Climatic impacts of decreased tree cover in sub-Saharan Africa

The human population in sub-Saharan Africa is growing the fastest in the world, which causes pressure on land resource together with climate change. More cropland needs to be cleared to maintain food security, but decreasing woody vegetation has climatic impacts. Loss of forests and woody vegetation decreases carbon sequestration from the air and carbon stocks of the above ground vegetation, while management of the land cleared for agriculture releases greenhouse gas emissions from soil. Loss of forest cover also leads to decreased soil organic carbon stocks. Loss of woody vegetation and trees in general causes increased land surface temperature, and consequently, increased air temperature. In the highlands, the decreasing forest cover also decreases the ability of the trees to capture atmospheric moisture by fog deposit, which also decreases the ability of water to infiltrate to the soil. Fog deposit is also decreased by increased land surface temperature, which causes the cloud base height to be at a higher level and out of the reach of forest canopy. While conservation and protected areas are typically considered to be positive, too high elephant populations overseeding the carrying capacity of the environment are decreasing the woody vegetation, thus having climatic impacts, too. This is because elephants tend to eat leaves and bark from the trees while not having grass to eat during the dry spells.

University of Helsinki has been studying climatic impacts of land cover change in Africa using Taita Taveta County in Kenya as a test site and model for whole sub-Saharan Africa applying remote sensing data and environmental sensing network since 2009. Currently, we are developing climate-smart agriculture and livestock management to mitigate climate change but improving food security.