Climate Change Mitigation in The Bahamas - The Power of Earth Observation for Blue Carbon Accounting

The seagrass ecosystem can sequester and store vast amounts of carbon in their soils and biomass, which renders them a strong natural climate solution for climate change mitigation. The carbon uptake capabilities of this coastal marine ecosystem have important implications for Multilateral Environmental Agreements like the National Determined Contributions of the Paris Agreement and the Sustainable Development Goals. However, the  value of seagrasses for these agendas is often overlooked due to a lack of spatially-explicit extent and carbon data. Modern Earth Observation advances can provide time- and cost-efficient solutions to minimise these data gaps.

We utilised multi-temporal Sentinel-2 data within the cloud computing platform Google Earth Engine to quantify the current Bahamian seagrass extent, associated carbon stocks, and sequestration rates. Our approach combines big satellite data, pixel and object-based feature analysis, and scalable machine learning algorithms. We are envisaging to assess ecosystem extent changes using historic image archives (e.g. Landsat), and the integration of biophysical variables into our models (e.g. bathymetry, meadow patchiness).

We estimate the current seagrass ecosystem extent to cover an area of up to 46,792 km², storing 723 Mg carbon and sequestering about 68 times the amount of carbon dioxide that was emitted by The Bahamas in 2018.

Our generated data highlights the importance of the seagrass ecosystem for climate change mitigation in The Bahamas and beyond, and showcases the necessity of including seagrass blue carbon in national climate agendas. This data and our developed earth observation approach can support policy makers and scientists from a national to a global climate action context.