Posted on behalf of Chloe McIvor.
The Horn of Africa has been struck by the worst drought in 60 years. According to the UN’s World Food Programme 9 million people will be affected, and the situation is worsened by rising food prices and conflict. But were meteorologists able to give any warning?
Every few months, African meteorologists from the region meet in the Greater Horn of Africa Climate Outlook Forum (GHACOF) to look at various seasonal forecast models and try to come to a consensus about whether the expected rainfall will be ‘above normal’, ‘normal’ and ‘below normal’. Their latest meeting, in February, dealt with the predictions for March/April rains, where they predicted below normal rainfall for the season.
But they did not predict such a severe deficit. The rainfall actually being experienced is approximately a third of their estimates, says David Grimes head of the Tropical Applications of Meteorology using SATellite data and ground-based observations programme (TAMSAT) at the University of Reading in the UK.
“Predictions are always very conservative” says Grimes, “Politically, they are very afraid of making extreme predictions.”
It is particularly difficult to forecast drought in this region because there so many different factors that influence rainfall. One of the more well-researched factors is La Nina phenomenon, which forms part of the El Nino Southern Oscillation pattern. But the sea-surface temperatures of the Indian and Atlantic Oceans and the Somalia Jet Stream associated with the Indian Monsoon also have varying effects that combine to determine the amount of rain experienced, and the topography of the region complicates the picture even further.
Scientists are also working to further understand the possible impact of climate change on the frequency of droughts in the Horn of Africa. A study conducted by researchers at the University of California, published in January in Climate Dynamics, suggested East Africa should expect more droughts in the future as a result of anthropogenic climate change (see our coverage of that paper here). The paper explained that the countries that make up the Horn of Africa – Eritrea, Djibouti, Ethiopia and Somalia – will experience much drier conditions due to warming of the Indian Ocean – although it would be unrealistic to link that prediction to the current droughts.
There have been undoubted improvements to our scientific understanding of the climate systems involved, but it is important to know where the limits to forecasting drought currently lie.
Overall, there is a lack of reliable data concerning global drought risk, according to a report by the UN International Strategy for Disaster Reduction (UNISDR). The report calls for improvements to drought surveillance at a global level, and recommends closer links between scientists and the policy-makers.
Image courtesy of TAMSAT, Dept of Meteorology, University of Reading.