Or other weapons of mass destruction. In other words, chemical and biological. Although they don't quite the attention of nuclear weapons, perhaps because they don't produce quite as big of a boom, they are classified as weapons of mass destruction for a reason. In fact biological weapons are actually deadlier that nuclear ones, pound for pound, if only they could be made reliable and safe for their user. See stats here The title of the article comes from a quote from the Iranian speaker of parliament in The Eighties, perhaps best capturing in this phrase what they are, very destructive weapons, that are much cheaper and easier to produce than nuclear weapons.
Chemical WarfareChemical Warfare is to quote The Other Wiki "Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons." Chemical weapons usage goes back to ancient times, people have been using poison in their weapons since the beginning of time. The ancients would burn noxious materials, such as pitch, arsenic etc. Modern Chemical Warfare dates from World War I, where the Germans started off using xylyl bromide and chlorine. Eventually, mustard gas and phosgene would be added to the mix. Gas was used in various conflicts between the wars, but wasn't really used during World War II, except for the Japanese invasion of China. The Germans and Japanese both researched Chemical Warfare, and both the Soviets and Americans used their research after the war to produce thousands of tons of chemical agents. Post World War II, chemical agents were used in a variety of places such as Yemen and allegedly in Vietnam by the Americans. The most infamous instance was in Halabja, a Kurdish village that Chemical Ali gassed, killing over 5,000 people.
Agents: There are four main types of lethal agents, Blister, Blood, Nerve and Choking
Biological WarfareLike chemical warfare, this one is very old. Medieval would throw corpses at each other during sieges. Black death in Europe started when the Tartars besieging Caffa in modern day Ukraine catapulted their plague infected corpses over the wall. When people fled the city, they took the disease with them. The US, meanwhile, committed one of the world's most lethal genocides against the Native American tribes by spreading smallpox, syphilis, and other diseases among other acts of war - killing, according to some figures, 90% of the Native population of North America (although how intentional this was is disputed; much if not most of the dying happened long before the English reached Jamestown, with the plagues coming accidentally from contact with the Spanish in Mexico and Florida). In modern times, we have only started to have the technology to grow pathogens in the 20th century. During World War 2, the infamous Unit 731 experimented with live human subjects. After Japan's surrender, the unit was given full immunity in exchange for its information. The US and the Soviet Union engaged in an arms race over biological warfare, at a time when the nuclear arms race was more noticeable. Eventually Nixon signed a treaty with the Soviet Union pledging to destroy their arsenals. Still the danger remains as the anthrax attacks after 9/11 show. Countries suspected of having or having Biological Weapons programs include the United States, Russia, North Korea, Israel, and Syria, among others. The American and Russian stockpiles are generally regarded as genuinely defensive research programs to find effective ways to counter the potential use of biological agents. The others are a bit more complicated/suspicious. Israel and Syria in particular have a peculiar one going: each one claims that its program is offensive and the other is defensive. The root cause of the problem from the Syrian perspective is that Israel has nukes and Syria doesn't have a deterrent; thus any "offensive" uses it thinks of are therefore defensive. The root cause of the problem from the Israeli perspective is that even in the absence of Israeli nukes, the Syrians would hate Israel enough to develop biological weapons anyway, and so both the nuclear program and the biological program are "defensive" deterrents. Yes, the logic of weapons of mass destruction can get quite counterintuitive.
Usage of these weaponsThese weapons have unlike their nuclear big brother; been employed many times in history. The use of sulphur fumes and diseased items was a major of ancient warfare. Since the late 1990's there are international conventions against their use, which most countries except Israel have joined. Chemical weapons are relatively easy to make and deploy, any country with a reasonable degree of industrialisation (meaning all countries with nukes) can make them if required. All nuclear powers have made them for example, except for Pakistan (http://www.nti.org/country-profiles/pakistan/chemical/) which never seems to have pursued them for reasons best known to the Pakistanis themselves. Germany pioneered their use in the First World War (the first modern use), when Chlorine was delivered via Artillery shells. The Allies soon retaliated. Fear of Chemical weapons was so bad, that all countries except Japan in China did not use it come the second World War (thats right, Hitler thought the use of Chemical weapons was inhumanenote ). That said, the use of Chemical weapons comes with several complications. Usage on a battlefield is iffy, depending on prevailing winds, and modern armies can take precautions (masks, suits etc) which greatly (meaning almost totally) alleviate the worst of the effects. Against civilians the use can be devastating, although less lethal than nuclear weapons and without the resultant damage to infrastructure of nukes, chemical weapons can easily cause thousands of casualties very quickly. Even then, retaliation is assured, lessening the attraction of striking. This is true even if your enemy does not have chemical weapons at the time of your initial strike, as Iraq discovered during the Iran-Iraq war, an attacked adversary can remedy that deficiency very quickly. If you enemy has nukes..........and you don't, usage of chemical or biological weapons will simply give them the excuse to hammer you seven ways to hell. Biological Weapons have been used throughout history. Usually the "delivery systems" were diseased individuals or contaminated items of clothing. The Mongols liked to poison wells by throwing horse carcasses and feces into them. Charming chaps. Like chemical weapons, Biological weapons do not require more than a middling degree of industrialisation to make and all nuclear powers have had or had them except once again the Pakistanis(http://www.nti.org/country-profiles/pakistan/biological/). Countries are very reluctant to use these kinds of weapons. For the simple reason that while a nuclear warhead will only directly harm the enemy and a chemical warhead will not harm you if you take sufficient precautions, ts pretty much impossible with current technology to develop pathogens where you can have high confidence that they will not spread to your own people. There have been some suggestions that nations might used biological warfare against enemy crops and livestock.
Thermobaric warheadsOne can technically Take a Third Option that conveniently isn't considered a weapon of mass destruction, and that's these things. Also called "fuel-air bombs" or "fuel-air explosives", they differ from "conventional" explosives on a technicality: the same one that differentiates "jet" engines from "rocket" engines. "Rocket" engines burn their fuel with an oxidizer carried onboard in a separate tank from the fuel proper (barring monopropellant rockets which there's not room enough to discuss here). This is why rockets can operate in the vacuum of space or in an atmosphere that lacks oxygen. "Conventional" explosives, like rocket engines, carry both the oxidizer and the fuel, usually pre-mixed so combustion occurs "all-at-once" instead of the slow, orderly "burn" of a rocket engine. On the other hand, jet engines (read: turbojet, ramjet, scramjet, pulsejet, turbofan, and turboprop) differ from rockets in that it uses oxygen in the ambient atmosphere as its oxidizer, reducing weight (since the vehicle no longer needs to carry oxidizer onboard) at the cost of making the engine's operability depend upon the atmosphere's chemical composition. Unlike "conventional" explosives, fuel-air explosives don't have the oxidizer pre-mixed (or even carried in the warhead at all) with the explosive "fuel". Instead, the fuel (which MUST be powdered if it's a solid) is carried in a vessel that ruptures at the target's location, dispersing the fuel into many millions of particles that spread and mix with ambient air BEFORE a spark is set off to ignite the mixture. An accidental example of a fuel-air bomb is the sometimes overlooked phenomenon of dust-explosions at grain-elevators or other sites where potentially flammable agricultural dusts are suspended in the (bone-dry) air as dust-clouds, needing only a single spark to set the whole mix off. The major thing about fuel-air bombs that makes them worth mentioning here is that they make their targets deadly even AFTER the explosion is over, because in their ignition, they consume most-to-all of the oxygen in the vicinity of their use, suffocating any remaining would-be survivors. Hypothetically, if the target were a building with a "dry" firefighting system that utilized halon or some similar liquid or gas fluid substance to 'smother' the fire of oxygen, that theoretically could hinder a thermobaric weapon from having its desired effect but it would also render the area uninhabitable to any oxygen-breathing life until the fire extinguishing substance, itself an asphyxiant, could disperse. And then again, halon is a known ozone-destroying substance, so that'd get green advocates angry at you. They have recently seen use in Afghanistan against enemies hiding in deep-cave systems. Some anti-war activists have protested their use, given they kill in particularly horrible ways - if enemies aren't incinerated, they are suffocated or have their lungs, and internal organs crushed by pressure waves. If the fuel ignites but does not detonate, the targets end up inhaling it as it burns. ISAF responds that whilst having ones internal organs and bones obliterated is indeed nasty, but the effects are so fast acting that you won't feel the pain before you die.