Using Satellite Earth Observation to Guide Coastal Planning and Reduce Erosion Risk in Ghana

Coastal communities in Ghana face increasing threats from erosion and flooding along the country’s 500 km coastline. Traditional planning has struggled with uncertainty due to limited, fragmented, and reactive data sources. Using satellite Earth observation (EO) data through the Digital Earth Africa platform, a multi-institutional Ghanaian collaboration involving academic institutions, planning authorities, and private sector partners implemented a long-term coastal monitoring approach to provide timely, spatially explicit information on shoreline dynamics.

The project enabled:

The approach supports planners in making proactive decisions, reducing risks to communities, safeguarding livelihoods, and protecting ecosystems, contributing to climate adaptation and multiple Sustainable Development Goals (SDGs).

“As someone who has seen our shoreline shrink year after year, watching our homes and livelihoods get closer to the waves, it’s both a relief and a concern to see people monitoring the erosion now. We’ve always known it’s happening.” – Knowledge Wisdom, fisherman, Ghana.

This quote reflects the stark reality for planners and the 3.2 billion people globally whose livelihoods are jeopardised by land degradation—a crisis that is particularly acute in developing nations where populations rely heavily on land resources for survival. Along Ghana’s 500 km coastline, particularly in Keta, this degradation manifests as a persistent, life-threatening struggle. Communities here have watched the sea reclaim not just land, but the very foundations of their social and economic resilience. In Keta, where poverty is widespread, the majority of residents depend entirely on fishing and agriculture for their survival. As sandy beaches disappear and the Keta Lagoon Complex faces threats from siltation and pollution, fish stocks decline and productive agricultural grounds are lost to the waves. The degradation of mangroves—once essential for stabilising the ecosystem—is a desperate trade-off, as these forests are harvested for charcoal, timber, and construction materials just to meet immediate needs. These changes are driven by the interplay of rising sea levels and human-induced pressures, such as the sediment deficit caused by the Akosombo Dam in addition to others such as sand mining, coastal construction, and ecosystem degradation. The result is a coastline that is constantly changing.

Until recently, planning around erosion was difficult. Long-term, consistent spatial data on shoreline change was limited. Decisions were often based on fragmented information or taken only after extreme events had already caused damage. This made it hard to clearly identify risk areas, guide development, or prioritise investments in protection measures. There was a clear need for reliable, up-to-date information that could show how the coastline is evolving and support more proactive decision-making.

To address the need for reliable, consistent, and spatially explicit information on shoreline dynamics, a satellite-based approach was developed by the Ghana Coastal Erosion Team as a multi-institutional collaboration, using the Digital Earth Africa platform.

The team brings together expertise from:

This collaboration is supported by the GEO-LDN Flagship to strengthen national capacities and enable coordinated, data-driven coastal planning.

The GEO-LDN flagship facilitated access to geospatial data and platforms such as Digital Earth Africa to strengthen risk analysis and enable an intersectoral approach. Using Landsat and Sentinel imagery, shoreline positions were mapped annually over the period from 1991 to 2023. From this, it was possible to measure how quickly the shoreline is moving, how much land has been lost or gained, and where erosion and accretion are taking place. The analysis shows that the coastline behaves in complex ways. Periods of erosion and accretion alternate, influenced by sediment dynamics, coastal structures, and climatic variability.

A set of information products has been developed from this work by the Ghana Coastal Erosion Team. These include multi-temporal shoreline maps, baseline reference datasets, indicators of shoreline change, and spatial hotspot identification. Together, they provide a clearer understanding of where the coastline is stable and where it is at risk. They are currently being integrated into national and subnational planning processes, enabling Earth observation data to directly contribute to Integrated Coastal Zone Management (ICZM) and land-use decisions.

The approach is based on open-access satellite data and cloud-based processing tools. Long-term analysis relies on the Landsat archive, which provides observations from the early 1990s to the present. This is complemented by higher-resolution Sentinel-2 imagery and Sentinel-1 radar data, which is particularly useful in areas with frequent cloud cover.

The analysis was carried out by Julia Quaicoe and the Ghana Coastal Erosion Team within the Digital Earth Africa Sandbox which allows large volumes of satellite data to be processed efficiently. To improve accuracy, tidal effects are accounted for using the FES2014 tidal model, ensuring that shoreline positions are comparable across time

Additional processing steps include calculating the Modified Normalized Difference Water Index (MNDWI), which uses water indices to distinguish land from water, and applying compositing techniques to reduce noise from clouds and atmospheric conditions. Spatial analysis and visualisation are supported using tools such as the Quantum Geographic Information System (QGIS). By relying on open data and shared platforms, the approach remains accessible and can be applied in other coastal contexts.

The use of Earth observation data has improved how coastal planning is carried out in Ghana by the Land Use and Spatial Planning Authority (LUSPA). Instead of relying on limited or reactive information, planners now have access to consistent and long-term evidence on how the coastline is changing. This enables earlier identification of high-risk areas before development takes place. As a result, infrastructure and settlements can be planned more carefully, reducing exposure to erosion and flooding. The information also supports more targeted prioritisation of coastal protection measures, including both engineered solutions such as revetments and ecosystem-based approaches such as mangrove restoration by LUSPA and the Ministry of Environment, Science and Technology in Ghana.

Beyond technical improvements, the approach has strengthened coordination across institutions. By working from a shared evidence base, planning authorities, environmental agencies, and other stakeholders are better aligned in their decision-making processes. This contributes to more integrated coastal management and more effective use of public resources. In addition, a dedicated storytelling online workshop implemented by GEO-LDN provided an opportunity for the coastal erosion country team in Ghana to reflect on how to translate Earth observation data into more accessible and decision-relevant information. Participants highlighted that challenges remain in communicating results clearly and linking data to real-world impacts.

The workshop also highlighted the importance of combining scientific analysis with local knowledge and lived experience, helping to make coastal changes more understandable and relevant for different stakeholders. For coastal communities, these changes have practical implications. Reducing exposure to erosion lowers the risk of displacement and helps protect livelihoods, particularly those linked to fisheries and coastal economies. At the same time, important ecosystems such as lagoons and mangroves can be better preserved. Overall, the approach supports climate adaptation efforts in Ghana by enabling more proactive and informed decision-making by LUSPA and MESTI. It also provides a scalable example of how Earth observation data, combined with stakeholder engagement, can support resilience in other vulnerable coastal regions.

The methodology is designed to be transferable and can be applied in other coastal regions facing similar challenges, particularly where data availability and technical capacity are limited. By relying on open satellite data and platforms such as Digital Earth Africa, the approach lowers barriers to entry and allows countries to build their own evidence base for coastal planning. This demonstrates how Earth observation can move beyond analysis to become an operational tool for policy and planning, supporting long-term resilience in the face of climate change and environmental degradation.