United States and weapons of mass destruction
The United States is known to have possessed three types of weapons of mass destruction: nuclear weapons, chemical weapons, and biological weapons. The U.S. is the only country to have used nuclear weapons in combat, when it detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki during World War II. It had secretly developed the earliest form of the atomic weapon during the 1940s under the title "Manhattan Project". The United States pioneered the development of both the nuclear fission and hydrogen bombs (the latter involving nuclear fusion). It was the world's first and only nuclear power for four years (1945–1949), until the Soviet Union managed to produce its own nuclear weapon. The United States has the second largest number of deployed nuclear weapons in the world, after Russia.
Nuclear famine
While the total number of global nuclear weapons had declined by two thirds following the U.S.-Soviet Strategic Arms Reduction Treaty (START) compared to the early 80s, some experts feel that the risk of nuclear conflict has not decreased, but has instead risen. This is due to nuclear proliferation as more countries such as India, Pakistan, and North Korea now have nuclear arsenals, increasing the risk of regional nuclear conflicts. Growing military tensions, accidents, sabotages and cyber-attacks are all potential trigger points of massive nuclear disruption and regional, if not global famine.