Goodbye, Cluster Munitions: Will we Regret it?

By Paul Smyth
6 June 2008

The recent international agreement achieved in Dublin to ban the use of cluster-munitions (CMs) is a clear victory for those who wish to rid the world of weapons and to minimise the effects of war.

The resolution will especially benefit the unknown communities who will now be saved from living with the consequences of the future use of such weapons, but the decision will not be so popular in military communities, where the loss of a capability is rarely appreciated and arguments remain for keeping CMs in a military arsenal. In order to provide the general reader with more information on CMs, and to perhaps explain why several nations did not endorse the Dublin agreement, the following questions might be of use.

What Are Cluster Munitions?

There are many different models of CM, but generally they come in two forms: Cluster Bomb Units (CBUs) which are dropped from aircraft and missiles fired from land-based rocket systems. In essence, both comprise an inert carrier (a bomb or missile) in which are contained the smaller sub-munitions that deliver the required destructive effect. A single carrier may contain hundreds of unguided sub-munitions, which are commonly the size of a yoghurt pot or a coffee jar. After the carrier is released from an aircraft or fired from its launcher, it then travels as a complete unit until activated by a variety of means (such as a timed delay system) to disperse its load of sub-munitions over the target area. There are many factors, including operator input, which influence the size of this area (for example, the height above ground that dispensing is initiated) and for an aircraft carrying CBUs, dispersing sub-munitions over an area the size of a couple of football pitches is typically possible, while one launcher of the Multiple Launch Rocket System (MLRS) in service in several western armies could deliver twelve rockets totalling over 7,700 sub-munitions into an area one kilometre square, earning it the sobriquet of ‘grid-square removal’ system.

Why Were Cluster Munitions Developed?

Fundamentally, the sub-munitions within a CBU or missile are of two types, being primarily designed as anti-armour or anti-personnel weapons. These sub-munitions may have utility against other target sets (for example, soft-skinned vehicles, aircraft parked in the open or fuel facilities) and in a global arms market there are many variations in CM design, but for the purposes of this work the armour/personnel distinction is sufficient. Traditional high-explosive general purpose (GP) bombs produce blast and fragmentation effects which make them a lethal weapon against troops in a range of environments, but these effects happen on bomb detonation and are short-lived. Although anti-personnel CMs lack the equivalent explosive power, they nevertheless have utility as they can provide a method of quickly laying a minefield that might hinder or deter the movement of enemy personnel, or disrupt the use of a location/facility for a considerable period. Such weapons would not explode on dispersal but instead lay dormant until detonated by an unwary foot or handling. When anti-personnel CMs entered service they therefore brought additional options to military planners, but it was against armour that CMs really established themselves as a weapon of choice.

In essence, anti-armour CMs offered a solution to a core problem of modern warfare: how to destroy enemy tanks before they engage with friendly troops. The Second World War brought about many changes in the nature of warfare: production of the atomic bomb ensured conventional forces were no longer sufficient to guarantee national security; air power reached a point where it became an essential element to military success; at sea, the aircraft carrier replaced the battleship as the foremost maritime platform, and on land, the tank replaced artillery as the principal weapon on the battlefield. In the Cold War period, decisive land warfare would be armoured warfare, and the challenge of how to negate the increasing capabilities of main battle tanks (MBTs) was especially pertinent to NATO.

Had the Cold War ignited into armed conflict, its cauldron would have been the states of mainland Western Europe where two opposing alliances of over a million troops would do battle. An assault by the Warsaw Pact would have involved major advances into NATO territory by armoured formations employing vast numbers of MBTs. In line with its defensive posture, NATO had to repel such an invasion of Western Europe, or at least contain it, until substantial US reinforcements could cross the Atlantic. NATO’s problem was compounded by both the Warsaw Pact’s greater tank numbers (which gave it a distinct offensive advantage), and by a defensive policy which ceded the military initiative to Soviet planners. In order to delay enemy advances NATO’s air power would have to be employed against armoured targets. To do this with any degree of success required an arsenal with more than traditional GP bombs.

It is possible for a GP bomb to destroy or significantly damage an MBT, but this would require a very close or direct hit. Against tactically deployed forces, one GP bomb could realistically only account for one tank. Given the unguided nature of GP bombs, plus the size and mobility of an MBT, it was unrealistic to expect such weapons to achieve any meaningful attrition on Warsaw Pact forces. The solution was therefore to provide aircraft with weapons that were specifically designed to defeat armour, that would reduce the difficulty of hitting a small, mobile, armoured vehicle and which might also inflict damage on more than one vehicle per weapon. Consequently, the primary airborne solution for attacking deployed land units became CBUs with sub-munitions that had a primary damage mechanism called a shaped-charge. On detonation, these munitions produced a high velocity jet of molten metal that could pierce an MBT’s armour, and a secondary fragmentation effect that made the weapon of use against a wider range of targets (such as troops and soft-skinned vehicles).

Without CBUs, the significant disadvantage in land forces which NATO, by design, would fight under could not be fully addressed by air power. NATO aircraft would have been able to interdict advancing forces by attacking bridges and other communication nodes, but it would have been extremely difficult to inflict significant attrition on deployed Warsaw Pact armoured forces using GP bombs, aircraft cannon and relatively few in-service anti-armour missiles. Put simply, to increase the effectiveness of NATO’s air power against the Soviet Army the Alliance required CBUs.

With regard to land warfare, there were similar needs. NATO had a range of very capable direct-fire anti-tank weapon systems (in other words, those used when the target is in view of the firer) including its own modern MBTs, but it made obvious sense to inflict attrition on the enemy before he could fire his own direct-fire weapons at NATO forces. This required longer-range (indirect-fire) weapons which could weaken Warsaw Pact units before they engaged NATO forces that would be routinely outnumbered. The fundamental logic behind the need for airborne CBUs remained valid in the ground environment and rocket-launched CMs were developed to meet the requirement. In short, therefore, CMs were developed because in the Cold War era they provided a potential solution to a significant operational challenge.

Why are Cluster Munitions not Precision-Guided?

Generically, both CBUs and rocket-delivered CMs were designed as unguided weapons. Their lack of precision-guidance reflected the Cold War-era level of available technology (they generally pre-date the advent of GPS systems), affordability issues (they were bought in huge numbers to reflect their anticipated utility) and their operational use (they were designed primarily with a particular target set in view). Their imprecision was mitigated by their area effect, which also alleviated the fact that their targets might be moving at speed when attacked, a problem that meant that even if the bombs or rockets were fired with extreme accuracy at a particular location, over the time of flight of the weapon the target could have moved to safety. In addition, the fact that CBUs could be used without the need for advanced avionics or a laser designator meant that they could be carried by aging or rudimentary aircraft such as those used for advanced aircrew training, usefully augmenting NATO’s fleet of combat assets. In short, CMs were required before technology made precision-guidance commonplace, and in many operational scenarios precision was not a tactical requirement. However, to cover a significant area with the required weapon effects demanded a large number of sub-munitions which ultimately fuelled the weapons appalling reputation and its eventual demise.

Why are Cluster Munitions so Dangerous to Civilians?

The large numbers of sub-munitions carried in a CBU or CM rocket would not pose a subsequent danger to civilians if they all exploded when used. Unfortunately, a proclivity to remain on the ground as duds exacerbates the risk posed by their widespread distribution within the target area, their low detection signature, their physical durability and their small size/weight which means even children can pick them up. The seemingly high dud rate for CMs is not merely a function of poor reliability, inferior build quality, their age or the way they have been stored. For a shaped-charge to work to best effect it must be detonated at a suitable range from the target armour. Consequently, such sub-munitions are generally detonated on impact with the (hard) target. However, if they land in trees, soft ground or water it is possible that the sub-munitions will not fuse or explode, leaving them as highly dangerous unexploded ordnance (UXO). In addition, if the CMs are specifically intended to be anti-personnel devices, they may be designed to remain inert until trodden on or handled. Furthermore, the manner in which CBUs and CMs have been employed in many conflicts has increased, not decreased, the potential danger to civilians (such as through their uncharted use in agricultural areas) while population expansion has seen people move into areas that were once unoccupied battlefields, where a latent threat from CMs persists. Ultimately, the vast numbers of CMs expended over decades in many conflicts across the globe amplify the danger they pose to civilians, especially as their unreliability means that many sub-munitions may be handled without exploding – fostering a familiarity with ‘duds’ which can have lethal consequences.

Is it Simply an Ethical Issue?

Cluster munitions have a justifiably bad reputation due to their enduring ability to kill and maim civilians, but they also attract a particular degree of infamy which is perhaps more subjective than objective in character. For example, they are often termed ‘evil’ or ‘illegal’ weapons because they cannot discriminate between military and civilian people or objects. But this inability to discriminate foe from friend or neutral is also true of artillery shells, mortar rounds and unguided bombs, all of which can be aimed at, but not controlled to their target, and all of which remain a hazard to civilian populations if they fail to detonate when expended. Neither can any of the above munitions recognise when a conflict has ended and their lethal services are no longer required. Some would argue that these similarities demonstrate all weapons are ‘evil’ and ‘illegal’ but the purpose here is to illustrate that cluster-munitions attract a particular censure which is incorrectly based – the latent danger they pose to civilians is due more to their proliferation and unreliability than to their inherent character.

Those in favour of banning CMs principally used ethical arguments to promote their cause. The weapons were deemed ‘indiscriminate’, ‘illegal’ and ‘evil’, but as outlined above, most non-precision weapons could be viewed similarly and the criticism rests largely on subjective arguments. Lobbyists could also logically link the problem of CM duds to the 1997 global ban on landmines, as in essence that is what many people judged dormant sub-munitions to be. But apart from anti-personnel sub-munitions which were indeed a form of mine, these were really UXOs and the landmine treaty did not provide sufficient grounds to force their prohibition. The use of CBUs by Israel in the 2006 War in Lebanon kept the issue of CMs topical, and subsequent civilian casualties generated international disapproval, however, sound arguments in favour of withdrawing CBUs and most rocket-launched CMs from military service rest elsewhere.

The decline in the operational utility of CMs began in the 1980s and accelerated in the 1990s when technology enhanced the levels of protection available to MBTs. Developments such as British Chobham (composite) armour increased the survivability of modern MBTs while the introduction of explosive reactive armour (ERA) that could be bolted to the exterior of even obsolete tanks meant that many shaped-charge sub-munitions could no longer expect to penetrate MBT armour and they became operationally obsolescent. In addition, a growth in the number of aircraft equipped with airborne laser designators and GP bombs fitted with laser seeker units provided aircrews with a degree of accuracy that could target individual MBTs. This new capability was used extensively in the 1991 War in Iraq, where American F-111 bombers destroyed an estimated 1,500+ Iraqi MBTs using Laser-Guided Bombs (LGBs) – an achievement that dwarfed even the most optimistic assessments of what CBUs were capable of. In addition, modern technology improved the quality and effectiveness of the guided anti-tank rockets which could be carried by aircraft and helicopters so that today the CBU has ceased to be the weapon of choice against deployed land forces.

As well as creating competitors to CMs, technological advances offered the chance to improve sub-munitions, and efforts were made to address the enduring problem of duds. These efforts introduced an updated generation of CMs to the market which, by minimising the danger to civilians, promised to extend the utility of cluster weapons by undermining the ethical argument against them. Unfortunately, the conflicts in Iraq, Kosovo and Afghanistan provided empirical data that even such modern CMs were unable to achieve a level of reliability that ensured the weapons detonated on use and did not pose a lingering danger to civilians. The overall impact of modern technology has therefore been to make CMs obsolescent or extraneous to operational requirements.

The Future

Continuing advances in engineering, miniaturisation, digitalisation and other technologies with military applications are producing unprecedented sensor, computing, reliability and precision capabilities. Consequently, a number of ‘smart’ munitions are being developed that will have the capability to loiter over the battlefield searching for armoured targets, discriminate MBTs from other types of vehicle, attack positively identified targets with great accuracy and self-destruct when they are unable to prosecute acceptable attacks. Some of these weapon systems may comprise a batch of munitions within a single carrier, and so would be considered CMs, but they would differ from their predecessors in several important aspects. First, the level of technology being applied to these weapons is of an order more capable of achieving the required degree of reliability in operation. Second, these weapons are being driven by the necessity for positive target identification. Third, once acquired and tracked, targets are attacked with precision, and lastly, it is widely understood within the defence industry that collateral considerations can no longer be ignored when designing and developing a future weapon systems, as the commercial consequences are potentially too great. Subsequently, in future it may be more accurate to consider such weapons to be munitions used in clusters rather than clustered munitions.

No Regret?

Will we regret the coming prohibition on CMs? Possibly, but probably not. It is not difficult to argue that traditional CMs have had their day. Their primary military contribution would have been as anti-armour weapons, but in practice their impact as indiscriminate anti-personnel weapons led to their eventual demise. The growth in alternative options for attacking armoured targets eroded their operational usefulness, as did enhanced protection for tanks. Militarily, it is the growing obsolescence of aging CMs, not their ‘illegality’, that provides the stronger case for their retirement from service, although it should be noted that they retain a capability against a range of un-armoured target sets, while more modern systems such as the MLRS should not yet be considered operationally obsolete.

Ultimately, if our Armed Forces are not put in a position where CMs would have decisive effect their removal from service should have negligible impact. In the past thirty years, UK forces have fought in several conflicts without a reliance on the use of CMs. Such weapons have been used in the Falklands, the Balkans and Middle East, but as a tiny fraction of the total munitions expended. What at times was effectively a self-imposed moratorium on the use of CMs has prepared the British military for their eventual prohibition. The British are therefore well postured to cope with the loss of CMs, but for a military that may be called upon to fight in a future inter-state conflict, the challenge of destroying protected, manoeuvrable vehicles that may be encountered in large numbers across the battlefield has not gone away. Fundamental to the issue of whether the loss of CMs will be regretted is therefore the provision of enduring capabilities to defeat armoured units at distance. This will logically require the continued research and development of advanced ‘smart’ weapons with an unprecedented capability to locate, identify, track and accurately attack targets.

Armed forces have many moral and legal obligations that place very proper limits on how they conduct their deadly business and with what weapons. Yet it is equally important to ensure that they are able to exercise their legal function and responsibilities to optimum effect. Any ban on CMs must ensure that constraints based on legacy issues are not inappropriately applied to future capabilities, or the decision to relinquish CMs may become one that is rued. Although current operations are focused on counter-insurgency campaigns against sub-state actors, military personnel are mindful that future conflicts may involve state actors where armoured warfare again becomes decisive. While most of the nations represented in Dublin may have no or only obsolete CMs in their armouries and may judge that their military forces will never be disadvantaged by the loss of these weapons, those who prepare for the eventuality of a major war between states will take a different view. For them, the Dublin agreement may be ethically sound but military folly.

Paul Smyth
Head, Operational Studies Programme

The views expressed above are the author's own, and do not necessarily reflect those of RUSI.

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