Intermittent rainfall in the 2007/08 crop year, for example, caused a terrible bout of the Coffee Berry Disease that cut Kenyan output 23 percent to 42,000 metric tons as farmers were caught out by rains and did not protect their crop in time.
We have seen climate change in intermittent rainfall patterns, extended drought and very high temperatures, said Joseph Kimemia, director of research at Kenya's Coffee Research Foundation (CRF).
Coffee operates within a very narrow temperature range of 19-25 degrees (Celsius). When you start getting temperatures above that, it affects photosynthesis and in some cases, trees wilt and dry up. We have see trees drying up in some marginal coffee areas.
For coffee to flower, for example, it needs a couple of months of dry weather followed by showers. This year, Kenya had rains in January, normally a very dry month when the bushes undergo what is known as stress before they flower.
Because of the unpredictable weather, bushes are flowering when they should not and have coffee berries at different stages of maturity. This means farmers have to hire labor through most of the year to pick very few kilos of coffee.
You look at a coffee tree and cannot determine the season because it has beans of all ages. That is a problem when it comes to disease management, insect management and the worst problem is in harvesting, he said. The cost is enormous.
IRRIGATION NOT AN OPTION
In a normal year, farmers spray their crop protectively against Coffee Berry Disease (CBD) as from April but because of unexpected rains, they are unable to plan.
It makes management totally difficult. That is one of the reasons we had CBD, Kimemia told Reuters on the sidelines of the annual African Fine Coffee Conference bringing together producers from nine African countries, buyers and suppliers.
Farmers went into spraying but the damage was done. It was throwing good money after bad money, making our coffee production cost higher than it should be.
Drought may mean crop losses ranging from 10 percent to the entire crop in some areas, but a bigger cost would be if the country were to lose its global market share.
Unlike Ethiopia and Uganda, which are Africa's top coffee producers, Kenyan coffee output is under 1 percent of global production but its beans are popular for blends and its buyers have specific volume requirements.
If you are not able to meet that volume in one, two years, they are traders, so naturally they will look for another coffee to replace your coffee. And when they do that, then they cannot come back, even when you get back to production.
The most immediate solution is for farmers to conserve whatever rainfall they receive through mulching, digging trenches to hold water, pruning, forking and planting shade trees.
We have no time for research because the problem is with us, Kimemia said. If we can get agronomic practices that conserve moisture, that is what we need before we talk about new technologies or new varieties that are drought tolerant.
($1=77.15 Kenyan Shilling)
(Editing by George Obulutsa and Clarence Fernandez)