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Implementing the Political Declaration on explosive weapons in populated areas: why engineering-perspectives on blast effects matter

Advocating for engineering perspectives on the protection of civilians from the use of explosive weapons in populated areas

In November 2022, Action on Armed violence conducted an interview with Dr Jack Denny, Lecturer at the University of Southampton, about ways in which engineering and data-driven approaches can both inform response strategies and complement ongoing advocacy campaigns to reduce harm from blast injuries. That same month, 83 states endorsed the Political Declaration on Strengthening the Protection of Civilians from the Humanitarian Consequences Arising from the Use of Explosive Weapons in Populated Areas. 

Since then, new conflicts in Gaza and Sudan have challenged these states’ commitment  to their responsibility to condemn the use of explosive weapons in populated areas, and ongoing international and non-international conflicts in Syria, Myanmar, Ukraine, Afghanistan, and Pakistan, amongst others, continue to illustrate the immediate and reverberating impacts of explosive weapons in population centres.

As states gather in Oslo, in April 2024, to discuss progress in the implementation and universalisation of the Political Declaration, AOAV analyses data on explosive weapons in populated areas alongside Dr Denny and his partners’ research in this area, highlighting how combined approaches can strengthen both advocacy and response strategies to strengthen the protection of civilians.

Read the full interview with Dr Denny here.

Over the past decade, Action on Armed Violence (AOAV) and our colleagues within the International Network on Explosive Weapons (INEW) advocated tirelessly towards the November 2022 ‘Political Declaration on Strengthening the Protection of Civilians from the Humanitarian Consequences Arising from the Use of Explosive Weapons in Populated Areas (EWIPA),’ endorsed by 83 states in Dublin. The issue remains a pressing one, as both state and non-state users of explosive weapons continue to target populated areas in their attacks: between 2010 and 2023, 64% (27,715) of all 43,578 incidents recorded by AOAV took place in populated areas. In 2023 alone, 76% (5,593) of all 7,368 recorded incidents occurred in populated areas.

AOAV has been documenting the causes and consequences of explosive weapons use around the world since 2010, managing a global monitor of casualty-causing incidents of explosive violence as reported in English-language news media. In this way, AOAV has been collecting data on the devastating and disproportionate impact of explosive weapons on civilians and civilian livelihoods – both as a direct result of the blast, and due to the long-term consequences this form of violence has on civilian environments and infrastructure.

Between 2010 and 2023, AOAV recorded 43,578 incidents of explosive weapons use around the world. These incidents, reported across 133 countries and territories, have resulted in 333,650 civilian casualties (120,053 killed) and 127,807 armed actor casualties (84,174 killed). Civilians consequently account for 72% of total casualties from explosive weapons use recorded by AOAV since 2010, and 59% of total deaths from such attacks. 

As part of the data collection process, AOAV differentiates between attacks in locations which are reported as populated – based on Protocol III of the 1980 Convention on Certain Conventional Weapons (CCW), which defines concentrations of civilians as: “any concentrations of civilians, be it permanent or temporary, such as in inhabited parts of cities, or inhabited towns or villages, or as in camps or columns of refugees or evacuees, or group of nomads” – and those which took place in locations not reported as populated. As mentioned above, the majority of incidents are recorded in such areas: between 2010 and 2023, 64% (27,715) of all 43,578 incidents recorded by AOAV took place in populated areas. The numbers don’t lie: when explosive weapons are used in populated areas, those most likely to be harmed, both directly and in the long-term, are civilians.

Since 2010, attacks recorded in locations reported as populated have killed and injured 306,312 civilians (108,271 fatalities) and 32,417 armed actors (18,775 killed). This means 92% of total civilian casualties in that time occurred in populated areas, and 90% of civilian fatalities. It also means that, when explosive weapons were used in these locations, 90% of those reported killed or injured were civilians rather than armed actors. More specifically, 85% of those reported killed in these locations were civilians rather than armed actors. In contrast, when explosive weapons are used in locations not reported as being populated, civilians account for 22% (27,338) of all 122,728 recorded casualties, and 15% (11,782) of all 77,181 recorded fatalities.

But what actually happens when explosive weapons are used in towns and cities, and what is it that makes these locations so dangerous during an explosion?

The International Blast Injury Research Network (IBRN) has harnessed engineering-driven approaches to better understand the consequences of explosive weapons use in urbanised environments, and how this impacts the risk of harm to civilians. As expected, Dr Jack Denny told us that urban settings present significant additional hazards following an explosion, compared to less built-up areas. He explained how collaborative engineering research between the University of Southampton (Dr Jack Denny), University of Sheffield (Prof Genevieve Langdon & Dr Sam Rigby) and University of Cape Town (Prof Steeve Chung Kim Yuen, Dr Sherlyn Gabriel) has found that the likelihood and severity of harm caused by blasts from explosive weapons increases in urban areas.

As Dr Denny explained, the IBRN was launched in 2019 to address the gap in existing blast research, which has tended to focus on military perspectives. Since then, they have fostered innovative research within the civilian context, with the goal of reducing harm from blast injuries. In particular, Dr Denny said he wants to improve our understanding of the interaction of blast waves and structures within urban environments, and the ways in which this modifies the risk of blast injury. 

According to Dr Denny, existing pre-clinical blast injury studies often applied explosive testing conditions with limited real-world relevance. Building on this, the IBRN developed guidelines to inform the design of explosive testing conditions which are clinically relevant as well as realistic – that is, which correspond to real-world threats. Dr Denny explained that the IBRN identified blast testing conditions that are equivalent to explosive events such as truck bombs, landmine detonations, and backpack IEDs. In this way, future pre-clinical blast injury studies can more accurately reflect the injury risk from real-world blast threats.

In the interview, Dr Denny described the key blast injury mechanisms which are at play following an explosion: primary blast injuries caused by high pressures from the blast wave itself; secondary blast injuries caused by fragmentation from the weapon itself or debris from damaged buildings, vehicles, and other objects that can become high velocity projectiles; and tertiary blast injuries, or crush-type blast injuries, caused by structure collapse or being thrown against surfaces by blast winds. Urban settings consequently present multiple additional hazards following a blast, compared to environments with fewer fragmentation hazards or structural obstacles. Such injury mechanisms were prominent in Dr Denny’s forensic study of the 2020 Beirut Blast in collaboration with Dr Samar Al-Hajj, which provided new understanding of how different factors (i.e. distance from the epicentre, inside vs. outside spaces etc.) affected the likelihood and patterns of blast injuries.

Even primary blast injuries – those caused directly by the blast pressures – are affected by built-up environments: Dr Denny described how blast pressures are modified in built-up settings, due to reflections, shielding, and channelling effects caused by the complex interaction of the blast wave with structural obstacles. For example, collaborative research between Dr Denny, Prof Genevieve Langdon, Dr Sam Rigby,  has shown that channelling effects – when a blast wave is squeezed between buildings – can amplify the effects of the blast, increasing the likelihood and severity of primary blast injuries, including ruptured ear drums and blast lung injury. 

Dr Denny sees an important future for this research: “Improved knowledge of blast effects in built up areas could help to inform urban planning, risk assessments and strategies to prevent or mitigate harm from future explosive events. This could involve further research into blast protection, leading to novel materials and structural protection systems for more resilient infrastructure and increased protection for their occupants.” According to him, modelling the consequences of a broad range of blast scenarios could also inform health system response and preparedness to blast incidents, predicting expected injury patterns and casualty estimates. 

Dr Denny and his colleagues identify a significant gap that such engineering-driven approaches and data can fill: he reminded us that the UN has acknowledged that our understanding of the consequences of EWIPA, and any action taken, need to be supported by scientific research. Dr Denny went on to explain that research into blast effects can quantify why the use of EWIPA is so harmful, by examining the underlying physics of blast interaction in urban environments and developing blast injury risk maps for different scales of weapons systems in different urban scenarios. As discussed above, these models could be used to develop disaster management plans and sheltering guidance, therefore strengthening the protection of civilians from blast incidents. This high-quality data would become a strong component of evidence-led decision-making and policy work, and powerfully complement ongoing advocacy campaigns.

States gathering in Oslo are there to discuss the state of implementation and universalisation of the Political Declaration. Both endorsing and non-endorsing states are attending. The engineering perspectives highlighted by Dr Denny are an invaluable advocacy tool for encouraging non-endorsing states to sign the Declaration, but they are also a singularly practical tool to guide implementation. Understanding how a particular explosive weapon will interact in a particular environment can inform humanitarian access, casualty recording, and victim assistance operations – all of which are responsibilities endorsing states have committed to. 

In order to implement the Declaration, we need to understand the blast effects of what we are trying to protect people from. 

Find out more about the IBRN here.