A Nuanced View of Global Warming

Monday, February 26, 2007

If you who wonder how (real) climatologists can "deny" that global warming is a foregone conclusion or know someone who does, I think this article will be helpful. Incidentally, it somehow reminded me of the Left's favorite "n-word" (nuanced) from the 2004 presidential campaign, a word which has been replaced by another (Nuremberg) in the completely inappropriate context of an ongoing scientific debate. Isn't it funny how Leftists attack any and all certainty when they want our ear, but feel powerless -- and yet suddenly know everything when they feel strong? If anything shows that Leftists regard philosophical ideas cynically, this shift in attitude is it.

Contrary to popular accounts, very few scientists in the world - possibly none - have a sufficiently thorough, "big picture" understanding of the climate system to be relied upon for a prediction of the magnitude of global warming. To the public, we all might seem like experts, but the vast majority of us work on only a small portion of the problem.

Here, for example, is an insight that even many climate scientists are unaware of: The one atmospheric process that has the greatest control on the Earth's climate is the one we understand the least - precipitation.

Over most of the planet, water is continuously evaporating, humidifying the air to form the Earth's dominant greenhouse gas: water vapor. Climate scientists will tell you that the extra CO2 we are putting in the atmosphere causes a "warming tendency" at the surface, which will evaporate even more water, which will amplify the warming. This positive water vapor feedback, so the theory goes, ends up turning the relative benign direct warming effect of CO2 - only 1 degree of warming late in this century - into a much more serious problem.

But surface evaporation is not what determines how much water vapor, on average, resides in the atmosphere - precipitation systems do. These not only control the water-vapor portion of the greenhouse effect, they directly or indirectly control most of the next most important greenhouse ingredient: clouds.

These systems continuously recycle the Earth's air, and so exert strong controls over the entire climate system. For instance, the rising air in precipitation systems is what causes the sinking, cloudless air over desert areas. Vast oceanic areas of stratus clouds form below a temperature inversion that is also caused by air being forced to sink by precipitation systems, usually thousands of miles away.

So, what does all this have to do with global warming? Unless we know how the greenhouse-limiting properties of precipitation systems change with warming, we don't know how much of our current warmth is due to mankind, and we can't estimate how much future warming there will be, either. To solve the global-warming puzzle, we first need to learn much more about the precipitation-system puzzle.

What little evidence we now have suggests that precipitation systems act as a natural thermostat to reduce warming. For instance, warm, tropical systems are more efficient at converting water vapor to precipitation than their cool high-latitude cousins. Hurricanes are believed to be the most efficient of all.

I believe that negative feedbacks such as this are the only way to explain the relative stability of our climate. Computerized models of our climate have had a habit of "drifting" too warm or too cold. This because they still don't contain all of the temperature-stabilizing processes that exist in nature. In fact, for the amount of solar energy available to it, our climate seems to have a "preferred" average temperature, damping out swings beyond 1 degree or so. [bold added]
There's much more.

I am glad to see so many good articles directed at laymen being put out on global warming. While these will certainly be wasted on most leftists, they do serve a crucial function: They strip away the veneer of scientific respectability this new form of socialism is appropriating for itself. It is this veneer which is being used to sell global warming to otherwise rational adults.

-- CAV

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