Global warming.

I thoroughly enjoyed and agreed with the articles on global warming (September 18 issue) by Dennis Behreandt, wherein he suggested that solar activity is to blame for the alleged rise in the "earth temperature," a questionable parameter to begin with.

Let us not forget that back in 1975 scientists were gloomily predicting a new ice age, apparently unaware of the rise in global temperatures taking place in about that same range of years, according to the new "hockey stick" graph, as best as I can read it. Why were they then predicting a new ice age when the graph clearly indicates what is now regarded as an alarming rise in Earth temperatures?

The case for anthropogenic global warming necessarily rests upon the presumptions that (1) the sun is an isotropic and isochronous radiator, and (2) that the energy density of space, filled with electromagnetic radiation across the entire electromagnetic spectrum from trillions of cosmic radiators, is a constant. Both of these propositions are preposterous, and as a result, one must be led to the conclusion put forward in your article that any heating of the Earth, and there may be some evidence that such is taking place, is due to cosmic influences, about which we can do nothing.

JOHN D. S. MUHLENBERG

Vienna, Virginia