Global warming will fire up West Africa mega droughts

Droughts worse than the catastrophic Sahel drought are part of the normal for West Africa but global warming could intensify them massively, a new study says. US researchers put together an almost year-by-year record of the last 3,000 years of West Africa's climate. In that time, droughts occurred every 30 to 65 years, and the pattern can be expected to continue in the future, the team reported.

Analysis of sediments in Ghana's Lake Bosumtwi a Ghanaian lake shows the last of these "mega droughts" ended 250 years ago. The droughts are going to happen again anyway, and societies should begin planning for them, said a report in the journal, Science yesterday. But man-made climate change may make the situation worse, it warned. "It's disconcerting – it suggests we're vulnerable to a longer-lasting drought than we've seen in our lifetime," Tim Shanahan from the University of Texas in Austin, who led the research team. “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," he told the BBC.

West Africa’s most recent dry episode was the Sahel drought, which claimed at least 100,000 lives, perhaps as many as one million, in the 1970s and 80s. But the historical "mega droughts" were longer lasting and even more devoid of precipitation, the researchers found. Kevin Watkins, director of the office of Human Development Reports of the United Nations described the study as a “critical report.” “Many of the 390 million people in Africa living on less than $1.25 a day are smallholder farmers that depend on two things: rain and land,” he said. “Even small climate blips such as a delay in rains, a modest shortening of the drought cycle, can have catastrophic effects.” Mr. Watkins said that the urgency was multiplied by high population growth rates in West Africa. Just in the last century, when its populations were far smaller, periodic droughts in sub-Saharan Africa claimed hundreds of thousands of lives or even more.

The possibility of man-made climate change causing worse droughts is an example of the impacts that many developing countries fear, and which causes them to seek money from richer countries to protect their societies and economies.