Results of studies carried out on Lake Bosumtwi in southern Ghana are far from comforting. The West African nation has been advised to begin preparations for an imminent and inevitable drought of severe measures, reports have claimed.
A research team headed by Tim Shanahan from the University of Texas in Austin have found similarities in the Ghanaian lake analytical report with results from the analysis of lakes in southeastern USA that show that a mega drought is impending. The records show that similar droughts lasting a few decades occur regularly over 3,000 years.
The researchers found that the forecast mega droughts were longer-lasting and even more devoid of precipitation. The drought appear to be linked to the Atlantic Multidecadal Oscillation (AMO), a natural climatic cycle in which sea surface temperatures in the tropical Atlantic Ocean vary over time. Professor Michael Schlesinge, of the University of Texas who first characterized the AMO a decade ago suggested a similarity between the outlook for Ghana and the southwestern portion of the US.
Speaking about the findings, Tim Shanahan told reporters from the BBC, “It’s disconcerting – it suggests we’re vulnerable to a longer-lasting drought than we’ve seen in our lifetime. If the region were to shift into one of these droughts it would be very difficult for people to adapt; and we need to develop an adaptation policy.”
West Africa’s most recent dry episode was the Sahel drought of the 1970s and 80s which claimed at least 100,000 to 1,000,000 lives. The Sahel drought coincided with a cool phase of the AMO, changing wind patterns, and decreasing the strength of the monsoon rains in the southern part of Ghana.
“There are two things that need to be done, one of which California and Arizona and so on have done – and that is put in the water collection and distribution infrastructure to deal with the short periods of not very intense water stress. What West Africa won’t handle – and neither will California – is the 100-year-long, deep mega drought. The only way I can see of dealing with that is desalination; if push comes to shove and these mega droughts appear – and they will, and it’ll probably be exacerbated by man-made global warming – that will be the only thing to do,” said professor Schlesinge.
The foretold 100-year-long, deep mega drought has been described as something that Ghana won’t be able to manage; the country along with neighboring west African countries may not have the infrastructure to move water inland.
Analysis of the Ghanaian lake shows that the last of such mega drought ended 250 years ago. Professor Schlesinger and Tim Shanahan’s team suggest that human-induced climate change would be likely to make droughts more severe, although computer models of climate produce varying projections for rainfall change over the West African region.