Heavy downpours are increasing globally over the last three to five decades. The frequency of heavy rainfall and the amount of rainfall in each event has increased especially since 1991.
The reason being attributed to global warming since warmer air traps more water vapor than cooler air, the extra moisture in the atmosphere falls in the form of precipitation.
3.2.1. Increased evaporation and water-cycle flow
Studies have depicted that a warmer climate results in a more increased flow in water cycle – the increased evaporation acting as fuel for the development of more powerful storms – leading to more hurricanes, which in turn will lead to more severe flood damage; and droughts over the years as more of a region’s precipitation would fall through one major storm rather than a series of smaller storms (Pielke ; Downtown 2000). In the US, there have been drastic increases in rainfall in the Northeast, Midwest, and upper Great Plains. Heavy rainfall events ultimately lead to flooding events. In this case, there has been an increase in flooding events in the areas where the largest increases in heavy downpours occurred. However, flooding can intensify even when total precipitation in an area is projected to decline. Floods are caused by both natural and human-related factors (National Climate Assessment 2014).
3.2.2. Heavy downpour and losses
Millions of people are stranded on the streets during the rains since several people lose their houses and properties. All businesses are affected including banks shut down. Contact with contaminated water can lead to water borne diseases and also cause an epidemic outbreak.
Stock markets close for a few days which severely affect the economy. In Mumbai, severe floods in 2005 contributed to huge financial losses to the Indian economy. The recovery costs for such disasters estimate to tens of millions. All the submerged lands, damaged crops, loss of livestock, food stock loss, damaged buildings and roads contribute to this cost. Continuous floods also drive away foreign investors (Kadave et al. 2016). All these factors weaken the economy leading to economy deterioration.