Friday, May 1, 2009

Part 4 of Debunking the Silliness of Global Warming Skeptics

Critique of continued...

The above referenced site seems to be a perfect example of advocacy over science - the author is guilty of every sin he accuses the opposition (using outdated and sloppy research, failing to understand science and the scientific method, confusing theory with fact and giving huge amounts of credence to research that agrees with his position and completely ignoring research that disagrees with it, etc.). I've found this pattern many times in looking at the skeptical arguments - their accusations of bias tend to apply more to their own positions and arguments than to those they accuse.

Picking up from where I left off...

"Confounding Variables"

I'm not going to debunk each of the entries in this section because there is no corroborating information to explain why these are reasons to doubt the AGW theory. But I will point out the following:

1) the reason "irrigation" is not mentioned in the science of AGW is that it has NOTHING TO DO WITH GLOBAL WARMING! The AGW theory does incorporate land use, which includes a variety of topics (most notable is deforestation), but irrigation barely makes the list. Mr. Transtronics makes some weak references here to water vapor (which is related to global warming), but there's no real science referenced, so there is nothing to indicate what irrigation (or any of these other variables) should be relevant to the scientific study of climate change.

2) the reference to "space weather" is the same reference I debunked previously - the outdated and discredited Friis-Christiansen-Lassen report of 1991.

3) "changes in volcanic eruptions" is part of AGW theory - in fact, it is the most cited variable in forecasting warming trends. Every climatologist recognizes that increased volcanic eruptions will increase the aerosols that block sunlight and decrease global temperatures, so if there were suddenly a series of volcanic eruptions, the global temperatures would go down, but only temporarily (3 to 5 years). This is a well known and accounted for variable, although it is obviously hard to predict.

4) most of the rest of these "confounding variables" (ozone, CO2 absorption, methane emissions, etc.) are well known and accounted for in the body of science around AGW. But these variables alone don't explain or affect the main drivers of AGW - namely increased CO2 and increasing temperatures. These are all examples of the complexity of climate science, not its "unknowablility".

"What would Richard Feynman say about Global warming?"

This section is more drivel, but it does prove one thing - the author has a glaring misunderstanding of science and climatology as evidenced by his attempt to draw parallels between "changing weather" and "climate change". This is so ignorant it is laughable. By way of example, the difference between predicting the weather and predicting climate change is the same as the difference between predicting the roll of the dice and predicting the casino's house odds. Of course it is difficult to predict the weather because you're trying to determine how the precise behavior of a chaotic system will affect a specific area or location, just like trying to predict the precise outcome of a chaotic roll of the dice. The most you can come up with is degrees of probability. But predicting climate is predicting aggregate behavior over broad areas and longer time frames and it is actually quite straightforward - it is a series of averages of averages, like predicting the house odds at a casino. On any given night, the casino might lose - but over time, its return is fairly easy to predict "scientifically". Granted, climatology is far more complex than the mathematical odds in a casino, so it cannot be predicted with the precision of casino gaming, but the analogy still holds. And Mr. Transtronics is an idiot.

"Correlation does not show cause and effect - Limitations on what is knowable"

This section is at least a little more coherent. He is right that a correlation does not prove anything and if the AGW theory were based solely on correlations, it would be drivel too. Correlations are hints at a cause and effect, not proof. And when researching the true cause and effect, correlations can help weed out good and bad hypothesis. For example, a correlation between pirates and global temperatures is meaningless unless there is something about a pirate that might affect global temperatures, in which case you'd want to study that something to see if it was indeed causing global temperatures to rise. Such is the case with CO2, so point taken. However, his point about "what we can know is quite limited" is more drivel. The carbon cycle is understood quite well and what we don't know we can research and learn more. And the point about CO2 levels lagging temperature and not leading is also well known and explained.

"Why is Water Vapor Swept Under the Rug?"

Next, Mr. Transtronics takes us through water vapor and how it is "swept under the rug" (which is really ironic, because this is one of the only sections where he points to an external scientific reference and it is the portion of the 2001 IPCC reports where the role of water vapor is discussed! Who's sweeping what under what rug?). Nonetheless, he is correct that water vapor is the most dominant greenhouse gas and that it has significant affect on global temperatures. What he's missing is the difference between a forcing variable and a feedback (which is discussed in the RealClimate entry above on temperature-CO2 lags in the ice core records). The thermal properties of water vapor are very different than CO2 - water has a thermodynamic equilibrium with temperature such that increases in vapor without a corresponding increase in temperature just cause increased precipitation to bring the level of water vapor back in equilibrium with temperature. Therefore, water vapor is a positive feedback to global warming, not a cause (as temperatures rise, so does the ability of the atmosphere to hold water vapor, which in turn increases temperature). In fact, on its own, the physical properties of CO2 are such that a doubling of CO2 in the atmosphere (independent of other forcings and feedbacks) would create about 1 degree Celsius of warming, but with water vapor feedback and other feedbacks (like the loss of albedo effect due to decreased surface ice), the warming effect of CO2 is doubled or even tripled (there has been much scientific debate about this, but the prevailing consensus is still that the combined forcing-feedback affect of CO2 is more like 3-4 degrees Celsius). So water vapor is not "swept under the rug" at all - it's just that its physical properties make it a feedback, not a forcing variable .


Here's another perfect example as to how Mr. Transtronics is so clueless. He has hit on the single greatest uncertainty in all the existing climate models and rather than explore it in depth, it is one of the shortest sections in his whole diatribe. The uncertainty over clouds can affect the projections of global warming as much as 2 degrees (which is huge), but he barely mentions it.

more to come later...

1 comment:

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