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Title: Global Warming Theory in a Nutshell -- Separating Science Fom Bullshit
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URL Source: http://www.drroyspencer.com/global-warming-101/
Published: Feb 5, 2011
Author: Roy W. Spencer, Ph. D
Post Date: 2011-02-05 09:10:50 by no gnu taxes
Keywords: None
Views: 47917
Comments: 66
Every scientific theory involves assumptions. Global warming theory starts with the assumption that the Earth naturally maintains a constant average temperature, which is the result of a balance between (1) the amount of sunlight the Earth absorbs, and (2) the amount of emitted infrared (“IR”) radiation that the Earth continuously emits to outer space. In other words, energy in equals energy out. Averaged over the whole planet for 1 year, those energy flows in and out of the climate system are estimated to be around 235 or 240 watts per square meter. Greenhouse components in the atmosphere (mostly water vapor, clouds, carbon dioxide, and methane) exert strong controls over how fast the Earth loses IR energy to outer space. Mankind’s burning of fossil fuels creates more atmospheric carbon dioxide. As we add more CO2, more infrared energy is trapped, strengthing the Earth’s greenhouse effect. This causes a warming tendency in the lower atmosphere and at the surface. As of 2008, it is believed that we have enhanced the Earth’s natural greenhouse effect by about 1%. Global warming theory says that the lower atmosphere must then respond to this energy imbalance (less IR radiation being lost than solar energy being absorbed) by causing an increase in temperature (which causes an increase in the IR escaping to space) until the emitted IR radiation once again equals the amount of absorbed sunlight. That is, the Earth must increase its temperature until global energy balance is once again restored. This is the basic explanation of global warming theory. (The same energy balance concept applies to a pot of water on a stove set on “low”. The water warms until the rate of energy loss through evaporation, convective air currents, and infrared radiation equals the rate of energy gain from the stove, at which point the water remains at a constant temperature. If you turn the heat up a tiny bit more, the temperature of the water will rise again until the extra amount of energy lost by the pot once again equals the energy gained from the stove, at which point a new, warmer equilibrium temperature is reached.) Now, you might be surprised to learn that the amount of warming directly caused by the extra CO2 is, by itself, relatively weak. It has been calculated theoretically that, if there are no other changes in the climate system, a doubling of the atmospheric CO2 concentration would cause less than 1 deg C of surface warming (about 1 deg. F). This is NOT a controversial statement…it is well understood by climate scientists. (As of 2008, we were about 40% to 45% of the way toward a doubling of atmospheric CO2.) BUT…everything this else in the climate system probably WON’T stay the same! For instance, clouds, water vapor, and precipitation systems can all be expected to respond to the warming tendency in some way, which could either amplify or reduce the manmade warming. These other changes are called “feedbacks,” and the sum of all the feedbacks in the climate system determines what is called ‘climate sensitivity’. Negative feedbacks (low climate sensitivity) would mean that manmade global warming might not even be measurable, lost in the noise of natural climate variability. But if feedbacks are sufficiently positive (high climate sensitivity), then manmade global warming could be catastrophic. Obviously, knowing the strength of feedbacks in the climate system is critical; this is the subject of most of my research. Here you can read about my latest work on the subject, in which I show that feedbacks previously estimated from satellite observations of natural climate variability have potentially large errors. A confusion between forcing and feedback (loosely speaking, cause and effect) when observing cloud behavior has led to the illusion of a sensitive climate system, when in fact our best satellite observations (when carefully and properly interpreted) suggest an IN-sensitive climate system. Finally, if the climate system is insensitive, this means that the extra carbon dioxide we pump into the atmosphere is not enough to cause the observed warming over the last 100 years — some natural mechanism must be involved. Here you can read about my favorite candidate: the Pacific Decadal Oscillation.
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#10. To: no gnu taxes, war, go65 (#0)
(Edited)
Go google Milankovitch Cycles. There are 26,000 year, 41,000 year, 95,000 year, 125,000 year and 413,000 cycles in the earth's axis procession, axis tilt, and orbital shape that are probably the cause of the earth's climate cycles. Yes, we are still in an ice, but in an inter-glacial period. The earth has been warming for 12,500 years, except for a 200 year cooling period that ended around 1800. For millions of years there wasn't any ice at the poles. Some warming would be better than some cooling because of food supplies. Something I just learned -- there is only 10% of the bio-diversity at the 45th parallel than there is at the equator. Life on earth likes hot weather.
you are talking about cycles that occur over thousands of years, i'm talking about rapid warming over 40 years, something the earth has never seen before. You have to also deny that CO2 is increasing and the CO2 is a greenhouse gas.
Misery solved: How we measured temperatures...
Another absolutely false argument. Historical temps are based on various reconstructions that are all consistent in their findings. Current temps are measured via land, sea, and satellite sensors that again, are consistent in their findings.
#14. To: go65 (#13)
United States and Global Data Integrity Issues The United States and global data bases have serious problems that render them highly questionable for determining accurate long term temperature trends. Especially since most of the issues mentioned produces a warm bias in the data. As shown here, though there has clearly been some cyclical warming in recent decades (most notably 1979 to 1998), the global surface station based data is seriously compromised by urbanization and other local factors (land-use/land- cover, improper siting, station dropout, instrument changes unaccounted for, and missing data) and uncertainties in ocean temperatures. Thus the data bases can’t be relied on to determine accurate trends. These factors all lead to overestimation of temperatures. Numerous peer-reviewed papers (referenced below in bold) in the last several years have shown this overestimation is the order of 30 to 50% from these issues alone.
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#11. To: jwpegler (#10)
Go google Milankovitch Cycles. There are 26,000 year, 41,000 year, 95,000 year, 125,000 year and 413,000 cycles in the earth's axis procession, axis tilt, and orbital shape that are probably the cause of the earth's climate cycles.
#12. To: go65 (#11)
i'm talking about rapid warming over 40 years
Yesterday And today 
#13. To: jwpegler (#12)
How we measured temperatures... Yesterday And today
Replies to Comment # 13. Current temps are measured via land, sea, and satellite sensors
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