The question of how much warming will result from adding carbon dioxide to the atmosphere is what we skeptics are skeptical of. The climate system is amazingly complex, and the IPCC position that elements within the climate system (especially clouds) will change in ways which amplify the resulting small warming tendency is highly questionable, to say the least. If the climate system instead acts to reduce the warming, then anthropogenic global warming (AGW) becomes for all practical purposes a non-issue.
This represents what I believe to be the simplest description of how greenhouse gases cause warming of the surface. It bypasses all of the esoteric discussions and instead deals only with observations, which I believe cannot be easily explained any other way:
FIRST, warming can be caused by a decrease in the rate of energy loss by the climate system (or any other system, for that matter).
SECOND, IR absorbing gases are observed from satellites to reduce the rate of energy loss to space.
THEREFORE, adding more IR absorbing gases will cause a warming tendency.
QED.
Again I emphasize, however, the above simple argument is necessarily true only to the extent that all other elements of the climate system remain the same, which they will not. These other changes are called ‘feedbacks’, and they can either make or break theories of global warming and associated climate change.
Slaying the Slayers with the Alabama Two-Step « Roy Spencer, Ph. D.
for konradv. you are both right and wrong with your simplistic view that CO2 runs the climate. the effect is real, the positive feedbacks are not. no positive feedback, no problem.
ever wonder why ocean water never exceeds 31C and is seldom above 29C? different pathways are expanded or contracted depending on how much energy is available to power them. and the natural order of things is to reduce the impact of disturbance to the system. negative feedback. homeostasis.
the climate models are rough projections of what may happen given the few parameters that are fed into them. slight changes in how clouds (or a host of other things) can radically change the outcome of those results. the feddbacks of the IPCC climate models are obviously only as good as the information and programing put into them. I think the real climate system acts to dampen the effect of extra CO2 as it does with many other things. obviously other disagree with me. but we shall see.
Don't you think that you've embarrassed yourself enough quoting someone like Roy Spencer?
Roy Spencer - SourceWatch
To account for warming Spencer's favored alternative theory is that it's due to the Pacific Decadal Oscillation; yet the PDO shows no [long-term] trend, and therefore...is not responsible for the trend of global warming.
Scientifically, the crucial point in Spencer's position is that of climate sensitivity. Spencer suggests in his blog that climate sensitivity may be low, due to mainstream climate scientists underestimating clouds, and he claims that satellite data will support him.
Rebuttal
"Roy Spencer has come up with yet another “silver bullet” to show that climate sensitivity is lower than IPCC estimates. I.e., he fits a simple 1-box climate model to the net flux of heat into the upper 700 m of the ocean, and infers a climate sensitivity of only about 1 °C (2x CO2). There are several flaws in his methods–inconsistent initial conditions, failure to use the appropriate data, and failure to account for ocean heating deeper than 700 m. (He fixed the last one in an update.) All of these flaws pushed his model to produce a lower climate sensitivity estimate. When the flaws are corrected, the model estimates climate sensitivities of at least 3 °C, which is the IPCC’s central estimate. ... while Spencer’s latest effort doesn’t really do any damage to the consensus position, it turns out that it does directly contradict the work he promoted in The Great Global Warming Blunder."
Dude, you are embarrassing yourself.
