Several decades of scientific work on a better understanding of the earth’s climate system have led to increasing certainty that changes in the climate system are influenced by human activity. As the 5th Assessment Report of the IPCC notes, there is 95% confidence that the increase in global surface temperature is caused by the anthropogenic increase in greenhouse gas concentrations \citep{stocker2013climate}. As a result, more extreme weather occurrences have been predicted for many regions for the upcoming decades. Successfully coping with changes in weather patterns requires mitigation measures for future GHG emissions reductions along with adaptation measures, the latter adopted particularly in those regions that will be severely affected by future weather extremes.
In most of the developed Annex I countries, a well-functioning governance system provides financial resources and institutional stability for potentially large-scale investments in adaptation and mitigation measures within the national territories. In many developing countries, however, governance and institutions are poorly developed, resulting in a lack of financial investments to cope with climate change. Given these circumstances, affordable adaptation measures are required to be taken by citizens themselves on a local level to avoid adverse effects on their livelihoods.
An important field for investigating the effectiveness of adaptation measures against climate change are African smallholder, or subsistence farmers. In many parts of the African continent, smallholder farmers cultivate more than 70% of the arable and permanent cropland and are responsible for a very high proportion of local food and crop production \citep{Morton_2007}. However, their lack of economic resources restricts them access to alternative livelihoods \citep{Slingo_2005}. Given these circumstances, a worsening of climate variability, primarily decreases in precipitation and increases of droughts that have been predicted for large parts of Africa, highlight the importance for cost-effective adaptation measures for the agricultural sector in Africa. Without these measures, severe effects on food production are to be expected that greatly endanger the livelihood of local farmers and the people that to a great extent dependent on local food supply \citep{Waha_2013}. If not adopted successfully, African food systems are unlikely to provide sufficient nutrition to a population that is growing by 4% annually, and that will thus further increase the stress on arable land \citep{POP_2012}.
This paper examines agroforestry as an adaptation measure that can be applied by smallholder farmers in order to increase the resilience of African food systems against increasing climate variability. In doing so this paper aims at responding to the following research question:
What is the adoption potential of agroforestry for smallholder farming in different countries of Sub-Saharan Africa to strengthen the resilience against increasing climate variability?
The paper proceeds as follows. Firstly, based on a literature review the predicted impacts following from climate change are synthesized for different African regions. Secondly, agroforestry is being introduced as a cost-effective adaptation measure. Lastly, adoption potentials for different regions are quantified and advice is given on increasing the adoption of agroforestry methods by addressing several identified barriers.