Unlike nuclear weapons, which require rare materials and complex engineering, biological and chemical weapons can be developed at a comparatively low cost, placing them within the reach of most or all states as well as organized non-state actors. Chemical and biological weapons carry various levels of risk. Toxic chemicals could be aerosolized or placed into water supplies, eventually contaminating an entire region. Biological weapons possess greater catastrophic potential, as released pathogens might spread worldwide, and cause a pandemic.
Recent developments in synthetic biology and genetic engineering are of particular concern. The normal evolution of most highly lethal pathogens ensures that they will fail to spread far before killing their host. Technology, however, has the potential to break this correlation, and create both highly lethal and highly infectious agents. Such pathogens could be released accidentally from a lab, or intentionally released in large population centres. Current trends towards more open knowledge sharing can both contribute to and mitigate such risks.
Unlike nuclear weapons, which require rare materials and complex engineering, biological and chemical weapons can be developed at a comparatively low cost.
Deadly agents like sulphur mustard were used during and between the World Wars, but the horrific results of such attacks eventually led to a global consensus to ban toxic chemical weapons, the most widely-used and easily proliferated weapon of mass destruction.
This consensus, however, represented by the near-universal 1993 Chemical Weapons Convention (CWC) is under strain. The Syrian Civil War has resulted in well-documented and indiscriminate uses of various deadly toxic chemicals against the civilian population, most recently in Khan Sheikhoun on 4 April28. The Khan Sheikhoun attack resulted in at least 85 victims – including some 20 children – dying from the deadly nerve agent Sarin (or ‘sarin-like’ compound). Though the risk may always exist from easily available dual-use chemicals, and from terrorists like the Aum Shinrikyo, which perpetrated the Tokyo attack in 1995, there is a global risk that the hard-won consensus on banning state-use of toxic chemicals will be further weakened29. This could lead to the devastating return of more advanced toxic chemical weapons of mass destruction in any potential large-scale conflict in the future, as well as long-term changes in how states understand the development, evaluation and use of ‘non-standard chemical substances’ (substances other than deadly substances like sarin) for domestic riot control purposes, counter-terrorism operations, international peacekeeping operations, and as a mechanism to maintain a standby offensive chemical weapons capability.
Though their production and use is banned by International conventions, biological and chemical weapons have been used at least on four occasions in the last forty years, three times in war, and once in an act of terrorism:
Senior Fellow, Vienna Centre for Disarmament and Non-Proliferation; visiting Professor, Sciences Po Paris; former High Representative for Disarmament Affairs at the United Nations