Adaptation for Smallholders to Climate Change

Facts on coffee and tea

Coffee is one of the most valuable primary products in world trade, in many years second in value to oil as a source of foreign exchange to developing countries. Its cultivation, processing, trading, transportation and marketing provide employment for millions of people worldwide. Coffee is crucial to the economies and politics of many developing countries; for many of the world's Least Developed Countries, exports of coffee account for a substantial part of their foreign exchange earnings (in some cases more than 80%).

Tea is a beverage made by steeping processed leaves, buds, or twigs of the tea bush, Camellia sinensis, in hot water for a few minutes. The processing can include oxidation, heating, drying, and the addition of other herbs, flowers, spices, and fruits. The four basic types of true tea are black tea, oolong tea, green tea, and white tea. Kenya is one of the largest tea producers of the world after China and India. For Kenya, Tanzania and Uganda tea exports are a major source for foreign exchange earnings and give employment to a large part of the population (10% in Kenya).

Effect of climate change on tea and coffee

The effects of climate change on the production of tea and coffee will differ greatly, depending on the region. The most severe impacts on the crops will be caused by rising temperatures and changing precipitation patterns.

Higher temperatures:

• Higher temperatures increase tea leaf temperatures and transpiration which, in turn close stomata and reduce photosynthesis.
• Higher mean temperatures during the cold season demand for earlier planting and ripening of annual coffee crops - reduced growth duration generally diminishes yields.
• Higher temperatures in mountainous areas will shift the area suitable for growing coffee to higher altitudes.
• Higher temperatures lead to a decline in the production of pollen grains of coffee and to reduce the distance to which pollen tubes extend. As pollen tubes need to extend to the area of the plant containing the female ova rising temperatures reduce the chances of fertilisation.

Changing precipitation patterns:

• During droughts, the coffee paring is glued to the grain, avoiding its maturation. Heavy rainfalls cause flooding and destroy infrastructure of transport and sale.
• Changes in seasonal precipitation and distribution and intensity harm the growth of the coffee plant. Coffee requires more than 150mm of precipitation per month (which equals 150 liters) during flowering and maturing, followed by a drier period in spring and summer. Heavy rains during the dry period or droughts during wet season disrupt flowering.
• Precipitation will become more intense but less frequent. This demands for adequate irrigation systems.

Exemplary adaptation measures:

Shade growing / Intercropping

Tea can be grown between rubber or coconut, coffee can be grown between various trees. This decreases temperatures, improves the quality of the soil and spreads economic risk of smallholders.

Improving soil quality

The capacity of soil to hold water and nutrients can be enhanced, for instance by organic fertilization.

Irrigation

Supplying water to tea plants during dry months can increase yields substantially. Water sources need to be secured.

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