A storm over the Amazon Rainforest, Brazil

Storms are common meteorological phenomena—there are 50,000 of them a day on the planet’s surface. They are due to rapid vertical movement of unstable, humid air. The air rises, cools, then condenses when it holds a maximum quantity of water vapor. It then forms an enormous cumulonimbus, which can be up to 15 mi (24 km) across and 10 mi (16 km) high in low latitudes. The movement of electric charges in these clouds causes lightning accompanied by thunder and heavy rain. In Amazonia, intense evaporation leads to frequent and sometimes extremely violent storms. Everywhere in the world, storms damage crops and buildings, disrupt air and land traffic, interfere with communication systems, and are responsible for the deaths of hundreds of people and thousands of animals. The warming of the planet would lead to a rise in the average amount of water vapor in the atmosphere and the volume of precipitation, but also to more frequent violent weather incidents such as storms, tornadoes, and cyclones, and an increase in the damage they do. The major insurance companies are already anticipating higher risks.