Like other parts of Africa, southern Africa is experiencing longer and more intense periods of drought, with far reaching consequences for the region.

In the past five years, the United Nations has had to feed up to 10 million people - particularly in Zimbabwe, Malawi and Lesotho - when crops failed due to poor or erratic rains and high temperatures.

Average temperatures across southern Africa have risen by as much as one percent over the past 30 years. At the same time, the number of warm days per year has increased by an average of 10, with an equal reduction in the number of cool days.

Scientists say that the effect of this has been widespread drying across the region, even though in some areas average precipitation has not decreased. The problem they say, is that localized climates in the region have become more extreme. Mary Scholes, professor in animal, plant and environmental sciences at Johannesburg's Witwatersrand university says that South Africa's winter rainfall area in the Western Cape, is a good example of this.

"But what's been happening in those parts of the country, they don't get any rain now often until late in June, July, and then their rain stops in September," she said. "So their rains have become much more concentrated in very short period, so in other words the dry period goes all the way through from August, September, October, November, all the way through until April, making it a very long dry period, and a very short intensive wet period."

Bradwell Garanganga of the regional Drought Monitoring Center in Harare, says that in a region with widespread poverty, where millions live on subsistence farming, the impact of extreme climatic changes is far reaching.

"There has been a recognition that climate plays a major role in socio-economic development, even in disease control," he said.

Commercial grain production also has been severely affected, with countries like Zimbabwe - traditionally a net exporter of food - having to import hundreds of tons of cereals and grain per year.

Scholes says part of the problem for commercial farmers is that they are unable to plan production in periods of extreme weather.

"It makes it extremely difficult for farmers, the people on the ground, to do any careful planning," she said. "Because many of them are tied into things like planting dates, hiring of labor, when to take people on in terms of preparing the ground, so that when it does rain, they can plant immediately.

Scholes adds that traditional subsistence farmers, who over hundreds of years have evolved farming methods to cope with periods of drought and flood, are now unable to do so.

"Even using their traditional technologies, their old and long used methods of avoiding risk - they can no longer adapt to the rapid change in climate that we are experiencing," she explained.

And regional drought monitoring official Garanganga says that even when dry stretches are replaced by periods of heavy rain, much of resulting water goes to waste.

"Most of that rain is never sufficiently harvested to be retained on the continent," he said. "It really rushes into the ocean. So I think there really should be a more concerted effort, a deliberate effort to make sure all these that we have, when they do occur which is not very frequent from the recent past trends, we should benefit from those rains by damming them, for example."

Garanganga says he hopes his center is now able to provide regional governments with the knowledge they need to develop infrastructure and systems that over time will cushion the impact of extreme weather in the region.