Wednesday, December 5, 1984

The intense cold that could follow a nuclear explosion may be the worst aspect of nuclear warfare, William A. Calder, a University of Arizona professor, said yesterday.

“”Temperatures could go below zero even in the middle of summer,”” said Calder, A UA professor of ecology and evolutionary biology.

The cold, known as “”nuclear winter,”” would be created when dust, smoke and soot from fires started by nuclear explosions block out sunlight and cause surface temperatures to drop below freezing for several months, Calder said.

As a result, all plant life would die and the world’s food supplies would be depleted, he said.

“”Those that would survive may face starvation,”” he said.

Current world food supply reserves can feed the Earth’s population for about 60 days, Calder said.

Although scientists cannot prove that a nuclear winter would occur, studies to date enforce the concept even in the case of a limited nuclear exchange between the United States and the Soviet Union, he said.

“”One scenario of a limited nuclear attack of 100 megatons would drop temperatures to below freezing for a couple of months,”” Calder said.

Such a scenario would involve two-megaton nuclear bombs being dropped on Tucson and 49 other cities in the United States, he said.

“”I don’t feel comfortable with the concept of a limited nuclear exchange,”” he said.

Calder hopes that the evidence for a nuclear winter will help bring a stop to the nuclear-arms race, but said the general public is not aware of the concept of a nuclear winter.

“”As a citizen, everyone has to be aware of this,”” he said.

The U.S. Department of Defense is conduction a $50 million study on the environmental impact of a nuclear war, he said. That study should be completed in the spring.

There has not been any official response by the U.S. government on the concept of a nuclear winter, Calder said. Several Society scientists have conducted similar studies on a nuclear winter and have reached the same conclusions, he said.

“”This was not dreamed up by a couple of anti-nukes, but came out of research,”” he said.

Calder will present a slide show and talk on nuclear winter tonight at 7:30 at the Wilmot Library, 530 N. Wilmot Road. The program will be sponsored by the American Friends Service Committee and is free and open to the public. An open discussion will follow the presentation.