Assessing the Cooling Potential of Land Restoration in Africa with Google Earth Engine

The African continent, although having one of the lowest per-capita contribution to greenhouse gas emissions, is already experiencing the effects of global climate change, resulting in biodiversity loss, droughts, reduced food production, reduced economic productivity and loss of lives. Land restoration and greening practices, such as active reforestation, natural regeneration, and water harvesting are seen as one of the major solutions to mitigate climate change through the carbon sequestration potential of trees. However, land restoration practices can also directly affect the local climate through changes in the biophysical properties of the earth surface (e.g. albedo, evapotranspiration and surface roughness) and can therefore be used as adaptation strategy to reduce the impact of climate change in Africa. Yet, it is currently unknown to what extend land restoration can be used to reduce local temperatures in Africa through biophysical processes, because the net cooling or warming effect of vegetation changes depends on latitude, scale and atmospheric conditions.

In this study, we aim to bridge this gap by determining the biophysical cooling and warming effects of land restoration in Africa. To this end, we use MODIS satellite imagery in Google Earth Engine to analyse the effects of vegetation changes (NDVI) in the twenty-first century on albedo and land surface temperature, after which we apply the found relations to predict the cooling effect of potential large-scale land restoration in Africa. Preliminary results show that increases in vegetation cause biophysical cooling in large parts of Africa and especially in dryland areas. Using these relations, we predict that large scale land restoration can decrease the land surface temperature in some areas up to 5 degrees Celsius. With these results we hope to provide more insight in the climate change adaptation potentials of land restoration projects in Africa, as well as other parts of the world.