Slavery from Space

High resolution satellite data were used to make a credible estimate of the number of brick kilns across the ‘Brick Belt’, helping to calculate the scale of modern slavery present. Brick kilns are high slavery-prevalent industries and before this work, the full scale of brick kilns and by proxy, slavery, was unknown, making action from the appropriate agencies difficult. This innovation provides data to help NGOs and governments fight modern slavery. This approach scales in time and space.

Innovation Summary

Innovation Overview

There is a global political commitment to ending slavery (UN Sustainable Development Goal 8.7), however, the difficulty of accurately estimating the number of slaves and their locations is a significant barrier to successful antislavery action. Remoteness in particular can make it difficult to locate and monitor sites of contemporary slavery on the ground, whilst the dynamic nature of the human system is an added challenge. Whilst a free worker cannot be distinguished from an enslaved worker from satellite remote sensing data, reliable, timely, spatially explicit and scalable metrics extracted from that satellite data can be used to reveal the location of sites associated with illegal, potentially slave-based labour. As shown in a recent documentary, NGOs on the ground in the “Brick Belt” have used the expertise from the University of Nottingham's Dr. Doreen Boyd's team to underpin rescue efforts. In short, NGOs gained more intelligence, and enslaved people were freed as a result of the data shared with NGOs by Boyd and team.

Slavery from Space specifically embraces the advantages of all forms of satellite remote sensing data (and other complementary and synergistic (geospatial) data) to unlock valuable knowledge about slavery activity and accelerate progress to its complete abolition. By combining image processing with machine learning algorithms within a number of methodological approaches, Slavery from Space aims to detect slavery but also to monitor antislavery intervention and ultimately, by being eyes in the sky, prevent slavery. The approach also includes a citizen-science component to bridge any gaps in the machine-generated knowledge, as well as aid algorithm development. A new citizen-science platform will allow citizen scientists to upload qualitative observations (e.g. notes, photographs) to further inform on spatial patterns and prevalence of slavery. Thus the objective of this innovation was to establish a methodology for using satellite data to develop reliable estimates of high slavery prevalent industries, such as brick kilns, as a proxy for slavery numbers. In common with other initiatives (e.g., the Global Partnership for Sustainable Development Data), we aim to fully harness the data revolution for antislavery and use the resultant new knowledge to eradicate slavery once and for all. Ending slavery will mean a better world for everyone: safer, greener, more prosperous, more equal. The aim is to demonstrate the role that satellite data will play in achieving this “Freedom Dividend”.

Boyd and team are currently working with private sector data providers to access even more spatially- and temporally-rich satellite data and to start thinking about other high slavery-prevalent industries to locate. The team is in dialogue with the UN to understand how to apply geospatial innovations to the wider modern slavery agenda, and open source information about the approach will be shared internationally through the UN’s Delta 8.7 knowledge platform.

Of the ILO estimates of slavery, Boyd and team estimate that a third of slavery may be detectible from space, as it takes place in stone quarries, brick kilns, fisheries, mines, forests and construction sites (rather than in domestic service, food and hospitality services, or sexual exploitation). Using satellite technology along with artificial intelligence and geospatial science methods and tools (e.g., crowd sourcing (both with proprietary and open source platforms); convoluted neural network machine learning), we can provide up-to-date, spatially explicit and defensible estimates of slavery. For example, charcoal camps are visible in Brazil, brick kilns in Cambodia, stone quarries in India, and gold mines in Tanzania. Our Slavery from Space work will extend the reach of antislavery enforcement. As one NGO (Free the Slaves) noted in a newspaper article: “Slavery from Space is a necessary addition to the Global Slavery Index, which focuses on the presence of slavery at the macro level. Slavery from Space, on the other hand, works at micro level, on the ground, and allows NGOs to tackle specific and localized cases of modern slavery. Most companies that operate illegally remain under the radar but are exposed by Slavery from Space.” The full technical methodology of one method (statistical inference and crowd sourcing) is described in ‘Slavery from Space: Demonstrating the role for satellite remote sensing to inform evidence-based action related to UN SDG 8’ in ISPRS Journal of Photogrammetry and Remote Sensing 142 (2018).

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  • Evaluation - understanding whether the innovative initiative has delivered what was needed

Innovation provided by:


  • Slavery from Space Powerpoint presentation of the Slavery from Space project of The Rights Lab, University of Nottingham, UK
  • Boyd et al 2018 Academic publication describing early results.

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