The use of explosive weapons with a wide impact area in populated areas is one of the main causes of civilian harm in today’s armed conflicts. Despite their widespread and reverberating effects, they are the weapons predominantly in use in urban warfare today.

In this post, part of our urban warfare series and marking the launch of a new ICRC report, ICRC Legal Adviser Eirini Giorgou unpacks the deadly effects of these weapons on civilians and the challenges of using them in compliance with international humanitarian law. She fleshes out the ICRC’s call to action to avoid using heavy explosive weapons in populated areas, as a matter of policy, and impose restrictions and limitations on their use.

What is the difference between being killed by a bomb or a bullet?

The answer may come intuitively. For the individual directly affected, there may be no difference at all. But for all those around them, the difference is massive. The bullet hits one person, the bomb maybe a dozen – and in a city it might mean a dozen civilians. It can damage homes, hospitals and schools, block roads, puncture water pipes, or lay unexploded, a lurking threat until long after hostilities have ended.

Civilian harm in urban warfare has many causes and compounding factors. But the choice of means and methods of warfare is of paramount importance.

We have seen this in practice. Mosul is a striking example. East Mosul, where there was, at least initially, restraint on the use of heavy firepower, suffered relatively low levels of damage during the 2016 military operation. West Mosul, where there was an increased resort to heavy indirect fire and air support, was in large parts reduced to rubble.

Airstrikes and indirect fire often involve the use of explosive weapons with a wide impact area, i.e. weapons that put entire areas at risk of harm either because of their large payload and consequent large destructive radius, because of their inaccuracy, or because they are designed to fire multiple munitions simultaneously over a wide area.

These are the weapons predominantly in use in urban warfare today: heavy, mostly unguided artillery, mortars and multi-barrel rocket launchers, large bombs and missiles, and improvised explosive devises (IEDs).

A grave pattern of civilian harm

While working tirelessly to protect and assist people affected by armed conflict around the globe, the ICRC observes first-hand the grave pattern of civilian harm when explosive weapons with a wide impact area are used to strike military objectives located in urban and other populated areas.

The harm directly caused by the explosion is devastating. Every year, thousands of men, women, boys and girls are killed or injured, left with disabilities or grave psychological trauma. Homes and critical infrastructure are damaged or destroyed. Equally important, but often disregarded, are the indirect or reverberating effects, especially when essential services like water, sanitation, electricity and health care are disrupted. As an example, Syria is facing an unprecedented water crisis following recurring damage to critical infrastructure such as water stations during the hostilities. Lack of essential services typically leads to more death, disease and displacement. For instance, between April and June 2019 only, over 90,000 civilians were displaced as a result of the continuous use of heavy explosive weapons in residential areas of Tripoli, Libya.

Major challenges to IHL compliance

There is no general prohibition in IHL on the use of explosive weapons with a wide impact area in populated areas. Every instance of such use must nevertheless comply with the rules regulating the conduct of hostilities, in particular the prohibitions of indiscriminate and disproportionate attacks and the obligation to take all feasible precautions in attack. However, using heavy explosive weapons in populated areas in conformity with IHL is very difficult.

Here is why.

Many heavy explosive weapons are intrinsically inaccurate or imprecise. Many factors, including wind and other meteorological conditions, can alter their munitions’ trajectory and cause them to land off-target. Some of these weapons are even designed precisely to have a wide dispersion and saturate entire areas. As a result, areas often hundreds of square meters wide around the target are at risk of impact.

In populated areas, military objectives are often located in close proximity to civilians and civilian objects. The heavy payload and/or inaccuracy of such weapons, and their consequent area effects, raise serious questions as to whether they can be directed against, and their effects be limited to, a specific military objective in these circumstances, as is required by the prohibition of indiscriminate attacks.

Even if the use of a heavy explosive weapon in a populated area is not indiscriminate in the circumstances of a specific attack, parties must still assess the proportionality of their attacks. In doing so, they must consider the civilian harm that may be expected to result from the attack, whether directly or indirectly. Indirect or reverberating effects of the attack must be considered as soon as they are reasonably foreseeable. This includes, for example, those civilians that will fall ill or die because there is no clean water or no functioning hospital, as a result of an explosion.

The extent of destruction, including on critical infrastructure, in recent conflicts raises serious questions as to whether, and how, armed forces factor reverberating effects into their proportionality assessments. Discussions with operators raise further doubt as to the extent to which collateral damage estimation methodologies currently in use account for such effects.

This confirms the paramount importance of complying with IHL, especially when hostilities are conducted in urban and other populated areas, exposing civilians to great risks.

But the conversation should not stop here. We have often heard the argument that ‘using heavy explosive weapons in populated areas is fine, as long as IHL is respected’. However, even in cases where parties to armed conflicts insist that they have complied with IHL, the level of civilian harm caused is often unacceptably high – from a moral, a humanitarian, and often also a legal point of view. This begs serious questions about how IHL rules are in fact being interpreted and applied.

As the 2019 ICRC report on IHL and the challenges of contemporary armed conflicts reiterated, there is often lack of clarity, and sometimes disagreement, on how parties to armed conflicts interpret and apply IHL in relation to the use of explosive weapons in populated areas. Debates about IHL compliance are undoubtedly important. But there is also an urgent need for concrete action to address the significant civilian harm caused by these weapons, regardless of the legality of their use.

A call to adopt a policy of avoidance

This significant likelihood of indiscriminate effects is why the ICRC is calling on all States and parties to armed conflict to avoid, as a matter of policy, the use of explosive weapons with a wide impact area in populated areas.

An avoidance policy is not a ban on the use of all or certain explosive weapons in populated areas. It does not imply that such use is in and of itself unlawful, nor does it purport to reinterpret or amend the law in this regard. It is, in essence, a change of mindset. A policy to ‘avoid’ entails that explosive weapons with a wide impact area should not be used in populated areas unless sufficient mitigation measures are taken to reduce significantly the weapons’ area effects and the consequent risk of civilian harm.

An avoidance policy is not a binary, ‘black-and-white’ approach; it does not always come down to choosing a small-yield precision-guided munition over a traditional artillery gun. Rather, it involves a combination of mitigation measures to help ensure that the weapon’s use in the circumstances will not have wide area effects, that the area of impact of the weapon is no longer populated, or that the risk for civilians and civilian objects is otherwise sufficiently reduced.

Changing the munitions’ fuze or warhead to ensure the effects are contained on the target, choosing the angle of attack so as to reduce the weapon’s impact area, maintaining minimum safety distances from civilians and civilian objects, ensuring the reverberating effects of attacks are avoided or minimized, are examples of such mitigation measures the ICRC has identified based on extensive dialogue with States and armed forces and on existing military policy and practice.

But the implementation of an avoidance policy starts well before the fighting. It is critical that preventive measures are taken already in peacetime, at all levels and covering all aspects of operations. This means in particular:

• ensuring that the protection of civilians is explicitly identified as a strategic objective at the highest level prior to military operations, and is integrated into all military orders;
• ensuring that armed forces are properly trained and equipped for fighting in populated areas, including by equipping them with weapons that do not have wide area effects;
• ensuring that the interconnectedness of critical civilian infrastructure and essential services and the risks this entails if they are damaged are understood and integrated into military doctrine, planning and decision-making processes;
• taking all feasible measures at the strategic, operational and tactical levels to minimize hostilities in populated areas or to displace them outside of populated areas;
• ensuring that lessons learned, including with regard to the effects of specific types of weapons in populated areas, are incorporated as soon as possible into future planning, doctrine, training and practice; and
• sharing such mitigation measures with partner forces and supported parties to armed conflict.

These measures will help ensure alternative options are available, reduce the instances where the use of heavy explosive weapons would be considered in the first place, and thus facilitate the implementation of an avoidance policy.

‘A deadly choice’

On 27 January 2022, the ICRC will launch its report Explosive Weapons with Wide Area Effects in Populated Areas: A Deadly Choice. This milestone report provides a broad evidence-based assessment of the devastating consequences of the use of these weapons in populated areas; a technical overview of weapons of concern; an analysis of the implications of their use under IHL; and a synopsis of relevant policies and practices adopted by parties to armed conflicts. It concludes by unpacking why an avoidance policy is necessary and what it entails in practice, and provides detailed practical recommendations for political authorities and armed forces on measures to be taken as a matter of good practice, to strengthen protection for civilians against the use of heavy explosive weapons in populated areas. These recommendations cover the entire spectrum from doctrine and policies, to training, planning and conduct.

The extent of civilian suffering and destruction in today’s armed conflicts makes it urgently necessary for States and all parties to armed conflicts to reassess and adapt their choice of weapons when conducting hostilities in populated areas. The recommendations put forward in this report – many of which also inform the recent ICRC’s Reducing Civilian Harm in Urban Warfare: A Commander’s Handbook – aim to induce a change in policies and practices, by assisting political authorities and armed forces to give effect to an avoidance policy.

A need for urgent action

States and non-State parties to armed conflict must simply do better.

It is estimated that some 50 million people bear the brunt of urban warfare, a number bound to increase given the growing urbanization of the world’s population. The use of heavy explosive weapons in populated areas is a major cause of civilian harm in urban warfare today, and action is urgently needed to change this. Some militaries have already taken steps in this direction, but more needs to be done, and urgently.

In this respect, it is encouraging that over 70 States participate in an ongoing diplomatic process to elaborate a Political Declaration on explosive weapons with wide area effects in populated areas. The ICRC firmly supports this process. We urge States to adopt strong and clear commitments to take concrete action to advance the protection of civilians, including by imposing restrictions and limitations to the use of explosive weapons in populated areas.

We are confident that our new report and its recommendations will contribute to these efforts and to tangible progress in preventing and mitigating civilian harm. To accompany its launch, we are introducing a series of posts by experts and practitioners on some of the key humanitarian, technical, legal and military aspects addressed in the report, as part of the broader urban warfare series.

The ICRC will continue to engage with States, their armed forces and non-State armed groups to identify good practices that can serve as preventive and mitigation measures in the context of an avoidance policy, to alleviate the human suffering caused by the increasingly well-documented and foreseeable direct and indirect effects of using explosive weapons with a wide impact area in populated areas.

We hope that this new ICRC report and its recommendations will serve as food-for-thought and constructive debate. We welcome further contributions from readers on policies and practices for strengthening the protection of civilians in urban and other populated areas, including by restricting or limiting the use of heavy explosive weapons.

See also

• Damian Copeland & Lauren Sanders, Engaging with the industry: integrating IHL into new technologies in urban warfare, October 7, 2021
• Daniel Palmieri, War and the city: a history, April 29, 2021
• Laurent Gisel, Pilar Gimeno Sarciada, Ken Hume & Abby Zeith, Urban warfare: an age-old problem in need of new solutions, April 27, 2021