Black Sky Event

The developed world relies on the smooth functioning of a host of subsystems all of which interact. Our key survival supplies: heat, water and food (and for some people medication also) are smoothly supplied by agencies which are opaque and mysterious to all but the tiniest expert fragment of the population. As is pointed out elsewhere on this site, practically everything depends on electricity but for electricity to be delivered it is obvious that the people responsible for it must themselves have access to food, water, fuel for transport, communications - so without, for example, fuel for transport, the electricity supply is put at risk, without which there would be extremely rapid collapse of everything else - including fuel for transport, completing the circular dependency.

Without exaggerating too much, we have reached the stage where everything depends on everything else. Even though the key infrastructure elements may themselves operate well and robustly when everything else is working, what complex failure modes do we have when there is so much interdependency? And what happens if failures occur which are large enough to have cascading effects? If there is a massive failure, how do you restart the entire system of systems "from cold"?

The cold-restart problem is a serious one. The electricity system depends on thousands of key workers being in the right place at the right times. They depend on water, food, fuel as does everyone else, but the water, food and fuel depends on electricity. The electricity system itself is designed to be able to restart without external input, something known as the "Black Start" procedure[1]. But would a black start succeed if the key people were displaced or unavailable or prevented from being present? And if so, who would be responsible for ensuring they could get there? If the electricity failure is due to a wide area electro magnetic pulse (EMP[2]) event it's conceivable that the engine management system of many vehicles will have been damaged by the same event[3], in which case where will the transport come from, and who will clear the roads blocked by immobile vehicles?

A systemic failure of infrastructure over a wide enough area to cause restart problems is sometimes called a "Black Sky Event"[4]. Small scale problems tend to fall within normal problem recovery scenarios but an event over a wide enough area to preclude hope of timely external assistance may be qualitatively rather than quantitatively different. Whilst such high-impact events may be improbable, that is not the same as impossible and it's appropriate to try to understand what could happen and to look for mitigation strategies.

Overview of Issues

A useful discussion of the issues surrounding Black Sky events is found in the proceedings of a workshop held at The Royal Society in London on 16th January 2017[5]. The Executive Summary starts by noting:

"In the modern world, our lives are empowered, enriched and sustained by unprecedented access to clean water, electricity, food, health care and pharmaceuticals, and a wide range of other vital products and services. In most modern nations, when disasters strike and the interconnected infrastructure networks that supply these goods and services fail, utilities, corporations, government agencies and mass care NGOs have always been able to depend on the continued availability of these networks in most of the country, setting aside other priorities to come to the aid of the affected region.

In Black Sky hazards, long duration, potentially nationwide power outages and associated cascading failures of all lifeline utilities will drastically limit availability of such "external" support, precisely at the time when it is desperately needed by the population. Thus "scaling up" disaster plans that depend on such external support will be insufficient to meet the unique needs of these severe scenarios.

In addition, to sustain or restore its services, each utility sector typically depends on products and services it receives from other, interdependent sectors. In a Black Sky outage, advance preparations of any one sector, without common, well-coordinated preparations across many sectors, will be unsuccessful due to the lack of these sector-external products and services."

In opening remarks, Avi Schnurr, CEO of the EIS Council drew attention to a number of points including

Schnurr identified key hazards as

(N.B. on this site, other potential causes are listed here.)

The report discusses a presentation made by Lord James Arbuthnot, a former Chair of the House of Commons Select Committee on Defence.

"Lord Arbuthnot outlined some of the implications of a Black Sky threats and suggested constructive ways to mitigate the threats. He began by challenging the assumption that in any crisis such as this, the military will step in and solve the problem. He assured the audience that the military is overstretched and unprepared to deal singlehandedly with a Black Sky event. "They say there's no evidence that anyone is planning a major attack on our infrastructure. They may be right, but they did say that about 9/11," cautioned Lord Arbuthnot.

Lord Arbuthnot sketched out a plausible scenario of "a multifaceted attack involving a dirty bomb in Waterloo Station, combined with a cyberattack on the ambulances and the national health system, and an electromagnetic pulse attack delivered by drone on the National Grid, all at the same time." He opined that if there to be a state-on-state war, "I'm sure that's exactly how it would begin."

He warned how shockingly easy it could be to launch a major cyber-attack on critical infrastructure."

The report goes on in some detail to discuss what needs to be done to provide coordinated responses to Black Sky events, but reading between the lines it appears that on a global basis this is not a subject that has been given detailed thought or adequate preparation.


Based on observation and also threads covered in the report above, there are serious concerns about the ability of a developed society to function and recover after a serious infrastructure failure across a wide area, no matter how it might be caused. Cascading collapse of related systems can potentially lead to situations which are very hard to recover from. This may be catastrophic for those who do not have their own well-prepared survival plans which are independent of infrastructure and can at least sustain life until some form of normality is restored.

Reliance on external agencies for support is only feasible in the case of small-scale events, those which are geographically large will exhaust any resources - there is no 'cavalry' to come to the rescue.

Whilst the risks may be small, the consequences are immense and severe. That serious people are taking this subject seriously is borne out by the speakers at the Royal Society conference.


  1. Wikipedia entry for power grid black start
  2. Wikipedia entry for Nuclear Electro Magnetic Pulse (EMP)
  3. Article from FutureScience on effects of EMP on vehicles
  4. EIS council description of Black Sky Event
  5. Workshop held at Royal Society on Black Sky Events, January 2017