Nuclear accidents can occur at any stage of the nuclear fuel cycle. The modern fusion bombs (nuclear bombs) are of explosive force of 500 kilotons and 10 megatons. Nuclear bombardment will cause combustion of wood, plastics, petroleum, forests etc.
Large quantity of black soot will be carried to the stratosphere. Black soot will absorb solar radiations and won’t allow the radiations to reach the earth.
Therefore, cooling will result. The infrared radiations, which are re-radiated from the atmosphere to the earth, will have very less water vapours and carbon dioxide to absorb them. If they leave the lower atmosphere the greenhouse effect will be disturbed and cooling will occur. Due to this cooling effect, water evaporation will also reduce.
Therefore, infrared radiations absorbing water vapours will reduce in the atmosphere. This will also cause cooling. In the stratosphere there won’t be significant moisture to rainout the thick soot. So due to nuclear explosions, a phenomenon opposite to global warming will occur.
This is called nuclear winter. It may result in lower global temperature. It will drastically affect crop production. Crop productivity will reduce substantially causing famines and human suffering.
The Chernobyl nuclear 1986 has resulted in wide spread contamination by radioactive substances. The devastation caused by nuclear bombs is not only immediate but may be long lasting. Towards, the end of World War II, bombing of Dresden, Germany caused huge firestorms. This caused particle laden updrafts in the atmosphere.
In nuclear holocaust in Japan 1945, two nuclear bombs were dropped on Hiroshima and Nagasaki cities in Japan. One fission bomb was dropped on Hiroshima. This holocaust (large scale destruction of human lives by fire) killed about 1, 00,000 people and destroyed the city.
This forceful explosion emitted neutrons and gamma radiations. It had a force of 12 kilotons of trinitrotoluene (TNT). The radioactive Strontium (90Sr) liberated in the explosion resembles calcium and had the property of replacing calcium of the bones.
As a result large scale bone deformities occurred in the inhabitants of these cities. Even after more than 50 years the impacts of nuclear fallout are still visible.