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RE: Nuclear Power Des NOT Need Gobal Warming Hoax!
Ruth Weiner wrote:
-----Original Message-----
From: owner-radsafe@list.vanderbilt.edu on behalf of RuthWeiner@AOL.COM
Sent: Tue 6/1/2004 1:26 PM
To: "John Fleck"; radsafe@list.vanderbilt.edu
Subject: Re: Nuclear Power Des NOT Need Gobal Warming Hoax!
Any model is only as credible as its input and the assumptions made in putting it together. In other words, a model never "tells you" anything that you didn't tell it first. Sometimes the data we put in are confirmed, and sometimes they are educated guesses. There are really only two sources of modeling assumptions: historical trends and the basic equations of physics and chemistry. For global climate change predictions, we depend heavily on the first of these.
Examples of modeled predictions that proved incorrect:
(1) In the years immediately after WWII, electric energy use in the United States increased about 7% per year, and the increase was pretty much linear, so utilities planned construction on that basis. However, by 1968, the annual increase was a little less than 3%/year and has stayed there ever since.
(2) Weather is predicted with about 65% accuracy on the average, in spite of reams and reams of good data.
(3) When I was a professor at WWU (1974-1993), we were consistently unable to predict the size of the entering freshman class to better than +/- 25%, in spite of the fact that Western had been a university since 1964.
We can now measure partial pressure of CO2 in the air pretty accurately. We can also measure temperature from satellite data. However, our models take past trends and project them into the future, with all the uncertainty that implies.
Ruth
--
Ruth F. Weiner
ruthweiner@aol.com
505-856-5011
(o)505-284-8406
==================
Contrary to Ruth's belief, climate models (usually called general circulation models) are almost entirely physical and chemical first principles. Some phenomena are too poorly understood or occur on a scale too small for the model resolution for strict first principles modeling. In those cases the physics and chemistry and/or large scale behavior of the phenomenon are parametrized and historical data is used to determine best-fit values of the parameters. Examples of such phenomena are aerosol behavior, cloud feedbacks, and a number of others. GCMs certainly have uncertainties that need to be understood in interpreting projections of future behavior, but those uncertainties arise from the model dynamics and parameter uncertainties and not because past trends are being projected into the future.
My memory of the history of mis-prediction of electrical demand is a bit different from Ruth's and because of it personal impact on me, I suspect better than hers. When I entered a nuclear engineering program in September 1973, utility managers had, almost universally, the quaint belief that the demand for electricity was inelastic. They believed that if the price went up the demand would be unaffected. In October 1973, the Yom Kippur war and the Arab Oil Embargo tripled or quadrupled the price of fossil fuels in the U.S. and uranium sellers thought that was a nice idea and followed the market up. It turned out that electricity demand was elastic. Demand growth projections dropped precipitously and within a few months US utilities had cancelled dozens of nuclear plants on order and some already under construction. When I finished to program, prospects for nuclear engineers were not nearly as golden as they were when I started.
My experience with short-term weather prediction is better than Ruth's, but I do live in a region that has climate rather than weather.
Best regards.
Jim Dukelow
Pacific Northwest National Laboratory
Richland, WA
jim.dukelow@pnl.gov
These comments are mine and have not been reviewed and/or approved by my management or by the U.S. Department of Energy.
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