takes the light several seconds to traverse it !

Well yes indeed ! You have just repeated exactly what I've already stated But what is the explanation ? It's no good just saying "it does" ! What we need to theorisze on is why, and what are the implications ?

What is the explanation for the slowing down of light to a snail's pace when it enters a Bose–Einstein condensate, only to regain its normal speed as it leaves ? Experiments have shown that a laser pulse several miles long is reduced to just a few microns in length when it strikes a Bose–Einstein condensate. Then, slowly passing through the medium, as it reaches its exit point, the laser pulse regains its length and speed. Must we now assume that, when testing the limits of our physical environment, there are in reality no constants ?

My apologies for the omission see: http://www.mnp.nl/ipcc/pages_media/FAR4docs/chapters/CH1_Introduction.pdf Chapter 1, Page 13 Better be quick, since I suspect this unacceptable data will be supressed shortly ! (Just a passing comment to antagonize the easily inflamed) (However somebody please prove me wrong by posting a live link to this chart in six months)

Here's an interesting little chart I stumbled on Looks like the guys camped out demonstrating at the airports should be hanging around the forests and coal / gas fired power stations instead !

You are correct in as much as the original radiosonde measurements were discredited, however you are incorrect in saying that the matter has been resolved. Later measurements submitted and approved by the IPCC failed to confirm that the troposphere is warming significantly faster than the surface, which is essential for the GHG cause to be substantiated. In fact the April 2007 IPCC report confirmed that many of the measurements showed that the surface was warming faster than the troposphere, and that in their opinion the combined results from all latitudes were inconclusive.

Something to consider for the open minded. Therefore one or two you probably need not bother reading this post ! Proxy temperature data relating to the ancient past will inevitably mask any minor short term variations, since it is unlikely that say data from 500,000 YBP or even 100,000 YBP would reveal small variations of 0.5C within a period of 50 years. Therefore, to say that temperatures today have risen faster than at anytime in the past 100,000 years, would seem to be an invalid observation. It would not be a legitimate comparison to directly compare short term temperature variations over the past 50 years to what’s happened even over the past few thousand years, since there seem to be no data that could accurately identify a 0.5C temperature change between say 125,000 and 125,050 YBP, and short term variations will inevitably have been masked. But, for the sake of argument, let’s say that our data are sufficiently accurate to detect 0.5C temperature variations between 125,000 and 125,100 YBP, it would then be valid for us to use a 100 year moving average temperature rate change. i.e. The sum of the average temperatures over the previous 100 years divided by 100 would generate each point on our chart. But, I hear you cry, this would mask what has happened over the past 50 years, since it would be averaged together with the preceding 50 years and divided by 100, so this wouldn’t be fair. On the contrary, this would put the last 100 years or so of accurate direct thermometer readings on the same footing as the proxy data to which we are comparing. (The four inventors of thermometer at the beginning of the seventeenth century were Galileo, Sanitorio, Fludd and Drebbel. Although Magia Naturalis ( Natural Magic,1558,1589) describes a simple air-thermoscope, which traps air in a bulb so that, as the air expands or contracts in response to a temperature increase or decrease, it moves a liquid column in a long tube. But the thermoscope is not deemed to be a thermometer, since it didn’t actually have a scale.) Therefore the points we would need to plot on our chart to legitimately assess whether temperatures are rising faster than at any time during the past 125,000 years would be as detailed below from 0 through to 125,000 YBP. Total annual average temperatures 0 to 100 YBP / 100 Total annual average temperatures 1 to 101 YBP / 100 Total annual average temperatures 2 to 102 YBP / 100 Total annual average temperatures - - - - - - - - Total annual average temperatures - - - - - - - - Total annual average temperatures 124,998 to 125,098 YBP / 100 Total annual average temperatures 124,999 to 125,099 YBP / 100 Total annual average temperatures 125,000 to 125,100 YBP / 100 I haven’t actually plotted this chart, but I very much doubt that it would substantiate any such conclusions.

Something to consider perhaps ! http://geography.about.com/od/globalproblemsandissues/a/nexticeage.htm As only 11,000 years has passed since the last Ice Age, scientists can not be certain that we are indeed living in a post-glacial Holocene epoch instead of an interglacial period of the Pleistocene and thus due for another ice age in the geologic future. Some scientists believe that an increase in global temperature, as we are now experiencing, could be a sign of an impending ice age and could actually increase the amount of ice on the earth's surface. The cold, dry air above the Arctic and Antarctica carries little moisture and drops little snow on the regions. An increase in global temperature could increase the amount of moisture in the air and increase the amount of snowfall. After years of more snowfall than melting, the polar regions could accumulate more ice. An accumulation of ice would lead to a lowering of the level of the oceans and there would be further, unanticipated changes in the global climate system as well.

I'm afraid I have to disagree with you on this one, and none of the information below encourages me to believe that anthropogenic GHGs are the driving force behind global warming - quite the opposite ! Climate Change 2007: The Physical Science Basis Summary for Policymakers Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change Available at http://www.icemelt.info/IPCCWGIAR4PSBFEB07.pdf Page 4 of this report states “New analyses of balloon-borne and satellite measurements of lower- and mid-tropospheric temperature show warming rates that are similar to those of the surface temperature record and are consistent within their respective uncertainties, largely reconciling a discrepancy noted in the TAR. {3.2, 3.4}” It does not say the troposphere is warming significantly faster, which is necessary for GHGs to be causing global warming. Page 9 of the same report states “Difficulties remain in reliably simulating and attributing observed temperature changes at smaller scales. On these scales, natural climate variability is relatively larger making it harder to distinguish changes expected due to external forcings. Uncertainties in local forcings and feedbacks also make it difficult to estimate the contribution of greenhouse gas increases to observed small-scale temperature changes. {8.3,9.4}” and on the same page “It is very unlikely that climate changes of at least the seven centuries prior to 1950 were due to variability generated within the climate system alone. A significant fraction of the reconstructed Northern Hemisphere interdecadal temperature variability over those centuries is very likely attributable to volcanic eruptions and changes in solar irradiance, and it is likely that anthropogenic forcing contributed to the early 20th century warming evident in these records. {2.7, 2.8, 6.6, 9.3}” It says "contributed to" It does not say anthropogenic forcing was the major contributor and more conclusively at: http://www.fraserinstitute.ca/shared/readmore.asp?sNav=pb&id=886 Independent Summary for Policymakers: IPCC Fourth Assessment Report Publication Date: February 2007 "Executive Summary: The Independent Summary for Policymakers is a detailed and thorough overview of the state of climate change science as laid out in the UN Intergovernmental Panel on Climate Change (IPCC) draft report. This independent summary has been reviewed by more than 50 scientists around the world and their views on its balance and reliability are tabulated for readers. It carefully connects summary paragraphs to the chapters and sections of the IPCC report from which they are drawn, allowing readers to refer directly to what is in the IPCC Report, including: Data collected by weather satellites since 1979 continue to exhibit some evidence of lower atmospheric warming, with estimated trends ranging near the low end of past IPCC forecasts. There is no significant warming in the tropical troposphere (the lowest portion of the Earth’s atmosphere), which accounts for half the world’s atmosphere, despite model predictions that warming should be amplified there."

I sometimes wonder just how many of the guys that comment on this movie have actually seen it ! Have you actually watched it all the way through ? Maybe take another look http://video.google.com/videoplay?docid=4499562022478442170 There’s so much in your post and the associated links that one could disagree with, but here’s a few for starters: 1) Having watched the movie several times, it is pretty difficult to see how the director misquoted Professor Carl Wunsch, who was very eloquent and clear on the subject. He had a good chunk of time to speak and his comments were not restricted to just a few phrases taken out of context. 2) I also seem have a very vivid memory of it being alleged that weather was likely to become more stable with global warming, since unstable weather patterns were more likely with a larger difference between equatorial and polar temperatures, and these would be narrowing with global warming. 3) There would now seem to be few who would disagree, including the IPCC, that climate models are intended to show POSSIBLE scenarios, based generally on conditions that do NOT currently exist, and they should not be used as climate forecasts. 4) I notice that the tropospheric anomalies have been omitted from your post. Most of us are aware that the original temperature measurements of the troposphere showed the opposite to the results expected, so the measuring techniques were discredited and trashed and a fresh analysis was undertaken. All agreed that for GHGs to be the driving force behind global warming the troposphere must be warming SIGNIFICANLTY faster than the surface. But how many of us aware that the later set of measurements were, as the IPCC reported “INCONCLUSIVE”, and that in many cases showed the opposite to what one would expect if GHGs were the cause of global warming ?

A warmer climate allows the atmosphere to sustain more water vapour, which is of course the most potent of the greenhouse gases, representing 95% of greenhouse effects. Some of this water vapour will inevitably condense and fall as additional snow in the polar and mountainous regions, and may contribute to sustaining or thickening ice sheets. The amount of water currently held in the atmosphere is equivalent to about 2.5cms of ocean depth, which represents the total rise in sea level over the past decade.

A most important distinction I think Surely nobody actually doubts global warming, yet there is large contingent, of which I am one, who consider that CO2 may not be the primary driving force behind global warming. Sure there is little doubt that CO2 contributes, along with umpteen other factors, but what's in dispute is whether it is the primary driving force.

Well, although one or two of the Profs interviewed got cold feet when their research funds came under threat, and subsequently selected reverse gear, 95% of the contributors still stand by their comments, and many more have joined their ranks since. For what it's worth, I give far more credence to these eminently qualified guys than to any unqualified wannabe president waving his baton about on stage ! Let’s face it, there is some significant irrefutable evidence included in the movie. And on my favourite subject, the tropospheric anomalies are still unresolved by the IPCC, despite the rejection of earlier erroneous measuring techniques. Their latest report confirms subsequent results remain inconclusive, with no clear evidence of tropospheric warming significantly greater than at the surface, and many tropical results showing the opposite effect. This of course throws into doubt the very suggestion that CO2 is the driving force behind global warming. It also seems, now more scientists pluck up their courage to question and scrutinize their reports, the IPCC comment that their climate models are intended to indicate what COULD happen under circumstances that do NOT currently exist, and should NOT be used for climate forecast purposes.

http://video.google.com/videoplay?docid=4499562022478442170

This is one of the points I've been harping on about. Global warming caused by GHGs results in the troposphere warming significantly faster than the surface. But the IPCC reports they are unable to conclude this is the case, since many measurements show the opposite effect, and none of the measurements show significantly faster warming of the troposphere.

I couldn't have put it better !

Ah yes “swansont”, perhaps I should have added the word “further” to have avoided such an instant dismissal. Let me therefore rephrase it as follows and add the explanation below: "if the Earth is tilted with the North Pole further away from the Sun, as it is when we enter an ice age" As you correctly point out, a normal tilt produces the seasonal effect, however as I’m sure you are aware the Earth circles the Sun in a flat plane. It is as if the spinning Earth is also rolling around the edge of a giant, flat plate, with the Sun in the center. The shape of the Earth’s orbit—the plate—changes from a nearly perfect circle to an oval shape on a 100,000-year cycle (eccentricity). Also, if you drew a line from the plate up through the Earth’s North and South Poles—Earth’s axis—the line would not rise straight up from the plate. Instead the axis is tilted, and the angle of the tilt varies between 22 and 24 degrees every 41,000 years (obliquity). Finally, the Earth wobbles on its axis as it spins. Like the handle of a toy top that wobbles toward you and away from you as the toy winds down, the “handle” of the Earth, the axis, wobbles toward and away from the Sun over the span of 19,000 to 23,000 years (precession). These small variations in Earth-Sun geometry change how much sunlight each hemisphere receives during the Earth’s year-long trek around the Sun, where in the orbit (the time of year) the seasons occur, and how extreme the seasonal changes are. In the early 1900s, a Serbian mathematician named Milutin Milankovitch meticulously calculated the amount of sunlight each latitude received in every phase of Earth’s orbital variations. His work culminated in the 1930 publication of Mathematical Climatology and the Astronomical Theory of Climate Change. He theorized that the ice ages occurred when orbital variations caused the Northern Hemisphere around the latitude of the Hudson Bay and northern Europe to receive less sunshine in the summer. Short, cool summers failed to melt all of the winter’s snow. The snow would slowly accumulate from year to year, and its shiny, white surface would reflect more radiation back into space. Temperatures would drop even further, and eventually, an ice age would be in full swing. Based on the orbital variations, Milankovitch predicted that the ice ages would peak every 100,000 and 41,000 years, with additional “blips” every 19,000 to 23,000 years. Evidence supporting Milankovitch’s theory of the precise timing of the ice ages first came from a series of fossil coral reefs that formed on a shallow ocean bench in the South Pacific during warm interglacial periods. As the ice ages came, more and more water froze into polar ice caps and the ocean levels dropped, leaving the reef exposed. When the ice melted, the ocean rose and warmed, and another reef formed. At the same time, the peninsula on which the reefs formed was steadily being pushed up by the motion of the Earth’s shifting tectonic plates. Today, the reefs form a visible series of steps along the shore of Papua New Guinea. The reefs, the age of which was well-defined because of the decaying uranium in the coral, measured out the millennia between ice ages. They also defined the maximum length of each ice age. The intervals fell exactly where Milankovitch said they would.