Are global locust outbreaks exacerbated by ongoing climate change?

Locust encompass a number of species of grasshoppers (Orthoptera: Acrididae) that have in common the ability to swarm, whereby otherwise solitary individuals gather into massive swarms with the potential to cause major economic and ecological damage. Recent years have seen several large outbreaks of locust of different species across the globe, and several studies suggest ongoing anthropogenic climate change could be driving, or at least strongly influencing, locust outbreak dynamics. Here we review the current literature on locust and climate change by describing climate sensitivity of major locust species, show existing data on outbreak dynamics, and attempt to link the complex life-cycle of the locusts with outbreak patterns. We primarily focus on the migratory locust (Locusta migratoria) and the desert locust (Schistocerca gregaria) in this presentation. While it seems clear climate drivers are influencing outbreak dynamics in both species, they critically seem to do so in a species- and region-dependent manner. Thus, there are both positive and negative trends in outbreaks, indicating climate change is not uniformly increasing or decreasing pest severity in these species. We finally highlight important ongoing research and future directions for research attempting to link the complex life-cycle of these important pest species to the equally complex patterns seen for ongoing climate change.