Why are locusts invading East Africa again?

They're like dark moving clouds, buzzing above your head.Swarms of locusts have been tearing through parts of East Africa… And they’re hungry.They’ve been devouring crop after crop, putting food supplies and farmers’ livelihoods at risk. These invasions aren’t new - and yet, they now seem to be happening more often than ever.Why is that? How did things get so bad? And can these locusts ever be stopped?Hosted by Alan Kasujja (@Kasujja on Twitter)#AfricaDaily