Dark clouds over Sahara desert: More rains are to come.

© afrol News

afrol News, 17 December - What will happen in Africa as our planet is growing warmer and warmer? Africa is by far the world's less studied climatic region and few projections have been made. New data however indicates that the Sahara will get much more rains, West and East Africa some more rains and Southern Africa somewhat less rains. This, however, is not necessarily good news.

Last year's torrential rains and floods in Western Sahara may have been a sign of the changing times in the world's largest desert. Global temperature have already risen by 0.7 degrees due to humanity's emissions of greenhouse gases during the last century, and further warming will produce significantly more rains in the Sahara.

But the same process will also leave the Sahara desert warmer. Temperatures are estimated to rise more than the world average all over Africa. Rains will therefore dry up faster as evaporation follows temperatures.

Heavier rains that dry up faster may not sound as an advantage to agriculture at all. It however may give new possibilities if good rain management is applied, for example by shadow-producing tree-planting. If Africa remains equally dependent on subsistence agriculture in some decades, the new climate in any case will bring new challenges.

The British Ministry of the Environment yesterday published a new scientific report on the impact of climate change on Africa - one of very few ever addressing this issue. "Far too little is currently known about the impact of climate change on development and poverty on Africa," the Ministry says. The study was considered "a first step in tackling this information deficit."

Indeed, the British report offers more questions than answers. The 'Africa Climate Report' found that "the scientific understanding of the African climate system as a whole is low," particularly in the vital climate system of the Congo Basin. Therefore, there is very little data to make good predictions on future climate changes in Africa due to the ongoing global warming.

The report however sums up the results of nine different "General Circulation Models" made on a global scale and producing predictions on climate change in Africa. In more than half of the cases, data by these models had been inconsistent, mostly due to the low understanding of Africa's climate systems. For the Congo Basin, there have yet to be made predictions at all.

The clearest result of these climate models, all producing the same results, was for the Sahara desert. There will be a "large increase" in rainfall in the months of June to August in the Sahara. Temperature increases would also be greater all year round, compared with the global average.

These results for the Sahara desert are also in agreement with earlier conclusions by paleoclimatologists, studying the climate in prehistoric times. What is now the Sahara desert was as forested area at the last climatic optimum 7-8000 years ago, which is also strongly demonstrated by the rock paintings of hunting and farming in Algeria's Tassili Mountains - in the middle of the Sahara - made in that era. The climate at that time was about 3 degrees warmer than now.

In West Africa and East Africa, the climate models predict fewer changes. There is believed to be a "small increase" in rainfall, meaning between 5 and 20 percent, in both regions in the December to January period. In West Africa, temperatures will also rise in the same part of the year, while there were no consistent temperature predictions for East Africa.

Apart from coastal areas and island states - which risk being flooded by a rising sea level - Southern Africa seems to become the continent's great looser regarding global warming. Here, the models predict a "small decrease" in the June to August rainfalls, accompanied with a significant rise in temperatures. While the Sahara will diminish, the Kalahari may be on its increase.

For future rainfall patterns in Africa, there is however little consensus, the British report emphasises. "The clearest signal is the large percentage increase in June-August in the Sahara, where [current] absolute rainfall amounts are extremely low."

Given the uncertainty of climate forecasts, predictions on their impact on agriculture are even more inconsistent. "The variety of methods used leads to a large range of predictions and associated uncertainties. For example, whilst most impacts studies predict a reduction of maize yields in Africa - anywhere up to 98 percent - under climate change, some predict an increase," the report says.

- African climate, as with other parts of the world, will undergo climate change, the British report concludes. As the subject still remains very poorly studied, Africans and African governments however are in no position to prepare for these climate changes, as is the case in other parts of the world.

By staff writers

© afrol News

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