Kampala, Feb 26 - A rise in average temperatures of just two degrees centigrade would wipe out coffee in Uganda and other east African countries that depend on the crop as a key export, a climate expert said on Monday.
Scientists at a U.N. panel on climate change last month predicted that the world will warm up by between 1.8 and 5.4 degrees C on average by the end of the century, largely as a result of human activities such as the burning of fossil fuels.
Higher temperatures are expected to cause drastic weather changes in many parts of the world, with most getting hotter.
"If we have an increase of 2 degrees centigrade in Uganda, coffee-growing areas would be drastically reduced to less than a tenth of their current size (in hectares)," deputy commissioner of meteorology, Philip Gwage, told Reuters.
The average temperature in Uganda's coffee-growing area now is about 25 C (77 F).
He added that although there are no accurate predictions on local climate, a 2-degree rise was a "realistic expectation".
"For coffee to grow you need certain temperatures (and) amounts of water. If temperatures go above certain limits, you would not be able (to grow it)," he said.
Gwage added that it would be the same for other east African coffee growers, but not top producer, Ethiopia, whose high altitude would keep the climate cool.
ROBUSTA TO "DISAPPEAR"
Coffee is Uganda's top export. The country has become a key player in the production of robusta after a political crisis in former top African producer, Ivory Coast, cut production.
It is the continent's second biggest grower after Ethiopia, which produces the highland arabica variety. Output is forecast at 2.7 million 60-kg bags in 2006/7.
Uganda's fertile central areas enjoy good rains and mild temperatures, despite being near the equator, because of an elevation to over 1,000 metres above the sea level.
Gwage said that could change with global warming.
"Robusta, literally, would disappear except for in the highland areas. Central (Uganda) would lose everything."
Unlike most of Africa, which is predicted to become parched as the world warms, Uganda would most likely get more rainfall from increased surface evaporation off the Great Lakes.
But that does not mean it would benefit from climate change, because the boost in rains needs to be evenly distributed, not erratic, as it increasingly is.
"Will (the rainfall) be spread over the growing season? If it is not, if it falls in one month (surrounded by) dry spells, then the benefits for agriculture are lost," he said.
Uganda, one of Africa's most well-watered countries, has suffered more droughts during planting seasons in the past 10 years than ever before. Floods, which destroy crops by washing them away and water-logging fields, were also common.
Gwage urged farmers to use irrigation systems to store water for when the weather is dry. He also said more drought resistant crops like mango trees should be grown with coffee.