The effects of changes in temperature and rainfall on agriculture in sub-Saharan Africa

Agricultural production in sub-Saharan Africa has not kept pace with other developing countries. One factor is the changes in temperature and rainfall across the region since the 1950s. What does this mean for the future of African agriculture?

Researchfrom the European Commission, the Ecole Polytechnique Palaiseau, inFrance, and Swansea University, in the UK, looks at the relationship betweenrainfall, temperature and agricultural production in sub-Saharan Africa (SSA).It compares SSA experiences with developing countries in other continents. Theresearchers found that climatic changes have had significant effects on totalagricultural output in SSA, more than in other developing countries.

Allover the world, there has been a steady rise in temperature over the past fewdecades. But in SSA, there has also been a decline in the amount of rainfall.The amount of water available for agriculture also varies hugely across theregion, because of diverse geographic conditions. As a result, a much smallerarea of land is irrigated in SSA than in other developing countries.

Rainfallis high in some areas of SSA, particularly around the Equator, but the run-offfrom these areas to semi-arid and arid regions is low. The parched soil indrier regions absorbs run-off quickly and high temperatures increase thewater-holding capacity of air, so less water reaches the ground. These factorsmake agriculture in SSA particularly sensitive to changes in rainfall andtemperature.

Theresearchers estimated future agricultural output across SSA with regard to changingtemperature and rainfall. They used data from the International Panel onClimate Change and the Food and Agriculture Organization concerning labour,livestock, fertiliser, capital, land, rainfall and temperature. While consideringthe whole region may overlook differences within this large and diverse region,it has the advantage of providing an indication of broad changes.

• Since themid-1970s, rainfall in SSA has been below the pre-1960 average. At the sametime, SSA's agricultural production has been relatively lower than in otherdeveloping countries.
• If rainfall hadremained at its pre-1960s average, then, at the end of the 20th century, thegap in agricultural production between SSA and other developing countries wouldhave been two-thirds smaller than it was.
• Changes intemperature have played a role in the rate of agricultural output in SSA, but decliningrainfall levels are more significant.
• Decliningrainfall had the greatest impact on agricultural productivity in CentralAfrica, followed by the Sahel-Sudan and Southern Africa regions. But datashowed no significant effect of declining rainfall in East Africa or the Gulfof Guinea.
• The more robustagricultural production in developing countries outside SSA is linked toclimate changes, but also higher levels of tractor and fertiliser use.

Giventhese historical impacts of climate change in SSA, it seems important thatpolicymakers take specific steps to lower the sensitivity of agriculture in theregion to future rainfall levels, which are predicted to decline further.

Theresearchers conclude:

• Policymakersshould encourage the adoption of agricultural techniques that make the mostefficient use of water.
• Improvedirrigation systems and the development of crop grazing areas are important.