The views expressed in this report are those of the authors. Their statements are not necessarily endorsed by the affiliated organisations or the Global Challenges Foundation.

How much do we know?

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.

What are key factors affecting risk levels?

  • Global frameworks controlling research on chemical or biological weapons including revised strategic trade controls on potentially sensitive dual-purpose goods, technology and materials, biological and chemical safety and security measures, as well as an ongoing commitment and capacity to enforce disarmament and arms control conventions.
  • The number of laboratories researching potential pandemic pathogens for military or civilian purposes, and the public availability of dangerous information circulating for scientific purposes, increase the level of risk.
  • Further developments in synthetic biology and genetic engineering lowering skill levels and costs to modify existing pathogens or to develop new pathogens which, in turn, may significantly increase biological risks to society.

Chemical weapons: an unravelling consensus?

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.

Recent usage

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: 

  • Rhodesia, late 1970s: cholera, anthrax, epidemic typhus and typhoid fever pathogens were released in water supplies used by guerillas. 
  • Iraq-Iran, 1980-1988: mustard gas used in trench warfare killed 20,000 and affected 100,000. In March 1988, poison gas killed between 3,200 to 5,000 people in Halabja and injured 7,000 to 10,000 more. Thousands have since died prematurely of the after-effects. Others continue to receive medical treatment and/or remain under periodic medical observation and care. 
  • Japan, March 1995: Sarin gas released on trains in Tokyo by the Aum Shinrikyo cult killed 12 people, and severely injured 50. 
  • Syria, 2012 – 2017: Sarin and chlorine gas attacks have been recurring and are still ongoing. The most lethal attack killed 837 people in August 2013, another killed up to 100 on April 2017.

Angela Kane

Senior Fellow, Vienna Centre for Disarmament and Non-Proliferation; visiting Professor, Sciences Po Paris; former High Representative for Disarmament Affairs at the United Nations