3. " . . . The amount of ionization produced by the radioactive material is insignificant in affecting general atmospheric conditions “ 4, "™ , . , Dust thrown into the air by past volcano eruptions decreased the direct solar radiation received at the ground by as much as 10-20%. The contamination of the atmosphere by past nuclear tests has not produced any measurable decrease in the amount of direct sunlight received at the earth's surface. There is a possibility that a series of explosions designed for the maximum efficiency in throwing debris into the upper atmosphere might significantly affect the radiation received at the ground " (The volume of material ejected by Krakatoa volcanic eruption in 1883 was approximately 13 cubic miles with an estimated one-third of the volume being spread worldwide*>-,. This resulted in a diménution of the amount of sunlight received on the ground. As a crude comparison, the 14 million ton TNT equivalent nuclear detonation on October 31, 1952 on the island of Elugelab in the Pacific left a crater of about one mile in diameter and 170 feet deep at its apex. Assuming conservatively that the crater was a right angle cone and that all of the debris was thrown into the atmosphere, i.e., none of the depression was caused by compression, it is estimated that 20,000 million tons TNI equivalent of surface detonations would be required to eject an amount of dust into the atmosphere equivalent of Krakatoa.) Following large nuclear detonations in the Pacific minor and temporary weather changes have been observed, such as local cloud formation sometimes with local precipitations, where the moisture conditions in the atmosphere are most favorable for this effect. my 39