Locusts, a group of swarming grasshoppers are legendary pests. Plagues of locusts that demolished crops are described in the Bible and Quran; more recently such plagues have occurred episodically in North Africa, the Middle East and elsewhere. And research suggests that climate change may make such plagues even more frequent in the future. Locusts include species of grasshoppers that have solitary and swarming phases in their life cycle. Research indicates that swarming occurs when the density of locusts is elevated. Swarms can include billions or even trillions of individuals and each locusts can fly as far as 500 km and eat the equivalent of their own weight in a day. A single swarm can eat enough food for 2,500 people in one day! Locusts, especially the desert locust of North Africa, have been known to completely demolish crops, and the only strategy is to hold populations in check with pesticides. There is evidence that swarms develop best when unusually wet weather is followed by prolonged warm conditions. The wet phase, which causes lush vegetation to grow, allows for prolific reproduction, and the warm phase enhances the gregarious, swarming behavior. Since climate change will cause more frequent intervals of elevated precipitation and heat waves, plagues may be more frequent, more populous in places such as North Africa, Southern Europe, the Middle East, China and Australia. Such massive and unrelenting plagues will be difficult to control with pesticides.
Insects are just one of many challenges that will make is harder and harder for humankind to receive ample nutrition. As we will show in this module, food is most definitely one of the Grand Challenges of the 21st Century and feeding the increasing global population will require a very different approach to the production and distribution of crops and other sources of nutrition. Climate change will make matters increasingly difficult, in particular in regions where food shortages already exist.