Posted on 05/19/2004 9:28:33 AM PDT by Graybeard58
Great! Now the news media have fears over global dimming to exploit. As reported by The Seattle Times, the earth's surface allegedly gets 15 percent less sunlight today than it did in the 1950s. Their methodology is dubious, but researchers say they have measured the decline of solar radiation at hundreds of sites and discerned dimming, a global-warming byproduct that partially counteracts it.
This is fascinating stuff until you realize it's poppycock piled on balderdash. To understand the reason only requires one to know the basics of "the greenhouse effect." It begins when short-wave solar radiation, not impeded by "greenhouse gases," heats the earth's surface, which emits longer-wave thermal energy that is radiated back toward space but absorbed by greenhouse gases. Consequently, the air above the surface warms, but since heat can't escape into space, it has nowhere else to go but down.
The greenhouse effect is a very good thing in moderation because it makes the climate temperate enough to support all manner of life, not all of it intelligent, as evidenced by all the global warmists and dimmists.
Global warming is the greenhouse effect gone wild, but for the theory to work, a dramatic upper atmospheric heating must occur first. Readings taken by satellites and weather balloons over several decades show no change in upper atmospheric temperatures, so whatever surface warming is taking place today is not the result of a runaway greenhouse effect. Many scientists agree the most likely culprit is the sun and its oscillating energy output.
The facts about the greenhouse effect explode the global-dimming theory. Dimmists hold that global warming causes more water evaporation that creates more clouds that block the sun's rays. As a result, the amount of solar energy reaching the ground is diminished. Professor Liepert says two-thirds of global dimming may be traced to the clouds.
In the context of global warming, this is good news because dimming diminishes the warming effect. But clouds are made of water vapor, which is far and away the main greenhouse gas. Since greenhouse gases don't stop short-wave solar radiation and trap longer-wave thermal energy, thicker and more numerous clouds should be contributing to global warming in a big way, and the effect would be showing up in temperature readings the world over.
Venus suffers from extreme global warming (not yet blamed on human civilization) and is covered with clouds. If global dimming is occurring, the cause must be something other than global warming or an increase in cloud cover.
In fairness, however, we must admit we noticed global dimming just yesterday, shortly before nightfall. We trust by the time you read this, global brightening will have set things right.
And Democrats.
Isn't it amazing that all (count them) all climate phenomena these days are evidence of global warming according to the global warmists and dimmists?
Gee whiz, that's like playing poker with marked cards.
Looks like it's time to make a withdrawal from the daylight savings time bank.
http://naturalscience.com/ns/cover/cover5.html
A new European ice age?
Image: NASA/GSFC. The Gulf Stream and North Atlantic Currents. Colors show differences in phytoplankton concentration (blue is cool plankton-rich water, red is warm plankton-poor water).
November 1, 1997: According to a recent paper in Nature, rising atmospheric carbon dioxide concentrations may cause sharp cooling in Western Europe. The study, authored by University of Bern researchers Thomas Stocker and Andreas Schmittner, shows by means of simplified climate models that unabated anthropogenic carbon dioxide emissions may disrupt the thermohaline circulation which transports a billion megawatts of heat (equivalent to the total energy output of a million nuclear power plants) from the Gulf of Mexico via the Gulf Stream to the North Atlantic and Europe.
Warm, salty surface water moves northward along the coast of North America and eastward to the European coast, where it loses heat to westerly onshore winds. As the surface water cools, it becomes more dense, sinks to a depth of about 2 km and flows at a rate of about 10 km per day back across the Atlantic and then southward.
This thermohaline circulation, or ocean overturning, is driven by comparatively small differences in sea water density, which depend on a balance between sea water cooling and salinity fluctuations arising from freshwater input (precipitation and river run-off) in the North Atlantic. A shift in this balance is foreseeable as models of global warming predict heavier precipitation at higher latitudes. The increase could reduce salinity in the North Atlantic enough to weaken or halt the thermohaline circulation.
Stocker and Schmittner's study concludes that the severity of a disruption in thermohaline circulation brought on by global warming will depend on the rate of warming and, hence, on the rate of greenhouse gas emissions. With a well-tested, coupled atmosphere-ocean climate model they show that, at present-day rates of carbon dioxide emission, thermohaline circulation will cease altogether by the time that atmospheric carbon dioxide concentration has doubled (to 750 p.p.m.v.). However, if carbon dioxide concentration increases more slowly, circulation will merely weaken with a doubling of atmospheric carbon dioxide concentration. The limits of climate models prevent exact predictions as it is impossible to include in the model all possible parameters and feedbacks. A particular source of uncertainty is change in precipitation, which is the deciding factor in thermohaline circulation shut-down.
The consequences of a shut-down in the Atlantic Ocean thermohaline circulation are uncertain. Paleoclimatological evidence shows that disruption of the thermohaline circulation has happened before. Deep ocean sediments dating from the last Ice Age (~11,000 year ago), suggest that the fresh water run-off from melting ice masses decreased sea water density sufficiently to cause a breakdown of ocean overturning. What followed was a European winter 10 degrees Celsius below normal and cold spells that lasted for hundreds of years.
Without offsetting effects of global warming, comparable cooling could be expected today with a shut-down in thermohaline circulation. For London, this could mean a climate similar to that now experienced by the Arctic island of Spitzbergen. However, studies that take account of global warming indicate that a halt to Atlantic Ocean overturning would cause only a small region of air cooling somewhere south of Greenland. But whatever the immediate climatic consequences, a slowdown or cessation of Atlantic overturning would reduce oceanic uptake of carbon dioxide. This, in turn, would impact the climate by exacerbating thermohaline instability and raising atmospheric carbon dioxide concentrations.
Despite the uncertainty surrounding climate models and their ability to predict future scenarios accurately, they indicate a range of possible outcomes to present climatological trends and are thus worthy of careful attention. As is evident from palaeoclimatic records, our climate system can be pushed from its present equilibrium state into one much less favourable. In December 1997, delegates from 160 countries will be meeting in Kyoto, Japan for a conference on greenhouse gas emissions. It remains to be seen whether the right course of action will be taken to limit not only the volume of greenhouse gas, but also the speed of change in emission rates.
Ping
This section of the article is incorrect, and the phrase "upper atmosphere" is vague. The most famous analysis of lower troposphere temperatures, performed by John Christy and Roy Spencer, from MSU instrument data, shows a warming of about 0.7 C per decade. This is definitely a warming trend in this atmospheric region, but lower than predicted by climate models. Other groups analyzing the same data have found a larger trend, as much as double. There is currently a controversy brewing due to a new study of the data (which has been criticized strongly by Christy and Spencer) in which the lower troposphere warming was found to be in accordance with model predictions.
The upper atmosphere (stratosphere) is actually cooling due to the combined effects of ozone depletion and greenhouse gas trapping of outgoing longwave radiation nearer to the surface (which is the process known as the greenhouse effect).
"Venus is scorched with a surface temperature of about 482° C (900° F). This high temperature is primarily due to a runaway greenhouse effect caused by the heavy atmosphere of carbon dioxide. Sunlight passes through the atmosphere to heat the surface of the planet. Heat is radiated out, but is trapped by the dense atmosphere and not allowed to escape into space. This makes Venus hotter than Mercury."
Note the "sunlight passes through the atmosphere". Even though Venus is covered with clouds, these clouds don't block incoming solar radiation. Also, the problem with modeling clouds in Earth's climate system is still a problem. There was recent confirmation of positive water vapor feedback, but the confirmation also indicated that the linear humidity model was incorrect, so that the positive feedback is less than what the models had been using.
"There was recent confirmation of positive water vapor feedback, but the confirmation also indicated that the linear humidity model was incorrect, so that the positive feedback is less than what the models had been using."
I thought that models had stopped binging and purging because of that lawsuit against Elle or Glamour, whichever. I think most models now do the low-carb thing which accounts for the increased decolletage' and sweating. parsy.
BTTT!!!!!!!
This is funny since it it the EviroWakos who want to put us in to the DARK AGES! So it is a good thing...right?
International Dark-Sky Association
"IDA's goals are to be effective in stopping the adverse environmental impact on dark skies by building awareness of the problem of light pollution..."
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