Recurrent dry spells 'cause for concern' in southern Africa

Many countries in the region, such as Swaziland and Lesotho, were now entering their fourth year of drought. According to a new Famine Early Warning Systems Network (FEWS NET) report, the 2004/05 season "has been marked by adverse conditions, including erratic rains, intermittent dry spells, and flooding in some areas".

Southern and central Malawi and Mozambique, the southern half of Zambia and most of Zimbabwe were already in the grip of a mid-season drought.
"This, together with reported low availability of agricultural inputs, has led to reduced crop yields, which will translate into production shortfalls, especially for the maize crop," the report pointed out.

Dr Guy Midgley, of the Climate Change Research Group at the Cape Town-based National Botanical Institute, said while it was difficult to establish a link between the dry spells and climate change, the connection with rising temperatures was clear. "The link between the warming trend and climate change is definitive: [and] rising temperatures do have a drying effect," he noted. The projected warming in Africa would be greatest over the semiarid margins of the Sahara and central southern Africa, covering Botswana, Namibia, Zimbabwe, Zambia and parts of Mozambique and Angola.

Observation records show that the continent has been warming at the rate of about 0.05 degrees celsius throughout the 20th century. Some experts predict that warming rates of greater than 0.1 degrees per decade are likely to lead to the risk of significant eco-system damage. Climate change scenarios show future warming across Africa ranging from 0.2 degrees per decade to more than 0.5 degrees, with 10 percent less rainfall in the interior.

Global warming is caused by increased atmospheric levels of so-called 'greenhouse gasses', such as carbon dioxide, methane and nitrous oxide. Industrialisation and human activity - including the burning of oil, gasoline and coal - push the concentration of these gasses to artificially high levels.

Crop production in the mountain kingdom of Lesotho has declined steadily over the past three years, mainly due to drought and the impact of HIV/AIDS. Citing a recent crop assessment conducted by the UN's Food and Agriculture Organisation (FAO) and the Ministry of Agriculture, FEWS NET said Lesotho's projected total cereal production was 14 percent below the five-year average, but 19 percent above last year's "very poor harvest of 102,900 mt".

Earlier this year relief agencies warned that the humanitarian crisis in Swaziland, brought on by drought and aggravated by AIDS, was worsening. "Preliminary forecasts, based on the Water Requirements Satisfaction model, suggest a national maize crop of 67,000 mt, representing a 13 percent decrease over last year's ... estimate of 77,000 mt" FEWS NET noted.

The Botswana Ministry of Agriculture predicted a total cereal production of 17,729 mt - 46 percent less than the 2003/04 harvest of 32,889 mt - as a result of delayed and sporadic rains, said the report. An erratic rainy season had also dampened Zambia's prospects of another good harvest, as poor rainfall in the southern half of the country had affected the major grain producing areas of Central, Southern and Eastern provinces, said FEWS NET. A mid-March rapid estimate by the Zambia Vulnerability Assessment Committee put crop failure rates in affected areas as ranging from 25 percent to as high as 95 percent. Dry spells in Zimbabwe during February and March coincided with the critical growth stages of maize, resulting in total crop failure, especially in the southern provinces, while significantly lowering yields in others.

Long dry periods in southern Mozambique had also caused widespread crop failure and reduced yields of more drought-tolerant crops, such as cassava, while overall crop production was expected to be near normal in the north and parts of central Mozambique, FEWS NET reported. However, current projections indicated that total cereal production would fall well below the 2003/04 total of 1.95 million mt. Despite the erratic performance of rain in Namibia, the forecast pointed to a cereal harvest 28 percent above the five-year average. However, in the northern provinces unfavourable growing conditions had lowered anticipated cereal production by 34 percent in Caprivi and by 16 percent in Kavango.

Good rains and continued mitigation measures by government and humanitarian agencies, such as the provision of farm inputs to internally displaced persons, have helped Angola make a production recovery. Of all the countries in the region, only South Africa was expected to have a bumper harvest because of good rains during the second half of the growing season.