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Correlation Vs. Causation...
Posted by Joe Johnson at 03/09/2001 11:27 AM EST
Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.
In Reply to: You Go, Patrick
Posted by Dodd Stacy on 03/09/2001 1:21 AM EST:
Global warming is a very big topic and I am not sure that I can stop myself once I get going.
I am not going to comment line by line to either Dodd or Patrick's messages, but I have to comment on the correlation vs. causation.
Causation is a VERY tough thing to prove. Believe it or not, even the link between cancer and smoking (something that nearly all folks take for unshakeable fact) was EXTREMELY difficult to prove.
Showing a correlation was easy. Showing that it was the smoking and not some other aspect of the lifestyle of the smoking population (e.g. folks who smoke are less well educated, on average, drink more, eat higher fat content diets, work in riskier jobs, live in different environments, etc. than non-smokers -- it might have been the case that these other things were causing cancer) was very tricky business and took a long time and a lot of good science.
Here is my approach to Global Warming:
1) It has yet to be proven to sufficient certainty, imho.
2) Once the effect has been proven, it is far from certain to be the man-made.
3) Without regard to its cause, mankind will have to decide what the result of it will be. Again, in my opinion, this is far from a settled matter.
My Ph.D. involved computer modeling of nonlinear differential equations (and chaos theory, thrown in just to bamboozle my graduate board enough to get them to sign my thesis ;-) Anyway, if my doctoral research taught me anything it was how computer models can be easily manipulated to give wildly different results. Very simple terms included or left out of a system of equations lead to vastly different steady state solutions.
I don't claim overt fixing by the computer modelers, but, as in all things, when the results of the model yield what you want, you consider yourself done. If the models give an answer that is unwanted or unexpected, you check hard trying to find problems or things you have left out. It is only human nature. Add to this the fact that funding tends to flow to researchers that make dire predictions not those that predict the sun will rise tomorrow just as it has a few billion time before. But I digress...
4) Having decided that Global Warming is real and that its effects are worth doing something to prevent or reduce, the question is what should we do?
One of my favorite questions to ask the promoters of taking drastic measures because the results MIGHT be drastic is: Would you advocate taking the same actions if it was certain that man had nothing to do with the cause? It is a significant question and one that many have difficulty answering consistently with other ideals they hold about the environment and man's place in it. But again, I digress...
5) In my view, the Kyoto agreement skipped the steps 1, 2 and 3 and raced right to answering #4 with the answer, "Well, we have to do SOMETHING -- even if it might not be needed and, assuming it is needed, it is not anywhere near enough to make a difference anyway."
Even so, Kyoto is going to be very painful to the developed world. I am very serious. Kyoto does not really address the problem. Much more significant changes in lifestyle are going to be needed if we are serious about addressing Global Warming by simply reducing CO2 emissions. In fact, I am quite sure that there will be rioting in the streets of the developed world before we will ever get anywhere close to the reductions needed to stop Global Warming (assuming the models are correct).
Here is my bottom bottom line:
Assuming it is real and that we want to prevent it, there is no reason to implement a 10% solution that is very painful today when a serious solution will have to be found that will address 100% of the problem over the next 10 or 20 or 50 years.
We can do it, if it is needed and if we are serious about finding a 100% solution.
Joseph Michael Johnson, Ph.D., P.E.
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