Biophysical indicator-based assessment of climate change severity in the Upper East Region, Ghana

Abstract

Climate change has continued to be a pressing concern, particularly for climate-vulnerable regions around the world, including Sub-Saharan Africa. While climate change is occurring at a rapid rate, its impact increases in severity. This article examines the biophysical assessment of climate change severity in the Upper East Region (UER) of Ghana. The study’s methodology combines satellite remote sensing data, field surveys, participatory mapping, and policy analysis. A year-long mean, Normalised Differential Vegetation Index (NDVI), rainfall pattern, evapotranspiration (ETa), and Land Surface Temperature (LST) were generated for four different years from Google Earth Engine. A survey involving 200 respondents was also conducted to complement the satellite-based imagery. The findings of the study showed a decline in the mean annual NDVI from 0.40 in 1990 to 0.35 in 2024, thus indicating a decline of 14% in vegetation health. The NDVI decline reveals a transition in vegetation from Sudan to Sahel savannah, suggesting an increasing climate change impact in the region. Rainfall also indicated a downward trend, thus reducing from 1216mm/yr in 1990 to 1089mm/yr in 2024. Also, we discovered an upward trend in LST, with mean maximum LST increasing from 39 0 C in 2013 to 45 0 C in 2024 and mean minimum LST increasing from 31 0 C to 33 0 C. In the same trend, ETa results suggest increasing evapotranspiration from a mean maximum of 113mm/yr in 2000 to 178mm/yr in 2024. While satellite-based data has revealed worsening climatic conditions in the UER, smallholder farmers acknowledge this and lament that its impact threatens their livelihoods and food security in the region. To address the situation, proactive climate action through collective effort, institutional commitment, and long-term localised adaptation strategies has been recommended.