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| 7/15 |
| 2006/11/9-10 [Science/GlobalWarming] UID:45299 Activity:nil |
11/9 Can someone explain the Stefan-Boltzmann law in reasonably plain
English? I don't know enough physics to understand the wikipedia
articles well enough to understand. Something about the amount of
energy an object radiates over time? Thanks.
\_ Wikipedia seems pretty clear: "The Stefan-Boltzmann law states that
the total energy radiated per unit surface area of a black body in
unit time is proportional to the fourth power of the black body's
temperature". Did you not understand part of that, or did you want
more detail? (Do you know what a black body is?)
\_ What is the fourth power of the bb's temp? Do they literally
mean temp^4? I can use a better idea of what a bb is, too, but
\_ yes.
\_ ah, thanks.
\_ Note that temp is in kelvins.
\_ LOL. I like the idea that blackbody radiation
is zero at 32 F. That would be a funny
universe.
I have the general idea.
\_ Real objects absorb some of the light that hits them (raising
their temperature), reflect some, and let some through. They
also radiate light, which lowers their temperature. Unless
the object is changing temperature, the amount of light it
radiates must be equal to the amount it absorbs (Kirchhoff's
law). Some objects reflect or transmit a lot of light, and
thus absorb and radiate very little; some are the opposite.
The limit where an object absorbs *everything* that hits it
(and therefore radiates as much as theoretically possible)
is called a black body.
\_ Thanks. That's a great explanation. Much appreciated.
\_ What is this for, exactly?
\_ I read http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/05/nosplit/nwarm05.xml
which has a link to more details at http://www.telegraph.co.uk/news/graphics/2006/11/05/warm-refs.pdf;jsessionid=EL4ZGZEGE0A4LQFIQMGCFF4AVCBQUIV0
\_ I read http://preview.tinyurl.com/yc4jtf (telegraph.co.uk)
which has a link to more details at
link:preview.tinyurl.com/y4cha4 (telegraph.co.uk)
and there's an entire chunk I can't understand without
knowing what S-B is talking about.
\_ If you really want to get into this in more detail, I
reccomend the book "Endoreversible Thermodynamics of
Solar Energy Conversion", by Alexis de Vos, which has
a really nice thermodynamic introduction at the
beginning laying out where the SB law comes from.
The fourth power comes from the fact that this is a
thee dimensional law. While this may sound like wankery,
the zero dimensional blackbody describes the thermal
radiation from a resistor in a circuit(Johnson Noise),
and that's linear in temperature.
http://csua.org/u/hf9
\_ Ok, this all makes a lot more sense now, thanks. |
| 7/15 |
|
| www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/05/nosplit/nwarm05.xml The Stern report last week predicted dire economic and social effects of unchecked global warming. In what many will see as a highly controversial polemic, Christopher Monckton disputes the 'facts' of this impending apocalypse and accuses the UN and its scientists of distorting the truth Biblical droughts, floods, plagues and extinctions? Last week, Gordon Brown and his chief economist both said global warming was the worst "market failure" ever. That loaded soundbite suggests that the "climate-change" scare is less about saving the planet than, in Jacques Chirac's chilling phrase, "creating world government". This week and next, I'll reveal how politicians, scientists and bureaucrats contrived a threat of Biblical floods, droughts, plagues, and extinctions worthier of St John the Divine than of science. Sir Nicholas Stern's report on the economics of climate change, which was published last week, says that the debate is over. There are more greenhouse gases in the air than there were, so the world should warm a bit, but that's as far as the "consensus" goes. After the recent hysteria, you may not find the truth easy to believe. The Royal Society says there's a worldwide scientific consensus. It brands Apocalypse-deniers as paid lackeys of coal and oil corporations. I declare my interest: I once took the taxpayer's shilling and advised Margaret Thatcher, FRS, on scientific scams and scares. In 1988, James Hansen, a climatologist, told the US Congress that temperature would rise 03C by the end of the century (it rose 01C), and that sea level would rise several feet (no, one inch). The UN set up a transnational bureaucracy, the Intergovernmental Panel on Climate Change (IPCC). The UK taxpayer unwittingly meets the entire cost of its scientific team, which, in 2001, produced the Third Assessment Report, a Bible-length document presenting apocalyptic conclusions well beyond previous reports. advertisement This week, I'll show how the UN undervalued the sun's effects on historical and contemporary climate, slashed the natural greenhouse effect, overstated the past century's temperature increase, repealed a fundamental law of physics and tripled the man-made greenhouse effect. Next week, I'll demonstrate the atrocious economic, political and environmental cost of the high-tax, zero-freedom, bureaucratic centralism implicit in Stern's report; I'll compare the global-warming scare with previous sci-fi alarums; and I'll show how the environmentalists' "precautionary principle" (get the state to interfere now, just in case) is killing people. First, the UN implies that carbon dioxide ended the last four ice ages. It displays two 450,000-year graphs: a sawtooth curve of temperature and a sawtooth of airborne CO2 that's scaled to look similar. Usually, similar curves are superimposed for comparison. If it had, the truth would have shown: the changes in temperature preceded the changes in CO2 levels. Next, the UN abolished the medieval warm period (the global warming at the end of the First Millennium AD). In 1995, David Deming, a geoscientist at the University of Oklahoma, had written an article reconstructing 150 years of North American temperatures from borehole data. He later wrote: "With the publication of the article in Science, I gained significant credibility in the community of scientists working on climate change. They thought I was one of them, someone who would pervert science in the service of social and political causes. The UN's second assessment report, in 1996, showed a 1,000-year graph demonstrating that temperature in the Middle Ages was warmer than today. But the 2001 report contained a new graph showing no medieval warm period. It wrongly concluded that the 20th century was the warmest for 1,000 years. The wrongly flat AD1000-AD1900 temperature line was the shaft: the uptick from 1900 to 2000 was the blade. Here's how they did it: They gave one technique for reconstructing pre-thermometer temperature 390 times more weight than any other (but didn't say so). The technique they overweighted was one which the UN's 1996 report had said was unsafe: measurement of tree-rings from bristlecone pines. Tree-rings are wider in warmer years, but pine-rings are also wider when there's more carbon dioxide in the air: it's plant food. This carbon dioxide fertilisation distorts the calculations. They said they had included 24 data sets going back to 1400. Without saying so, they left out the set showing the medieval warm period, tucking it into a folder marked "Censored Data". They used a computer model to draw the graph from the data, but scientists later found that the model almost always drew hockey-sticks even if they fed in random, electronic "red noise". The large, full-colour "hockey-stick" was the key graph in the UN's 2001 report, and the only one to appear six times. Four years passed before a leading scientific journal would publish the truth about the graph. Even after the "hockey stick" graph was exposed, scientific papers apparently confirming its abolition of the medieval warm period appeared. The US Senate asked independent statisticians to investigate. They found that the graph was meretricious, and that known associates of the scientists who had compiled it had written many of the papers supporting its conclusion. The UN, echoed by Stern, says the graph isn't important. Scores of scientific papers show that the medieval warm period was real, global and up to 3C warmer than now. Then, there were no glaciers in the tropical Andes: today they're there. There were Viking farms in Greenland: now they're under permafrost. There was little ice at the North Pole: a Chinese naval squadron sailed right round the Arctic in 1421 and found none. The Antarctic, which holds 90 per cent of the world's ice and nearly all its 160,000 glaciers, has cooled and gained ice-mass in the past 30 years, reversing a 6,000-year melting trend. Data from 6,000 boreholes worldwide show global temperatures were higher in the Middle Ages than now. And the snows of Kilimanjaro are vanishing not because summit temperature is rising (it isn't) but because post-colonial deforestation has dried the air. In some places it was also warmer than now in the Bronze Age and in Roman times. So the UN adjusted the maths and all but extinguished the sun's role in today's warming. Here's how: The UN dated its list of "forcings" (influences on temperature) from 1750, when the sun, and consequently air temperature, was almost as warm as now. But its start-date for the increase in world temperature was 1900, when the sun, and temperature, were much cooler. Every "forcing" produces "climate feedbacks" making temperature rise faster. For instance, as temperature rises in response to a forcing, the air carries more water vapour, the most important greenhouse gas; The UN more than doubled the base forcings from greenhouse gases to allow for climate feedbacks. Two centuries ago, the astronomer William Herschel was reading Adam Smith's Wealth of Nations when he noticed that quoted grain prices fell when the number of sunspots rose. At solar maxima, when the sun was at its hottest and sunspots showed, temperature was warmer, grain grew faster and prices fell. Such observations show that even small solar changes affect climate detectably. Sami Solanki, a solar physicist, says that in the past half-century the sun has been warmer, for longer, than at any time in at least the past 11,400 years, contributing a base forcing equivalent to a quarter of the past century's warming. The UN expresses its heat-energy forcings in watts per square metre per second. It estimates that the sun caused just 03 watts of forcing since 1750. Begin in 1900 to match the temperature start-date, and the base solar forcing more than doubles to 07 watts. Multiply by 27, which the Royal Society suggests is the UN's current factor for climate feedbacks, and you get 19 watts - more than six times the UN's figure. The entire 20th-century warming from all sources was below 2 watts. Next, the UN slashed the natural greenhouse effect by 40 per cent from 33C in the climate-physics textbooks to 20C, making the man-mad... |
| preview.tinyurl.com/yc4jtf -> www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/05/nosplit/nwarm05.xml The Stern report last week predicted dire economic and social effects of unchecked global warming. In what many will see as a highly controversial polemic, Christopher Monckton disputes the 'facts' of this impending apocalypse and accuses the UN and its scientists of distorting the truth Biblical droughts, floods, plagues and extinctions? Last week, Gordon Brown and his chief economist both said global warming was the worst "market failure" ever. That loaded soundbite suggests that the "climate-change" scare is less about saving the planet than, in Jacques Chirac's chilling phrase, "creating world government". This week and next, I'll reveal how politicians, scientists and bureaucrats contrived a threat of Biblical floods, droughts, plagues, and extinctions worthier of St John the Divine than of science. Sir Nicholas Stern's report on the economics of climate change, which was published last week, says that the debate is over. There are more greenhouse gases in the air than there were, so the world should warm a bit, but that's as far as the "consensus" goes. After the recent hysteria, you may not find the truth easy to believe. The Royal Society says there's a worldwide scientific consensus. It brands Apocalypse-deniers as paid lackeys of coal and oil corporations. I declare my interest: I once took the taxpayer's shilling and advised Margaret Thatcher, FRS, on scientific scams and scares. In 1988, James Hansen, a climatologist, told the US Congress that temperature would rise 03C by the end of the century (it rose 01C), and that sea level would rise several feet (no, one inch). The UN set up a transnational bureaucracy, the Intergovernmental Panel on Climate Change (IPCC). The UK taxpayer unwittingly meets the entire cost of its scientific team, which, in 2001, produced the Third Assessment Report, a Bible-length document presenting apocalyptic conclusions well beyond previous reports. advertisement This week, I'll show how the UN undervalued the sun's effects on historical and contemporary climate, slashed the natural greenhouse effect, overstated the past century's temperature increase, repealed a fundamental law of physics and tripled the man-made greenhouse effect. Next week, I'll demonstrate the atrocious economic, political and environmental cost of the high-tax, zero-freedom, bureaucratic centralism implicit in Stern's report; I'll compare the global-warming scare with previous sci-fi alarums; and I'll show how the environmentalists' "precautionary principle" (get the state to interfere now, just in case) is killing people. First, the UN implies that carbon dioxide ended the last four ice ages. It displays two 450,000-year graphs: a sawtooth curve of temperature and a sawtooth of airborne CO2 that's scaled to look similar. Usually, similar curves are superimposed for comparison. If it had, the truth would have shown: the changes in temperature preceded the changes in CO2 levels. Next, the UN abolished the medieval warm period (the global warming at the end of the First Millennium AD). In 1995, David Deming, a geoscientist at the University of Oklahoma, had written an article reconstructing 150 years of North American temperatures from borehole data. He later wrote: "With the publication of the article in Science, I gained significant credibility in the community of scientists working on climate change. They thought I was one of them, someone who would pervert science in the service of social and political causes. The UN's second assessment report, in 1996, showed a 1,000-year graph demonstrating that temperature in the Middle Ages was warmer than today. But the 2001 report contained a new graph showing no medieval warm period. It wrongly concluded that the 20th century was the warmest for 1,000 years. The wrongly flat AD1000-AD1900 temperature line was the shaft: the uptick from 1900 to 2000 was the blade. Here's how they did it: They gave one technique for reconstructing pre-thermometer temperature 390 times more weight than any other (but didn't say so). The technique they overweighted was one which the UN's 1996 report had said was unsafe: measurement of tree-rings from bristlecone pines. Tree-rings are wider in warmer years, but pine-rings are also wider when there's more carbon dioxide in the air: it's plant food. This carbon dioxide fertilisation distorts the calculations. They said they had included 24 data sets going back to 1400. Without saying so, they left out the set showing the medieval warm period, tucking it into a folder marked "Censored Data". They used a computer model to draw the graph from the data, but scientists later found that the model almost always drew hockey-sticks even if they fed in random, electronic "red noise". The large, full-colour "hockey-stick" was the key graph in the UN's 2001 report, and the only one to appear six times. Four years passed before a leading scientific journal would publish the truth about the graph. Even after the "hockey stick" graph was exposed, scientific papers apparently confirming its abolition of the medieval warm period appeared. The US Senate asked independent statisticians to investigate. They found that the graph was meretricious, and that known associates of the scientists who had compiled it had written many of the papers supporting its conclusion. The UN, echoed by Stern, says the graph isn't important. Scores of scientific papers show that the medieval warm period was real, global and up to 3C warmer than now. Then, there were no glaciers in the tropical Andes: today they're there. There were Viking farms in Greenland: now they're under permafrost. There was little ice at the North Pole: a Chinese naval squadron sailed right round the Arctic in 1421 and found none. The Antarctic, which holds 90 per cent of the world's ice and nearly all its 160,000 glaciers, has cooled and gained ice-mass in the past 30 years, reversing a 6,000-year melting trend. Data from 6,000 boreholes worldwide show global temperatures were higher in the Middle Ages than now. And the snows of Kilimanjaro are vanishing not because summit temperature is rising (it isn't) but because post-colonial deforestation has dried the air. In some places it was also warmer than now in the Bronze Age and in Roman times. So the UN adjusted the maths and all but extinguished the sun's role in today's warming. Here's how: The UN dated its list of "forcings" (influences on temperature) from 1750, when the sun, and consequently air temperature, was almost as warm as now. But its start-date for the increase in world temperature was 1900, when the sun, and temperature, were much cooler. Every "forcing" produces "climate feedbacks" making temperature rise faster. For instance, as temperature rises in response to a forcing, the air carries more water vapour, the most important greenhouse gas; The UN more than doubled the base forcings from greenhouse gases to allow for climate feedbacks. Two centuries ago, the astronomer William Herschel was reading Adam Smith's Wealth of Nations when he noticed that quoted grain prices fell when the number of sunspots rose. At solar maxima, when the sun was at its hottest and sunspots showed, temperature was warmer, grain grew faster and prices fell. Such observations show that even small solar changes affect climate detectably. Sami Solanki, a solar physicist, says that in the past half-century the sun has been warmer, for longer, than at any time in at least the past 11,400 years, contributing a base forcing equivalent to a quarter of the past century's warming. The UN expresses its heat-energy forcings in watts per square metre per second. It estimates that the sun caused just 03 watts of forcing since 1750. Begin in 1900 to match the temperature start-date, and the base solar forcing more than doubles to 07 watts. Multiply by 27, which the Royal Society suggests is the UN's current factor for climate feedbacks, and you get 19 watts - more than six times the UN's figure. The entire 20th-century warming from all sources was below 2 watts. Next, the UN slashed the natural greenhouse effect by 40 per cent from 33C in the climate-physics textbooks to 20C, making the man-mad... |
| csua.org/u/hf9 -> melvyl.cdlib.org/F/J18RG16PQEJKUIJR6B13PL6F4I1IHIV41JA1RJTRM9YCK6JC9F-09224?func=full-set-set&set_number=020973&set_entry=000001&format=999 Title Endoreversible thermodynamics of solar energy conversion / Alexis de Vos ; |