West Africa faces 'megadroughts'

Severe droughts lasting centuries have happened often in West Africa's recent history, and another one is almost inevitable, researchers say.

Analysis of sediments in a Ghanaian lake shows the last of these "megadroughts" ended 250 years ago.

Writing in the journal Science, the researchers suggest man-made climate change may make the situation worse.

But, they say, the droughts are going to happen again anyway, and societies should begin planning for them.

"It's disconcerting - it suggests we're vulnerable to a longer-lasting drought than we've seen in our lifetime," said Tim Shanahan from the University of Texas in Austin, who led the research team.

"What West Africa won't handle - and neither will California - is the 100-year-long, deep megadrought"
Professor Michael Schlesinger