Commercial satellite imagery made available through ESA’s Third Party Missions programme is guiding an ambitious community-focused initiative to regrow natural grasslands in Sub-Saharan Africa. 

Led by non-profit foundation Justdiggit, this impressive project is revitalising native ecosystems, boosting prosperity – and contributing to global climate action.  

During the past decades, the impacts of climate change combined with unsustainable practices have caused large areas of land in parts of Africa to degrade, leading to falling crop yields, rising local tensions, weakened resilience to extreme weather events, and further loss of fertile soils.

Justdiggit aims to arrest this alarming cascade of events by engaging with communities on the ground to unlock the enormous potential of nature-based land management approaches. 

The foundation employs a simple and effective technique in which a small and shallow semicircular-shaped pit – called a ‘bund’ – is dug into the dry earth. This then fills up during rainfall, allowing water to seep into the soil and rehydrate the land, which promotes the regrowth of vegetation. 

Some 315 000 bunds have now been excavated by local communities in selected areas of Sub-Saharan Africa and optical imagery collected by commercial remote sensing missions is key to this success.

Sander de Haas, Chief Technical Officer at Justdiggit, said: “Data made available to us through ESA’s Third Party Missions programme is proving to be a vital asset to our regreening initiative.

“In combination with data collected on the ground, we draw on a range of optical satellite imagery to help us choose appropriate areas for our project sites and provide quantifiable metrics on subsequent regrowth.” 

Sander and his team use imagery collected by Planet Lab’s SkySat and PlanetScope constellations, which were added to the Third Party Mission programme in 2022. 

SkySat consists of around 20 high-resolution Earth imaging satellites that collect thousands of square kilometres of data every day. Very high resolution imagery gathered over a project site near the settlement of Rombo, Kenya in Spring 2023 revealed substantial regrowth following a period of rainfall. 

PlanetScope is composed of more than 100 nanosatellites, delivering global imagery at a resolution of 3.7m to 4m. In a similar analysis, these data were used to chart the restoration of a site near Pembamoto in Tanzania.

Imagery from these constellations aligned excellently with measurements of regrowth gathered on the ground or by drones, and using satellite data was found to be a far more efficient and cost-effective way of collecting such observations. 

The availability of commercial data is also enabling Justdiggit to explore new technologies; the team is currently developing a machine learning algorithm that will support the management of project sites by detecting and counting individual bunds. 

Another key aim of the project is to raise awareness of climate-related land degradation, and imagery from Third Party Missions is regularly posted on social media to engage young and diverse audiences about the potential of regreening initiatives.

Sander de Haas concluded: “This project is a great demonstration of how satellite data can make a positive impact on the ground, by helping to address important environmental and community challenges. 

“Justdiggit leads several other regreening initiatives across Africa and we hope to employ satellite data to support these projects in the future.”