A nuclear explosion produces a fireball, shock waves and intense radiation that can cause far-reaching environmental damage. The mushroom cloud formed from vaporized waste scatters radioactive particles that fall to the ground and contaminate the air, soil, water and food supply. The particles can be carried by wind currents and rains, causing contamination over a wide area. Above-ground detonation of nuclear weapons sends radioactive materials up to 50 miles into the atmosphere.
Large particles fall to the ground near the explosion site, but lighter particles and gases move to the upper atmosphere. Particles that are dragged into the atmosphere and fall back to Earth are called rain. Rain can circulate around the world for years until it gradually falls to Earth or is brought back to the surface by precipitation. The trajectory of rain depends on wind and weather patterns. The effects of nuclear fallout are not limited to humans.
A full-fledged global conflict would cause a nuclear winter that would not reverse the effect of traditional man-made climate change. In the short term, ocean acidification would worsen, not improve. The smoke layer in the atmosphere would destroy up to 75 percent of the ozone layer, allowing more UV radiation to reach the planet's surface and causing a pandemic of skin cancer and other medical problems. Plants and animals that would otherwise not be affected by global slaughter would also be endangered. The health effects of nuclear explosions are mainly due to air explosion, thermal radiation, initial nuclear radiation and residual nuclear radiation or rain.
Compared to deaths from rapid cancer, from acute and latent side effects, the absolute number of effects on the fetus is small and captured within the limits of uncertainty. However, according to Chernobyl workers' experience, the number of eye cataracts is not small and is several tens of percent among those most exposed in Japan. The area affected by a nuclear weapon depends mainly on its explosive performance and height or depth of detonation. The areas affected by initial nuclear radiation and rain also depend on weapon design (in particular, fraction of performance derived from fission reactions) and weather conditions during and after explosion (in particular, wind speed and direction, atmosphere stability, precipitation, etc.), terrain and geology in area of explosion. For example, an outdoor individual would face a 10%, 50% or 90% chance of dying or serious injury from an immediate effect of a 10-kiloton earth penetrating weapon (EPW) detonated at a depth of 3 meters or from an immediate effect of a 250 kiloton surface explosion. The probability of death or serious injury from acute exposure to external gamma radiation from rain is also included for illustrative weather conditions. Under these conditions and assumptions, the 10-kiloton EPW is estimated to result in around 100,000 victims compared to 800,000 casualties for the 250 kiloton surface explosion.
In each case, the committee asked the DTRA to estimate the average number of victims (deaths and serious injuries from immediate effects, acute effects from gamma radiation consequences).Assuming that the entire population remains indoors and is therefore protected from radiation, mean total casualties are reduced by a factor of up to 4 for Objective A, and by a factor of 2 to 8 for Objectives B and C. However, if people move through highly polluted areas they could greatly increase their exposure to rain. The devastating effects of nuclear fallout on environment are clear: it can cause far-reaching contamination over a wide area; it can endanger plants and animals; it can cause pandemics of skin cancer; it can result in tens of percent eye cataracts among those most exposed; it can cause hundreds of thousands casualties; it can reduce ozone layer protection; it can worsen ocean acidification; it can increase exposure to rain if people move through highly polluted areas.
