Weapons of mass destruction (WMD) are weapons capable of causing widespread death and destruction. The term encompasses nuclear, chemical, biological, and radiological weapons. Their proliferation is considered one of the greatest threats to global security.
Nuclear Weapons
Nuclear weapons derive their destructive force from nuclear fission or fusion reactions. They are the most powerful weapons ever created, with modern thermonuclear warheads capable of destroying entire cities. The five recognized nuclear-weapon states under the NPT are the United States, Russia, United Kingdom, France, and China.
Chemical Weapons
Chemical weapons use toxic chemicals to cause death or harm. Categories include nerve agents (sarin, VX), blister agents (mustard gas), blood agents (hydrogen cyanide), and choking agents (phosgene). The Chemical Weapons Convention (CWC) of 1993 prohibits their development, production, and use.
Biological Weapons
Biological weapons use pathogens or toxins to cause disease in humans, animals, or plants. Potential agents include anthrax, smallpox, plague, and botulinum toxin. The Biological Weapons Convention (BWC) of 1972 prohibits their development and use.
Countries That May Possess WMD
Beyond the five recognized nuclear states, India, Pakistan, and North Korea are known to possess nuclear weapons. Israel is widely believed to have a nuclear arsenal but maintains a policy of ambiguity. Several countries have been accused of pursuing or maintaining chemical and biological weapons programs.
Responses to WMD
International efforts to control WMD include the Nuclear Non-Proliferation Treaty (NPT), Chemical Weapons Convention (CWC), Biological Weapons Convention (BWC), Comprehensive Nuclear-Test-Ban Treaty (CTBT), and various export control regimes.