Swarms of locusts are roaring back in east Africa. The bugs are a grasshopper variant. Usually they’re solitary. But in the right conditions -- dry spells followed by rain -- they can turn into large, hungry swarms. Climate change has contributed to more frequent locust swarms. And that’s bad news for farmers, and any vegetation in their path. While locusts aren’t known to directly hurt humans, they can strip green areas quickly, devastating crops and habitats.