Natural resources, including alluvial minerals such as diamonds, have been at the centre of brutal wars in Africa. This column evaluates one of the first schemes aimed at preventing the illicit exploitation of natural resources to promote peace: the Kimberley Process Certification Scheme. The introduction of the diamond certification scheme significantly reduced armed conflict. Rebel groups were less likely to engage in armed conflict, and their operations became geographically more concentrated. This suggests that the certification scheme was successful in limiting rebel groups’ ability to finance violent activities.
A substantial body of empirical research has established a link between natural resources and violent conflict in low- and middle-income countries – a phenomenon often referred to as the ‘natural resource curse’ (Berman et al. 2017, Rigterink 2020, Bhattacharyya and Mamo 2021, Blair et al. 2021, Nordvik et al. 2021, Hodler et al. 2023, Rigterink et al. 2023). In this column, we focus specifically on alluvial minerals, with particular attention to alluvial diamonds, which are extracted across Africa by individual diggers using simple tools.
Exploiting commodity price changes, previous studies have demonstrated that the presence of alluvial minerals – such as diamonds and gold – has contributed to increased incidence of violent conflict in Africa (Rigterink 2020, Blair et al. 2021, Rigterink et al. 2023). Efforts to mitigate the resource curse through international agreements, national regulations, and transparency or certification schemes have sparked considerable debate, mainly due to a lack of rigorous empirical evidence (Berman et al. 2017, Oya et al. 2017). A major challenge to many initiatives is that countries affected by the resource curse often exhibit weak governance and widespread corruption, conditions that are likely to undermine the effectiveness of these efforts.
In our research (Binzel et al. 2023), we examine one of the first major international efforts to curb the illicit trade in natural resources and foster peace: the Kimberley Process Certification Scheme. This initiative was designed to stop so-called conflict diamonds – defined by the certification scheme as ‘rough diamonds used to finance wars against governments’ – from reaching global markets by requiring certification and tracking of diamond exports (e.g. Haufler 2009).
The Kimberley Process emerged in the early 2000s, following mounting pressure from civil society and the United Nations to address the role of ‘blood diamonds’ in fuelling devastating wars in countries like Angola, the Democratic Republic of the Congo, and Sierra Leone (Bieri 2015, Haufler 2009). While trade data suggest that the scheme helped boost official diamond exports in several producing nations, its actual effect on reducing armed conflict in Africa remains unclear.
Impact of the Kimberley Process on armed conflict
To study the causal impact of the Kimberley Process Certification Scheme on armed conflicts in Africa, we exploit cross-sectional variation in the suitability for secondary diamond mining within ×ばつ0.5 degree grid cells and compare the incidence of armed conflict in grid cells with and without secondary diamond suitability between 1997 and 2013, accounting for grid-cell and region×ばつyear fixed effects and time-varying controls.
We use data on secondary diamond suitability from Rigterink (2020) rather than actual mining activities, as the latter is likely endogenous to armed conflict. Geo-referenced data on armed conflict comes from the Armed Conflict Location and Event Data Project and the UCDP/PRIO Armed Conflict Dataset.
Our empirical approach builds on the fact that the certification scheme aims to make areas with alluvial diamonds less attractive to rebel groups by curtailing their ability to sell rough diamonds in the formal market. Thus, its impact on armed conflicts should primarily be concentrated in grid cells suitable for secondary diamond mining, which is also consistent with the evidence we provide in Figure 1.
Panel (a) of Figure 1 shows, by year, the share of grid cells with and without secondary diamond propensity for which Armed Conflict Location and Event Data Project or UCDP/PRIO Armed Conflict Dataset reports at least one armed conflict. The figure documents two facts. First, before 2002, secondary diamond suitability grid cells experienced, on average, more armed conflict than non-secondary diamond suitability grid cells (8.7% compared to 3.5%). Second, following the introduction of the Kimberley Process in 2002, the incidence of armed conflict declined sharply in secondary diamond suitability grid cells while it remained flat in non-secondary diamond suitability grid cells.
Figure 1 The effect of the Kimberley Process on armed conflicts
(a) Share of grid cells with armed conflicts over time
Figure 1a Share of grid cells with armed conflicts over time
(b) Difference-in-differences estimates
Figure 1b Difference-in-differences estimates
Notes: Panel (a) shows, by year, the share of grid cells with and without secondary diamond propensity for which Armed Conflict Location and Event Data Project (ACLED) (left panel) and UCDP/PRIO Armed Conflict Dataset (UCDP) (right panel) reported at least one armed conflict. Panel (b) plots the difference-in-differences estimates based on ACLED (left panel) and UCDP (right panel) of the interactions between a dummy for grid cells with secondary diamond suitability and year fixed effects with their 95% confidence intervals. The dependent variable is an indicator variable equal to 1 if at least one armed conflict occurred in grid cell i and year t, and 0 otherwise. The omitted year is 2001. The dashed vertical line indicates the start of the Kimberley Process Certification Scheme in 2002.
Panel (b) plots the event-study difference-in-differences estimates. They show no statistically significant pre-trend. However, after 2001, when member countries began implementing the Kimberley Process, we find a permanent decline in the incidence of armed conflict in secondary diamond suitability grid cells. Our estimates based on a simple difference-in-differences model suggest that the Kimberley Process reduced the incidence of armed conflict by about half in the first 12 years after its introduction.
Our results are robust across several alternative specifications and robustness checks, and we show that other forms of violence did not increase in secondary diamond suitability grid cells following the introduction of the Kimberley Process.
In addition, we exploit variation in treatment intensity and document that the impact is larger for secondary diamond suitability grid cells that are located in early member countries of the Kimberley Process (versus late or non-member countries) and for grid cells with high secondary diamond suitability (versus low). This provides further evidence that the observed decline is indeed due to the certification scheme.
Finally, we document that, as intended, it is mainly countries with weak political institutions – as defined by the Polity 5 Democracy Index or by the Worldwide Governance Indicators – that benefit from the introduction of the Kimberley Process.
Did the Kimberley Process displace armed conflict or other violence to other areas?
Our findings of a permanent decline in armed conflict are consistent with the Kimberley Process’s core idea of breaking the link between alluvial diamond mining and violent conflict by making it difficult for rebel groups to finance their activities through diamond revenues. The loss of diamond revenues, however, put rebel groups under pressure to relocate their activities or shift to other activities and revenue sources, potentially leading to different forms of violence.
In a final step, we therefore examine whether rebels relocated their activities away from secondary diamond suitability grid cells, and whether this shift fuelled violence elsewhere in the form of armed conflict or other violence. To do so, we first use our grid-cell-level data and examine geographic spillovers. We find evidence that the certification scheme reduced armed conflict within and around secondary diamond suitability grid cells, without increasing other forms of violence. This suggests that rebel groups found it difficult to replace lost diamond revenues.
One caveat is that rebel groups may have relocated their violent activities to places further away from secondary diamond suitability grid cells. We therefore turn to rebel-group-level data from Armed Conflict Location and Event Data Project. We limit the analysis to rebel groups that were involved in armed conflicts before the introduction of the Kimberley Process. We then compare rebel groups with armed-conflict activities in secondary diamond suitability grid cells before the Kimberley Process was introduced with rebel groups without such activities.
We document that after the introduction of the Kimberley Process, rebel groups engage in fewer armed conflicts and fewer violent conflicts overall, and their violent activities become more geographically limited. These results support the idea that the Kimberley Process Certification Scheme was successful in its intended manner: restricting or even removing a core source of income for rebel groups, thereby leading to an overall decline in violent conflict.
Conclusion
Over the past decades, there has been a rise in international agreements, national regulations, and transparency and certification schemes that aim to address global challenges, such as poverty and vulnerability, climate change, and violent conflicts (e.g. Dragusanu et al. 2022, Christensen et al. 2021, Rohner 2024). Our evaluation of the Kimberley Process Certification Scheme, one of the first international certification schemes, provides evidence that such initiatives can promote peace even in countries with weak governance structures.
One possible reason for the effectiveness of the Kimberley Process is that its strict enforcement may not always be necessary, as long as governments and other stakeholders remain committed to cutting off rebel groups from their funding sources. It remains an open question whether initiatives that focus on other forms of violence associated with alluvial diamond mining, such as military violence and violations of human rights, can be similarly effective.
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