changes due to nuclear war might decrease global surface temperatures by
only negligible amounts or by as much as a few degrees. To calibrate the
significance of this, the study mentioned that a cooling of even 1 degree
centigrade would eliminate commercial wheat growing in Canada.

Thus, the possibility of a serious increase in ultraviolet radiation has
been added to widespread radioactive fallout as a fearsome consequence of
the large-scale use of nuclear weapons. And it is likely that we must
reckon with still other complex and subtle processes, global in scope,
which could seriously threaten the health of distant populations in the
event of an all-out nuclear war.

Up to now, many of the important discoveries about nuclear weapon effects
have been made not through deliberate scientific inquiry but by accident.
And as the following historical examples show, there has been a series of
surprises.

"Castle/Bravo" was the largest nuclear weapon ever detonated by the United
States. Before it was set off at Bikini on February 28, 1954, it was
expected to explode with an energy equivalent of about 8 million tons of
TNT. Actually, it produced almost twice that explosive power--equivalent
to 15 million tons of TNT.

If the power of the bomb was unexpected, so were the after-effects. About
6 hours after the explosion, a fine, sandy ash began to sprinkle the
Japanese fishing vessel Lucky Dragon, some 90 miles downwind of the burst
point, and Rongelap Atoll, 100 miles downwind. Though 40 to 50 miles away
from the proscribed test area, the vessel's crew and the islanders received
heavy doses of radiation from the weapon's "fallout”--the coral rock, soil,
and other debris sucked up in the fireball and made intensively radioactive